scanner: Improve compatibility with OS X

While gobject-introspection works on OS X, a few circumstances are
handled a little different there. For one, libraries are linked using
absolute paths. The current gobject-introspection code however strips
any path components and just uses the filename in the .gir file –
while this doesn't cause failure, the generated typlibs will only work
in presence of a correctly set DYLD_LIBRARY_PATH or
DYLD_FALLBACK_LIBRARY_PATH environment variable.

Setting DYLD_LIBRARY_PATH on OS X often is a bad idea due to the
side-effects: Doing so causes the directory parts of libraries
referenced using an absolute path to be ignored if there is a equally
named file in the directory listed in $DYLD_LIBRARY_PATH, possibly
overriding referenced system libraries with incompatible versions.

Setting DYLD_FALLBACK_LIBRARY_PATH is the better solution for this
problem; however because this variable has an implicit default value
it's not simple to do so correctly.

The best solution to the problem is referencing libraries from .girs
using absolute paths, just as all other binaries on OS X. The attached
patches against 2.38.0 implement that.

Another quirk one needs to be aware of on OS X is that Apple ships a
program called libtool, which is not GNU libtool and incompatible with
it. GNU libtool, if present, is usually called glibtool on OS X. The
patches also fix this.

https://bugzilla.gnome.org/show_bug.cgi?id=709583

2 files changed, 35 insertions, 4 deletions

diff --git a/giscanner/shlibs.py b/giscanner/shlibs.py
index 1241827d..21fcafd0 100644
--- a/giscanner/shlibs.py
+++ b/giscanner/shlibs.py
@@ -49,9 +49,13 @@ def _resolve_libtool(options, binary, libraries):
 # The negative lookbehind at the start is to avoid problems if someone
 # is crazy enough to name a library liblib<foo> when lib<foo> exists.
 #
+# Match absolute paths on OS X to conform to how libraries are usually
+# referenced on OS X systems.
 def _ldd_library_pattern(library_name):
-    return re.compile("(?<![A-Za-z0-9_-])(lib*%s[^A-Za-z0-9_-][^\s\(\)]*)"
-                      % re.escape(library_name))
+    pattern = "(?<![A-Za-z0-9_-])(lib*%s[^A-Za-z0-9_-][^\s\(\)]*)"
+    if platform.system() == 'Darwin':
+        pattern = "([^\s]*lib*%s[^A-Za-z0-9_-][^\s\(\)]*)"
+    return re.compile(pattern % re.escape(library_name))
 
 
 # This is a what we do for non-la files. We assume that we are on an
diff --git a/giscanner/utils.py b/giscanner/utils.py
index def53fe4..abd1a266 100644
--- a/giscanner/utils.py
+++ b/giscanner/utils.py
@@ -21,6 +21,7 @@
 import re
 import os
 import subprocess
+import platform
 
 
 _debugflags = None
@@ -88,6 +89,20 @@ def _extract_dlname_field(la_file):
         return None
 
 
+_libtool_libdir_pat = re.compile("libdir='([^']+)'")
+
+
+def _extract_libdir_field(la_file):
+    f = open(la_file)
+    data = f.read()
+    f.close()
+    m = _libtool_libdir_pat.search(data)
+    if m:
+        return m.groups()[0]
+    else:
+        return None
+
+
 # Returns the name that we would pass to dlopen() the library
 # corresponding to this .la file
 def extract_libtool_shlib(la_file):
@@ -95,6 +110,14 @@ def extract_libtool_shlib(la_file):
     if dlname is None:
         return None
 
+    # Darwin uses absolute paths where possible; since the libtool files never
+    # contain absolute paths, use the libdir field
+    if platform.system() == 'Darwin':
+        dlbasename = os.path.basename(dlname)
+        libdir = _extract_libdir_field(la_file)
+        if libdir is None:
+            return dlbasename
+        return libdir + '/' + dlbasename
     # From the comments in extract_libtool(), older libtools had
     # a path rather than the raw dlname
     return os.path.basename(dlname)
@@ -127,14 +150,18 @@ def get_libtool_command(options):
         # we simply split().
         return libtool_path.split(' ')
 
+    libtool_cmd = 'libtool'
+    if platform.system() == 'Darwin':
+        # libtool on OS X is a completely different program written by Apple
+        libtool_cmd = 'glibtool'
     try:
-        subprocess.check_call(['libtool', '--version'],
+        subprocess.check_call([libtool_cmd, '--version'],
                               stdout=open(os.devnull))
     except (subprocess.CalledProcessError, OSError):
         # If libtool's not installed, assume we don't need it
         return None
 
-    return ['libtool']
+    return [libtool_cmd]
 
 
 def files_are_identical(path1, path2):