neovim

tag.c (110101B)

---

// Code to handle tags and the tag stack

#include <assert.h>
#include <ctype.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "nvim/ascii_defs.h"
#include "nvim/autocmd.h"
#include "nvim/autocmd_defs.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/charset.h"
#include "nvim/cmdexpand.h"
#include "nvim/cmdexpand_defs.h"
#include "nvim/cursor.h"
#include "nvim/drawscreen.h"
#include "nvim/errors.h"
#include "nvim/eval.h"
#include "nvim/eval/typval.h"
#include "nvim/eval/vars.h"
#include "nvim/ex_cmds.h"
#include "nvim/ex_cmds_defs.h"
#include "nvim/ex_docmd.h"
#include "nvim/file_search.h"
#include "nvim/fileio.h"
#include "nvim/fold.h"
#include "nvim/garray.h"
#include "nvim/garray_defs.h"
#include "nvim/gettext_defs.h"
#include "nvim/globals.h"
#include "nvim/hashtab.h"
#include "nvim/hashtab_defs.h"
#include "nvim/help.h"
#include "nvim/highlight_defs.h"
#include "nvim/input.h"
#include "nvim/insexpand.h"
#include "nvim/macros_defs.h"
#include "nvim/mark.h"
#include "nvim/mark_defs.h"
#include "nvim/mbyte.h"
#include "nvim/mbyte_defs.h"
#include "nvim/memory.h"
#include "nvim/message.h"
#include "nvim/move.h"
#include "nvim/option.h"
#include "nvim/option_defs.h"
#include "nvim/option_vars.h"
#include "nvim/optionstr.h"
#include "nvim/os/fs.h"
#include "nvim/os/input.h"
#include "nvim/os/os_defs.h"
#include "nvim/os/time.h"
#include "nvim/path.h"
#include "nvim/pos_defs.h"
#include "nvim/quickfix.h"
#include "nvim/regexp.h"
#include "nvim/regexp_defs.h"
#include "nvim/runtime.h"
#include "nvim/search.h"
#include "nvim/state_defs.h"
#include "nvim/strings.h"
#include "nvim/tag.h"
#include "nvim/types_defs.h"
#include "nvim/ui.h"
#include "nvim/vim_defs.h"
#include "nvim/window.h"

// Structure to hold pointers to various items in a tag line.
typedef struct {
 // filled in by parse_tag_line():
 char *tagname;        // start of tag name (skip "file:")
 char *tagname_end;    // char after tag name
 char *fname;          // first char of file name
 char *fname_end;      // char after file name
 char *command;        // first char of command
 // filled in by parse_match():
 char *command_end;    // first char after command
 char *tag_fname;      // file name of the tags file. This is used
 // when 'tr' is set.
 char *tagkind;          // "kind:" value
 char *tagkind_end;      // end of tagkind
 char *user_data;        // user_data string
 char *user_data_end;    // end of user_data
 linenr_T tagline;       // "line:" value
} tagptrs_T;

// Structure to hold info about the tag pattern being used.
typedef struct {
 char *pat;            // the pattern
 int len;              // length of pat[]
 char *head;           // start of pattern head
 int headlen;          // length of head[]
 regmatch_T regmatch;  // regexp program, may be NULL
} pat_T;

// The matching tags are first stored in one of the hash tables.  In
// which one depends on the priority of the match.
// ht_match[] is used to find duplicates, ga_match[] to keep them in sequence.
// At the end, the matches from ga_match[] are concatenated, to make a list
// sorted on priority.
enum {
 MT_ST_CUR = 0,  // static match in current file
 MT_GL_CUR = 1,  // global match in current file
 MT_GL_OTH = 2,  // global match in other file
 MT_ST_OTH = 3,  // static match in other file
 MT_IC_OFF = 4,  // add for icase match
 MT_RE_OFF = 8,  // add for regexp match
 MT_MASK = 7,    // mask for printing priority
 MT_COUNT = 16,
};

static char *mt_names[MT_COUNT/2] =
{ "FSC", "F C", "F  ", "FS ", " SC", "  C", "   ", " S " };

#define NOTAGFILE       99              // return value for jumpto_tag
static char *nofile_fname = NULL;       // fname for NOTAGFILE error

/// Return values used when reading lines from a tags file.
typedef enum {
 TAGS_READ_SUCCESS = 1,
 TAGS_READ_EOF,
 TAGS_READ_IGNORE,
} tags_read_status_T;

/// States used during a tags search
typedef enum {
 TS_START,         ///< at start of file
 TS_LINEAR,        ///< linear searching forward, till EOF
 TS_BINARY,        ///< binary searching
 TS_SKIP_BACK,     ///< skipping backwards
 TS_STEP_FORWARD,  ///< stepping forwards
} tagsearch_state_T;

/// Binary search file offsets in a tags file
typedef struct {
 off_T low_offset;        ///< offset for first char of first line that
                          ///< could match
 off_T high_offset;       ///< offset of char after last line that could
                          ///< match
 off_T curr_offset;       ///< Current file offset in search range
 off_T curr_offset_used;  ///< curr_offset used when skipping back
 off_T match_offset;      ///< Where the binary search found a tag
 int low_char;            ///< first char at low_offset
 int high_char;           ///< first char at high_offset
} tagsearch_info_T;

/// Return values used when matching tags against a pattern.
typedef enum {
 TAG_MATCH_SUCCESS = 1,
 TAG_MATCH_FAIL,
 TAG_MATCH_STOP,
 TAG_MATCH_NEXT,
} tagmatch_status_T;

/// Arguments used for matching tags read from a tags file against a pattern.
typedef struct {
 int matchoff;      ///< tag match offset
 bool match_re;     ///< true if the tag matches a regexp
 bool match_no_ic;  ///< true if the tag matches with case
 bool has_re;       ///< regular expression used
 bool sortic;       ///< tags file sorted ignoring case (foldcase)
 bool sort_error;   ///< tags file not sorted
} findtags_match_args_T;

/// State information used during a tag search
typedef struct {
 tagsearch_state_T state;       ///< tag search state
 bool stop_searching;           ///< stop when match found or error
 pat_T *orgpat;                 ///< holds unconverted pattern info
 char *lbuf;                    ///< line buffer
 int lbuf_size;                 ///< length of lbuf
 char *tag_fname;               ///< name of the tag file
 FILE *fp;                      ///< current tags file pointer
 int flags;                     ///< flags used for tag search
 int tag_file_sorted;           ///< !_TAG_FILE_SORTED value
 bool get_searchpat;            ///< used for 'showfulltag'
 bool help_only;                ///< only search for help tags
 bool did_open;                 ///< did open a tag file
 int mincount;                  ///< MAXCOL: find all matches
                                ///< other: minimal number of matches
 bool linear;                   ///< do a linear search
 vimconv_T vimconv;
 char help_lang[3];             ///< lang of current tags file
 int help_pri;                  ///< help language priority
 char *help_lang_find;          ///< lang to be found
 bool is_txt;                   ///< flag of file extension
 int match_count;               ///< number of matches found
 garray_T ga_match[MT_COUNT];   ///< stores matches in sequence
 hashtab_T ht_match[MT_COUNT];  ///< stores matches by key
} findtags_state_T;

#include "tag.c.generated.h"

static const char e_tag_stack_empty[]
 = N_("E73: Tag stack empty");
static const char e_tag_not_found_str[]
 = N_("E426: Tag not found: %s");
static const char e_at_bottom_of_tag_stack[]
 = N_("E555: At bottom of tag stack");
static const char e_at_top_of_tag_stack[]
 = N_("E556: At top of tag stack");
static const char e_cannot_modify_tag_stack_within_tagfunc[]
 = N_("E986: Cannot modify the tag stack within tagfunc");
static const char e_invalid_return_value_from_tagfunc[]
 = N_("E987: Invalid return value from tagfunc");
static const char e_window_unexpectedly_close_while_searching_for_tags[]
 = N_("E1299: Window unexpectedly closed while searching for tags");

static char *tagmatchname = NULL;   // name of last used tag

// Tag for preview window is remembered separately, to avoid messing up the
// normal tagstack.
static taggy_T ptag_entry = { NULL, INIT_FMARK, 0, 0, NULL };

static bool tfu_in_use = false;  // disallow recursive call of tagfunc
static Callback tfu_cb;          // 'tagfunc' callback function

// Used instead of NUL to separate tag fields in the growarrays.
#define TAG_SEP 0x02

/// Reads the 'tagfunc' option value and convert that to a callback value.
/// Invoked when the 'tagfunc' option is set. The option value can be a name of
/// a function (string), or function(<name>) or funcref(<name>) or a lambda.
const char *did_set_tagfunc(optset_T *args)
{
 buf_T *buf = (buf_T *)args->os_buf;
 int retval;

 if (args->os_flags & OPT_LOCAL) {
   retval = option_set_callback_func(args->os_newval.string.data, &buf->b_tfu_cb);
 } else {
   retval = option_set_callback_func(args->os_newval.string.data, &tfu_cb);
   if (retval == OK && !(args->os_flags & OPT_GLOBAL)) {
     set_buflocal_tfu_callback(buf);
   }
 }

 return retval == FAIL ? e_invarg : NULL;
}

#if defined(EXITFREE)
void free_tagfunc_option(void)
{
 callback_free(&tfu_cb);
}
#endif

/// Mark the global 'tagfunc' callback with "copyID" so that it is not garbage
/// collected.
bool set_ref_in_tagfunc(int copyID)
{
 return set_ref_in_callback(&tfu_cb, copyID, NULL, NULL);
}

/// Copy the global 'tagfunc' callback function to the buffer-local 'tagfunc'
/// callback for 'buf'.
void set_buflocal_tfu_callback(buf_T *buf)
{
 callback_free(&buf->b_tfu_cb);
 if (tfu_cb.type != kCallbackNone) {
   callback_copy(&buf->b_tfu_cb, &tfu_cb);
 }
}

/// Jump to tag; handling of tag commands and tag stack
///
/// *tag != NUL: ":tag {tag}", jump to new tag, add to tag stack
///
/// type == DT_TAG:      ":tag [tag]", jump to newer position or same tag again
/// type == DT_HELP:     like DT_TAG, but don't use regexp.
/// type == DT_POP:      ":pop" or CTRL-T, jump to old position
/// type == DT_NEXT:     jump to next match of same tag
/// type == DT_PREV:     jump to previous match of same tag
/// type == DT_FIRST:    jump to first match of same tag
/// type == DT_LAST:     jump to last match of same tag
/// type == DT_SELECT:   ":tselect [tag]", select tag from a list of all matches
/// type == DT_JUMP:     ":tjump [tag]", jump to tag or select tag from a list
/// type == DT_LTAG:     use location list for displaying tag matches
/// type == DT_FREE:     free cached matches
///
/// @param tag  tag (pattern) to jump to
/// @param forceit  :ta with !
/// @param verbose  print "tag not found" message
void do_tag(char *tag, int type, int count, int forceit, bool verbose)
{
 taggy_T *tagstack = curwin->w_tagstack;
 int tagstackidx = curwin->w_tagstackidx;
 int tagstacklen = curwin->w_tagstacklen;
 int cur_match = 0;
 int cur_fnum = curbuf->b_fnum;
 int oldtagstackidx = tagstackidx;
 int prevtagstackidx = tagstackidx;
 bool new_tag = false;
 bool no_regexp = false;
 int error_cur_match = 0;
 bool save_pos = false;
 fmark_T saved_fmark;
 int new_num_matches;
 char **new_matches;
 bool use_tagstack;
 bool skip_msg = false;
 char *buf_ffname = curbuf->b_ffname;  // name for priority computation
 bool use_tfu = true;
 char *tofree = NULL;

 // remember the matches for the last used tag
 static int num_matches = 0;
 static int max_num_matches = 0;             // limit used for match search
 static char **matches = NULL;
 static int flags;

#ifdef EXITFREE
 if (type == DT_FREE) {
   // remove the list of matches
   FreeWild(num_matches, matches);
   num_matches = 0;
   return;
 }
#endif

 if (tfu_in_use) {
   emsg(_(e_cannot_modify_tag_stack_within_tagfunc));
   return;
 }

 if (postponed_split == 0 && !check_can_set_curbuf_forceit(forceit)) {
   return;
 }

 if (type == DT_HELP) {
   type = DT_TAG;
   no_regexp = true;
   use_tfu = false;
 }

 int prev_num_matches = num_matches;
 free_string_option(nofile_fname);
 nofile_fname = NULL;

 clearpos(&saved_fmark.mark);          // shutup gcc 4.0
 saved_fmark.fnum = 0;
 saved_fmark.view = (fmarkv_T)INIT_FMARKV;

 // Don't add a tag to the tagstack if 'tagstack' has been reset.
 assert(tag != NULL);
 if (!p_tgst && *tag != NUL) {
   use_tagstack = false;
   new_tag = true;
   if (g_do_tagpreview != 0) {
     tagstack_clear_entry(&ptag_entry);
     ptag_entry.tagname = xstrdup(tag);
   }
 } else {
   if (g_do_tagpreview != 0) {
     use_tagstack = false;
   } else {
     use_tagstack = true;
   }

   // new pattern, add to the tag stack
   if (*tag != NUL
       && (type == DT_TAG || type == DT_SELECT || type == DT_JUMP
           || type == DT_LTAG)) {
     if (g_do_tagpreview != 0) {
       if (ptag_entry.tagname != NULL
           && strcmp(ptag_entry.tagname, tag) == 0) {
         // Jumping to same tag: keep the current match, so that
         // the CursorHold autocommand example works.
         cur_match = ptag_entry.cur_match;
         cur_fnum = ptag_entry.cur_fnum;
       } else {
         tagstack_clear_entry(&ptag_entry);
         ptag_entry.tagname = xstrdup(tag);
       }
     } else {
       // If the last used entry is not at the top, delete all tag
       // stack entries above it.
       while (tagstackidx < tagstacklen) {
         tagstack_clear_entry(&tagstack[--tagstacklen]);
       }

       // if the tagstack is full: remove oldest entry
       if (++tagstacklen > TAGSTACKSIZE) {
         tagstacklen = TAGSTACKSIZE;
         tagstack_clear_entry(&tagstack[0]);
         for (int i = 1; i < tagstacklen; i++) {
           tagstack[i - 1] = tagstack[i];
         }
         tagstack[--tagstackidx].user_data = NULL;
       }

       // put the tag name in the tag stack
       tagstack[tagstackidx].tagname = xstrdup(tag);

       curwin->w_tagstacklen = tagstacklen;

       save_pos = true;                // save the cursor position below
     }

     new_tag = true;
   } else {
     if (g_do_tagpreview != 0 ? ptag_entry.tagname == NULL
                              : tagstacklen == 0) {
       // empty stack
       emsg(_(e_tag_stack_empty));
       goto end_do_tag;
     }

     if (type == DT_POP) {             // go to older position
       const bool old_KeyTyped = KeyTyped;
       if ((tagstackidx -= count) < 0) {
         emsg(_(e_at_bottom_of_tag_stack));
         if (tagstackidx + count == 0) {
           // We did [num]^T from the bottom of the stack
           tagstackidx = 0;
           goto end_do_tag;
         }
         // We weren't at the bottom of the stack, so jump all the
         // way to the bottom now.
         tagstackidx = 0;
       } else if (tagstackidx >= tagstacklen) {        // count == 0?
         emsg(_(e_at_top_of_tag_stack));
         goto end_do_tag;
       }

