plug-ins, extension: goat-exercises becomes a GIMP extension.

This is an extension containing a few demo plug-ins. This is good to
demonstrate the extension format. It will also allow to disable these
plug-ins (if at some point, one doesn't want to show these demo
plug-ins anymore).

And finally it deals with the fact that our plug-in code is stupid, as
it just tries to find the first executable with the same name (minus
extension) as the plug-in folder. This doesn't go well on Windows, where
the permission system is non-existent. So our code just ends up trying
to run the first file with a similar name in a plug-in folder. As the C
goat-exercise contains both an exe and the C source (and the system
probably returns files in alphabetic order), GIMP under Windows tries to
run the C source instead of the executable (this obviously doesn't go
well).
We could try to do more complex logics, like not aborting if the first
file run fails and try the next one in the plug-in folder. Or maybe just
rename the C file to another name. But any of these is just in the end
the proof that our plug-in discovery right now is just bogus. The
extension system is explicit, not based on randomly trying out files.
Plug-ins entry points are explicitly listed in the metadata manifest.

Makefile.am

@@ -35,6 +35,7 @@ SUBDIRS = \
 	app-tools		\
 	$(GIMP_MODULES)		\
 	$(GIMP_PLUGINS)		\
+	$(GIMP_EXTENSIONS)	\
 	etc			\
 	devel-docs		\
 	docs			\

configure.ac

@@ -2263,6 +2263,8 @@ PKG_CHECK_MODULES(JSON_GLIB, json-glib-1.0 >= json_glib_required_version,,
 # Check for python runtime dependencies
 #######################################
 
+GOAT_EXERCISES="goat-exercise-c$BUILD_EXEEXT"
+
 # By default, we want packagers to install Python plug-ins to get the
 # optimum experience. --with-python=yes will check for a Python 3
 # interpreter and PyGObject, and fails without.
@@ -2331,6 +2333,8 @@ if test "x$with_python" = "xyes"; then
     PYBIN_PATH="$PYTHON"
   fi
   AC_SUBST(PYBIN_PATH)
+
+  GOAT_EXERCISES="$GOAT_EXERCISES:goat-exercise-py3.py"
 fi
 AM_CONDITIONAL(HAS_PYTHON_INTERP, test "x$PYBIN_PATH" != "x")
 AM_CONDITIONAL(BUILD_PYTHON, test "x$with_python" != xno)
@@ -2378,6 +2382,10 @@ else
   fi
 fi
 
+if test "x$with_javascript" = "xyes"; then
+  GOAT_EXERCISES="$GOAT_EXERCISES:goat-exercise-gjs.js"
+fi
+
 AM_CONDITIONAL(HAS_JAVASCRIPT_INTERP, test "x$GJS" != "xno")
 AM_CONDITIONAL(BUILD_JAVASCRIPT, test "x$with_javascript" != xno)
 
@@ -2424,6 +2432,10 @@ else
   fi
 fi
 
+if test "x$with_lua" = "xyes"; then
+  GOAT_EXERCISES="$GOAT_EXERCISES:goat-exercise-lua.lua"
+fi
+
 AM_CONDITIONAL(HAS_LUA_INTERP, test "x$LUA" != "xno")
 AM_CONDITIONAL(BUILD_LUA, test "x$with_lua" != xno)
 
@@ -2450,7 +2462,12 @@ else
   fi
 fi
 
+if test "x$with_vala" = "xyes"; then
+  GOAT_EXERCISES="$GOAT_EXERCISES:goat-exercise-vala$BUILD_EXEEXT"
+fi
+
 AM_CONDITIONAL(BUILD_VALA, test "x$with_vala" != xno)
+AC_SUBST(GOAT_EXERCISES)
 
 ###########################################################
 # Some plug-ins don't build on Win32, others are Win32-only
@@ -2862,8 +2879,10 @@ fi
 ##################
 
 # easy way to skip the plug-in build
+GIMP_EXTENSIONS=extensions
 GIMP_PLUGINS=plug-ins
 GIMP_MODULES=modules
+AC_SUBST(GIMP_EXTENSIONS)
 AC_SUBST(GIMP_PLUGINS)
 AC_SUBST(GIMP_MODULES)
 
