[tracker/tracker-0.16] tracker-extract: Make PNG extractor optional, using --enable-libpng

[Martyn James Russell <mr src gnome org>]

commit fc338acc0912012f471ff359ac793c5732e5bffd
Author: Jonatan Pålsson <jonatan palsson pelagicore com>
Date:   Tue Jul 9 08:25:35 2013 +0200

    tracker-extract: Make PNG extractor optional, using --enable-libpng

 configure.ac                    |   50 ++++++++++++++++++++++++++++++++++++++-
 src/tracker-extract/Makefile.am |    7 ++++-
 2 files changed, 54 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 0b83d6d..281f686 100644
--- a/configure.ac
+++ b/configure.ac
@@ -198,6 +198,7 @@ REST_REQUIRED=0.6
 NETWORK_MANAGER_REQUIRED=0.8
 GSTREAMER_REQUIRED=0.10.31
 GUPNP_DLNA_REQUIRED=0.9.4
+LIBPNG_REQUIRED=0.89
 
 # 3.6.11 for sqlite_backup API
 # 3.6.16 to fix test failures
@@ -2033,6 +2034,53 @@ CFLAGS="$OLD_CFLAGS"
 LIBS="$OLD_LIBS"
 
 ##################################################################
+# Check for tracker-extract: libpng
+##################################################################
+
+# FIXME: This should be package based. Unfortunately in several main
+# distros, it is not.
+
+OLD_CFLAGS="$CFLAGS"
+OLD_LIBS="$LIBS"
+CFLAGS=""
+LIBS=""
+
+AC_ARG_ENABLE(libpng,
+              AS_HELP_STRING([--enable-libpng],
+                             [enable extractor for PNG data [[default=auto]]]),,
+              [enable_libpng=auto])
+
+if test "x$enable_libpng" != "xno" ; then
+   AC_CHECK_HEADER(png.h,
+                   AC_CHECK_LIB(png, png_create_read_struct))
+
+   have_libpng=${ac_cv_lib_png_png_create_read_struct:-no}
+
+   LIBPNG_CFLAGS="$CFLAGS"
+   LIBPNG_LIBS="$LIBS"
+
+   AC_SUBST(LIBPNG_CFLAGS)
+   AC_SUBST(LIBPNG_LIBS)
+
+   if test "x$have_libpng" = "xyes"; then
+      AC_DEFINE(HAVE_LIBPNG, [], [Define if we have libpng])
+   fi
+else
+   have_libpng="no  (disabled)"
+fi
+
+if test "x$enable_libpng" = "xyes"; then
+   if test "x$have_libpng" != "xyes"; then
+      AC_MSG_ERROR([Couldn't find libpng >= $LIBPNG_REQUIRED.])
+   fi
+fi
+
+AM_CONDITIONAL(HAVE_LIBPNG, test "x$have_libpng" = "xyes")
+
+CFLAGS="$OLD_CFLAGS"
+LIBS="$OLD_LIBS"
+
+##################################################################
 # Check for tracker-extract: vorbis
 ##################################################################
 
@@ -2390,7 +2438,7 @@ Applications:
 Metadata Extractors:
 
        Support libstreamanalyzer:              $have_libstreamanalyzer
-       Support PNG:                            yes
+       Support PNG:                            $have_libpng
        Support PDF:                            $have_poppler
        Support XPS:                            $have_libgxps
        Support GIF:                            $have_libgif (xmp: $have_exempi)
diff --git a/src/tracker-extract/Makefile.am b/src/tracker-extract/Makefile.am
index a3ccff9..6584258 100644
--- a/src/tracker-extract/Makefile.am
+++ b/src/tracker-extract/Makefile.am
@@ -57,7 +57,6 @@ modules_LTLIBRARIES = \
        libextract-abw.la \
        libextract-dvi.la \
        libextract-mp3.la \
-       libextract-png.la \
        libextract-ps.la \
        libextract-text.la \
        libextract-icon.la
@@ -67,7 +66,6 @@ rules_DATA = \
        10-dvi.rule \
        10-ico.rule \
        10-mp3.rule \
-       10-png.rule \
        10-ps.rule \
        90-text-generic.rule
 
@@ -156,6 +154,11 @@ modules_LTLIBRARIES += libextract-iso.la
 rules_DATA += 11-iso.rule
 endif
 
+if HAVE_LIBPNG
+modules_LTLIBRARIES += libextract-png.la
+rules_DATA += 10-png.rule
+endif
+
 # ABW
 libextract_abw_la_SOURCES = tracker-extract-abw.c
 libextract_abw_la_CFLAGS = $(TRACKER_EXTRACT_MODULES_CFLAGS)