       // Make a copy of the fmark, autocommands may invalidate the
       // tagstack before it's used.
       saved_fmark = tagstack[tagstackidx].fmark;
       if (saved_fmark.fnum != curbuf->b_fnum) {
         // Jump to other file. If this fails (e.g. because the
         // file was changed) keep original position in tag stack.
         if (buflist_getfile(saved_fmark.fnum, saved_fmark.mark.lnum,
                             GETF_SETMARK, forceit) == FAIL) {
           tagstackidx = oldtagstackidx;              // back to old posn
           goto end_do_tag;
         }
         // A BufReadPost autocommand may jump to the '" mark, but
         // we don't what that here.
         curwin->w_cursor.lnum = saved_fmark.mark.lnum;
       } else {
         setpcmark();
         curwin->w_cursor.lnum = saved_fmark.mark.lnum;
       }
       curwin->w_cursor.col = saved_fmark.mark.col;
       curwin->w_set_curswant = true;
       if (jop_flags & kOptJopFlagView) {
         mark_view_restore(&saved_fmark);
       }
       check_cursor(curwin);
       if ((fdo_flags & kOptFdoFlagTag) && old_KeyTyped) {
         foldOpenCursor();
       }

       // remove the old list of matches
       FreeWild(num_matches, matches);
       num_matches = 0;
       tag_freematch();
       goto end_do_tag;
     }

     if (type == DT_TAG
         || type == DT_LTAG) {
       if (g_do_tagpreview != 0) {
         cur_match = ptag_entry.cur_match;
         cur_fnum = ptag_entry.cur_fnum;
       } else {
         // ":tag" (no argument): go to newer pattern
         save_pos = true;              // save the cursor position below
         if ((tagstackidx += count - 1) >= tagstacklen) {
           // Beyond the last one, just give an error message and
           // go to the last one.  Don't store the cursor
           // position.
           tagstackidx = tagstacklen - 1;
           emsg(_(e_at_top_of_tag_stack));
           save_pos = false;
         } else if (tagstackidx < 0) {         // must have been count == 0
           emsg(_(e_at_bottom_of_tag_stack));
           tagstackidx = 0;
           goto end_do_tag;
         }
         cur_match = tagstack[tagstackidx].cur_match;
         cur_fnum = tagstack[tagstackidx].cur_fnum;
       }
       new_tag = true;
     } else {                                // go to other matching tag
       // Save index for when selection is cancelled.
       prevtagstackidx = tagstackidx;

       if (g_do_tagpreview != 0) {
         cur_match = ptag_entry.cur_match;
         cur_fnum = ptag_entry.cur_fnum;
       } else {
         if (--tagstackidx < 0) {
           tagstackidx = 0;
         }
         cur_match = tagstack[tagstackidx].cur_match;
         cur_fnum = tagstack[tagstackidx].cur_fnum;
       }
       switch (type) {
       case DT_FIRST:
         cur_match = count - 1; break;
       case DT_SELECT:
       case DT_JUMP:
       case DT_LAST:
         cur_match = MAXCOL - 1; break;
       case DT_NEXT:
         cur_match += count; break;
       case DT_PREV:
         cur_match -= count; break;
       }
       if (cur_match >= MAXCOL) {
         cur_match = MAXCOL - 1;
       } else if (cur_match < 0) {
         emsg(_("E425: Cannot go before first matching tag"));
         skip_msg = true;
         cur_match = 0;
         cur_fnum = curbuf->b_fnum;
       }
     }
   }

   if (g_do_tagpreview != 0) {
     if (type != DT_SELECT && type != DT_JUMP) {
       ptag_entry.cur_match = cur_match;
       ptag_entry.cur_fnum = cur_fnum;
     }
   } else {
     // For ":tag [arg]" or ":tselect" remember position before the jump.
     saved_fmark = tagstack[tagstackidx].fmark;
     if (save_pos) {
       tagstack[tagstackidx].fmark.mark = curwin->w_cursor;
       tagstack[tagstackidx].fmark.fnum = curbuf->b_fnum;
       tagstack[tagstackidx].fmark.view = mark_view_make(curwin->w_topline, curwin->w_cursor);
     }

     // Curwin will change in the call to jumpto_tag() if ":stag" was
     // used or an autocommand jumps to another window; store value of
     // tagstackidx now.
     curwin->w_tagstackidx = tagstackidx;
     if (type != DT_SELECT && type != DT_JUMP) {
       curwin->w_tagstack[tagstackidx].cur_match = cur_match;
       curwin->w_tagstack[tagstackidx].cur_fnum = cur_fnum;
     }
   }
 }

 // When not using the current buffer get the name of buffer "cur_fnum".
 // Makes sure that the tag order doesn't change when using a remembered
 // position for "cur_match".
 if (cur_fnum != curbuf->b_fnum) {
   buf_T *buf = buflist_findnr(cur_fnum);

   if (buf != NULL) {
     buf_ffname = buf->b_ffname;
   }
 }

 // Repeat searching for tags, when a file has not been found.
 while (true) {
   char *name;

   // When desired match not found yet, try to find it (and others).
   if (use_tagstack) {
     // make a copy, the tagstack may change in 'tagfunc'
     name = xstrdup(tagstack[tagstackidx].tagname);
     xfree(tofree);
     tofree = name;
   } else if (g_do_tagpreview != 0) {
     name = ptag_entry.tagname;
   } else {
     name = tag;
   }
   bool other_name = (tagmatchname == NULL || strcmp(tagmatchname, name) != 0);
   if (new_tag
       || (cur_match >= num_matches && max_num_matches != MAXCOL)
       || other_name) {
     if (other_name) {
       xfree(tagmatchname);
       tagmatchname = xstrdup(name);
     }

     if (type == DT_SELECT || type == DT_JUMP
         || type == DT_LTAG) {
       cur_match = MAXCOL - 1;
     }
     max_num_matches = type == DT_TAG ? MAXCOL : cur_match + 1;

     // when the argument starts with '/', use it as a regexp
     if (!no_regexp && *name == '/') {
       flags = TAG_REGEXP;
       name++;
     } else {
       flags = TAG_NOIC;
     }

     flags |= verbose ? TAG_VERBOSE : 0;
     flags |= !use_tfu ? TAG_NO_TAGFUNC : 0;

     if (find_tags(name, &new_num_matches, &new_matches, flags,
                   max_num_matches, buf_ffname) == OK
         && new_num_matches < max_num_matches) {
       max_num_matches = MAXCOL;  // If less than max_num_matches
                                  // found: all matches found.
     }

     // A tag function may do anything, which may cause various
     // information to become invalid.  At least check for the tagstack
     // to still be the same.
     if (tagstack != curwin->w_tagstack) {
       emsg(_(e_window_unexpectedly_close_while_searching_for_tags));
       FreeWild(new_num_matches, new_matches);
       break;
     }

     // If there already were some matches for the same name, move them
     // to the start.  Avoids that the order changes when using
     // ":tnext" and jumping to another file.
     if (!new_tag && !other_name) {
       int idx = 0;
       tagptrs_T tagp, tagp2;

       // Find the position of each old match in the new list.  Need
       // to use parse_match() to find the tag line.
       for (int j = 0; j < num_matches; j++) {
         parse_match(matches[j], &tagp);
         for (int i = idx; i < new_num_matches; i++) {
           parse_match(new_matches[i], &tagp2);
           if (strcmp(tagp.tagname, tagp2.tagname) == 0) {
             char *p = new_matches[i];
             for (int k = i; k > idx; k--) {
               new_matches[k] = new_matches[k - 1];
             }
             new_matches[idx++] = p;
             break;
           }
         }
       }
     }
     FreeWild(num_matches, matches);
     num_matches = new_num_matches;
     matches = new_matches;
   }

   if (num_matches <= 0) {
     if (verbose) {
       semsg(_(e_tag_not_found_str), name);
     }
     g_do_tagpreview = 0;
   } else {
     bool ask_for_selection = false;

     if (type == DT_TAG && *tag != NUL) {
       // If a count is supplied to the ":tag <name>" command, then
       // jump to count'th matching tag.
       cur_match = count > 0 ? count - 1 : 0;
     } else if (type == DT_SELECT || (type == DT_JUMP && num_matches > 1)) {
       print_tag_list(new_tag, use_tagstack, num_matches, matches);
       ask_for_selection = true;
     } else if (type == DT_LTAG) {
       if (add_llist_tags(tag, num_matches, matches) == FAIL) {
         goto end_do_tag;
       }

       cur_match = 0;                  // Jump to the first tag
     }

     if (ask_for_selection) {
       // Ask to select a tag from the list.
       int i = prompt_for_input(NULL, 0, false, NULL);
       if (i <= 0 || i > num_matches || got_int) {
         // no valid choice: don't change anything
         if (use_tagstack) {
           tagstack[tagstackidx].fmark = saved_fmark;
           tagstackidx = prevtagstackidx;
         }
         break;
       }
       cur_match = i - 1;
     }

     if (cur_match >= num_matches) {
       // Avoid giving this error when a file wasn't found and we're
       // looking for a match in another file, which wasn't found.
       // There will be an emsg("file doesn't exist") below then.
       if ((type == DT_NEXT || type == DT_FIRST)
           && nofile_fname == NULL) {
         if (num_matches == 1) {
           emsg(_("E427: There is only one matching tag"));
         } else {
           emsg(_("E428: Cannot go beyond last matching tag"));
         }
         skip_msg = true;
       }
       cur_match = num_matches - 1;
     }
     if (use_tagstack) {
       tagptrs_T tagp2;

       tagstack[tagstackidx].cur_match = cur_match;
       tagstack[tagstackidx].cur_fnum = cur_fnum;

       // store user-provided data originating from tagfunc
       if (use_tfu && parse_match(matches[cur_match], &tagp2) == OK
           && tagp2.user_data) {
         XFREE_CLEAR(tagstack[tagstackidx].user_data);
         tagstack[tagstackidx].user_data =
           xmemdupz(tagp2.user_data, (size_t)(tagp2.user_data_end - tagp2.user_data));
       }

       tagstackidx++;
     } else if (g_do_tagpreview != 0) {
       ptag_entry.cur_match = cur_match;
       ptag_entry.cur_fnum = cur_fnum;
     }

     // Only when going to try the next match, report that the previous
     // file didn't exist.  Otherwise an emsg() is given below.
     if (nofile_fname != NULL && error_cur_match != cur_match) {
       smsg(0, _("File \"%s\" does not exist"), nofile_fname);
     }

     bool ic = (matches[cur_match][0] & MT_IC_OFF);
     if (type != DT_TAG && type != DT_SELECT && type != DT_JUMP
         && (num_matches > 1 || ic)
         && !skip_msg) {
       // Give an indication of the number of matching tags
       snprintf(IObuff, sizeof(IObuff), _("tag %d of %d%s"),
                cur_match + 1,
                num_matches,
                max_num_matches != MAXCOL ? _(" or more") : "");
       if (ic) {
         xstrlcat(IObuff, _("  Using tag with different case!"), IOSIZE);
       }
       if ((num_matches > prev_num_matches || new_tag)
           && num_matches > 1) {
         msg(IObuff, ic ? HLF_W : 0);
         msg_scroll = true;  // Don't overwrite this message.
       } else {
         give_warning(IObuff, ic, true);
       }
       if (ic && !msg_scrolled && msg_silent == 0) {
         msg_delay(1007, true);
       }
     }

     // Let the SwapExists event know what tag we are jumping to.
     vim_snprintf(IObuff, IOSIZE, ":ta %s\r", name);
     set_vim_var_string(VV_SWAPCOMMAND, IObuff, -1);

     // Jump to the desired match.
     int i = jumpto_tag(matches[cur_match], forceit, true);

     set_vim_var_string(VV_SWAPCOMMAND, NULL, -1);

     if (i == NOTAGFILE) {
       // File not found: try again with another matching tag
       if ((type == DT_PREV && cur_match > 0)
           || ((type == DT_TAG || type == DT_NEXT
                || type == DT_FIRST)
               && (max_num_matches != MAXCOL
                   || cur_match < num_matches - 1))) {
         error_cur_match = cur_match;
         if (use_tagstack) {
           tagstackidx--;
         }
         if (type == DT_PREV) {
           cur_match--;
         } else {
           type = DT_NEXT;
           cur_match++;
         }
         continue;
       }
       semsg(_("E429: File \"%s\" does not exist"), nofile_fname);
     } else {
       // We may have jumped to another window, check that
       // tagstackidx is still valid.
       if (use_tagstack && tagstackidx > curwin->w_tagstacklen) {
         tagstackidx = curwin->w_tagstackidx;
       }
     }
   }
   break;
 }

end_do_tag:
 // Only store the new index when using the tagstack and it's valid.
 if (use_tagstack && tagstackidx <= curwin->w_tagstacklen) {
   curwin->w_tagstackidx = tagstackidx;
 }
 postponed_split = 0;          // don't split next time
 g_do_tagpreview = 0;          // don't do tag preview next time
 xfree(tofree);
}

// List all the matching tags.
static void print_tag_list(bool new_tag, bool use_tagstack, int num_matches, char **matches)
{
 taggy_T *tagstack = curwin->w_tagstack;
 int tagstackidx = curwin->w_tagstackidx;
 tagptrs_T tagp;

 // Assume that the first match indicates how long the tags can
 // be, and align the file names to that.
 parse_match(matches[0], &tagp);
 int taglen = MAX((int)(tagp.tagname_end - tagp.tagname + 2), 18);
 if (taglen > Columns - 25) {
   taglen = MAXCOL;
 }
 if (msg_col == 0) {
   msg_didout = false;     // overwrite previous message
 }
 msg_ext_set_kind("confirm");
 msg_start();
 msg_puts_hl(_("  # pri kind tag"), HLF_T, false);
 msg_clr_eos();
 taglen_advance(taglen);
 msg_puts_hl(_("file\n"), HLF_T, false);

 for (int i = 0; i < num_matches && !got_int; i++) {
   parse_match(matches[i], &tagp);
   if (!new_tag && (
                    (g_do_tagpreview != 0
                     && i == ptag_entry.cur_match)
                    || (use_tagstack
                        && i == tagstack[tagstackidx].cur_match))) {
     *IObuff = '>';
   } else {
     *IObuff = ' ';
   }
   vim_snprintf(IObuff + 1, IOSIZE - 1,
                "%2d %s ", i + 1,
                mt_names[matches[i][0] & MT_MASK]);
   msg_puts(IObuff);
   if (tagp.tagkind != NULL) {
     msg_outtrans_len(tagp.tagkind, (int)(tagp.tagkind_end - tagp.tagkind), 0, false);
   }
   msg_advance(13);
   msg_outtrans_len(tagp.tagname, (int)(tagp.tagname_end - tagp.tagname), HLF_T, false);
   msg_putchar(' ');
   taglen_advance(taglen);