@@ -3015,6 +3034,9 @@ build/windows/gimp.rc
 build/windows/gimp-plug-ins.rc
 build/windows/installer/Makefile
 build/windows/installer/lang/Makefile
+extensions/Makefile
+extensions/goat-exercises/Makefile
+extensions/goat-exercises/org.gimp.extension.goat-exercises.metainfo.xml.in
 plug-ins/Makefile
 plug-ins/file-bmp/Makefile
 plug-ins/file-dds/Makefile
@@ -3064,7 +3086,6 @@ plug-ins/script-fu/tinyscheme/Makefile
 plug-ins/selection-to-path/Makefile
 plug-ins/twain/Makefile
 plug-ins/common/Makefile
-plug-ins/goat-exercises/Makefile
 modules/Makefile
 devel-docs/Makefile
 devel-docs/version

extensions/.gitignore

@@ -0,0 +1,2 @@
+/Makefile.in
+/Makefile

extensions/Makefile.am

@@ -0,0 +1,2 @@
+SUBDIRS = \
+	  goat-exercises

extensions/goat-exercises/Makefile.am

@@ -36,12 +36,14 @@ AM_CPPFLAGS = \
 
 # C version.
 
-goat_exercise_c_libexecdir = $(gimpplugindir)/plug-ins/goat-exercise-c
+goat_exercise_c_libexecdir = $(gimpplugindir)/extensions/org.gimp.extension.goat-exercises
 goat_exercise_c_datadir    = $(goat_exercise_c_libexecdir)
 
 goat_exercise_c_libexec_PROGRAMS = goat-exercise-c
 goat_exercise_c_libexec_DATA = goat-exercise-c.c
 
+PLUG_INS = 'goat-exercise-c$(EXEEXT)'
+
 goat_exercise_c_SOURCES = \
 	goat-exercise-c.c
 
@@ -64,21 +66,21 @@ goat_exercise_c_LDADD = \
 # Javascript (GJS) version.
 
 if BUILD_JAVASCRIPT
-goat_exercise_gjsdir = $(gimpplugindir)/plug-ins/goat-exercise-gjs
+goat_exercise_gjsdir = $(goat_exercise_c_libexecdir)
 goat_exercise_gjs_SCRIPTS = goat-exercise-gjs.js
 endif
 
 # Lua (lua-jit + LGI) version.
 
 if BUILD_LUA
-goat_exercise_luadir = $(gimpplugindir)/plug-ins/goat-exercise-lua
+goat_exercise_luadir = $(goat_exercise_c_libexecdir)
 goat_exercise_lua_SCRIPTS = goat-exercise-lua.lua
 endif
 
 # Python 3 (pygobject) version.
 
 if BUILD_PYTHON
-goat_exercise_py3dir = $(gimpplugindir)/plug-ins/goat-exercise-py3
+goat_exercise_py3dir = $(goat_exercise_c_libexecdir)
 goat_exercise_py3_SCRIPTS = goat-exercise-py3.py
 endif
 
@@ -86,7 +88,7 @@ endif
 
 if ENABLE_VAPIGEN
 
-goat_exercise_vala_libexecdir = $(gimpplugindir)/plug-ins/goat-exercise-vala
+goat_exercise_vala_libexecdir = $(goat_exercise_c_libexecdir)
 goat_exercise_vala_datadir    = $(goat_exercise_vala_libexecdir)
 
 goat_exercise_vala_libexec_PROGRAMS = goat-exercise-vala
@@ -118,7 +120,20 @@ goat_exercise_vala_VALAFLAGS = \
 
 endif
 
+appstream_in_files = \
+	org.gimp.extension.goat-exercises.metainfo.xml.in
+
+appstream_files = $(appstream_in_files:.xml.in=.xml)
+
+appdatadir = $(goat_exercise_c_libexecdir)
+appdata_DATA = $(appstream_files)
+
+@INTLTOOL_XML_RULE@
+
 EXTRA_DIST = \
 	goat-exercise-gjs.js	\
 	goat-exercise-lua.lua	\
-	goat-exercise-py3.py
+	goat-exercise-py3.py	\
+	$(appstream_in_files)
+
+DISTCLEANFILES = $(appstream_files)

extensions/goat-exercises/goat-exercise-c.c

@@ -193,8 +193,8 @@ goat_run (GimpProcedure        *procedure,
       gtk_widget_set_vexpand (GTK_WIDGET (scrolled), TRUE);
       gtk_widget_show (scrolled);
 
