[gobject-introspection/wip/meson: 10/23] g-ir-scanner: Don't require SRCDIR and BUILDDIR env vars

[Nirbheek Chauhan <nirbheekc src gnome org>]

commit 9b41d08057ed1ee2f4ce3a733413a8b2ad5a98d8
Author: Nirbheek Chauhan <nirbheek centricular com>
Date:   Fri Nov 24 02:29:01 2017 +0530

    g-ir-scanner: Don't require SRCDIR and BUILDDIR env vars
    
    When building with Meson, we cannot set environment variables while
    running custom targets and our builddir layout is different from
    Autotools anyway.
    
    Now g-ir-scanner and friends can autodetect when they're being run
    uninstalled by Meson and will find _giscanner.so and the giscanner
    python files in the build directory. This is very similar to what
    gdbus-codegen uses in glib/gio.
    
    Same for girepository/gdump.c.

 gir/meson.build             |    8 ++++--
 girepository/meson.build    |    8 +++++-
 giscanner/dumper.py         |    7 ++++-
 giscanner/meson.build       |   17 ++++++++++++---
 tools/g-ir-tool-template.in |   45 +++++++++++++++++++++++++++++++-----------
 5 files changed, 62 insertions(+), 23 deletions(-)
---
diff --git a/gir/meson.build b/gir/meson.build
index 5ae0acd..e471b26 100644
--- a/gir/meson.build
+++ b/gir/meson.build
@@ -38,9 +38,6 @@ girdir = join_paths(get_option('datadir'), 'gir-1.0')
 install_data(gir_files, install_dir: girdir)
 
 scanner_command = [
-  find_program('env'),
-  'UNINSTALLED_INTROSPECTION_SRCDIR=' + meson.source_root(),
-  'UNINSTALLED_INTROSPECTION_BUILDDIR=' + meson.build_root(),
   girscanner,
   '--output=@OUTPUT@',
   '--no-libtool',
@@ -136,6 +133,7 @@ glib_gir = custom_target('gir-glib',
   input: glib_files,
   output: 'GLib-2.0.gir',
   depends: giscanner_pymod,
+  depend_files: giscanner_built_files,
   install: true,
   install_dir: girdir,
   command: glib_command + [
@@ -193,6 +191,7 @@ gobject_gir = custom_target('gir-gobject',
   input: gobject_files,
   output: 'GObject-2.0.gir',
   depends: [glib_gir, giscanner_pymod],
+  depend_files: giscanner_built_files,
   install: true,
   install_dir: girdir,
   command: gobject_command + [
@@ -234,6 +233,7 @@ gir_files += custom_target('gir-gmodule',
   input: gmodule_files,
   output: 'GModule-2.0.gir',
   depends: [glib_gir, giscanner_pymod],
+  depend_files: giscanner_built_files,
   install: true,
   install_dir: girdir,
   command: gmodule_command + [
@@ -316,6 +316,7 @@ gir_files += custom_target('gir-gio',
   input: gio_files,
   output: 'Gio-2.0.gir',
   depends: [gobject_gir, giscanner_pymod],
+  depend_files: giscanner_built_files,
   install: true,
   install_dir: girdir,
   command: gio_command + [
@@ -333,6 +334,7 @@ gir_files += custom_target('gir-girepository',
   input: girepo_gir_sources,
   output: 'GIRepository-2.0.gir',
   depends: [gobject_gir, giscanner_pymod],
+  depend_files: giscanner_built_files,
   install: true,
   install_dir: girdir,
   command: scanner_command + [
diff --git a/girepository/meson.build b/girepository/meson.build
index b020caa..6a8c5b5 100644
--- a/girepository/meson.build
+++ b/girepository/meson.build
@@ -136,8 +136,12 @@ girepo_lib = shared_library('girepository-1.0',
   install: true,
 )
 
-install_data('gdump.c',
-  install_dir: join_paths(get_option('datadir'), 'gobject-introspection-1.0')
+# Copy to builddir for use with giscanner/dumper.py when running uninstalled
+configure_file(input : 'gdump.c',
+  output : 'gdump.c',
+  configuration : configuration_data(),
+  install_dir: join_paths(get_option('datadir'), 'gobject-introspection-1.0'),
+  install : true,
 )
 
