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
5import json
6import os
7import subprocess
8import sys
9import re
10from 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.
32if sys.platform.find("linux") == -1:
33  print "[[],[],[],[],[]]"
34  sys.exit(0)
35
36
37def 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
65def 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
83def 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
92def 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
103parser = OptionParser()
104parser.add_option('-p', action='store', dest='pkg_config', type='string',
105                  default='pkg-config')
106parser.add_option('-v', action='append', dest='strip_out', type='string')
107parser.add_option('-s', action='store', dest='sysroot', type='string')
108parser.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.
112strip_out = []
113if options.strip_out != None:
114  for regexp in options.strip_out:
115    strip_out.append(re.compile(regexp))
116
117SetConfigPath(options)
118if options.sysroot:
119  prefix = GetPkgConfigPrefixToStrip(args)
120else:
121  prefix = ''
122
123try:
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(' ')
131except:
132  print "Could not run pkg-config."
133  sys.exit(1)
134
135
136sysroot = options.sysroot
137if not sysroot:
138  sysroot = ''
139
140includes = []
141cflags = []
142libs = []
143lib_dirs = []
144ldflags = []
145
146for 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.
169print json.dumps([includes, cflags, libs, lib_dirs, ldflags])
170