tor-browser

The Tor Browser
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Types.h (4423B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 /* mfbt foundational types and macros. */
      8 
      9 #ifndef mozilla_Types_h
     10 #define mozilla_Types_h
     11 
     12 /*
     13 * This header must be valid C and C++, includable by code embedding either
     14 * SpiderMonkey or Gecko.
     15 */
     16 
     17 /* Expose all <stdint.h> types and size_t. */
     18 #include <stddef.h>
     19 
     20 /* Implement compiler and linker macros needed for APIs. */
     21 
     22 /*
     23 * MOZ_EXPORT is used to declare and define a symbol or type which is externally
     24 * visible to users of the current library.  It encapsulates various decorations
     25 * needed to properly export the method's symbol.
     26 *
     27 *   api.h:
     28 *     extern MOZ_EXPORT int MeaningOfLife(void);
     29 *     extern MOZ_EXPORT int LuggageCombination;
     30 *
     31 *   api.c:
     32 *     int MeaningOfLife(void) { return 42; }
     33 *     int LuggageCombination = 12345;
     34 *
     35 * If you are merely sharing a method across files, just use plain |extern|.
     36 * These macros are designed for use by library interfaces -- not for normal
     37 * methods or data used cross-file.
     38 */
     39 #if defined(WIN32)
     40 #  define MOZ_EXPORT __declspec(dllexport)
     41 #else /* Unix */
     42 #  ifdef HAVE_VISIBILITY_ATTRIBUTE
     43 #    define MOZ_EXPORT __attribute__((visibility("default")))
     44 #  elif defined(__SUNPRO_C) || defined(__SUNPRO_CC)
     45 #    define MOZ_EXPORT __global
     46 #  else
     47 #    define MOZ_EXPORT /* nothing */
     48 #  endif
     49 #endif
     50 
     51 /*
     52 * Whereas implementers use MOZ_EXPORT to declare and define library symbols,
     53 * users use MOZ_IMPORT_API and MOZ_IMPORT_DATA to access them.  Most often the
     54 * implementer of the library will expose an API macro which expands to either
     55 * the export or import version of the macro, depending upon the compilation
     56 * mode.
     57 */
     58 #ifdef _WIN32
     59 #  if defined(__MWERKS__)
     60 #    define MOZ_IMPORT_API /* nothing */
     61 #  else
     62 #    define MOZ_IMPORT_API __declspec(dllimport)
     63 #  endif
     64 #else
     65 #  define MOZ_IMPORT_API MOZ_EXPORT
     66 #endif
     67 
     68 #if defined(_WIN32) && !defined(__MWERKS__)
     69 #  define MOZ_IMPORT_DATA __declspec(dllimport)
     70 #else
     71 #  define MOZ_IMPORT_DATA MOZ_EXPORT
     72 #endif
     73 
     74 /*
     75 * Consistent with the above comment, the MFBT_API and MFBT_DATA macros expose
     76 * export mfbt declarations when building mfbt, and they expose import mfbt
     77 * declarations when using mfbt.
     78 */
     79 #if defined(IMPL_MFBT) ||                              \
     80    (defined(JS_STANDALONE) && !defined(MOZ_MEMORY) && \
     81     (defined(EXPORT_JS_API) || defined(STATIC_EXPORTABLE_JS_API)))
     82 #  define MFBT_API MOZ_EXPORT
     83 #  define MFBT_DATA MOZ_EXPORT
     84 #else
     85 #  if defined(JS_STANDALONE) && !defined(MOZ_MEMORY) && defined(STATIC_JS_API)
     86 #    define MFBT_API
     87 #    define MFBT_DATA
     88 #  else
     89 /*
     90 * On linux mozglue is linked in the program and we link libxul.so with
     91 * -z,defs. Normally that causes the linker to reject undefined references in
     92 * libxul.so, but as a loophole it allows undefined references to weak
     93 * symbols. We add the weak attribute to the import version of the MFBT API
     94 * macros to exploit this.
     95 */
     96 #    if defined(MOZ_GLUE_IN_PROGRAM)
     97 #      define MFBT_API __attribute__((weak)) MOZ_IMPORT_API
     98 #      define MFBT_DATA __attribute__((weak)) MOZ_IMPORT_DATA
     99 #    else
    100 #      define MFBT_API MOZ_IMPORT_API
    101 #      define MFBT_DATA MOZ_IMPORT_DATA
    102 #    endif
    103 #  endif
    104 #endif
    105 
    106 /*
    107 * C symbols in C++ code must be declared immediately within |extern "C"|
    108 * blocks.  However, in C code, they need not be declared specially.  This
    109 * difference is abstracted behind the MOZ_BEGIN_EXTERN_C and MOZ_END_EXTERN_C
    110 * macros, so that the user need not know whether he is being used in C or C++
    111 * code.
    112 *
    113 *   MOZ_BEGIN_EXTERN_C
    114 *
    115 *   extern MOZ_EXPORT int MostRandomNumber(void);
    116 *   ...other declarations...
    117 *
    118 *   MOZ_END_EXTERN_C
    119 *
    120 * This said, it is preferable to just use |extern "C"| in C++ header files for
    121 * its greater clarity.
    122 */
    123 #ifdef __cplusplus
    124 #  define MOZ_BEGIN_EXTERN_C extern "C" {
    125 #  define MOZ_END_EXTERN_C }
    126 #else
    127 #  define MOZ_BEGIN_EXTERN_C
    128 #  define MOZ_END_EXTERN_C
    129 #endif
    130 
    131 /*
    132 * GCC's typeof is available when decltype is not.
    133 */
    134 #if defined(__GNUC__) && defined(__cplusplus) && \
    135    !defined(__GXX_EXPERIMENTAL_CXX0X__) && __cplusplus < 201103L
    136 #  define decltype __typeof__
    137 #endif
    138 
    139 #endif /* mozilla_Types_h */