Add support for Meson as alternative/parallel build system

https://github.com/mesonbuild/meson

With contributions from:

Tim-Philipp Müller <tim@centricular.com>
Matej Knopp <matej.knopp@gmail.com>
Jussi Pakkanen <jpakkane@gmail.com> (original port)

Highlights of the features provided are:
* Faster builds on Linux (~40-50% faster)
* The ability to build with MSVC on Windows
* Generate Visual Studio project files
* Generate XCode project files
* Much faster builds on Windows (on-par with Linux)
* Seriously fast configure and building on embedded

... and many more. For more details see:

http://blog.nirbheek.in/2016/05/gstreamer-and-meson-new-hope.html
http://blog.nirbheek.in/2016/07/building-and-developing-gstreamer-using.html

Building with Meson should work on both Linux and Windows, but may
need a few more tweaks on other operating systems.

2 files changed, 88 insertions, 0 deletions

diff --git a/gst-libs/gst/interfaces/build_mkenum.py b/gst-libs/gst/interfaces/build_mkenum.py
new file mode 100755
index 000000000..cbbf06a56
--- /dev/null
+++ b/gst-libs/gst/interfaces/build_mkenum.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+
+# This is in its own file rather than inside meson.build
+# because a) mixing the two is ugly and b) trying to
+# make special characters such as \n go through all
+# backends is a fool's errand.
+
+import sys, os, shutil, subprocess
+
+h_array = ['--fhead',
+           "#ifndef __GST_PHOTO_ENUM_TYPES_H__\n#define __GST_PHOTO_ENUM_TYPES_H__\n\n#include <glib-object.h>\n\nG_BEGIN_DECLS\n",
+           '--fprod',
+           "\n/* enumerations from \"@filename@\" */\n",
+           '--vhead',
+           "GType @enum_name@_get_type (void);\n#define GST_TYPE_@ENUMSHORT@ (@enum_name@_get_type())\n",
+           '--ftail',
+           "G_END_DECLS\n\n#endif /* __GST_PHOTO_ENUM_TYPES_H__ */"]
+
+c_array = [
+    '--fhead',
+    "#include \"photography-enumtypes.h\"\n#include\"photography.h\"\n#define C_ENUM(v) ((gint) v)\n#define C_FLAGS(v) ((guint) v)\n",
+    '--fprod',
+    "\n/* enumerations from \"@filename@\" */",
+    '--vhead',
+    "GType\n@enum_name@_get_type (void)\n{\n  static gsize id = 0;\n  static const G@Type@Value values[] = {",
+    '--vprod',
+    "    { C_@TYPE@(@VALUENAME@), \"@VALUENAME@\", \"@valuenick@\" },",
+    '--vtail',
+    "    { 0, NULL, NULL }\n  };\n\n  if (g_once_init_enter (&id)) {\n    GType tmp = g_@type@_register_static (\"@EnumName@\", values);\n    g_once_init_leave (&id, tmp);\n  }\n\n  return (GType) id;\n}"
+    ]
+
+cmd = []
+argn = 1
+# Find the full command needed to run glib-mkenums
+# On UNIX-like, this is just the full path to glib-mkenums
+# On Windows, this is the full path to interpreter + full path to glib-mkenums
+for arg in sys.argv[1:]:
+    cmd.append(arg)
+    argn += 1
+    if arg.endswith('glib-mkenums'):
+        break
+ofilename = sys.argv[argn]
+headers = sys.argv[argn + 1:]
+
+if ofilename.endswith('.h'):
+    arg_array = h_array
+else:
+    arg_array = c_array
+
+cmd_array = cmd + arg_array + headers
+pc = subprocess.Popen(cmd_array, stdout=subprocess.PIPE)
+(stdo, _) = pc.communicate()
+if pc.returncode != 0:
+    sys.exit(pc.returncode)
+open(ofilename, 'wb').write(stdo)
diff --git a/gst-libs/gst/interfaces/meson.build b/gst-libs/gst/interfaces/meson.build
new file mode 100644
index 000000000..2349349be
--- /dev/null
+++ b/gst-libs/gst/interfaces/meson.build
@@ -0,0 +1,33 @@
+photography_sources = ['photography.c']
+photo_headers = ['photography.h']
+install_headers(photo_headers, subdir : 'gstreamer-1.0/gst/interfaces')
+
+mkenums = find_program('build_mkenum.py')
+
+photoenum_h = custom_target('photoenum_h',
+  output : 'photography-enumtypes.h',
+  input : photo_headers,
+  install : true,
+  install_dir : 'include/gstreamer-1.0/gst/interfaces',
+  command : [mkenums, glib_mkenums, '@OUTPUT@', '@INPUT@'])
+
+photoenum_c = custom_target('photoenum_c',
+  output : 'photography-enumtypes.c',
+  input : photo_headers,
+  command : [mkenums, glib_mkenums, '@OUTPUT@', '@INPUT@'])
+
+gstphotography = library('gstphotography-' + api_version,
+  photography_sources, photoenum_h, photoenum_c,
+  c_args : gst_plugins_bad_args + ['-DGST_USE_UNSTABLE_API'],
+  include_directories : [configinc, libsinc],
+  version : libversion,
+  soversion : soversion,
+  install : true,
+  dependencies : [gst_dep],
+  vs_module_defs: vs_module_defs_dir + 'libgstphotography.def',
+)
+
+gstphotography_dep = declare_dependency(link_with : gstphotography,
+  include_directories : [libsinc],
+  dependencies : [gst_dep],
+  sources : [photoenum_h])