-      path = g_build_filename (gimp_plug_in_directory (), "plug-ins",
+      path = g_build_filename (gimp_plug_in_directory (), "extensions",
-                               PLUG_IN_BINARY, PLUG_IN_SOURCE,
+                               "org.gimp.extension.goat-exercises", PLUG_IN_SOURCE,
                                NULL);
       file = g_file_new_for_path (path);
       g_free (path);

extensions/goat-exercises/goat-exercise-vala.vala

@@ -91,7 +91,7 @@ public class Goat : Gimp.PlugIn {
       label.show();
 
 
-      string file = Path.build_filename(Gimp.PlugIn.directory(), "plug-ins", PLUG_IN_BINARY, PLUG_IN_SOURCE);
+      string file = Path.build_filename(Gimp.PlugIn.directory(), "extensions", "org.gimp.extension.goat-exercises", PLUG_IN_SOURCE);
       string contents;
       try {
         FileUtils.get_contents(file, out contents);

extensions/goat-exercises/meson.build

@@ -0,0 +1,122 @@
+# C version
+
+extension_name = 'org.gimp.extension.goat-exercises'
+plug_in_name   = 'goat-exercise'
+
+plugin_sources = [
+  'goat-exercise-c.c',
+]
+
+if platform_windows
+  plugin_sources += windows.compile_resources(
+    gimp_plugins_rc,
+    args: [
+      '--define', 'ORIGINALFILENAME_STR="@0@"'.format(plug_in_name + '-c.exe'),
+      '--define', 'INTERNALNAME_STR="@0@"'    .format(plug_in_name),
+      '--define', 'TOP_SRCDIR="@0@"'          .format(meson.source_root()),
+    ],
+    include_directories: [
+      rootInclude, appInclude,
+    ],
+  )
+endif
+
+exe = executable(plug_in_name + '-c',
+  plugin_sources,
+  dependencies: [
+    libgimpui_dep,
+    math,
+  ],
+  install: true,
+  install_dir: gimpplugindir /  'extensions' / extension_name,
+)
+
+# XXX This is so ugly!
+# From meson 0.54.0, we will be able to use exe.name().
+plug_ins = exe.full_path().split('/')[-1].split('\\')[-1]
+
+install_data(
+  'goat-exercise-c.c',
+  install_dir: gimpplugindir /  'extensions' / extension_name,
+)
+
+# Vala version
+
+if have_vala
+  exe = executable('goat-exercise-vala',
+    'goat-exercise-vala.vala',
+    include_directories: [ rootInclude, ],
+    dependencies: [
+      libgimp_vapi, libgimpui_vapi, gtk3, gegl, math,
+    ],
+    c_args: [
+      '-DGETTEXT_PACKAGE="@0@"'.format(gettext_package),
+    ],
+    install: true,
+    install_dir: gimpplugindir /  'extensions' / extension_name,
+  )
+  plug_ins = plug_ins + ':' + exe.full_path().split('/')[-1].split('\\')[-1]
+
+  install_data(
+    'goat-exercise-vala.vala',
+    install_dir: gimpplugindir /  'extensions' / extension_name,
+  )
+endif
+
+# Python 3 (pygobject) version.
+
+if have_python
+  install_data(
+    'goat-exercise-py3.py',
+    install_dir: gimpplugindir /  'extensions' / extension_name,
+  )
+  plug_ins = plug_ins + ':goat-exercise-py3.py'
+endif
+
+# Javascript (GJS) version.
+
+if have_javascript
+  install_data(
+    'goat-exercise-gjs.js',
+    install_dir: gimpplugindir /  'extensions' / extension_name,
+  )
+  plug_ins = plug_ins + ':goat-exercise-gjs.js'
+endif
+
+# Lua (lua-jit + LGI) version.
+
+if have_lua
+  install_data(
+    'goat-exercise-lua.lua',
+    install_dir: gimpplugindir /  'extensions' / extension_name,
+  )
+  plug_ins = plug_ins + ':goat-exercise-lua.lua'
+endif
+
+# Generate the AppData.
+
+conf = configuration_data()
+conf.set('GOAT_EXERCISES', plug_ins)
+
+appdatafilename = 'org.gimp.extension.goat-exercises.metainfo.xml'
+appdatafilein = configure_file(
+  input : appdatafilename + '.in.in',
+  output: appdatafilename + '.in',
+  configuration: conf,
+)
+
+appdatafile = custom_target(appdatafilename,
+  input : [ appdatafilein, ],
+  output: [ appdatafilename, ],
+  command: [
+    intltool_merge,
+    po_dir,
+    '@INPUT@',
+    '@OUTPUT@',
+    '--xml-style',
+    '--utf8',
+    '--cache=' + '@OUTDIR@' / 'intltool-merge-cache',
+  ],
+  install: true,
+  install_dir: gimpplugindir /  'extensions' / extension_name,
+)

