write_buildflag_header.py (3525B)
1 #!/usr/bin/env python3 2 # Copyright 2015 The Chromium Authors 3 # Use of this source code is governed by a BSD-style license that can be 4 # found in the LICENSE file. 5 6 # This writes headers for build flags. See buildflag_header.gni for usage of 7 # this system as a whole. 8 # 9 # The parameters are passed in a response file so we don't have to worry 10 # about command line lengths. The name of the response file is passed on the 11 # command line. 12 # 13 # The format of the response file is: 14 # [--flags <list of one or more flag values>] 15 16 import optparse 17 import os 18 import re 19 import shlex 20 21 22 class Options: 23 def __init__(self, output, rulename, header_guard, flags): 24 self.output = output 25 self.rulename = rulename 26 self.header_guard = header_guard 27 self.flags = flags 28 29 30 def GetOptions(): 31 parser = optparse.OptionParser() 32 parser.add_option('--output', help="Output header name inside --gen-dir.") 33 parser.add_option('--rulename', 34 help="Helpful name of build rule for including in the " + 35 "comment at the top of the file.") 36 parser.add_option('--gen-dir', 37 help="Path to root of generated file directory tree.") 38 parser.add_option('--definitions', 39 help="Name of the response file containing the flags.") 40 cmdline_options, cmdline_flags = parser.parse_args() 41 42 # Compute a valid C++ header guard by replacing non valid chars with '_', 43 # upper-casing everything and prepending '_' if first symbol is digit. 44 header_guard = cmdline_options.output.upper() 45 if header_guard[0].isdigit(): 46 header_guard = '_' + header_guard 47 header_guard = re.sub(r'[^\w]', '_', header_guard) 48 header_guard += '_' 49 50 # The actual output file is inside the gen dir. 51 output = os.path.join(cmdline_options.gen_dir, cmdline_options.output) 52 53 # Definition file in GYP is newline separated, in GN they are shell formatted. 54 # shlex can parse both of these. 55 with open(cmdline_options.definitions, 'r') as def_file: 56 defs = shlex.split(def_file.read()) 57 flags_index = defs.index('--flags') 58 59 # Everything after --flags are flags. true/false are remapped to 1/0, 60 # everything else is passed through. 61 flags = [] 62 for flag in defs[flags_index + 1 :]: 63 equals_index = flag.index('=') 64 key = flag[:equals_index] 65 value = flag[equals_index + 1:] 66 67 # Canonicalize and validate the value. 68 if value == 'true': 69 value = '1' 70 elif value == 'false': 71 value = '0' 72 flags.append((key, str(value))) 73 74 return Options(output=output, 75 rulename=cmdline_options.rulename, 76 header_guard=header_guard, 77 flags=flags) 78 79 80 def WriteHeader(options): 81 with open(options.output, 'w') as output_file: 82 output_file.write("// Generated by build/write_buildflag_header.py\n") 83 if options.rulename: 84 output_file.write('// From "' + options.rulename + '"\n') 85 86 output_file.write('\n#ifndef %s\n' % options.header_guard) 87 output_file.write('#define %s\n\n' % options.header_guard) 88 output_file.write('#include "build/buildflag.h" // IWYU pragma: export\n\n') 89 # Clangd does not detect BUILDFLAG_INTERNAL_* indirect usage, so mark the 90 # header as "always_keep" to avoid "unused include" warning. 91 output_file.write('// IWYU pragma: always_keep\n\n') 92 93 for pair in options.flags: 94 output_file.write('#define BUILDFLAG_INTERNAL_%s() (%s)\n' % pair) 95 96 output_file.write('\n#endif // %s\n' % options.header_guard) 97 98 99 options = GetOptions() 100 WriteHeader(options)