Meson build: Make it possible to use gtkmm as a subproject

gtk, gdk-pixbuf, epoxy, cairomm, pangomm and glibmm can be
subprojects of gtkmm. See MR !62

Makefile.am

@@ -69,6 +69,12 @@ EXTRA_DIST = \
   gtk/meson.build \
   gtk/gtkmmconfig.h.meson \
   gtk/gtkmm/meson.build \
+  subprojects/cairomm-1.16.wrap \
+  subprojects/gdk-pixbuf.wrap \
+  subprojects/glibmm-2.68.wrap \
+  subprojects/gtk4.wrap \
+  subprojects/libepoxy.wrap \
+  subprojects/pangomm-2.48.wrap \
   tests/meson.build \
   tools/dummy-header.py \
   tools/extra_defs_gen/meson.build \

demos/gtk-demo/meson.build

@@ -1,6 +1,6 @@
 # demos/gtk-demo
 
-# Input: gtkmm_dep, epoxy_dep, build_demos, gui_app_ldflags
+# Input: gtkmm_own_dep, epoxy_dep, build_demos, gui_app_ldflags
 # Output: -
 
 gtkmm_demo_cc_files = [
@@ -45,7 +45,7 @@ if epoxy_dep.found()
 
   executable('gtkmm-demo',
     gtkmm_demo_cc_files, demo_resources,
-    dependencies: [gtkmm_dep, epoxy_dep],
+    dependencies: [gtkmm_own_dep, epoxy_dep],
     gui_app: true,
     build_by_default: build_demos,
     link_args: gui_app_ldflags,

docs/reference/meson.build

@@ -5,7 +5,7 @@
 #        gtkmm_extra_h_files, gdkmm_built_h_file_targets,
 #        gtkmm_built_h_file_targets, install_datadir, python3,
 #        doc_reference_py, build_documentation
-# Output: install_docdir, install_devhelpdir
+# Output: install_docdir, install_devhelpdir, tag_file
 
 tag_file_modules = [
   'mm-common-libstdc++',
@@ -19,9 +19,9 @@ docinstall_flags = []
 foreach module : tag_file_modules
   depmod = dependency(module, required: false)
   if depmod.found()
-    doxytagfile = depmod.get_pkgconfig_variable('doxytagfile')
-    htmlrefpub = depmod.get_pkgconfig_variable('htmlrefpub', default: '')
-    htmlrefdir = depmod.get_pkgconfig_variable('htmlrefdir', default: '')
+    doxytagfile = depmod.get_variable(pkgconfig: 'doxytagfile', internal: 'doxytagfile')
+    htmlrefpub = depmod.get_variable(pkgconfig: 'htmlrefpub', internal: 'htmlrefpub', default_value: '')
+    htmlrefdir = depmod.get_variable(pkgconfig: 'htmlrefdir', internal: 'htmlrefdir', default_value: '')
     if htmlrefpub == ''
       htmlrefpub = htmlrefdir
     elif htmlrefdir == ''

gtk/gtkmm/meson.build

@@ -6,7 +6,7 @@
 #        build_deprecated_api, gmmproc_extra_m4_dirs, is_host_windows,
 #        gdkmm_library, gdkmm_used_built_h_file_targets, gtkmm_libname
 # Output: gtkmm_hg_ccg_basenames, gtkmm_extra_h_files, built_files_root,
-#         gtkmm_built_h_file_targets, gtkmm_dep
+#         gtkmm_built_h_file_targets, gtkmm_own_dep
 
 gtkmm_defs_basefiles = [
   'gtk.defs',
@@ -519,9 +519,9 @@ if not meson.is_subproject()
   )
 endif
 
-# This is useful in the main project when gtkmm is used as a subproject.
-# It's also used when building demo programs and test programs.
-gtkmm_dep = declare_dependency(
+# This is used when building demo programs and test programs.
+# It's also a part of gtkmm_dep, when gtkmm is a subproject.
+gtkmm_own_dep = declare_dependency(
   sources: gdkmm_used_built_h_file_targets + gtkmm_used_built_h_file_targets,
   link_with: gtkmm_library,
   include_directories: extra_include_dirs,

meson.build

@@ -7,7 +7,8 @@ project('gtkmm', 'c', 'cpp',
   default_options: [
     'cpp_std=c++17'
   ],
-  meson_version: '>= 0.50.0', # required for python3.path()
+  meson_version: '>= 0.54.0', # required for meson.override_dependency()
+                              # and dep.get_variable(internal:)
 )
 
 gtkmm_api_version = '4.0'
@@ -125,9 +126,9 @@ glibmm_dep = dependency('glibmm-2.@0@'.format(glibmm_req_minor_ver), version: gl
 giomm_dep = dependency('giomm-2.@0@'.format(glibmm_req_minor_ver), version: glibmm_req)
 
 # Where to find gmmproc and generate_wrap_init.pl.
-gmmproc_dir = glibmm_dep.get_pkgconfig_variable('gmmprocdir')
+gmmproc_dir = glibmm_dep.get_variable(pkgconfig: 'gmmprocdir', internal: 'gmmprocdir')
 
