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      1 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 # Use of this source code is governed by a BSD-style license that can be
      3 # found in the LICENSE file.
      4 
      5 import json
      6 import os
      7 import subprocess
      8 import sys
      9 import re
     10 from optparse import OptionParser
     11 
     12 # This script runs pkg-config, optionally filtering out some results, and
     13 # returns the result.
     14 #
     15 # The result will be [ <includes>, <cflags>, <libs>, <lib_dirs>, <ldflags> ]
     16 # where each member is itself a list of strings.
     17 #
     18 # You can filter out matches using "-v <regexp>" where all results from
     19 # pkgconfig matching the given regular expression will be ignored. You can
     20 # specify more than one regular expression my specifying "-v" more than once.
     21 #
     22 # You can specify a sysroot using "-s <sysroot>" where sysroot is the absolute
     23 # system path to the sysroot used for compiling. This script will attempt to
     24 # generate correct paths for the sysroot.
     25 #
     26 # When using a sysroot, you must also specify the architecture via
     27 # "-a <arch>" where arch is either "x86" or "x64".
     28 
     29 # If this is run on non-Linux platforms, just return nothing and indicate
     30 # success. This allows us to "kind of emulate" a Linux build from other
     31 # platforms.
     32 if sys.platform.find("linux") == -1:
     33   print "[[],[],[],[],[]]"
     34   sys.exit(0)
     35 
     36 
     37 def SetConfigPath(options):
     38   """Set the PKG_CONFIG_PATH environment variable.
     39   This takes into account any sysroot and architecture specification from the
     40   options on the given command line."""
     41 
     42   sysroot = options.sysroot
     43   if not sysroot:
     44     sysroot = ""
     45 
     46   # Compute the library path name based on the architecture.
     47   arch = options.arch
     48   if sysroot and not arch:
     49     print "You must specify an architecture via -a if using a sysroot."
     50     sys.exit(1)
     51   if arch == 'x64':
     52     libpath = 'lib64'
     53   else:
     54     libpath = 'lib'
     55 
     56   # Add the sysroot path to the environment's PKG_CONFIG_PATH
     57   config_path = sysroot + '/usr/' + libpath + '/pkgconfig'
     58   config_path += ':' + sysroot + '/usr/share/pkgconfig'
     59   if 'PKG_CONFIG_PATH' in os.environ:
     60     os.environ['PKG_CONFIG_PATH'] += ':' + config_path
     61   else:
     62     os.environ['PKG_CONFIG_PATH'] = config_path
     63 
     64 
     65 def GetPkgConfigPrefixToStrip(args):
     66   """Returns the prefix from pkg-config where packages are installed.
     67   This returned prefix is the one that should be stripped from the beginning of
     68   directory names to take into account sysroots."""
     69   # Some sysroots, like the Chromium OS ones, may generate paths that are not
     70   # relative to the sysroot. For example,
     71   # /path/to/chroot/build/x86-generic/usr/lib/pkgconfig/pkg.pc may have all
     72   # paths relative to /path/to/chroot (i.e. prefix=/build/x86-generic/usr)
     73   # instead of relative to /path/to/chroot/build/x86-generic (i.e prefix=/usr).
     74   # To support this correctly, it's necessary to extract the prefix to strip
     75   # from pkg-config's |prefix| variable.
     76   prefix = subprocess.check_output(["pkg-config", "--variable=prefix"] + args,
     77       env=os.environ)
     78   if prefix[-4] == '/usr':
     79     return prefix[4:]
     80   return prefix
     81 
     82 
     83 def MatchesAnyRegexp(flag, list_of_regexps):
     84   """Returns true if the first argument matches any regular expression in the
     85   given list."""
     86   for regexp in list_of_regexps:
     87     if regexp.search(flag) != None:
     88       return True
     89   return False
     90 
     91 
     92 def RewritePath(path, strip_prefix, sysroot):
     93   """Rewrites a path by stripping the prefix and prepending the sysroot."""
     94   if os.path.isabs(path) and not path.startswith(sysroot):
     95     if path.startswith(strip_prefix):
     96       path = path[len(strip_prefix):]
     97     path = path.lstrip('/')
     98     return os.path.join(sysroot, path)
     99   else:
    100     return path
    101 
    102 
    103 parser = OptionParser()
    104 parser.add_option('-p', action='store', dest='pkg_config', type='string',
    105                   default='pkg-config')
    106 parser.add_option('-v', action='append', dest='strip_out', type='string')
    107 parser.add_option('-s', action='store', dest='sysroot', type='string')
    108 parser.add_option('-a', action='store', dest='arch', type='string')
    109 (options, args) = parser.parse_args()
    110 
    111 # Make a list of regular expressions to strip out.
    112 strip_out = []
    113 if options.strip_out != None:
    114   for regexp in options.strip_out:
    115     strip_out.append(re.compile(regexp))
    116 
    117 SetConfigPath(options)
    118 if options.sysroot:
    119   prefix = GetPkgConfigPrefixToStrip(args)
    120 else:
    121   prefix = ''
    122 
    123 try:
    124   flag_string = subprocess.check_output(
    125       [ options.pkg_config, "--cflags", "--libs-only-l", "--libs-only-L" ] +
    126       args, env=os.environ)
    127   # For now just split on spaces to get the args out. This will break if
    128   # pkgconfig returns quoted things with spaces in them, but that doesn't seem
    129   # to happen in practice.
    130   all_flags = flag_string.strip().split(' ')
    131 except:
    132   print "Could not run pkg-config."
    133   sys.exit(1)
    134 
    135 
    136 sysroot = options.sysroot
    137 if not sysroot:
    138   sysroot = ''
    139 
    140 includes = []
    141 cflags = []
    142 libs = []
    143 lib_dirs = []
    144 ldflags = []
    145 
    146 for flag in all_flags[:]:
    147   if len(flag) == 0 or MatchesAnyRegexp(flag, strip_out):
    148     continue;
    149 
    150   if flag[:2] == '-l':
    151     libs.append(RewritePath(flag[2:], prefix, sysroot))
    152   elif flag[:2] == '-L':
    153     lib_dirs.append(RewritePath(flag[2:], prefix, sysroot))
    154   elif flag[:2] == '-I':
    155     includes.append(RewritePath(flag[2:], prefix, sysroot))
    156   elif flag[:3] == '-Wl':
    157     ldflags.append(flag)
    158   elif flag == '-pthread':
    159     # Many libs specify "-pthread" which we don't need since we always include
    160     # this anyway. Removing it here prevents a bunch of duplicate inclusions on
    161     # the command line.
    162     pass
    163   else:
    164     cflags.append(flag)
    165 
    166 # Output a GN array, the first one is the cflags, the second are the libs. The
    167 # JSON formatter prints GN compatible lists when everything is a list of
    168 # strings.
    169 print json.dumps([includes, cflags, libs, lib_dirs, ldflags])
    170