   // Find out the actual file name. If it is long, truncate
   // it and put "..." in the middle
   const char *p = tag_full_fname(&tagp);
   if (p != NULL) {
     msg_outtrans(p, HLF_D, false);
     XFREE_CLEAR(p);
   }
   if (msg_col > 0) {
     msg_putchar('\n');
   }
   if (got_int) {
     break;
   }
   msg_advance(15);

   // print any extra fields
   const char *command_end = tagp.command_end;
   if (command_end != NULL) {
     p = command_end + 3;
     while (*p && *p != '\r' && *p != '\n') {
       while (*p == TAB) {
         p++;
       }

       // skip "file:" without a value (static tag)
       if (strncmp(p, "file:", 5) == 0 && ascii_isspace(p[5])) {
         p += 5;
         continue;
       }
       // skip "kind:<kind>" and "<kind>"
       if (p == tagp.tagkind
           || (p + 5 == tagp.tagkind
               && strncmp(p, "kind:", 5) == 0)) {
         p = tagp.tagkind_end;
         continue;
       }
       // print all other extra fields
       int hl_id = HLF_CM;
       while (*p && *p != '\r' && *p != '\n') {
         if (msg_col + ptr2cells(p) >= Columns) {
           msg_putchar('\n');
           if (got_int) {
             break;
           }
           msg_advance(15);
         }
         p = msg_outtrans_one(p, hl_id, false);
         if (*p == TAB) {
           msg_puts_hl(" ", hl_id, false);
           break;
         }
         if (*p == ':') {
           hl_id = 0;
         }
       }
     }
     if (msg_col > 15) {
       msg_putchar('\n');
       if (got_int) {
         break;
       }
       msg_advance(15);
     }
   } else {
     for (p = tagp.command;
          *p && *p != '\r' && *p != '\n';
          p++) {}
     command_end = p;
   }

   // Put the info (in several lines) at column 15.
   // Don't display "/^" and "?^".
   p = tagp.command;
   if (*p == '/' || *p == '?') {
     p++;
     if (*p == '^') {
       p++;
     }
   }
   // Remove leading whitespace from pattern
   while (p != command_end && ascii_isspace(*p)) {
     p++;
   }

   while (p != command_end) {
     if (msg_col + (*p == TAB ? 1 : ptr2cells(p)) > Columns) {
       msg_putchar('\n');
     }
     if (got_int) {
       break;
     }
     msg_advance(15);

     // skip backslash used for escaping a command char or
     // a backslash
     if (*p == '\\' && (*(p + 1) == *tagp.command
                        || *(p + 1) == '\\')) {
       p++;
     }

     if (*p == TAB) {
       msg_putchar(' ');
       p++;
     } else {
       p = msg_outtrans_one(p, 0, false);
     }

     // don't display the "$/;\"" and "$?;\""
     if (p == command_end - 2 && *p == '$'
         && *(p + 1) == *tagp.command) {
       break;
     }
     // don't display matching '/' or '?'
     if (p == command_end - 1 && *p == *tagp.command
         && (*p == '/' || *p == '?')) {
       break;
     }
   }
   if (msg_col && (!ui_has(kUIMessages) || i < num_matches - 1)) {
     msg_putchar('\n');
   }
   os_breakcheck();
 }
 if (got_int) {
   got_int = false;        // only stop the listing
 }
}

/// Add the matching tags to the location list for the current
/// window.
static int add_llist_tags(char *tag, int num_matches, char **matches)
{
 char tag_name[128 + 1];
 tagptrs_T tagp;

 char *fname = xmalloc(MAXPATHL + 1);
 char *cmd = xmalloc(CMDBUFFSIZE + 1);
 list_T *list = tv_list_alloc(0);

 for (int i = 0; i < num_matches; i++) {
   dict_T *dict;

   parse_match(matches[i], &tagp);

   // Save the tag name
   int len = MIN((int)(tagp.tagname_end - tagp.tagname), 128);
   xmemcpyz(tag_name, tagp.tagname, (size_t)len);
   tag_name[len] = NUL;

   // Save the tag file name
   char *p = tag_full_fname(&tagp);
   if (p == NULL) {
     continue;
   }
   xstrlcpy(fname, p, MAXPATHL);
   XFREE_CLEAR(p);

   // Get the line number or the search pattern used to locate
   // the tag.
   linenr_T lnum = 0;
   if (isdigit((uint8_t)(*tagp.command))) {
     // Line number is used to locate the tag
     lnum = atoi(tagp.command);
   } else {
     // Search pattern is used to locate the tag

     // Locate the end of the command
     char *cmd_start = tagp.command;
     char *cmd_end = tagp.command_end;
     if (cmd_end == NULL) {
       for (p = tagp.command;
            *p && *p != '\r' && *p != '\n'; p++) {}
       cmd_end = p;
     }

     // Now, cmd_end points to the character after the
     // command. Adjust it to point to the last
     // character of the command.
     cmd_end--;

     // Skip the '/' and '?' characters at the
     // beginning and end of the search pattern.
     if (*cmd_start == '/' || *cmd_start == '?') {
       cmd_start++;
     }

     if (*cmd_end == '/' || *cmd_end == '?') {
       cmd_end--;
     }

     len = 0;
     cmd[0] = NUL;

     // If "^" is present in the tag search pattern, then
     // copy it first.
     if (*cmd_start == '^') {
       STRCPY(cmd, "^");
       cmd_start++;
       len++;
     }

     // Precede the tag pattern with \V to make it very
     // nomagic.
     strcat(cmd, "\\V");
     len += 2;

     int cmd_len = MIN((int)(cmd_end - cmd_start + 1), CMDBUFFSIZE - 5);
     snprintf(cmd + len, (size_t)(CMDBUFFSIZE + 1 - len),
              "%.*s", cmd_len, cmd_start);
     len += cmd_len;

     if (cmd[len - 1] == '$') {
       // Replace '$' at the end of the search pattern
       // with '\$'
       cmd[len - 1] = '\\';
       cmd[len] = '$';
       len++;
     }

     cmd[len] = NUL;
   }

   dict = tv_dict_alloc();
   tv_list_append_dict(list, dict);

   tv_dict_add_str(dict, S_LEN("text"), tag_name);
   tv_dict_add_str(dict, S_LEN("filename"), fname);
   tv_dict_add_nr(dict, S_LEN("lnum"), lnum);
   if (lnum == 0) {
     tv_dict_add_str(dict, S_LEN("pattern"), cmd);
   }
 }

 vim_snprintf(IObuff, IOSIZE, "ltag %s", tag);
 set_errorlist(curwin, list, ' ', IObuff, NULL);

 tv_list_free(list);
 XFREE_CLEAR(fname);
 XFREE_CLEAR(cmd);

 return OK;
}

// Free cached tags.
void tag_freematch(void)
{
 XFREE_CLEAR(tagmatchname);
}

static void taglen_advance(int l)
{
 if (l == MAXCOL) {
   msg_putchar('\n');
   msg_advance(24);
 } else {
   msg_advance(13 + l);
 }
}

// Print the tag stack
void do_tags(exarg_T *eap)
{
 taggy_T *tagstack = curwin->w_tagstack;
 int tagstackidx = curwin->w_tagstackidx;
 int tagstacklen = curwin->w_tagstacklen;

 // Highlight title
 msg_puts_title(_("\n  # TO tag         FROM line  in file/text"));
 for (int i = 0; i < tagstacklen; i++) {
   if (tagstack[i].tagname != NULL) {
     char *name = fm_getname(&(tagstack[i].fmark), 30);
     if (name == NULL) {           // file name not available
       continue;
     }

     msg_putchar('\n');
     vim_snprintf(IObuff, IOSIZE, "%c%2d %2d %-15s %5" PRIdLINENR "  ",
                  i == tagstackidx ? '>' : ' ',
                  i + 1,
                  tagstack[i].cur_match + 1,
                  tagstack[i].tagname,
                  tagstack[i].fmark.mark.lnum);
     msg_outtrans(IObuff, 0, false);
     msg_outtrans(name, tagstack[i].fmark.fnum == curbuf->b_fnum ? HLF_D : 0, false);
     xfree(name);
   }
 }
 if (tagstackidx == tagstacklen) {     // idx at top of stack
   msg_puts("\n>");
 }
}

// Compare two strings, for length "len", ignoring case the ASCII way.
// return 0 for match, < 0 for smaller, > 0 for bigger
// Make sure case is folded to uppercase in comparison (like for 'sort -f')
static int tag_strnicmp(char *s1, char *s2, size_t len)
{
 while (len > 0) {
   int i = TOUPPER_ASC((uint8_t)(*s1)) - TOUPPER_ASC((uint8_t)(*s2));
   if (i != 0) {
     return i;                         // this character different
   }
   if (*s1 == NUL) {
     break;                            // strings match until NUL
   }
   s1++;
   s2++;
   len--;
 }
 return 0;                             // strings match
}

// Extract info from the tag search pattern "pats->pat".
static void prepare_pats(pat_T *pats, bool has_re)
{
 pats->head = pats->pat;
 pats->headlen = pats->len;
 if (has_re) {
   // When the pattern starts with '^' or "\\<", binary searching can be
   // used (much faster).
   if (pats->pat[0] == '^') {
     pats->head = pats->pat + 1;
   } else if (pats->pat[0] == '\\' && pats->pat[1] == '<') {
     pats->head = pats->pat + 2;
   }
   if (pats->head == pats->pat) {
     pats->headlen = 0;
   } else {
     for (pats->headlen = 0; pats->head[pats->headlen] != NUL; pats->headlen++) {
       if (vim_strchr(magic_isset() ? ".[~*\\$" : "\\$",
                      (uint8_t)pats->head[pats->headlen]) != NULL) {
         break;
       }
     }
   }
   if (p_tl != 0 && pats->headlen > p_tl) {    // adjust for 'taglength'
     pats->headlen = (int)p_tl;
   }
 }

 if (has_re) {
   pats->regmatch.regprog = vim_regcomp(pats->pat, magic_isset() ? RE_MAGIC : 0);
 } else {
   pats->regmatch.regprog = NULL;
 }
}

/// Call the user-defined function to generate a list of tags used by
/// find_tags().
///
/// Return OK if at least 1 tag has been successfully found,
/// NOTDONE if the function returns v:null, and FAIL otherwise.
///
/// @param pat  pattern supplied to the user-defined function
/// @param ga  the tags will be placed here
/// @param match_count  here the number of tags found will be placed
/// @param flags  flags from find_tags (TAG_*)
/// @param buf_ffname  name of buffer for priority
static int find_tagfunc_tags(char *pat, garray_T *ga, int *match_count, int flags, char *buf_ffname)
{
 int ntags = 0;
 typval_T args[4];
 typval_T rettv;
 char flagString[4];
 taggy_T *tag = NULL;

 if (curwin->w_tagstacklen > 0) {
   if (curwin->w_tagstackidx == curwin->w_tagstacklen) {
     tag = &curwin->w_tagstack[curwin->w_tagstackidx - 1];
   } else {
     tag = &curwin->w_tagstack[curwin->w_tagstackidx];
   }
 }

 if (*curbuf->b_p_tfu == NUL || curbuf->b_tfu_cb.type == kCallbackNone) {
   return FAIL;
 }

 args[0].v_type = VAR_STRING;
 args[0].vval.v_string = pat;
 args[1].v_type = VAR_STRING;
 args[1].vval.v_string = flagString;

 // create 'info' dict argument
 dict_T *const d = tv_dict_alloc_lock(VAR_FIXED);
 if (!(flags & TAG_INS_COMP) && tag != NULL && tag->user_data != NULL) {
   tv_dict_add_str(d, S_LEN("user_data"), tag->user_data);
 }
 if (buf_ffname != NULL) {
   tv_dict_add_str(d, S_LEN("buf_ffname"), buf_ffname);
 }

 d->dv_refcount++;
 args[2].v_type = VAR_DICT;
 args[2].vval.v_dict = d;

 args[3].v_type = VAR_UNKNOWN;

 vim_snprintf(flagString, sizeof(flagString),
              "%s%s%s",
              g_tag_at_cursor ? "c" : "",
              flags & TAG_INS_COMP ? "i" : "",
              flags & TAG_REGEXP ? "r" : "");

 pos_T save_pos = curwin->w_cursor;
 int result = callback_call(&curbuf->b_tfu_cb, 3, args, &rettv);
 curwin->w_cursor = save_pos;  // restore the cursor position
 check_cursor(curwin);         // make sure cursor position is valid
 d->dv_refcount--;

 if (result == FAIL) {
   return FAIL;
 }
 if (rettv.v_type == VAR_SPECIAL && rettv.vval.v_special == kSpecialVarNull) {
   tv_clear(&rettv);
   return NOTDONE;
 }
 if (rettv.v_type != VAR_LIST || !rettv.vval.v_list) {
   tv_clear(&rettv);
   emsg(_(e_invalid_return_value_from_tagfunc));
   return FAIL;
 }
 list_T *taglist = rettv.vval.v_list;

 TV_LIST_ITER_CONST(taglist, li, {
   char *res_name;
   char *res_fname;
   char *res_cmd;
   char *res_kind;
   bool has_extra = false;
   int name_only = flags & TAG_NAMES;

   if (TV_LIST_ITEM_TV(li)->v_type != VAR_DICT) {
     emsg(_(e_invalid_return_value_from_tagfunc));
     break;
   }

   size_t len = 2;
   res_name = NULL;
   res_fname = NULL;
   res_cmd = NULL;
   res_kind = NULL;

   TV_DICT_ITER(TV_LIST_ITEM_TV(li)->vval.v_dict, di, {
     const char *dict_key = di->di_key;
     typval_T *tv = &di->di_tv;

     if (tv->v_type != VAR_STRING || tv->vval.v_string == NULL) {
       continue;
     }

     len += strlen(tv->vval.v_string) + 1;   // Space for "\tVALUE"
     if (!strcmp(dict_key, "name")) {
       res_name = tv->vval.v_string;
       continue;
     }
     if (!strcmp(dict_key, "filename")) {
       res_fname = tv->vval.v_string;
       continue;
     }
     if (!strcmp(dict_key, "cmd")) {
       res_cmd = tv->vval.v_string;
       continue;
     }
     has_extra = true;
     if (!strcmp(dict_key, "kind")) {
       res_kind = tv->vval.v_string;
       continue;
     }
     // Other elements will be stored as "\tKEY:VALUE"
     // Allocate space for the key and the colon
     len += strlen(dict_key) + 1;
   });

   if (has_extra) {
     len += 2;  // need space for ;"
   }

   if (!res_name || !res_fname || !res_cmd) {
     emsg(_(e_invalid_return_value_from_tagfunc));
     break;
   }

   char *const mfp = name_only ? xstrdup(res_name) : xmalloc(len + 2);

   if (!name_only) {
     char *p = mfp;