extensions/goat-exercises/org.gimp.extension.goat-exercises.metainfo.xml.in.in

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="addon">
+  <id>org.gimp.extension.goat-exercises</id>
+  <extends>org.gimp.GIMP</extends>
+  <_name>Goat Exercises</_name>
+  <_summary>Official Demo Plug-ins</_summary>
+  <description>
+    <_p>
+    This extension provides a set of basic examples to demonstrate
+    how to create your own plug-ins.
+    Each plug-in does the same thing, except it is developed in a
+    different programming language.
+    They all create a GTK+ dialog with a text view displaying their own code
+    (hence also demonstrating how to package data) and a button which calls
+    a GEGL operation on the active layer.
+    </_p>
+  </description>
+  <url type="homepage">https://gimp.org</url>
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-3.0+</project_license>
+  <releases>
+   <release version="1.0.0" date="2020-10-08" />
+  </releases>
+  <requires>
+   <id version="2.99.0" compare="ge">org.gimp.GIMP</id>
+  </requires>
+  <metadata>
+   <value key="GIMP::plug-in-path">@GOAT_EXERCISES@</value>
+  </metadata>
+</component>

extensions/meson.build

@@ -0,0 +1 @@
+subdir('goat-exercises')

meson.build

@@ -1701,6 +1701,7 @@ subdir('libgimpwidgets')
 subdir('libgimp')
 
 # Executables, plugins
+subdir('extensions')
 subdir('modules')
 subdir('plug-ins')
 subdir('app')

plug-ins/Makefile.am

@@ -44,7 +44,6 @@ SUBDIRS = \
 	fractal-explorer	\
 	gfig			\
 	gimpressionist		\
-	goat-exercises		\
 	gradient-flare		\
 	help			\
 	$(help_browser)		\