 girepo_dep = declare_dependency(
diff --git a/giscanner/dumper.py b/giscanner/dumper.py
index 7f77bd2..2913d0b 100644
--- a/giscanner/dumper.py
+++ b/giscanner/dumper.py
@@ -116,8 +116,11 @@ class DumpCompiler(object):
         if self._uninst_srcdir is not None:
             gdump_path = os.path.join(self._uninst_srcdir, 'girepository', 'gdump.c')
         else:
-            gdump_path = os.path.join(os.path.join(DATADIR), 'gobject-introspection-1.0',
-                                      'gdump.c')
+            try:
+                gdump_path = GDUMP_PATH
+            except NameError:
+                gdump_path = os.path.join(os.path.join(DATADIR),
+                                          'gobject-introspection-1.0', 'gdump.c')
         if not os.path.isfile(gdump_path):
             raise SystemExit("Couldn't find %r" % (gdump_path, ))
         with open(gdump_path) as gdump_file:
diff --git a/giscanner/meson.build b/giscanner/meson.build
index acf1486..5357ae5 100644
--- a/giscanner/meson.build
+++ b/giscanner/meson.build
@@ -1,6 +1,4 @@
-pkglibdir = join_paths(get_option('libdir'), meson.project_name())
-giscannerdir = join_paths(pkglibdir, 'giscanner')
-install_data([
+giscanner_files = [
   '__init__.py',
   'annotationmain.py',
   'annotationparser.py',
@@ -27,8 +25,19 @@ install_data([
   'transformer.py',
   'utils.py',
   'xmlwriter.py',
-], install_dir: giscannerdir)
+]
+
+pkglibdir = join_paths(get_option('libdir'), meson.project_name())
+giscannerdir = join_paths(pkglibdir, 'giscanner')
 
+giscanner_built_files = []
+blank_conf = configuration_data()
+foreach f : giscanner_files
+  giscanner_built_files += configure_file(input : f, output : f,
+                                          install : true,
+                                          install_dir : giscannerdir,
+                                          configuration : blank_conf)
+endforeach
 
 install_subdir('doctemplates', install_dir: giscannerdir)
 
diff --git a/tools/g-ir-tool-template.in b/tools/g-ir-tool-template.in
index 2eac21f..1008217 100755
--- a/tools/g-ir-tool-template.in
+++ b/tools/g-ir-tool-template.in
@@ -47,24 +47,45 @@ if debug:
             pdb.pm()
         sys.excepthook = on_exception
 
-if os.name == 'nt':
-    datadir = os.path.join(os.path.dirname(__file__), '..', 'share')
-    pylibdir = os.path.join(os.path.dirname(__file__), '..', 'lib', 'gobject-introspection')
-else:
+# Detect and set datadir, pylibdir, etc as applicable
+# Similar to the method used in gdbus-codegen
+filedir = os.path.dirname(__file__)
+
+# Try using relative paths first so that the installation prefix is relocatable
+datadir = os.path.abspath(os.path.join(filedir, '..', 'share'))
+# Fallback to hard-coded paths if the relocatable paths are wrong
+if not os.path.isdir(os.path.join(datadir, 'gir-1.0')):
     datadir = "@datarootdir@"
-    pylibdir = os.path.join('@libdir@', 'gobject-introspection')
 
 builtins.__dict__['DATADIR'] = datadir
 
-srcdir = os.getenv('UNINSTALLED_INTROSPECTION_SRCDIR', None)
-if srcdir is not None:
-    pylibdir = srcdir
+# Again, relative paths first so that the installation prefix is relocatable
+pylibdir = os.path.abspath(os.path.join(filedir, '..', 'lib', 'gobject-introspection'))
+if not os.path.isfile(os.path.join(pylibdir, 'giscanner', '_giscanner.so')):
+    # Running uninstalled?
+    builddir = os.getenv('UNINSTALLED_INTROSPECTION_BUILDDIR', None)
+    if builddir is not None:
+        # Autotools, most likely
+        builddir = os.path.abspath(builddir)
+        # For _giscanner.so
+        sys.path.insert(0, os.path.join(builddir, 'giscanner'))
+        srcdir = os.getenv('UNINSTALLED_INTROSPECTION_SRCDIR', None)
+        if srcdir:
+            # For the giscanner python files
+            pylibdir = srcdir
+    elif os.path.isdir(os.path.join(filedir, '..', 'giscanner')):
+        # We're running uninstalled inside meson
+        builddir = os.path.abspath(os.path.join(filedir, '..'))
+        pylibdir = builddir
+        gdump_path = os.path.join(builddir, 'girepository', 'gdump.c')
+        if os.path.isfile(gdump_path):
+            builtins.__dict__['GDUMP_PATH'] = gdump_path
+    else:
+        # Okay, we're not running uninstalled and the prefix is not
+        # relocatable. Use hard-coded libdir.
+        pylibdir = os.path.join('@libdir@', 'gobject-introspection')
 
 sys.path.insert(0, pylibdir)
 
-builddir = os.getenv('UNINSTALLED_INTROSPECTION_BUILDDIR', None)
-if builddir is not None:
-    sys.path.insert(0, os.path.join(builddir, 'giscanner'))
-
 from giscanner.@TOOL_MODULE@ import @TOOL_FUNCTION@
 sys.exit(@TOOL_FUNCTION@(sys.argv))