     *p++ = MT_GL_OTH + 1;   // mtt
     *p++ = TAG_SEP;     // no tag file name

     STRCPY(p, res_name);
     p += strlen(p);

     *p++ = TAB;
     STRCPY(p, res_fname);
     p += strlen(p);

     *p++ = TAB;
     STRCPY(p, res_cmd);
     p += strlen(p);

     if (has_extra) {
       STRCPY(p, ";\"");
       p += strlen(p);

       if (res_kind) {
         *p++ = TAB;
         STRCPY(p, res_kind);
         p += strlen(p);
       }

       TV_DICT_ITER(TV_LIST_ITEM_TV(li)->vval.v_dict, di, {
         const char *dict_key = di->di_key;
         typval_T *tv = &di->di_tv;
         if (tv->v_type != VAR_STRING || tv->vval.v_string == NULL) {
           continue;
         }

         if (!strcmp(dict_key, "name")) {
           continue;
         }
         if (!strcmp(dict_key, "filename")) {
           continue;
         }
         if (!strcmp(dict_key, "cmd")) {
           continue;
         }
         if (!strcmp(dict_key, "kind")) {
           continue;
         }

         *p++ = TAB;
         STRCPY(p, dict_key);
         p += strlen(p);
         STRCPY(p, ":");
         p += strlen(p);
         STRCPY(p, tv->vval.v_string);
         p += strlen(p);
       });
     }
   }

   // Add all matches because tagfunc should do filtering.
   ga_grow(ga, 1);
   ((char **)(ga->ga_data))[ga->ga_len++] = (char *)mfp;
   ntags++;
   result = OK;
 });

 tv_clear(&rettv);

 *match_count = ntags;
 return result;
}

/// Initialize the state used by find_tags()
static void findtags_state_init(findtags_state_T *st, char *pat, int flags, int mincount)
{
 st->tag_fname = xmalloc(MAXPATHL + 1);
 st->fp = NULL;
 st->orgpat = xmalloc(sizeof(pat_T));
 st->orgpat->pat = pat;
 st->orgpat->len = (int)strlen(pat);
 st->orgpat->regmatch.regprog = NULL;
 st->flags = flags;
 st->tag_file_sorted = NUL;
 st->help_lang_find = NULL;
 st->is_txt = false;
 st->did_open = false;
 st->help_only = (flags & TAG_HELP);
 st->get_searchpat = false;
 st->help_lang[0] = NUL;
 st->help_pri = 0;
 st->mincount = mincount;
 st->lbuf_size = LSIZE;
 st->lbuf = xmalloc((size_t)st->lbuf_size);
 st->match_count = 0;
 st->stop_searching = false;

 for (int mtt = 0; mtt < MT_COUNT; mtt++) {
   ga_init(&st->ga_match[mtt], sizeof(char *), 100);
   hash_init(&st->ht_match[mtt]);
 }
}

/// Free the state used by find_tags()
static void findtags_state_free(findtags_state_T *st)
{
 xfree(st->tag_fname);
 xfree(st->lbuf);
 vim_regfree(st->orgpat->regmatch.regprog);
 xfree(st->orgpat);
}

/// Initialize the language and priority used for searching tags in a Vim help
/// file.
/// Returns true to process the help file for tags and false to skip the file.
static bool findtags_in_help_init(findtags_state_T *st)
{
 int i;

 // Keep "en" as the language if the file extension is ".txt"
 if (st->is_txt) {
   STRCPY(st->help_lang, "en");
 } else {
   // Prefer help tags according to 'helplang'.  Put the two-letter
   // language name in help_lang[].
   i = (int)strlen(st->tag_fname);
   if (i > 3 && st->tag_fname[i - 3] == '-') {
     xmemcpyz(st->help_lang, st->tag_fname + i - 2, 2);
   } else {
     STRCPY(st->help_lang, "en");
   }
 }
 // When searching for a specific language skip tags files for other
 // languages.
 if (st->help_lang_find != NULL
     && STRICMP(st->help_lang, st->help_lang_find) != 0) {
   return false;
 }

 // For CTRL-] in a help file prefer a match with the same language.
 if ((st->flags & TAG_KEEP_LANG)
     && st->help_lang_find == NULL
     && curbuf->b_fname != NULL
     && (i = (int)strlen(curbuf->b_fname)) > 4
     && curbuf->b_fname[i - 1] == 'x'
     && curbuf->b_fname[i - 4] == '.'
     && STRNICMP(curbuf->b_fname + i - 3, st->help_lang, 2) == 0) {
   st->help_pri = 0;
 } else {
   st->help_pri = 1;
   char *s;
   for (s = p_hlg; *s != NUL; s++) {
     if (STRNICMP(s, st->help_lang, 2) == 0) {
       break;
     }
     st->help_pri++;
     if ((s = vim_strchr(s, ',')) == NULL) {
       break;
     }
   }
   if (s == NULL || *s == NUL) {
     // Language not in 'helplang': use last, prefer English, unless
     // found already.
     st->help_pri++;
     if (STRICMP(st->help_lang, "en") != 0) {
       st->help_pri++;
     }
   }
 }

 return true;
}

/// Use the function set in 'tagfunc' (if configured and enabled) to get the
/// tags.
/// Return OK if at least 1 tag has been successfully found, NOTDONE if the
/// 'tagfunc' is not used, still executing or the 'tagfunc' returned v:null and
/// FAIL otherwise.
static int findtags_apply_tfu(findtags_state_T *st, char *pat, char *buf_ffname)
{
 const bool use_tfu = ((st->flags & TAG_NO_TAGFUNC) == 0);

 if (!use_tfu || tfu_in_use || *curbuf->b_p_tfu == NUL) {
   return NOTDONE;
 }

 tfu_in_use = true;
 int retval = find_tagfunc_tags(pat, st->ga_match, &st->match_count,
                                st->flags, buf_ffname);
 tfu_in_use = false;

 return retval;
}

/// Read the next line from a tags file.
/// Returns TAGS_READ_SUCCESS if a tags line is successfully read and should be
/// processed.
/// Returns TAGS_READ_EOF if the end of file is reached.
/// Returns TAGS_READ_IGNORE if the current line should be ignored (used when
/// reached end of a emacs included tags file)
static tags_read_status_T findtags_get_next_line(findtags_state_T *st, tagsearch_info_T *sinfo_p)
{
 bool eof;

 // For binary search: compute the next offset to use.
 if (st->state == TS_BINARY) {
   off_T offset = sinfo_p->low_offset + ((sinfo_p->high_offset - sinfo_p->low_offset) / 2);
   if (offset == sinfo_p->curr_offset) {
     return TAGS_READ_EOF;  // End the binary search without a match.
   } else {
     sinfo_p->curr_offset = offset;
   }
 } else if (st->state == TS_SKIP_BACK) {
   // Skipping back (after a match during binary search).
   sinfo_p->curr_offset -= st->lbuf_size * 2;
   if (sinfo_p->curr_offset < 0) {
     sinfo_p->curr_offset = 0;
     fseek(st->fp, 0, SEEK_SET);
     st->state = TS_STEP_FORWARD;
   }
 }

 // When jumping around in the file, first read a line to find the
 // start of the next line.
 if (st->state == TS_BINARY || st->state == TS_SKIP_BACK) {
   // Adjust the search file offset to the correct position
   sinfo_p->curr_offset_used = sinfo_p->curr_offset;
   vim_ignored = vim_fseek(st->fp, sinfo_p->curr_offset, SEEK_SET);
   eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
   if (!eof && sinfo_p->curr_offset != 0) {
     sinfo_p->curr_offset = vim_ftell(st->fp);
     if (sinfo_p->curr_offset == sinfo_p->high_offset) {
       // oops, gone a bit too far; try from low offset
       vim_ignored = vim_fseek(st->fp, sinfo_p->low_offset, SEEK_SET);
       sinfo_p->curr_offset = sinfo_p->low_offset;
     }
     eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
   }
   // skip empty and blank lines
   while (!eof && vim_isblankline(st->lbuf)) {
     sinfo_p->curr_offset = vim_ftell(st->fp);
     eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
   }
   if (eof) {
     // Hit end of file.  Skip backwards.
     st->state = TS_SKIP_BACK;
     sinfo_p->match_offset = vim_ftell(st->fp);
     sinfo_p->curr_offset = sinfo_p->curr_offset_used;
     return TAGS_READ_IGNORE;
   }
 } else {
   // Not jumping around in the file: Read the next line.

   // skip empty and blank lines
   do {
     eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
   } while (!eof && vim_isblankline(st->lbuf));

   if (eof) {
     return TAGS_READ_EOF;
   }
 }

 return TAGS_READ_SUCCESS;
}

/// Parse a tags file header line in "st->lbuf".
/// Returns true if the current line in st->lbuf is not a tags header line and
/// should be parsed as a regular tag line. Returns false if the line is a
/// header line and the next header line should be read.
static bool findtags_hdr_parse(findtags_state_T *st)
{
 // Header lines in a tags file start with "!_TAG_"
 if (strncmp(st->lbuf, "!_TAG_", 6) != 0) {
   // Non-header item before the header, e.g. "!" itself.
   return true;
 }

 // Process the header line.
 if (strncmp(st->lbuf, "!_TAG_FILE_SORTED\t", 18) == 0) {
   st->tag_file_sorted = (uint8_t)st->lbuf[18];
 }
 if (strncmp(st->lbuf, "!_TAG_FILE_ENCODING\t", 20) == 0) {
   // Prepare to convert every line from the specified encoding to
   // 'encoding'.
   char *p;
   for (p = st->lbuf + 20; *p > ' ' && *p < 127; p++) {}
   *p = NUL;
   convert_setup(&st->vimconv, st->lbuf + 20, p_enc);
 }

 // Read the next line.  Unrecognized flags are ignored.
 return false;
}

/// Handler to initialize the state when starting to process a new tags file.
/// Called in the TS_START state when finding tags from a tags file.
/// Returns true if the line read from the tags file should be parsed and
/// false if the line should be ignored.
static bool findtags_start_state_handler(findtags_state_T *st, bool *sortic,
                                        tagsearch_info_T *sinfo_p)
{
 const bool noic = (st->flags & TAG_NOIC);

 // The header ends when the line sorts below "!_TAG_".  When case is
 // folded lower case letters sort before "_".
 if (strncmp(st->lbuf, "!_TAG_", 6) <= 0
     || (st->lbuf[0] == '!' && ASCII_ISLOWER(st->lbuf[1]))) {
   return findtags_hdr_parse(st);
 }

 // Headers ends.

 // When there is no tag head, or ignoring case, need to do a
 // linear search.
 // When no "!_TAG_" is found, default to binary search.  If
 // the tag file isn't sorted, the second loop will find it.
 // When "!_TAG_FILE_SORTED" found: start binary search if
 // flag set.
 if (st->linear) {
   st->state = TS_LINEAR;
 } else if (st->tag_file_sorted == NUL) {
   st->state = TS_BINARY;
 } else if (st->tag_file_sorted == '1') {
   st->state = TS_BINARY;
 } else if (st->tag_file_sorted == '2') {
   st->state = TS_BINARY;
   *sortic = true;
   st->orgpat->regmatch.rm_ic = (p_ic || !noic);
 } else {
   st->state = TS_LINEAR;
 }

 if (st->state == TS_BINARY && st->orgpat->regmatch.rm_ic && !*sortic) {
   // Binary search won't work for ignoring case, use linear
   // search.
   st->linear = true;
   st->state = TS_LINEAR;
 }

 // When starting a binary search, get the size of the file and
 // compute the first offset.
 if (st->state == TS_BINARY) {
   if (vim_fseek(st->fp, 0, SEEK_END) != 0) {
     // can't seek, don't use binary search
     st->state = TS_LINEAR;
   } else {
     // Get the tag file size.
     // Don't use lseek(), it doesn't work
     // properly on MacOS Catalina.
     const off_T filesize = vim_ftell(st->fp);
     vim_ignored = vim_fseek(st->fp, 0, SEEK_SET);

     // Calculate the first read offset in the file.  Start
     // the search in the middle of the file.
     sinfo_p->low_offset = 0;
     sinfo_p->low_char = 0;
     sinfo_p->high_offset = filesize;
     sinfo_p->curr_offset = 0;
     sinfo_p->high_char = 0xff;
   }
   return false;
 }

 return true;
}

/// Parse a tag line read from a tags file.
/// Also compares the tag name in "tagpp->tagname" with a search pattern in
/// "st->orgpat->head" as a quick check if the tag may match.
/// Returns:
/// - TAG_MATCH_SUCCESS if the tag may match
/// - TAG_MATCH_FAIL if the tag doesn't match
/// - TAG_MATCH_NEXT to look for the next matching tag (used in a binary search)
/// - TAG_MATCH_STOP if all the tags are processed without a match.
/// Uses the values in "margs" for doing the comparison.
static tagmatch_status_T findtags_parse_line(findtags_state_T *st, tagptrs_T *tagpp,
                                            findtags_match_args_T *margs,
                                            tagsearch_info_T *sinfo_p)
{
 int status;

 // Figure out where the different strings are in this line.
 // For "normal" tags: Do a quick check if the tag matches.
 // This speeds up tag searching a lot!
 if (st->orgpat->headlen) {
   CLEAR_FIELD(*tagpp);
   tagpp->tagname = st->lbuf;
   tagpp->tagname_end = vim_strchr(st->lbuf, TAB);
   if (tagpp->tagname_end == NULL) {
     // Corrupted tag line.
     return TAG_MATCH_FAIL;
   }

   // Skip this line if the length of the tag is different and
   // there is no regexp, or the tag is too short.
   int cmplen = (int)(tagpp->tagname_end - tagpp->tagname);
   if (p_tl != 0 && cmplen > p_tl) {  // adjust for 'taglength'
     cmplen = (int)p_tl;
   }
   if ((st->flags & TAG_REGEXP) && st->orgpat->headlen < cmplen) {
     cmplen = st->orgpat->headlen;
   } else if (st->state == TS_LINEAR && st->orgpat->headlen != cmplen) {
     return TAG_MATCH_NEXT;
   }

   if (st->state == TS_BINARY) {
     int tagcmp;
     // Simplistic check for unsorted tags file.
     int i = (uint8_t)tagpp->tagname[0];
     if (margs->sortic) {
       i = TOUPPER_ASC(tagpp->tagname[0]);
     }
     if (i < sinfo_p->low_char || i > sinfo_p->high_char) {
       margs->sort_error = true;
     }

     // Compare the current tag with the searched tag.
     if (margs->sortic) {
       tagcmp = tag_strnicmp(tagpp->tagname, st->orgpat->head,
                             (size_t)cmplen);
     } else {
       tagcmp = strncmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen);
     }