plug-ins/goat-exercises/meson.build

@@ -1,85 +0,0 @@
-# C version
-
-plugin_name = 'goat-exercise'
-
-plugin_sources = [
-  'goat-exercise-c.c',
-]
-
-if platform_windows
-  plugin_sources += windows.compile_resources(
-    gimp_plugins_rc,
-    args: [
-      '--define', 'ORIGINALFILENAME_STR="@0@"'.format(plugin_name + '-c.exe'),
-      '--define', 'INTERNALNAME_STR="@0@"'    .format(plugin_name),
-      '--define', 'TOP_SRCDIR="@0@"'          .format(meson.source_root()),
-    ],
-    include_directories: [
-      rootInclude, appInclude,
-    ],
-  )
-endif
-
-executable(plugin_name + '-c',
-  plugin_sources,
-  dependencies: [
-    libgimpui_dep,
-    math,
-  ],
-  install: true,
-  install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-c',
-)
-
-install_data(
-  'goat-exercise-c.c',
-  install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-c',
-)
-
-# Vala version
-
-if have_vala
-  goat_exercise_vala = executable('goat-exercise-vala',
-    'goat-exercise-vala.vala',
-    include_directories: [ rootInclude, ],
-    dependencies: [
-      libgimp_vapi, libgimpui_vapi, gtk3, gegl, math,
-    ],
-    c_args: [
-      '-DGETTEXT_PACKAGE="@0@"'.format(gettext_package),
-    ],
-    install: true,
-    install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-vala',
-  )
-
-  install_data(
-    'goat-exercise-vala.vala',
-    install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-vala',
-  )
-endif
-
-# Python 3 (pygobject) version.
-
-if have_python
-  install_data(
-    'goat-exercise-py3.py',
-    install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-py3',
-  )
-endif
-
-# Javascript (GJS) version.
-
-if have_javascript
-  install_data(
-    'goat-exercise-gjs.js',
-    install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-gjs',
-  )
-endif
-
-# Lua (lua-jit + LGI) version.
-
-if have_lua
-  install_data(
-    'goat-exercise-lua.lua',
-    install_dir: gimpplugindir /  'plug-ins' / plugin_name + '-lua',
-  )
-endif

plug-ins/meson.build

@@ -16,7 +16,6 @@ subdir('flame')
 subdir('fractal-explorer')
 subdir('gfig')
 subdir('gimpressionist')
-subdir('goat-exercises')
 subdir('gradient-flare')
 subdir('help')
 subdir('help-browser')

po-plug-ins/POTFILES.in

@@ -3,6 +3,10 @@
 
 [encoding: UTF-8]
 
+extensions/goat-exercises/goat-exercise-c.c
+extensions/goat-exercises/goat-exercise-vala.vala
+extensions/goat-exercises/org.gimp.extension.goat-exercises.metainfo.xml.in.in
+
 plug-ins/common/align-layers.c
 plug-ins/common/animation-optimize.c
 #plug-ins/common/animation-play.c
@@ -141,9 +145,6 @@ plug-ins/gimpressionist/repaint.c
 plug-ins/gimpressionist/size.c
 plug-ins/gimpressionist/sizemap.c
 plug-ins/gimpressionist/utils.c
-plug-ins/goat-exercises/goat-exercise-c.c
-plug-ins/goat-exercises/goat-exercise-py3.py
-plug-ins/goat-exercises/goat-exercise-vala.vala
 [type: gettext/glade]plug-ins/ui/plug-in-metadata-editor.ui
 [type: gettext/glade]plug-ins/ui/plug-in-metadata-viewer.ui
 plug-ins/gradient-flare/gradient-flare.c

po-plug-ins/POTFILES.skip

@@ -5,6 +5,7 @@ data/tags
 data/tips
 desktop
 desktop/gimp.desktop.in
+extensions/goat-exercises/org.gimp.extension.goat-exercises.metainfo.xml.in
 libgimp
 libgimpbase
 libgimpcolor

po-python/POTFILES.in

@@ -3,6 +3,8 @@
 
 [encoding: UTF-8]
 
+extensions/goat-exercises/goat-exercise-py3.py
+
 plug-ins/python/benchmark-foreground-extract.py
 plug-ins/python/colorxhtml.py
 plug-ins/python/foggify.py

po-python/POTFILES.skip

@@ -36,7 +36,6 @@ plug-ins/flame
 plug-ins/fractal-explorer
 plug-ins/gfig
 plug-ins/gimpressionist
-plug-ins/goat-exercises
 plug-ins/gradient-flare
 plug-ins/help
 plug-ins/help-browser

po-script-fu/POTFILES.skip

@@ -5,6 +5,7 @@ data/tags
 data/tips
 desktop
 desktop/gimp.desktop.in
+extensions/goat-exercises
 libgimp
 libgimpbase
 libgimpcolor
@@ -35,7 +36,6 @@ plug-ins/flame
 plug-ins/fractal-explorer
 plug-ins/gfig
 plug-ins/gimpressionist
-plug-ins/goat-exercises
 plug-ins/gradient-flare
 plug-ins/help
 plug-ins/help-browser