autoconf: provide a harfbuzz-config for use from CMake (#822)

configure.ac

@@ -184,6 +184,7 @@ if $have_gobject; then
 	AC_SUBST(GLIB_MKENUMS)
 fi
 AM_CONDITIONAL(HAVE_GOBJECT, $have_gobject)
+AC_SUBST(have_gobject)
 
 dnl ===========================================================================
 
@@ -491,6 +492,7 @@ AC_CONFIG_FILES([
 Makefile
 src/Makefile
 src/hb-version.h
+src/harfbuzz-config.cmake
 src/hb-ucdn/Makefile
 util/Makefile
 test/Makefile

src/Makefile.am

@@ -156,7 +156,9 @@ pkginclude_HEADERS = $(HBHEADERS)
 nodist_pkginclude_HEADERS = $(HBNODISTHEADERS)
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = harfbuzz.pc
-EXTRA_DIST += harfbuzz.pc.in
+cmakedir = $(libdir)/cmake/harfbuzz
+cmake_DATA = harfbuzz-config.cmake
+EXTRA_DIST += harfbuzz.pc.in harfbuzz-config.cmake.in
 
 lib_LTLIBRARIES += libharfbuzz-subset.la
 libharfbuzz_subset_la_SOURCES = $(HB_SUBSET_sources)

src/harfbuzz-config.cmake.in

@@ -0,0 +1,82 @@
+# Set these variables so that the `${prefix}/lib` expands to something we can
+# remove.
+set(_harfbuzz_remove_string "REMOVE_ME")
+set(exec_prefix "${_harfbuzz_remove_string}")
+set(prefix "${_harfbuzz_remove_string}")
+
+# Compute the installation prefix by stripping components from our current
+# location.
+get_filename_component(_harfbuzz_prefix "${CMAKE_CURRENT_LIST_DIR}" DIRECTORY)
+get_filename_component(_harfbuzz_prefix "${_harfbuzz_prefix}" DIRECTORY)
+set(_harfbuzz_libdir "@libdir@")
+string(REPLACE "${_harfbuzz_remove_string}/" "" _harfbuzz_libdir "${_harfbuzz_libdir}")
+set(_harfbuzz_libdir_iter "${_harfbuzz_libdir}")
+while (_harfbuzz_libdir_iter)
+  get_filename_component(_harfbuzz_libdir_iter "${_harfbuzz_libdir_iter}" DIRECTORY)
+  get_filename_component(_harfbuzz_prefix "${_harfbuzz_prefix}" DIRECTORY)
+endwhile ()
+unset(_harfbuzz_libdir_iter)
+
+# Get the include subdir.
+set(_harfbuzz_includedir "@includedir@")
+string(REPLACE "${_harfbuzz_remove_string}/" "" _harfbuzz_includedir "${_harfbuzz_includedir}")
+
+# Extract version information from libtool.
+set(_harfbuzz_version_info "@HB_LIBTOOL_VERSION_INFO@")
+string(REPLACE ":" ";" _harfbuzz_version_info "${_harfbuzz_version_info}")
+list(GET _harfbuzz_version_info 0
+  _harfbuzz_current)
+list(GET _harfbuzz_version_info 1
+  _harfbuzz_revision)
+list(GET _harfbuzz_version_info 2
+  _harfbuzz_age)
+unset(_harfbuzz_version_info)
+
+if (APPLE)
+  set(_harfbuzz_lib_suffix ".0${CMAKE_SHARED_LIBRARY_SUFFIX}")
+elseif (UNIX)
+  set(_harfbuzz_lib_suffix "${CMAKE_SHARED_LIBRARY_SUFFIX}.0.${_harfbuzz_current}.${_harfbuzz_revision}")
+else ()
+  # Unsupported.
+  set(harfbuzz_FOUND 0)
+endif ()
+
+# Add the libraries.
+add_library(harfbuzz::harfbuzz SHARED IMPORTED)
+set_target_properties(harfbuzz::harfbuzz PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${_harfbuzz_prefix}/${_harfbuzz_includedir}/harfbuzz"
+  IMPORTED_LOCATION "${_harfbuzz_prefix}/${_harfbuzz_libdir}/libharfbuzz${_harfbuzz_lib_suffix}")
+
+add_library(harfbuzz::icu SHARED IMPORTED)
+set_target_properties(harfbuzz::icu PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${_harfbuzz_prefix}/${_harfbuzz_includedir}/harfbuzz"
+  INTERFACE_LINK_LIBRARIES "harfbuzz::harfbuzz"
+  IMPORTED_LOCATION "${_harfbuzz_prefix}/${_harfbuzz_libdir}/libharfbuzz-icu${_harfbuzz_lib_suffix}")
+
+add_library(harfbuzz::subset SHARED IMPORTED)
+set_target_properties(harfbuzz::subset PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "${_harfbuzz_prefix}/${_harfbuzz_includedir}/harfbuzz"
+  INTERFACE_LINK_LIBRARIES "harfbuzz::harfbuzz"
+  IMPORTED_LOCATION "${_harfbuzz_prefix}/${_harfbuzz_libdir}/libharfbuzz-subset${_harfbuzz_lib_suffix}")
+
+# Only add the gobject library if it was built.
+set(_harfbuzz_have_gobject "@have_gobject@")
+if (_harfbuzz_have_gobject)
+  add_library(harfbuzz::gobject SHARED IMPORTED)
+  set_target_properties(harfbuzz::gobject PROPERTIES
+    INTERFACE_INCLUDE_DIRECTORIES "${_harfbuzz_prefix}/${_harfbuzz_includedir}/harfbuzz"
+    INTERFACE_LINK_LIBRARIES "harfbuzz::harfbuzz"
+    IMPORTED_LOCATION "${_harfbuzz_prefix}/${_harfbuzz_libdir}/libharfbuzz-gobject${_harfbuzz_lib_suffix}")
+endif ()
+
+# Clean out variables we used in our scope.
+unset(_harfbuzz_lib_suffix)
+unset(_harfbuzz_current)
+unset(_harfbuzz_revision)
+unset(_harfbuzz_age)
+unset(_harfbuzz_includedir)
+unset(_harfbuzz_libdir)
+unset(_harfbuzz_prefix)
+unset(exec_prefix)
+unset(prefix)
+unset(_harfbuzz_remove_string)