     // A match with a shorter tag means to search forward.
     // A match with a longer tag means to search backward.
     if (tagcmp == 0) {
       if (cmplen < st->orgpat->headlen) {
         tagcmp = -1;
       } else if (cmplen > st->orgpat->headlen) {
         tagcmp = 1;
       }
     }

     if (tagcmp == 0) {
       // We've located the tag, now skip back and search
       // forward until the first matching tag is found.
       st->state = TS_SKIP_BACK;
       sinfo_p->match_offset = sinfo_p->curr_offset;
       return TAG_MATCH_NEXT;
     }
     if (tagcmp < 0) {
       sinfo_p->curr_offset = vim_ftell(st->fp);
       if (sinfo_p->curr_offset < sinfo_p->high_offset) {
         sinfo_p->low_offset = sinfo_p->curr_offset;
         if (margs->sortic) {
           sinfo_p->low_char = TOUPPER_ASC(tagpp->tagname[0]);
         } else {
           sinfo_p->low_char = (uint8_t)tagpp->tagname[0];
         }
         return TAG_MATCH_NEXT;
       }
     }
     if (tagcmp > 0 && sinfo_p->curr_offset != sinfo_p->high_offset) {
       sinfo_p->high_offset = sinfo_p->curr_offset;
       if (margs->sortic) {
         sinfo_p->high_char = TOUPPER_ASC(tagpp->tagname[0]);
       } else {
         sinfo_p->high_char = (uint8_t)tagpp->tagname[0];
       }
       return TAG_MATCH_NEXT;
     }

     // No match yet and are at the end of the binary search.
     return TAG_MATCH_STOP;
   } else if (st->state == TS_SKIP_BACK) {
     assert(cmplen >= 0);
     if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
       st->state = TS_STEP_FORWARD;
     } else {
       // Have to skip back more.  Restore the curr_offset
       // used, otherwise we get stuck at a long line.
       sinfo_p->curr_offset = sinfo_p->curr_offset_used;
     }
     return TAG_MATCH_NEXT;
   } else if (st->state == TS_STEP_FORWARD) {
     assert(cmplen >= 0);
     if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
       return ((off_T)vim_ftell(st->fp) > sinfo_p->match_offset)
              ? TAG_MATCH_STOP   // past last match
              : TAG_MATCH_NEXT;  // before first match
     }
   } else {
     // skip this match if it can't match
     assert(cmplen >= 0);
     if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
       return TAG_MATCH_NEXT;
     }
   }

   // Can be a matching tag, isolate the file name and command.
   tagpp->fname = tagpp->tagname_end + 1;
   tagpp->fname_end = vim_strchr(tagpp->fname, TAB);
   if (tagpp->fname_end == NULL) {
     status = FAIL;
   } else {
     tagpp->command = tagpp->fname_end + 1;
     status = OK;
   }
 } else {
   status = parse_tag_line(st->lbuf, tagpp);
 }

 return status == FAIL
        ? TAG_MATCH_FAIL
        : TAG_MATCH_SUCCESS;
}

/// Initialize the structure used for tag matching.
static void findtags_matchargs_init(findtags_match_args_T *margs, int flags)
{
 margs->matchoff = 0;                        // match offset
 margs->match_re = false;                    // match with regexp
 margs->match_no_ic = false;                 // matches with case
 margs->has_re = (flags & TAG_REGEXP);       // regexp used
 margs->sortic = false;                      // tag file sorted in nocase
 margs->sort_error = false;                  // tags file not sorted
}

/// Compares the tag name in "tagpp->tagname" with a search pattern in
/// "st->orgpat->pat".
/// Returns true if the tag matches, false if the tag doesn't match.
/// Uses the values in "margs" for doing the comparison.
static bool findtags_match_tag(findtags_state_T *st, tagptrs_T *tagpp, findtags_match_args_T *margs)
{
 bool match = false;

 // First try matching with the pattern literally (also when it is
 // a regexp).
 int cmplen = (int)(tagpp->tagname_end - tagpp->tagname);
 if (p_tl != 0 && cmplen > p_tl) {           // adjust for 'taglength'
   cmplen = (int)p_tl;
 }
 // if tag length does not match, don't try comparing
 if (st->orgpat->len != cmplen) {
   match = false;
 } else {
   if (st->orgpat->regmatch.rm_ic) {
     assert(cmplen >= 0);
     match = mb_strnicmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
     if (match) {
       margs->match_no_ic = strncmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
     }
   } else {
     match = strncmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
   }
 }

 // Has a regexp: Also find tags matching regexp.
 margs->match_re = false;
 if (!match && st->orgpat->regmatch.regprog != NULL) {
   char cc = *tagpp->tagname_end;
   *tagpp->tagname_end = NUL;
   match = vim_regexec(&st->orgpat->regmatch, tagpp->tagname, 0);
   if (match) {
     margs->matchoff = (int)(st->orgpat->regmatch.startp[0] - tagpp->tagname);
     if (st->orgpat->regmatch.rm_ic) {
       st->orgpat->regmatch.rm_ic = false;
       margs->match_no_ic = vim_regexec(&st->orgpat->regmatch,
                                        tagpp->tagname, 0);
       st->orgpat->regmatch.rm_ic = true;
     }
   }
   *tagpp->tagname_end = cc;
   margs->match_re = true;
 }

 return match;
}

/// Convert the encoding of a line read from a tags file in "st->lbuf".
/// Converting the pattern from 'enc' to the tags file encoding doesn't work,
/// because characters are not recognized. The converted line is saved in
/// st->lbuf.
static void findtags_string_convert(findtags_state_T *st)
{
 char *conv_line = string_convert(&st->vimconv, st->lbuf, NULL);
 if (conv_line == NULL) {
   return;
 }

 // Copy or swap lbuf and conv_line.
 int len = (int)strlen(conv_line) + 1;
 if (len > st->lbuf_size) {
   xfree(st->lbuf);
   st->lbuf = conv_line;
   st->lbuf_size = len;
 } else {
   STRCPY(st->lbuf, conv_line);
   xfree(conv_line);
 }
}

/// Add a matching tag found in a tags file to st->ht_match and st->ga_match.
static void findtags_add_match(findtags_state_T *st, tagptrs_T *tagpp, findtags_match_args_T *margs,
                              char *buf_ffname, hash_T *hash)
{
 const bool name_only = (st->flags & TAG_NAMES);
 size_t len = 0;
 size_t mfp_size = 0;
 char *mfp;

 // Decide in which array to store this match.
 bool is_current = test_for_current(tagpp->fname, tagpp->fname_end,
                                    st->tag_fname, buf_ffname);

 // current tag line is static
 bool is_static = test_for_static(tagpp);

 // Decide in which of the sixteen tables to store this match.
 int mtt = is_static
           ? is_current ? MT_ST_CUR : MT_ST_OTH
           : is_current ? MT_GL_CUR : MT_GL_OTH;

 if (st->orgpat->regmatch.rm_ic && !margs->match_no_ic) {
   mtt += MT_IC_OFF;
 }
 if (margs->match_re) {
   mtt += MT_RE_OFF;
 }

 // Add the found match in ht_match[mtt] and ga_match[mtt].
 // Store the info we need later, which depends on the kind of
 // tags we are dealing with.
 if (st->help_only) {
#define ML_EXTRA 3
   // Append the help-heuristic number after the tagname, for
   // sorting it later.  The heuristic is ignored for
   // detecting duplicates.
   // The format is {tagname}@{lang}NUL{heuristic}NUL
   *tagpp->tagname_end = NUL;
   len = (size_t)(tagpp->tagname_end - tagpp->tagname);
   mfp_size = sizeof(char) + len + 10 + ML_EXTRA + 1;
   mfp = xmalloc(mfp_size);

   char *p = mfp;
   STRCPY(p, tagpp->tagname);
   p[len] = '@';
   STRCPY(p + len + 1, st->help_lang);
   snprintf(p + len + 1 + ML_EXTRA, mfp_size - (len + 1 + ML_EXTRA), "%06d",
            help_heuristic(tagpp->tagname,
                           margs->match_re ? margs->matchoff : 0,
                           !margs->match_no_ic) + st->help_pri);

   *tagpp->tagname_end = TAB;
 } else if (name_only) {
   if (st->get_searchpat) {
     char *temp_end = tagpp->command;

     if (*temp_end == '/') {
       while (*temp_end && *temp_end != '\r'
              && *temp_end != '\n'
              && *temp_end != '$') {
         temp_end++;
       }
     }

     if (tagpp->command + 2 < temp_end) {
       len = (size_t)(temp_end - tagpp->command - 2);
       mfp = xmalloc(len + 2);
       xmemcpyz(mfp, tagpp->command + 2, len);
     } else {
       mfp = NULL;
     }
     st->get_searchpat = false;
   } else {
     len = (size_t)(tagpp->tagname_end - tagpp->tagname);
     mfp = xmalloc(sizeof(char) + len + 1);
     xmemcpyz(mfp, tagpp->tagname, len);

     // if wanted, re-read line to get long form too
     if (State & MODE_INSERT) {
       st->get_searchpat = p_sft;
     }
   }
 } else {
   size_t tag_fname_len = strlen(st->tag_fname);
   // Save the tag in a buffer.
   // Use 0x02 to separate fields (Can't use NUL, because the
   // hash key is terminated by NUL).
   // Emacs tag: <mtt><tag_fname><0x02><ebuf><0x02><lbuf><NUL>
   // other tag: <mtt><tag_fname><0x02><0x02><lbuf><NUL>
   // without Emacs tags: <mtt><tag_fname><0x02><lbuf><NUL>
   // Here <mtt> is the "mtt" value plus 1 to avoid NUL.
   len = tag_fname_len + strlen(st->lbuf) + 3;
   mfp = xmalloc(sizeof(char) + len + 1);
   char *p = mfp;
   p[0] = (char)(mtt + 1);
   STRCPY(p + 1, st->tag_fname);
#ifdef BACKSLASH_IN_FILENAME
   // Ignore differences in slashes, avoid adding
   // both path/file and path\file.
   slash_adjust(p + 1);
#endif
   p[tag_fname_len + 1] = TAG_SEP;
   char *s = p + 1 + tag_fname_len + 1;
   STRCPY(s, st->lbuf);
 }

 if (mfp != NULL) {
   hashitem_T *hi;

   // Don't add identical matches.
   // "mfp" is used as a hash key, there is a NUL byte to end
   // the part that matters for comparing, more bytes may
   // follow after it.  E.g. help tags store the priority
   // after the NUL.
   *hash = hash_hash(mfp);
   hi = hash_lookup(&st->ht_match[mtt], mfp, strlen(mfp), *hash);
   if (HASHITEM_EMPTY(hi)) {
     hash_add_item(&st->ht_match[mtt], hi, mfp, *hash);
     GA_APPEND(char *, &st->ga_match[mtt], mfp);
     st->match_count++;
   } else {
     // duplicate tag, drop it
     xfree(mfp);
   }
 }
}

/// Read and get all the tags from file st->tag_fname.
/// Sets "st->stop_searching" to true to stop searching for additional tags.
static void findtags_get_all_tags(findtags_state_T *st, findtags_match_args_T *margs,
                                 char *buf_ffname)
{
 tagptrs_T tagp;
 tagsearch_info_T search_info;
 hash_T hash = 0;

 // This is only to avoid a compiler warning for using search_info
 // uninitialised.
 CLEAR_FIELD(search_info);

 // Read and parse the lines in the file one by one
 while (true) {
   // check for CTRL-C typed, more often when jumping around
   if (st->state == TS_BINARY || st->state == TS_SKIP_BACK) {
     line_breakcheck();
   } else {
     fast_breakcheck();
   }
   if ((st->flags & TAG_INS_COMP)) {   // Double brackets for gcc
     ins_compl_check_keys(30, false);
   }
   if (got_int || ins_compl_interrupted()) {
     st->stop_searching = true;
     break;
   }
   // When mincount is TAG_MANY, stop when enough matches have been
   // found (for completion).
   if (st->mincount == TAG_MANY && st->match_count >= TAG_MANY) {
     st->stop_searching = true;
     break;
   }
   if (st->get_searchpat) {
     goto line_read_in;
   }

   int retval = (int)findtags_get_next_line(st, &search_info);
   if (retval == TAGS_READ_IGNORE) {
     continue;
   }
   if (retval == TAGS_READ_EOF) {
     break;
   }

line_read_in:

   if (st->vimconv.vc_type != CONV_NONE) {
     findtags_string_convert(st);
   }

   // When still at the start of the file, check for Emacs tags file
   // format, and for "not sorted" flag.
   if (st->state == TS_START) {
     if (!findtags_start_state_handler(st, &margs->sortic, &search_info)) {
       continue;
     }
   }

   // When the line is too long the NUL will not be in the
   // last-but-one byte (see vim_fgets()).
   // Has been reported for Mozilla JS with extremely long names.
   // In that case we need to increase lbuf_size.
   if (st->lbuf[st->lbuf_size - 2] != NUL) {
     st->lbuf_size *= 2;
     xfree(st->lbuf);
     st->lbuf = xmalloc((size_t)st->lbuf_size);

     if (st->state == TS_STEP_FORWARD || st->state == TS_LINEAR) {
       // Seek to the same position to read the same line again
       vim_ignored = vim_fseek(st->fp, search_info.curr_offset, SEEK_SET);
     }
     // this will try the same thing again, make sure the offset is
     // different
     search_info.curr_offset = 0;
     continue;
   }

   retval = (int)findtags_parse_line(st, &tagp, margs, &search_info);
   if (retval == TAG_MATCH_NEXT) {
     continue;
   }
   if (retval == TAG_MATCH_STOP) {
     break;
   }
   if (retval == TAG_MATCH_FAIL) {
     semsg(_("E431: Format error in tags file \"%s\""), st->tag_fname);
     semsg(_("Before byte %" PRId64), (int64_t)vim_ftell(st->fp));
     st->stop_searching = true;
     return;
   }

   // If a match is found, add it to ht_match[] and ga_match[].
   if (findtags_match_tag(st, &tagp, margs)) {
     findtags_add_match(st, &tagp, margs, buf_ffname, &hash);
   }
 }  // forever
}

/// Search for tags matching "st->orgpat.pat" in the "st->tag_fname" tags file.
/// Information needed to search for the tags is in the "st" state structure.
/// The matching tags are returned in "st". If an error is encountered, then
/// "st->stop_searching" is set to true.
static void findtags_in_file(findtags_state_T *st, int flags, char *buf_ffname)
{
 findtags_match_args_T margs;

 st->vimconv.vc_type = CONV_NONE;
 st->tag_file_sorted = NUL;
 st->fp = NULL;
 findtags_matchargs_init(&margs, st->flags);

 // A file that doesn't exist is silently ignored.  Only when not a
 // single file is found, an error message is given (further on).
 if (curbuf->b_help) {
   if (!findtags_in_help_init(st)) {
     return;
   }
 }

 st->fp = os_fopen(st->tag_fname, "r");
 if (st->fp == NULL) {
   return;
 }

 if (p_verbose >= 5) {
   verbose_enter();
   smsg(0, _("Searching tags file %s"), st->tag_fname);
   verbose_leave();
 }
 st->did_open = true;   // remember that we found at least one file

 st->state = TS_START;  // we're at the start of the file

 // Read and parse the lines in the file one by one
 findtags_get_all_tags(st, &margs, buf_ffname);

 if (st->fp != NULL) {
   fclose(st->fp);
   st->fp = NULL;
 }
 if (st->vimconv.vc_type != CONV_NONE) {
   convert_setup(&st->vimconv, NULL, NULL);
 }

 if (margs.sort_error) {
   semsg(_("E432: Tags file not sorted: %s"), st->tag_fname);
 }

