gobject-introspection: Fix patching shared objects

The gi-r-scanner is generating a list of shared libraries that are
referenced in the shared-library attribute of the <namespace/> element
of the GIR file. However, this attribute only contains the names of the
libraries and not the full store paths, like for example while preparing
to package libblockdev, the following items were included in the
shared-library attribute:

  /nix/store/...-libblockdev-1.3/lib/libblockdev.so.0
  libm.so.6
  libdmraid.so.1.0.0.rc16
  libbd_utils.so.0

Unfortunately, loading such a library without setting LD_LIBRARY_PATH is
going to fail finding libm.so.6 and libdmraid.so.1.0.0.rc16.

Now the first attempt at solving this was to put absolute paths of all
the libraries referenced in the shared-library attribute, but this also
led up to including paths of build-time shared objects into that
attribute:

  /nix/store/...-libblockdev-1.3/lib/libblockdev.so.0
  /nix/store/...-glibc-2.21/lib/libm.so.6
  /nix/store/...-dmraid-1.0.0.rc16/lib/libdmraid.so.1.0.0.rc16
  /tmp/nix-build-libblockdev-1.3.drv-0/.../utils/.libs/libbd_utils.so.0

This of course is not what we want, so the final solution is to only
use the absolute path whenever it is a Nix path and leave the library
name as-is if the path doesn't reside within the store, like this:

  /nix/store/...-libblockdev-1.3/lib/libblockdev.so.0
  /nix/store/...-glibc-2.21/lib/libm.so.6
  /nix/store/...-dmraid-1.0.0.rc16/lib/libdmraid.so.1.0.0.rc16
  libbd_utils.so.0

The downside of this approach is that if not even the output path of the
library is in LD_LIBRARY_PATH, even loading of libbd_utils.so.0 could
fail, so we need to patch the loader as well.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/development/libraries/gobject-introspection/absolute_shlib_path.patch

@@ -1,6 +1,40 @@
---- ./giscanner/utils.py.orig	2014-08-14 22:05:05.055334080 +0200
+diff --git a/giscanner/shlibs.py b/giscanner/shlibs.py
-+++ ./giscanner/utils.py	2014-08-14 22:05:24.687497334 +0200
+index 838d343..9dbdc0f 100644
-@@ -110,17 +110,11 @@
+--- a/giscanner/shlibs.py
++++ b/giscanner/shlibs.py
+@@ -53,10 +53,24 @@ def _resolve_libtool(options, binary, libraries):
+ # Match absolute paths on OS X to conform to how libraries are usually
+ # referenced on OS X systems.
+ def _ldd_library_pattern(library_name):
++    nix_store_dir = re.escape('@nixStoreDir@'.rstrip('/'))
+     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))
++    pattern = r'''
++        (
++          (?:
++            # First match Nix store paths because they need to be absolute.
++            (?:%s(?:/[^/]*)+)
++            # Everything else not a store path remains relative, because we
++            # would end up having absolute build paths in the resulting GIR
++            # file.
++            | (?<=/)
++          )
++          # And finally the library itself:
++          (?:lib%s[^A-Za-z0-9_-][^\s\(\)]*)
++        )
++    '''
++    return re.compile(pattern % (nix_store_dir, re.escape(library_name)),
++                      re.VERBOSE)
+ 
+ 
+ # 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 660081e..c9c767a 100644
+--- a/giscanner/utils.py
++++ b/giscanner/utils.py
+@@ -109,17 +109,11 @@ def extract_libtool_shlib(la_file):
      if dlname is None:
          return None
  

pkgs/development/libraries/gobject-introspection/default.nix

@@ -1,5 +1,7 @@
 { stdenv, fetchurl, glib, flex, bison, pkgconfig, libffi, python
-, libintlOrEmpty, autoconf, automake, otool }:
+, libintlOrEmpty, autoconf, automake, otool
+, substituteAll, nixStoreDir ? "/nix/store"
+}:
 # now that gobjectIntrospection creates large .gir files (eg gtk3 case)
 # it may be worth thinking about using multiple derivation outputs
 # In that case its about 6MB which could be separated
@@ -33,7 +35,10 @@ stdenv.mkDerivation rec {
 
   setupHook = ./setup-hook.sh;
 
-  patches = [ ./absolute_shlib_path.patch ];
+  patches = stdenv.lib.singleton (substituteAll {
+    src = ./absolute_shlib_path.patch;
+    inherit nixStoreDir;
+  });
 
   meta = with stdenv.lib; {
     description = "A middleware layer between C libraries and language bindings";

pkgs/top-level/all-packages.nix

@@ -6639,7 +6639,9 @@ let
   #GMP ex-satellite, so better keep it near gmp
   mpfr = callPackage ../development/libraries/mpfr/default.nix { };
 
-  gobjectIntrospection = callPackage ../development/libraries/gobject-introspection { };
+  gobjectIntrospection = callPackage ../development/libraries/gobject-introspection {
+    nixStoreDir = config.nix.storeDir or "/nix/store";
+  };
 
   goocanvas = callPackage ../development/libraries/goocanvas { };