[babl] build: subproject improvements: - don't expose source in dependency to avoid name clashes - add ba

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 4383ee8693c6cfc1c11214cd294c9648fb361daa
Author: John <jtm home gmail com>
Date:   Fri Feb 26 07:19:44 2021 +0000

    build: subproject improvements:
     - don't expose source in dependency to avoid name clashes
     - add babl path variables to dependency object
     - add babl path variables to uninstalled pc

 babl/babl/meson.build |  9 ++++++++
 babl/git-version.h.in |  6 -----
 babl/meson.build      | 52 +++++++++++-------------------------------
 git-version.h.in      |  6 +++++
 meson.build           | 63 +++++++++++++++++++++++++++++++++++++++++++++------
 5 files changed, 84 insertions(+), 52 deletions(-)
---
diff --git a/babl/babl/meson.build b/babl/babl/meson.build
new file mode 100644
index 000000000..461625a7b
--- /dev/null
+++ b/babl/babl/meson.build
@@ -0,0 +1,9 @@
+# Copy the public headers here for subproject builds.
+
+foreach _hdr : babl_headers
+  configure_file(
+    input: _hdr,
+    output: '@PLAINNAME@',
+    copy: true,
+  )
+endforeach
diff --git a/babl/meson.build b/babl/meson.build
index 623367804..d19210a28 100644
--- a/babl/meson.build
+++ b/babl/meson.build
@@ -54,43 +54,14 @@ if platform_win32
   babl_link_args += no_undefined
 endif
 
+# sources
 babl_version_h = configure_file(
   input:  'babl-version.h.in',
   output: 'babl-version.h',
   configuration: conf,
 )
 
-# If git is available, always check if git-version.h should be
-# updated. If git is not available, don't do anything if git-version.h
-# already exists because then we are probably working with a tarball
-# in which case the git-version.h we ship is correct.
-if git_bin.found() and run_command(
-    git_bin,
-    'rev-parse',
-    '--is-inside-work-tree',
-).returncode() == 0
-  git_version_h = vcs_tag(
-    input : 'git-version.h.in',
-    output: 'git-version.h',
-    replace_string: '@BABL_GIT_VERSION@',
-    command: [ git_bin.path(), 'describe', '--always' ],
-  )
-
-  if env_bin.found() and not meson.is_subproject()
-    meson.add_dist_script(
-      [ 'ninja', 'babl/git-version.h', ],
-    )
-    meson.add_dist_script(
-      [ 'sh', '-c', ' '.join(
-      [ 'cp', git_version_h.full_path(), '${MESON_DIST_ROOT}/babl' ]
-      )]
-    )
-  endif
-else
-  git_version_h = files('git-version.h')
-endif
-
-babl_sources = [
+babl_sources = files(
   'babl-cache.c',
   'babl-component.c',
   'babl-conversion.c',
@@ -123,25 +94,34 @@ babl_sources = [
   'babl-util.c',
   'babl-version.c',
   'babl.c',
+) + [
   babl_version_h,
   git_version_h,
 ]
 
-babl_headers = [
+babl_headers = files(
   'babl-introspect.h',
   'babl-macros.h',
   'babl-types.h',
   'babl.h',
+) + [
   babl_version_h,
 ]
 
 install_headers(babl_headers,
-  subdir: join_paths(lib_name, 'babl')
+  subdir: lib_name / 'babl'
 )
+# copy external headers to babl subdirectory for subproject builds as
+# we don't want to expose the project root folder due to potential
+# name clashes.
+if meson.is_subproject()
+  subdir('babl')
+endif
 
 babl_deps = [math, thread, dl, lcms]
 babl_includes = [rootInclude, bablBaseInclude]
 
+# build library
 babl = library(
   lib_name,
   babl_sources,
@@ -155,12 +135,6 @@ babl = library(
   install: true,
 )
 
-libbabl_dep = declare_dependency(
-  include_directories: babl_includes,
-  link_with: babl,
-  dependencies: babl_deps
-)
-
 if build_gir
   # identity filter, so GIR doesn't choke on the Babl type
   # (since it has the same name as the Babl namespace)
diff --git a/git-version.h.in b/git-version.h.in
new file mode 100644
index 000000000..41bdefbbd
--- /dev/null
+++ b/git-version.h.in
@@ -0,0 +1,6 @@
+#ifndef __BABL_GIT_VERSION_H__
+#define __BABL_GIT_VERSION_H__
+
+#define BABL_GIT_VERSION "@BABL_GIT_VERSION@"
+
+#endif /* __BABL_GIT_VERSION_H__ */
diff --git a/meson.build b/meson.build
index 62b6475b7..d08cb6bb5 100644
--- a/meson.build
+++ b/meson.build
@@ -30,6 +30,9 @@ buildtype = get_option('buildtype')
 babl_prefix = get_option('prefix')
 babl_libdir = join_paths(babl_prefix, get_option('libdir'))
 
+project_build_root = meson.current_build_dir()
+project_source_root = meson.current_source_dir()
+
 ################################################################################
 # Projects infos
 
@@ -409,12 +412,46 @@ endif
 ################################################################################
 # Configuration files
 
+# This should not be made visible in babl_dep due to possible name clash
+# when built as a sub-project.
+rootInclude = include_directories('.')
+
 # config.h
 configure_file(
   output: 'config.h',
   configuration: conf
 )
 
+# If git is available, always check if git-version.h should be
+# updated. If git is not available, don't do anything if git-version.h
+# already exists because then we are probably working with a tarball
+# in which case the git-version.h we ship is correct.
+if git_bin.found() and run_command(
+    git_bin,
+    'rev-parse',
+    '--is-inside-work-tree',
+).returncode() == 0
+  git_version_h = vcs_tag(
+    input : 'git-version.h.in',
+    output: 'git-version.h',
+    replace_string: '@BABL_GIT_VERSION@',
+    command: [ git_bin.path(), 'describe', '--always' ],
+  )
+
+  if not meson.is_subproject()
+    meson.add_dist_script(
+      [ 'ninja', 'git-version.h', ],
+    )
+    meson.add_dist_script(
+      [ 'sh', '-c', ' '.join(
+      [ 'cp', git_version_h.full_path(), '${MESON_DIST_ROOT}' ]
+      )]
+    )
+  endif
+else
+  git_version_h = files('git-version.h')
+endif
+
 ################################################################################
 # Global variables
 
@@ -428,8 +465,6 @@ gen_babl_map_file = files('gen_babl_map.py')
 ################################################################################
 # Subdirs
 
-rootInclude = include_directories('.')
-
 subdir('babl')
 subdir('extensions')
 subdir('tests')
@@ -456,17 +491,31 @@ endif
 
 
 # pkg-config file
-pkgconfig.generate(babl,
+pkgconfig.generate(
+  babl,
   filebase: 'babl',
   name: 'babl',
   description: 'Pixel encoding and color space conversion engine.',
   version: meson.project_version(),
-  libraries_private: [
-    '-lm',
+  subdirs: lib_name,
+  uninstalled_variables: [
+    'babl_path=@0@'.format(babl_extensions_build_dir),
+    'babl_libdir=@0@'.format(babl_library_build_dir),
   ],
-  subdirs: [
-    lib_name,
+)
+
+# dependency for wrap builds
+babl_dep = declare_dependency(
+  include_directories: bablInclude,
+  link_with : babl,
+  sources: [
+    babl_version_h,
+    is_variable('babl_gir') ? babl_gir : []
   ],
+  variables: {
+    'babl_path'   : babl_extensions_build_dir,
+    'babl_libdir' : babl_library_build_dir,
+  },
 )
 
 ################################################################################