 // Stop searching if sufficient tags have been found.
 if (st->match_count >= st->mincount) {
   st->stop_searching = true;
 }
}

/// Copy the tags found by find_tags() to "matchesp".
/// Returns the number of matches copied.
static int findtags_copy_matches(findtags_state_T *st, char ***matchesp)
{
 const bool name_only = (st->flags & TAG_NAMES);

 char **matches = st->match_count > 0
                  ? xmalloc((size_t)st->match_count * sizeof(char *))
                  : NULL;

 st->match_count = 0;
 for (int mtt = 0; mtt < MT_COUNT; mtt++) {
   for (int i = 0; i < st->ga_match[mtt].ga_len; i++) {
     char *mfp = ((char **)(st->ga_match[mtt].ga_data))[i];
     if (matches == NULL) {
       xfree(mfp);
     } else {
       if (!name_only) {
         // Change mtt back to zero-based.
         *mfp = (char)(*mfp - 1);

         // change the TAG_SEP back to NUL
         for (char *p = mfp + 1; *p != NUL; p++) {
           if (*p == TAG_SEP) {
             *p = NUL;
           }
         }
       }
       matches[st->match_count++] = mfp;
     }
   }

   ga_clear(&st->ga_match[mtt]);
   hash_clear(&st->ht_match[mtt]);
 }

 *matchesp = matches;
 return st->match_count;
}

/// find_tags() - search for tags in tags files
///
/// Return FAIL if search completely failed (*num_matches will be 0, *matchesp
/// will be NULL), OK otherwise.
///
/// There is a priority in which type of tag is recognized.
///
///  6.  A static or global tag with a full matching tag for the current file.
///  5.  A global tag with a full matching tag for another file.
///  4.  A static tag with a full matching tag for another file.
///  3.  A static or global tag with an ignore-case matching tag for the
///      current file.
///  2.  A global tag with an ignore-case matching tag for another file.
///  1.  A static tag with an ignore-case matching tag for another file.
///
/// Tags in an emacs-style tags file are always global.
///
/// flags:
/// TAG_HELP       only search for help tags
/// TAG_NAMES      only return name of tag
/// TAG_REGEXP     use "pat" as a regexp
/// TAG_NOIC       don't always ignore case
/// TAG_KEEP_LANG  keep language
/// TAG_NO_TAGFUNC do not call the 'tagfunc' function
///
/// @param pat  pattern to search for
/// @param num_matches  return: number of matches found
/// @param matchesp  return: array of matches found
/// @param mincount  MAXCOL: find all matches
///                  other: minimal number of matches
/// @param buf_ffname  name of buffer for priority
int find_tags(char *pat, int *num_matches, char ***matchesp, int flags, int mincount,
             char *buf_ffname)
{
 findtags_state_T st;
 tagname_T tn;                         // info for get_tagfname()
 int first_file;                       // trying first tag file
 int retval = FAIL;                    // return value

 int i;
 char *saved_pat = NULL;                // copy of pat[]

 int findall = (mincount == MAXCOL || mincount == TAG_MANY);  // find all matching tags
 bool has_re = (flags & TAG_REGEXP);            // regexp used
 int noic = (flags & TAG_NOIC);
 int verbose = (flags & TAG_VERBOSE);
 int save_p_ic = p_ic;

 // uncrustify:off

 // Change the value of 'ignorecase' according to 'tagcase' for the
 // duration of this function.
 switch (curbuf->b_tc_flags ? curbuf->b_tc_flags : tc_flags) {
 case kOptTcFlagFollowic: break;
 case kOptTcFlagIgnore:
   p_ic = true;
   break;
 case kOptTcFlagMatch:
   p_ic = false;
   break;
 case kOptTcFlagFollowscs:
   p_ic = ignorecase(pat);
   break;
 case kOptTcFlagSmart:
   p_ic = ignorecase_opt(pat, true, true);
   break;
 default:
   abort();
 }

 // uncrustify:on

 int help_save = curbuf->b_help;

 findtags_state_init(&st, pat, flags, mincount);

 // Initialize a few variables
 if (st.help_only) {                           // want tags from help file
   curbuf->b_help = true;                      // will be restored later
 }

 if (curbuf->b_help) {
   // When "@ab" is specified use only the "ab" language, otherwise
   // search all languages.
   if (st.orgpat->len > 3 && pat[st.orgpat->len - 3] == '@'
       && ASCII_ISALPHA(pat[st.orgpat->len - 2])
       && ASCII_ISALPHA(pat[st.orgpat->len - 1])) {
     saved_pat = xstrnsave(pat, (size_t)st.orgpat->len - 3);
     st.help_lang_find = &pat[st.orgpat->len - 2];
     st.orgpat->pat = saved_pat;
     st.orgpat->len -= 3;
   }
 }
 if (p_tl != 0 && st.orgpat->len > p_tl) {  // adjust for 'taglength'
   st.orgpat->len = (int)p_tl;
 }

 int save_emsg_off = emsg_off;
 emsg_off = true;    // don't want error for invalid RE here
 prepare_pats(st.orgpat, has_re);
 emsg_off = save_emsg_off;
 if (has_re && st.orgpat->regmatch.regprog == NULL) {
   goto findtag_end;
 }

 retval = findtags_apply_tfu(&st, pat, buf_ffname);
 if (retval != NOTDONE) {
   goto findtag_end;
 }

 // re-initialize the default return value
 retval = FAIL;

 // Set a flag if the file extension is .txt
 if ((flags & TAG_KEEP_LANG)
     && st.help_lang_find == NULL
     && curbuf->b_fname != NULL
     && (i = (int)strlen(curbuf->b_fname)) > 4
     && STRICMP(curbuf->b_fname + i - 4, ".txt") == 0) {
   st.is_txt = true;
 }

 // When finding a specified number of matches, first try with matching
 // case, so binary search can be used, and try ignore-case matches in a
 // second loop.
 // When finding all matches, 'tagbsearch' is off, or there is no fixed
 // string to look for, ignore case right away to avoid going though the
 // tags files twice.
 // When the tag file is case-fold sorted, it is either one or the other.
 // Only ignore case when TAG_NOIC not used or 'ignorecase' set.
 st.orgpat->regmatch.rm_ic = ((p_ic || !noic)
                              && (findall || st.orgpat->headlen == 0 || !p_tbs));
 for (int round = 1; round <= 2; round++) {
   st.linear = (st.orgpat->headlen == 0 || !p_tbs || round == 2);

   // Try tag file names from tags option one by one.
   for (first_file = true;
        get_tagfname(&tn, first_file, st.tag_fname) == OK;
        first_file = false) {
     findtags_in_file(&st, flags, buf_ffname);
     if (st.stop_searching) {
       retval = OK;
       break;
     }
   }   // end of for-each-file loop

   tagname_free(&tn);

   // stop searching when already did a linear search, or when TAG_NOIC
   // used, and 'ignorecase' not set or already did case-ignore search
   if (st.stop_searching || st.linear || (!p_ic && noic)
       || st.orgpat->regmatch.rm_ic) {
     break;
   }

   // try another time while ignoring case
   st.orgpat->regmatch.rm_ic = true;
 }

 if (!st.stop_searching) {
   if (!st.did_open && verbose) {  // never opened any tags file
     emsg(_("E433: No tags file"));
   }
   retval = OK;                // It's OK even when no tag found
 }

findtag_end:
 findtags_state_free(&st);

 // Move the matches from the ga_match[] arrays into one list of
 // matches.  When retval == FAIL, free the matches.
 if (retval == FAIL) {
   st.match_count = 0;
 }

 *num_matches = findtags_copy_matches(&st, matchesp);

 curbuf->b_help = help_save;
 xfree(saved_pat);

 p_ic = save_p_ic;

 return retval;
}

static garray_T tag_fnames = GA_EMPTY_INIT_VALUE;

// Callback function for finding all "tags" and "tags-??" files in
// 'runtimepath' doc directories.
static bool found_tagfile_cb(int num_fnames, char **fnames, bool all, void *cookie)
{
 for (int i = 0; i < num_fnames; i++) {
   char *const tag_fname = xstrdup(fnames[i]);

#ifdef BACKSLASH_IN_FILENAME
   slash_adjust(tag_fname);
#endif
   simplify_filename(tag_fname);
   GA_APPEND(char *, &tag_fnames, tag_fname);

   if (!all) {
     break;
   }
 }

 return num_fnames > 0;
}

#if defined(EXITFREE)
void free_tag_stuff(void)
{
 ga_clear_strings(&tag_fnames);
 if (curwin != NULL) {
   do_tag(NULL, DT_FREE, 0, 0, 0);
 }
 tag_freematch();

 tagstack_clear_entry(&ptag_entry);
}

#endif

/// Get the next name of a tag file from the tag file list.
/// For help files, use "tags" file only.
///
/// @param tnp  holds status info
/// @param first  true when first file name is wanted
/// @param buf  pointer to buffer of MAXPATHL chars
///
/// @return  FAIL if no more tag file names, OK otherwise.
int get_tagfname(tagname_T *tnp, int first, char *buf)
{
 char *fname = NULL;

 if (first) {
   CLEAR_POINTER(tnp);
 }

 if (curbuf->b_help) {
   // For help files it's done in a completely different way:
   // Find "doc/tags" and "doc/tags-??" in all directories in
   // 'runtimepath'.
   if (first) {
     ga_clear_strings(&tag_fnames);
     ga_init(&tag_fnames, (int)sizeof(char *), 10);
     do_in_runtimepath("doc/tags doc/tags-??", DIP_ALL,
                       found_tagfile_cb, NULL);
   }

   if (tnp->tn_hf_idx >= tag_fnames.ga_len) {
     // Not found in 'runtimepath', use 'helpfile', if it exists and
     // wasn't used yet, replacing "help.txt" with "tags".
     if (tnp->tn_hf_idx > tag_fnames.ga_len || *p_hf == NUL) {
       return FAIL;
     }
     tnp->tn_hf_idx++;
     xstrlcpy(buf, p_hf, MAXPATHL - STRLEN_LITERAL("tags"));
     STRCPY(path_tail(buf), "tags");
#ifdef BACKSLASH_IN_FILENAME
     slash_adjust(buf);
#endif
     simplify_filename(buf);

     for (int i = 0; i < tag_fnames.ga_len; i++) {
       if (strcmp(buf, ((char **)(tag_fnames.ga_data))[i]) == 0) {
         return FAIL;  // avoid duplicate file names
       }
     }
   } else {
     xstrlcpy(buf, ((char **)(tag_fnames.ga_data))[tnp->tn_hf_idx++], MAXPATHL);
   }
   return OK;
 }

 if (first) {
   // Init.  We make a copy of 'tags', because autocommands may change
   // the value without notifying us.
   tnp->tn_tags = xstrdup((*curbuf->b_p_tags != NUL) ? curbuf->b_p_tags : p_tags);
   tnp->tn_np = tnp->tn_tags;
 }

 // Loop until we have found a file name that can be used.
 // There are two states:
 // tnp->tn_did_filefind_init == false: setup for next part in 'tags'.
 // tnp->tn_did_filefind_init == true: find next file in this part.
 while (true) {
   if (tnp->tn_did_filefind_init) {
     fname = vim_findfile(tnp->tn_search_ctx);
     if (fname != NULL) {
       break;
     }

     tnp->tn_did_filefind_init = false;
   } else {
     char *filename = NULL;

     // Stop when used all parts of 'tags'.
     if (*tnp->tn_np == NUL) {
       vim_findfile_cleanup(tnp->tn_search_ctx);
       tnp->tn_search_ctx = NULL;
       return FAIL;
     }

     // Copy next file name into buf.
     buf[0] = NUL;
     copy_option_part(&tnp->tn_np, buf, MAXPATHL - 1, " ,");

     char *r_ptr = vim_findfile_stopdir(buf);
     // move the filename one char forward and truncate the
     // filepath with a NUL
     filename = path_tail(buf);
     if (r_ptr != NULL) {
       STRMOVE(r_ptr + 1, r_ptr);
       r_ptr++;
     }
     STRMOVE(filename + 1, filename);
     *filename++ = NUL;

     tnp->tn_search_ctx = vim_findfile_init(buf, filename, strlen(filename),
                                            r_ptr, 100,
                                            false,                   // don't free visited list
                                            FINDFILE_FILE,           // we search for a file
                                            tnp->tn_search_ctx, true, curbuf->b_ffname);
     if (tnp->tn_search_ctx != NULL) {
       tnp->tn_did_filefind_init = true;
     }
   }
 }

 STRCPY(buf, fname);
 xfree(fname);
 return OK;
}

// Free the contents of a tagname_T that was filled by get_tagfname().
void tagname_free(tagname_T *tnp)
{
 xfree(tnp->tn_tags);
 vim_findfile_cleanup(tnp->tn_search_ctx);
 tnp->tn_search_ctx = NULL;
 ga_clear_strings(&tag_fnames);
}

/// Parse one line from the tags file. Find start/end of tag name, start/end of
/// file name and start of search pattern.
///
/// If is_etag is true, tagp->fname and tagp->fname_end are not set.
///
/// @param lbuf  line to be parsed
///
/// @return  FAIL if there is a format error in this line, OK otherwise.
static int parse_tag_line(char *lbuf, tagptrs_T *tagp)
{
 // Isolate the tagname, from lbuf up to the first white
 tagp->tagname = lbuf;
 char *p = vim_strchr(lbuf, TAB);
 if (p == NULL) {
   return FAIL;
 }
 tagp->tagname_end = p;

 // Isolate file name, from first to second white space
 if (*p != NUL) {
   p++;
 }
 tagp->fname = p;
 p = vim_strchr(p, TAB);
 if (p == NULL) {
   return FAIL;
 }
 tagp->fname_end = p;

 // find start of search command, after second white space
 if (*p != NUL) {
   p++;
 }
 if (*p == NUL) {
   return FAIL;
 }
 tagp->command = p;

 return OK;
}

// Check if tagname is a static tag
//
// Static tags produced by the older ctags program have the format:
//      'file:tag  file  /pattern'.
// This is only recognized when both occurrence of 'file' are the same, to
// avoid recognizing "string::string" or ":exit".
//
// Static tags produced by the new ctags program have the format:
//      'tag  file  /pattern/;"<Tab>file:'          "
//
// Return true if it is a static tag and adjust *tagname to the real tag.
// Return false if it is not a static tag.
static bool test_for_static(tagptrs_T *tagp)
{
 // Check for new style static tag ":...<Tab>file:[<Tab>...]"
 char *p = tagp->command;
 while ((p = vim_strchr(p, '\t')) != NULL) {
   p++;
   if (strncmp(p, "file:", 5) == 0) {
     return true;
   }
 }

 return false;
}

/// @return  the length of a matching tag line.
static size_t matching_line_len(const char *const lbuf)
{
 const char *p = lbuf + 1;