-gmmproc_extra_m4_dirs = [pangomm_dep.get_pkgconfig_variable('gmmprocm4dir')]
+gmmproc_extra_m4_dirs = [pangomm_dep.get_variable(pkgconfig: 'gmmprocm4dir', internal: 'gmmprocm4dir')]
 
 gdkmm_build_dep = [giomm_dep, gtk_dep, cairomm_dep, pangomm_dep, gdk_pixbuf_dep]
 gdkmm_requires = [
@@ -143,8 +144,15 @@ gtkmm_requires = gdkmm_requires
 
 # not Windows
 if host_machine.system() != 'windows'
-  gtk_unix_print_dep = dependency('gtk4-unix-print')
-  gtkmm_build_dep += [gtk_unix_print_dep]
+  # gtk4-unix-print consists of only header files (no library).
+  # In gtk's source directory, those header files are stored in the same
+  # directory as other gtk/gtk files. No extra directory need be searched for
+  # header files, when gtk is used uninstalled.
+  gtk_unix_print_dep = dependency('gtk4-unix-print',
+                       required: gtk_dep.type_name() != 'internal')
+  if gtk_unix_print_dep.found()
+    gtkmm_build_dep += [gtk_unix_print_dep]
+  endif
   gtkmm_requires += ['gtk4-unix-print', '']
 endif
 
@@ -290,6 +298,20 @@ if not meson.is_subproject()
     'untracked' / 'build_scripts',
     dont_distribute,
   )
+else
+  # This is a subproject.
+  gtkmm_dep = declare_dependency(
+    dependencies: gtkmm_own_dep,
+    variables: {
+      'gmmprocm4dir': project_source_root / 'tools' / 'm4',
+      'doxytagfile': tag_file.full_path(),
+      'htmlrefdir': install_prefix / install_docdir / 'reference' / 'html',
+      'htmlrefpub': 'http://library.gnome.org/devel/' + pkg_conf_data.get_unquoted('PACKAGE_TARNAME') + '/unstable/'
+    }
+  )
+
+  # A main project that looks for gtkmm_pcname.pc shall find gtkmm_dep.
+  meson.override_dependency(gtkmm_pcname, gtkmm_dep)
 endif
 
 # Print a summary.

subprojects/cairomm-1.16.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=cairomm
+url=https://gitlab.freedesktop.org/cairo/cairomm.git
+revision=master
+depth=1
+
+[provide]
+dependency_names = cairomm-1.16

subprojects/gdk-pixbuf.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=gdk-pixbuf
+url=https://gitlab.gnome.org/GNOME/gdk-pixbuf.git
+revision=master
+depth=1
+
+[provide]
+gdk-pixbuf-2.0 = gdkpixbuf_dep

subprojects/glibmm-2.68.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=glibmm
+url=https://gitlab.gnome.org/GNOME/glibmm.git
+revision=master
+depth=1
+
+[provide]
+dependency_names = glibmm-2.68, giomm-2.68

subprojects/gtk4.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=gtk
+url=https://gitlab.gnome.org/GNOME/gtk.git
+revision=master
+depth=1
+
+[provide]
+gtk4 = libgtk_dep

subprojects/libepoxy.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=libepoxy
+url=https://github.com/anholt/libepoxy.git
+revision=master
+depth=1
+
+[provide]
+epoxy = libepoxy_dep

subprojects/pangomm-2.48.wrap

@@ -0,0 +1,8 @@
+[wrap-git]
+directory=pangomm
+url=https://gitlab.gnome.org/GNOME/pangomm.git
+revision=master
+depth=1
+
+[provide]
+dependency_names = pangomm-2.48

tests/meson.build

@@ -1,6 +1,6 @@
 # tests
 
-# Input: gtkmm_dep, build_tests, gui_app_ldflags
+# Input: gtkmm_own_dep, build_tests, gui_app_ldflags
 # Output: -
 
 test_programs = [
@@ -34,7 +34,7 @@ foreach ex : test_programs
   endforeach
 
   exe_file = executable(ex_name, ex_sources,
-    dependencies: gtkmm_dep,
+    dependencies: gtkmm_own_dep,
     gui_app: ex[3],
     build_by_default: build_tests,
     link_args: ex[3] ? gui_app_ldflags : [],

tools/extra_defs_gen/meson.build

@@ -1,12 +1,18 @@
 # tools/extra_defs_gen
 
 # Input: cpp_compiler, gdkmm_build_dep, gtkmm_build_dep, install_libdir,
-#        gtkmm_pcname, msvc14x_toolset_ver
+#        gtkmm_pcname, msvc14x_toolset_ver, glibmm_dep
 # Output: m4_files, install_m4dir
 
 glibmm_generate_extra_defs_dep = cpp_compiler.find_library(
   'glibmm_generate_extra_defs@[email protected]'.format(msvc14x_toolset_ver),
+  required: glibmm_dep.type_name() != 'internal',
 )
+if not glibmm_generate_extra_defs_dep.found()
+  glibmm_generate_extra_defs_dep = dependency(
+    '', fallback: ['glibmm-2.68', 'glibmm_generate_extra_defs_dep'],
+  )
+endif
 
 executable('generate_defs_gdk', 'generate_defs_gdk.cc',
   dependencies: [gdkmm_build_dep, glibmm_generate_extra_defs_dep],