 // does the same thing as parse_match()
 p += strlen(p) + 1;
 return (size_t)(p - lbuf) + strlen(p);
}

/// Parse a line from a matching tag.  Does not change the line itself.
///
/// The line that we get looks like this:
/// Emacs tag: <mtt><tag_fname><NUL><ebuf><NUL><lbuf>
/// other tag: <mtt><tag_fname><NUL><NUL><lbuf>
/// without Emacs tags: <mtt><tag_fname><NUL><lbuf>
///
/// @param lbuf  input: matching line
/// @param tagp  output: pointers into the line
///
/// @return  OK or FAIL.
static int parse_match(char *lbuf, tagptrs_T *tagp)
{
 tagp->tag_fname = lbuf + 1;
 lbuf += strlen(tagp->tag_fname) + 2;

 // Find search pattern and the file name for non-etags.
 int retval = parse_tag_line(lbuf, tagp);

 tagp->tagkind = NULL;
 tagp->user_data = NULL;
 tagp->tagline = 0;
 tagp->command_end = NULL;

 if (retval != OK) {
   return retval;
 }

 // Try to find a kind field: "kind:<kind>" or just "<kind>"
 char *p = tagp->command;
 if (find_extra(&p) == OK) {
   tagp->command_end = p;
   if (p > tagp->command && p[-1] == '|') {
     tagp->command_end = p - 1;  // drop trailing bar
   }
   p += 2;  // skip ";\""
   if (*p++ == TAB) {
     // Accept ASCII alphabetic kind characters and any multi-byte
     // character.
     while (ASCII_ISALPHA(*p) || utfc_ptr2len(p) > 1) {
       if (strncmp(p, "kind:", 5) == 0) {
         tagp->tagkind = p + 5;
       } else if (strncmp(p, "user_data:", 10) == 0) {
         tagp->user_data = p + 10;
       } else if (strncmp(p, "line:", 5) == 0) {
         tagp->tagline = atoi(p + 5);
       }
       if (tagp->tagkind != NULL && tagp->user_data != NULL) {
         break;
       }

       char *pc = vim_strchr(p, ':');
       char *pt = vim_strchr(p, '\t');
       if (pc == NULL || (pt != NULL && pc > pt)) {
         tagp->tagkind = p;
       }
       if (pt == NULL) {
         break;
       }
       p = pt;
       MB_PTR_ADV(p);
     }
   }
 }
 if (tagp->tagkind != NULL) {
   for (p = tagp->tagkind;
        *p && *p != '\t' && *p != '\r' && *p != '\n';
        MB_PTR_ADV(p)) {}
   tagp->tagkind_end = p;
 }
 if (tagp->user_data != NULL) {
   for (p = tagp->user_data;
        *p && *p != '\t' && *p != '\r' && *p != '\n';
        MB_PTR_ADV(p)) {}
   tagp->user_data_end = p;
 }
 return retval;
}

// Find out the actual file name of a tag.  Concatenate the tags file name
// with the matching tag file name.
// Returns an allocated string.
static char *tag_full_fname(tagptrs_T *tagp)
{
 char c = *tagp->fname_end;
 *tagp->fname_end = NUL;
 char *fullname = expand_tag_fname(tagp->fname, tagp->tag_fname, false);
 *tagp->fname_end = c;

 return fullname;
}

/// Jump to a tag that has been found in one of the tag files
///
/// @param lbuf_arg  line from the tags file for this tag
/// @param forceit  :ta with !
/// @param keep_help  keep help flag
///
/// @return  OK for success, NOTAGFILE when file not found, FAIL otherwise.
static int jumpto_tag(const char *lbuf_arg, int forceit, bool keep_help)
{
 if (postponed_split == 0 && !check_can_set_curbuf_forceit(forceit)) {
   return FAIL;
 }

 char *pbuf_end;
 char *tofree_fname = NULL;
 tagptrs_T tagp;
 int retval = FAIL;
 int getfile_result = GETFILE_UNUSED;
 int search_options;
 win_T *curwin_save = NULL;
 char *full_fname = NULL;
 const bool old_KeyTyped = KeyTyped;       // getting the file may reset it
 const int l_g_do_tagpreview = g_do_tagpreview;
 const size_t len = matching_line_len(lbuf_arg) + 1;
 char *lbuf = xmalloc(len);
 memmove(lbuf, lbuf_arg, len);

 char *pbuf = xmalloc(LSIZE);  // search pattern buffer

 // parse the match line into the tagp structure
 if (parse_match(lbuf, &tagp) == FAIL) {
   tagp.fname_end = NULL;
   goto erret;
 }

 // truncate the file name, so it can be used as a string
 *tagp.fname_end = NUL;
 char *fname = tagp.fname;

 // copy the command to pbuf[], remove trailing CR/NL
 char *str = tagp.command;
 for (pbuf_end = pbuf; *str && *str != '\n' && *str != '\r';) {
   *pbuf_end++ = *str++;
   if (pbuf_end - pbuf + 1 >= LSIZE) {
     break;
   }
 }
 *pbuf_end = NUL;

 {
   // Remove the "<Tab>fieldname:value" stuff; we don't need it here.
   str = pbuf;
   if (find_extra(&str) == OK) {
     pbuf_end = str;
     *pbuf_end = NUL;
   }
 }

 // Expand file name, when needed (for environment variables).
 // If 'tagrelative' option set, may change file name.
 fname = expand_tag_fname(fname, tagp.tag_fname, true);
 tofree_fname = fname;         // free() it later

 // Check if the file with the tag exists before abandoning the current
 // file.  Also accept a file name for which there is a matching BufReadCmd
 // autocommand event (e.g., http://sys/file).
 if (!os_path_exists(fname)
     && !has_autocmd(EVENT_BUFREADCMD, fname, NULL)) {
   retval = NOTAGFILE;
   xfree(nofile_fname);
   nofile_fname = xstrdup(fname);
   goto erret;
 }

 RedrawingDisabled++;

 if (l_g_do_tagpreview != 0) {
   postponed_split = 0;        // don't split again below
   curwin_save = curwin;       // Save current window

   // If we are reusing a window, we may change dir when
   // entering it (autocommands) so turn the tag filename
   // into a fullpath
   if (!curwin->w_p_pvw) {
     full_fname = FullName_save(fname, false);
     fname = full_fname;

     // Make the preview window the current window.
     // Open a preview window when needed.
     prepare_tagpreview(true);
   }
 }

 // If it was a CTRL-W CTRL-] command split window now.  For ":tab tag"
 // open a new tab page.
 if (postponed_split && (swb_flags & (kOptSwbFlagUseopen | kOptSwbFlagUsetab))) {
   buf_T *const existing_buf = buflist_findname_exp(fname);

   if (existing_buf != NULL) {
     // If 'switchbuf' is set jump to the window containing "buf".
     if (swbuf_goto_win_with_buf(existing_buf) != NULL) {
       // We've switched to the buffer, the usual loading of the file
       // must be skipped.
       getfile_result = GETFILE_SAME_FILE;
     }
   }
 }
 if (getfile_result == GETFILE_UNUSED
     && (postponed_split || cmdmod.cmod_tab != 0)) {
   if (swb_flags & kOptSwbFlagVsplit) {
     // If 'switchbuf' contains 'vsplit', then use a new vertically
     // split window.
     cmdmod.cmod_split |= WSP_VERT;
   }

   if ((swb_flags & kOptSwbFlagNewtab) && cmdmod.cmod_tab == 0) {
     // If 'switchbuf' contains 'newtab', then use a new tabpage
     cmdmod.cmod_tab = tabpage_index(curtab) + 1;
   }

   if (win_split(postponed_split > 0 ? postponed_split : 0,
                 postponed_split_flags) == FAIL) {
     RedrawingDisabled--;
     goto erret;
   }
   RESET_BINDING(curwin);
 }

 if (keep_help) {
   // A :ta from a help file will keep the b_help flag set.  For ":ptag"
   // we need to use the flag from the window where we came from.
   if (l_g_do_tagpreview != 0) {
     keep_help_flag = bt_help(curwin_save->w_buffer);
   } else {
     keep_help_flag = curbuf->b_help;
   }
 }

 if (getfile_result == GETFILE_UNUSED) {
   // Careful: getfile() may trigger autocommands and call jumpto_tag()
   // recursively.
   getfile_result = getfile(0, fname, NULL, true, 0, forceit);
 }
 keep_help_flag = false;

 if (GETFILE_SUCCESS(getfile_result)) {    // got to the right file
   curwin->w_set_curswant = true;
   postponed_split = 0;

   const optmagic_T save_magic_overruled = magic_overruled;
   magic_overruled = OPTION_MAGIC_OFF;  // always execute with 'nomagic'
   // Save value of no_hlsearch, jumping to a tag is not a real search
   const bool save_no_hlsearch = no_hlsearch;

   // If 'cpoptions' contains 't', store the search pattern for the "n"
   // command.  If 'cpoptions' does not contain 't', the search pattern
   // is not stored.
   if (vim_strchr(p_cpo, CPO_TAGPAT) != NULL) {
     search_options = 0;
   } else {
     search_options = SEARCH_KEEP;
   }

   // If the command is a search, try here.
   //
   // Reset 'smartcase' for the search, since the search pattern was not
   // typed by the user.
   // Only use do_search() when there is a full search command, without
   // anything following.
   str = pbuf;
   if (pbuf[0] == '/' || pbuf[0] == '?') {
     str = skip_regexp(pbuf + 1, pbuf[0], false) + 1;
   }
   if (str > pbuf_end - 1) {   // search command with nothing following
     size_t pbuflen = (size_t)(pbuf_end - pbuf);

     bool save_p_ws = p_ws;
     int save_p_ic = p_ic;
     int save_p_scs = p_scs;
     p_ws = true;              // need 'wrapscan' for backward searches
     p_ic = false;             // don't ignore case now
     p_scs = false;
     linenr_T save_lnum = curwin->w_cursor.lnum;

     curwin->w_cursor.lnum = tagp.tagline > 0
                             // start search before line from "line:" field
                             ? tagp.tagline - 1
                             // start search before first line
                             : 0;

     if (do_search(NULL, pbuf[0], pbuf[0], pbuf + 1, pbuflen - 1, 1,
                   search_options, NULL)) {
       retval = OK;
     } else {
       int found = 1;

       // try again, ignore case now
       p_ic = true;
       if (!do_search(NULL, pbuf[0], pbuf[0], pbuf + 1, pbuflen - 1, 1,
                      search_options, NULL)) {
         // Failed to find pattern, take a guess: "^func  ("
         found = 2;
         test_for_static(&tagp);
         char cc = *tagp.tagname_end;
         *tagp.tagname_end = NUL;
         pbuflen = (size_t)snprintf(pbuf, LSIZE, "^%s\\s\\*(", tagp.tagname);
         if (!do_search(NULL, '/', '/', pbuf, pbuflen, 1, search_options, NULL)) {
           // Guess again: "^char * \<func  ("
           pbuflen = (size_t)snprintf(pbuf, LSIZE, "^\\[#a-zA-Z_]\\.\\*\\<%s\\s\\*(",
                                      tagp.tagname);
           if (!do_search(NULL, '/', '/', pbuf, pbuflen, 1, search_options, NULL)) {
             found = 0;
           }
         }
         *tagp.tagname_end = cc;
       }
       if (found == 0) {
         emsg(_("E434: Can't find tag pattern"));
         curwin->w_cursor.lnum = save_lnum;
       } else {
         // Only give a message when really guessed, not when 'ic'
         // is set and match found while ignoring case.
         if (found == 2 || !save_p_ic) {
           msg(_("E435: Couldn't find tag, just guessing!"), 0);
           if (!msg_scrolled && msg_silent == 0) {
             msg_delay(1010, true);
           }
         }
         retval = OK;
       }
     }
     p_ws = save_p_ws;
     p_ic = save_p_ic;
     p_scs = save_p_scs;

     // A search command may have positioned the cursor beyond the end
     // of the line.  May need to correct that here.
     check_cursor(curwin);
   } else {
     const int save_secure = secure;

     // Setup the sandbox for executing the command from the tags file.
     secure = 1;
     sandbox++;
     curwin->w_cursor.lnum = 1;  // start command in line 1
     curwin->w_cursor.col = 0;
     curwin->w_cursor.coladd = 0;
     do_cmdline_cmd(pbuf);
     retval = OK;

     // When the command has done something that is not allowed make sure
     // the error message can be seen.
     if (secure == 2) {
       wait_return(true);
     }
     secure = save_secure;
     sandbox--;
   }

   magic_overruled = save_magic_overruled;
   // restore no_hlsearch when keeping the old search pattern
   if (search_options) {
     set_no_hlsearch(save_no_hlsearch);
   }

   // Return OK if jumped to another file (at least we found the file!).
   if (getfile_result == GETFILE_OPEN_OTHER) {
     retval = OK;
   }

   if (retval == OK) {
     // For a help buffer: Put the cursor line at the top of the window,
     // the help subject will be below it.
     if (curbuf->b_help) {
       set_topline(curwin, curwin->w_cursor.lnum);
     }
     if ((fdo_flags & kOptFdoFlagTag) && old_KeyTyped) {
       foldOpenCursor();
     }
   }

   if (l_g_do_tagpreview != 0
       && curwin != curwin_save && win_valid(curwin_save)) {
     // Return cursor to where we were
     validate_cursor(curwin);
     redraw_later(curwin, UPD_VALID);
     win_enter(curwin_save, true);
   }

   RedrawingDisabled--;
 } else {
   RedrawingDisabled--;
   if (postponed_split) {              // close the window
     win_close(curwin, false, false);
     postponed_split = 0;
   }
 }

erret:
 g_do_tagpreview = 0;  // For next time
 xfree(lbuf);
 xfree(pbuf);
 xfree(tofree_fname);
 xfree(full_fname);

 return retval;
}

/// If "expand" is true, expand wildcards in fname.
/// If 'tagrelative' option set, change fname (name of file containing tag)
/// according to tag_fname (name of tag file containing fname).
///
/// @return  a pointer to allocated memory.
static char *expand_tag_fname(char *fname, char *const tag_fname, const bool expand)
{
 char *p;
 char *expanded_fname = NULL;
 expand_T xpc;

 // Expand file name (for environment variables) when needed.
 if (expand && path_has_wildcard(fname)) {
   ExpandInit(&xpc);
   xpc.xp_context = EXPAND_FILES;
   expanded_fname = ExpandOne(&xpc, fname, NULL,
                              WILD_LIST_NOTFOUND|WILD_SILENT, WILD_EXPAND_FREE);
   if (expanded_fname != NULL) {
     fname = expanded_fname;
   }
 }

 char *retval;
 if ((p_tr || curbuf->b_help)
     && !vim_isAbsName(fname)
     && (p = path_tail(tag_fname)) != tag_fname) {
   retval = xmalloc(MAXPATHL);
   STRCPY(retval, tag_fname);
   xstrlcpy(retval + (p - tag_fname), fname, (size_t)(MAXPATHL - (p - tag_fname)));
   // Translate names like "src/a/../b/file.c" into "src/b/file.c".
   simplify_filename(retval);
 } else {
   retval = xstrdup(fname);
 }

 xfree(expanded_fname);

 return retval;
}

/// Check if we have a tag for the buffer with name "buf_ffname".
/// This is a bit slow, because of the full path compare in path_full_compare().
///
/// @return  true if tag for file "fname" if tag file "tag_fname" is for current
///          file.
static int test_for_current(char *fname, char *fname_end, char *tag_fname, char *buf_ffname)
{
 int retval = false;

 if (buf_ffname != NULL) {     // if the buffer has a name
   char c;
   {
     c = *fname_end;
     *fname_end = NUL;
   }
   char *fullname = expand_tag_fname(fname, tag_fname, true);
   retval = (path_full_compare(fullname, buf_ffname, true, true) & kEqualFiles);
   xfree(fullname);
   *fname_end = c;
 }

 return retval;
}

// Find the end of the tagaddress.
// Return OK if ";\"" is following, FAIL otherwise.
static int find_extra(char **pp)
{
 char *str = *pp;
 char first_char = **pp;

 // Repeat for addresses separated with ';'
 while (true) {
   if (ascii_isdigit(*str)) {
     str = skipdigits(str + 1);
   } else if (*str == '/' || *str == '?') {
     str = skip_regexp(str + 1, *str, false);
     if (*str != first_char) {
       str = NULL;
     } else {
       str++;
     }
   } else {
     // not a line number or search string, look for terminator.
     str = strstr(str, "|;\"");
     if (str != NULL) {
       str++;
       break;
     }
   }
   if (str == NULL || *str != ';'
       || !(ascii_isdigit(str[1]) || str[1] == '/' || str[1] == '?')) {
     break;
   }
   str++;  // skip ';'
   first_char = *str;
 }

 if (str != NULL && strncmp(str, ";\"", 2) == 0) {
   *pp = str;
   return OK;
 }
 return FAIL;
}

/// Free a single entry in a tag stack
void tagstack_clear_entry(taggy_T *item)
{
 XFREE_CLEAR(item->tagname);
 XFREE_CLEAR(item->user_data);
}

/// @param tagnames  expand tag names
int expand_tags(bool tagnames, char *pat, int *num_file, char ***file)
{
 size_t name_buf_size = 100;
 int ret;

 char *name_buf = xmalloc(name_buf_size);

 int extra_flag = tagnames ? TAG_NAMES : 0;
 if (pat[0] == '/') {
   ret = find_tags(pat + 1, num_file, file,
                   TAG_REGEXP | extra_flag | TAG_VERBOSE | TAG_NO_TAGFUNC,
                   TAG_MANY, curbuf->b_ffname);
 } else {
   ret = find_tags(pat, num_file, file,
                   TAG_REGEXP | extra_flag | TAG_VERBOSE | TAG_NO_TAGFUNC | TAG_NOIC,
                   TAG_MANY, curbuf->b_ffname);
 }
 if (ret == OK && !tagnames) {
   // Reorganize the tags for display and matching as strings of:
   // "<tagname>\0<kind>\0<filename>\0"
   for (int i = 0; i < *num_file; i++) {
     tagptrs_T t_p;
     parse_match((*file)[i], &t_p);
     size_t len = (size_t)(t_p.tagname_end - t_p.tagname);
     if (len > name_buf_size - 3) {
       name_buf_size = len + 3;
       char *buf = xrealloc(name_buf, name_buf_size);
       name_buf = buf;
     }

     memmove(name_buf, t_p.tagname, len);
     name_buf[len++] = 0;
     name_buf[len++] = (t_p.tagkind != NULL && *t_p.tagkind)
                       ? *t_p.tagkind : 'f';
     name_buf[len++] = 0;
     memmove((*file)[i] + len, t_p.fname, (size_t)(t_p.fname_end - t_p.fname));
     (*file)[i][len + (size_t)(t_p.fname_end - t_p.fname)] = 0;
     memmove((*file)[i], name_buf, len);
   }
 }
 xfree(name_buf);
 return ret;
}

/// Add a tag field to the dictionary "dict".
/// Return OK or FAIL.
///
/// @param start  start of the value
/// @param end  after the value; can be NULL
static int add_tag_field(dict_T *dict, const char *field_name, const char *start, const char *end)
 FUNC_ATTR_NONNULL_ARG(1, 2)
{
 // Check that the field name doesn't exist yet.
 if (tv_dict_find(dict, field_name, -1) != NULL) {
   if (p_verbose > 0) {
     verbose_enter();
     smsg(0, _("Duplicate field name: %s"), field_name);
     verbose_leave();
   }
   return FAIL;
 }
 int len = 0;
 char *buf = xmalloc(MAXPATHL);
 if (start != NULL) {
   if (end == NULL) {
     end = start + strlen(start);
     while (end > start && (end[-1] == '\r' || end[-1] == '\n')) {
       end--;
     }
   }
   len = MIN((int)(end - start), MAXPATHL - 1);
   xmemcpyz(buf, start, (size_t)len);
 }
 buf[len] = NUL;
 int retval = tv_dict_add_str(dict, field_name, strlen(field_name), buf);
 xfree(buf);
 return retval;
}

/// Add the tags matching the specified pattern "pat" to the list "list"
/// as a dictionary. Use "buf_fname" for priority, unless NULL.
int get_tags(list_T *list, char *pat, char *buf_fname)
{
 int num_matches;
 char **matches;
 tagptrs_T tp;

 int ret = find_tags(pat, &num_matches, &matches, TAG_REGEXP | TAG_NOIC, MAXCOL, buf_fname);
 if (ret != OK || num_matches <= 0) {
   return ret;
 }

 for (int i = 0; i < num_matches; i++) {
   if (parse_match(matches[i], &tp) == FAIL) {
     xfree(matches[i]);
     continue;
   }

   bool is_static = test_for_static(&tp);

   // Skip pseudo-tag lines.
   if (strncmp(tp.tagname, "!_TAG_", 6) == 0) {
     xfree(matches[i]);
     continue;
   }

   dict_T *dict = tv_dict_alloc();
   tv_list_append_dict(list, dict);

   char *full_fname = tag_full_fname(&tp);
   if (add_tag_field(dict, "name", tp.tagname, tp.tagname_end) == FAIL
       || add_tag_field(dict, "filename", full_fname, NULL) == FAIL
       || add_tag_field(dict, "cmd", tp.command, tp.command_end) == FAIL
       || add_tag_field(dict, "kind", tp.tagkind,
                        tp.tagkind ? tp.tagkind_end : NULL) == FAIL
       || tv_dict_add_nr(dict, S_LEN("static"), is_static) == FAIL) {
     ret = FAIL;
   }

   xfree(full_fname);

   if (tp.command_end != NULL) {
     for (char *p = tp.command_end + 3;
          *p != NUL && *p != '\n' && *p != '\r';
          MB_PTR_ADV(p)) {
       if (p == tp.tagkind
           || (p + 5 == tp.tagkind && strncmp(p, "kind:", 5) == 0)) {
         // skip "kind:<kind>" and "<kind>"
         p = tp.tagkind_end - 1;
       } else if (strncmp(p, "file:", 5) == 0) {
         // skip "file:" (static tag)
         p += 4;
       } else if (!ascii_iswhite(*p)) {
         int len;

         // Add extra field as a dict entry.  Fields are
         // separated by Tabs.
         char *n = p;
         while (*p != NUL && *p >= ' ' && *p < 127 && *p != ':') {
           p++;
         }
         len = (int)(p - n);
         if (*p == ':' && len > 0) {
           char *s = ++p;
           while (*p != NUL && (uint8_t)(*p) >= ' ') {
             p++;
           }
           n[len] = NUL;
           if (add_tag_field(dict, n, s, p) == FAIL) {
             ret = FAIL;
           }
           n[len] = ':';
         } else {
           // Skip field without colon.
           while (*p != NUL && (uint8_t)(*p) >= ' ') {
             p++;
           }
         }
         if (*p == NUL) {
           break;
         }
       }
     }
   }

   xfree(matches[i]);
 }
 xfree(matches);
 return ret;
}

// Return information about 'tag' in dict 'retdict'.
static void get_tag_details(taggy_T *tag, dict_T *retdict)
{
 tv_dict_add_str(retdict, S_LEN("tagname"), tag->tagname);
 tv_dict_add_nr(retdict, S_LEN("matchnr"), tag->cur_match + 1);
 tv_dict_add_nr(retdict, S_LEN("bufnr"), tag->cur_fnum);
 if (tag->user_data) {
   tv_dict_add_str(retdict, S_LEN("user_data"), tag->user_data);
 }

 list_T *pos = tv_list_alloc(4);
 tv_dict_add_list(retdict, S_LEN("from"), pos);

 fmark_T *fmark = &tag->fmark;
 tv_list_append_number(pos,
                       (varnumber_T)(fmark->fnum != -1 ? fmark->fnum : 0));
 tv_list_append_number(pos, (varnumber_T)fmark->mark.lnum);
 tv_list_append_number(pos, (varnumber_T)(fmark->mark.col == MAXCOL
                                          ? MAXCOL : fmark->mark.col + 1));
 tv_list_append_number(pos, (varnumber_T)fmark->mark.coladd);
}

// Return the tag stack entries of the specified window 'wp' in dictionary
// 'retdict'.
void get_tagstack(win_T *wp, dict_T *retdict)
{
 tv_dict_add_nr(retdict, S_LEN("length"), wp->w_tagstacklen);
 tv_dict_add_nr(retdict, S_LEN("curidx"), wp->w_tagstackidx + 1);
 list_T *l = tv_list_alloc(2);
 tv_dict_add_list(retdict, S_LEN("items"), l);

 for (int i = 0; i < wp->w_tagstacklen; i++) {
   dict_T *d = tv_dict_alloc();
   tv_list_append_dict(l, d);
   get_tag_details(&wp->w_tagstack[i], d);
 }
}

// Free all the entries in the tag stack of the specified window
static void tagstack_clear(win_T *wp)
{
 // Free the current tag stack
 for (int i = 0; i < wp->w_tagstacklen; i++) {
   tagstack_clear_entry(&wp->w_tagstack[i]);
 }
 wp->w_tagstacklen = 0;
 wp->w_tagstackidx = 0;
}

// Remove the oldest entry from the tag stack and shift the rest of
// the entries to free up the top of the stack.
static void tagstack_shift(win_T *wp)
{
 taggy_T *tagstack = wp->w_tagstack;
 tagstack_clear_entry(&tagstack[0]);
 for (int i = 1; i < wp->w_tagstacklen; i++) {
   tagstack[i - 1] = tagstack[i];
 }
 wp->w_tagstacklen--;
}

/// Push a new item to the tag stack
static void tagstack_push_item(win_T *wp, char *tagname, int cur_fnum, int cur_match, pos_T mark,
                              int fnum, char *user_data)
{
 taggy_T *tagstack = wp->w_tagstack;
 int idx = wp->w_tagstacklen;  // top of the stack

 // if the tagstack is full: remove the oldest entry
 if (idx >= TAGSTACKSIZE) {
   tagstack_shift(wp);
   idx = TAGSTACKSIZE - 1;
 }

 wp->w_tagstacklen++;
 tagstack[idx].tagname = tagname;
 tagstack[idx].cur_fnum = cur_fnum;
 tagstack[idx].cur_match = cur_match;
 tagstack[idx].cur_match = MAX(tagstack[idx].cur_match, 0);
 tagstack[idx].fmark.mark = mark;
 tagstack[idx].fmark.fnum = fnum;
 tagstack[idx].fmark.view = (fmarkv_T)INIT_FMARKV;
 tagstack[idx].user_data = user_data;
}

/// Add a list of items to the tag stack in the specified window
static void tagstack_push_items(win_T *wp, list_T *l)
{
 dictitem_T *di;
 char *tagname;
 pos_T mark;
 int fnum;

 // Add one entry at a time to the tag stack
 for (listitem_T *li = tv_list_first(l); li != NULL; li = TV_LIST_ITEM_NEXT(l, li)) {
   if (TV_LIST_ITEM_TV(li)->v_type != VAR_DICT
       || TV_LIST_ITEM_TV(li)->vval.v_dict == NULL) {
     continue;  // Skip non-dict items
   }
   dict_T *itemdict = TV_LIST_ITEM_TV(li)->vval.v_dict;

   // parse 'from' for the cursor position before the tag jump
   if ((di = tv_dict_find(itemdict, "from", -1)) == NULL) {
     continue;
   }
   if (list2fpos(&di->di_tv, &mark, &fnum, NULL, false) != OK) {
     continue;
   }
   if ((tagname = tv_dict_get_string(itemdict, "tagname", true)) == NULL) {
     continue;
   }

   if (mark.col > 0) {
     mark.col--;
   }
   tagstack_push_item(wp,
                      tagname,
                      (int)tv_dict_get_number(itemdict, "bufnr"),
                      (int)tv_dict_get_number(itemdict, "matchnr") - 1,
                      mark, fnum,
                      tv_dict_get_string(itemdict, "user_data", true));
 }
}

// Set the current index in the tag stack. Valid values are between 0
// and the stack length (inclusive).
static void tagstack_set_curidx(win_T *wp, int curidx)
{
 wp->w_tagstackidx = curidx;
 // sanity check
 wp->w_tagstackidx = MIN(MAX(wp->w_tagstackidx, 0), wp->w_tagstacklen);
}

// Set the tag stack entries of the specified window.
// 'action' is set to one of:
//    'a' for append
//    'r' for replace
//    't' for truncate
int set_tagstack(win_T *wp, const dict_T *d, int action)
 FUNC_ATTR_NONNULL_ARG(1)
{
 // not allowed to alter the tag stack entries from inside tagfunc
 if (tfu_in_use) {
   emsg(_(e_cannot_modify_tag_stack_within_tagfunc));
   return FAIL;
 }

 dictitem_T *di;
 list_T *l = NULL;

 if ((di = tv_dict_find(d, "items", -1)) != NULL) {
   if (di->di_tv.v_type != VAR_LIST) {
     emsg(_(e_listreq));
     return FAIL;
   }
   l = di->di_tv.vval.v_list;
 }

 if ((di = tv_dict_find(d, "curidx", -1)) != NULL) {
   tagstack_set_curidx(wp, (int)tv_get_number(&di->di_tv) - 1);
 }

 if (action == 't') {  // truncate the stack
   taggy_T *const tagstack = wp->w_tagstack;
   const int tagstackidx = wp->w_tagstackidx;
   int tagstacklen = wp->w_tagstacklen;

   // delete all the tag stack entries above the current entry
   while (tagstackidx < tagstacklen) {
     tagstack_clear_entry(&tagstack[--tagstacklen]);
   }
   wp->w_tagstacklen = tagstacklen;
 }

 if (l != NULL) {
   if (action == 'r') {  // replace the stack
     tagstack_clear(wp);
   }

   tagstack_push_items(wp, l);
   // set the current index after the last entry
   wp->w_tagstackidx = wp->w_tagstacklen;
 }

 return OK;
}