Add GStreamer plugin and element skeleton

This implements the GStreamer plugin interface and adds libcamerasrc
element feature to it. This is just enough to allow plugin
introspection.

gst-inspect-1.0 build/src/gstreamer/libgstlibcamera.so
Plugin Details:
  Name                     libcamera
  Description              libcamera capture plugin
  Filename                 build/src/gstreamer/libgstlibcamera.so
  Version                  0.0.0+1042-6c9f16d3-dirty
  License                  LGPL
  Source module            libcamera
  Binary package           libcamera
  Origin URL               https://libcamera.org

  libcamerasrc: libcamera Source

  1 features:

GST_PLUGIN_PATH=$(pwd)/build/src/gstreamer gst-inspect-1.0 libcamerasrc
Factory Details:
  Rank                     primary (256)
  Long-name                libcamera Source
  Klass                    Source/Video
  Description              Linux Camera source using libcamera
  Author                   Nicolas Dufresne <nicolas.dufresne@collabora.com

Plugin Details:
  Name                     libcamera
  Description              libcamera capture plugin
  Filename                 /home/nicolas/Sources/libcamera/build/src/gstreamer/libgstlibcamera.so
  Version                  0.0.0+1042-6c9f16d3-dirty
  License                  LGPL
  Source module            libcamera
  Binary package           libcamera
  Origin URL               https://libcamera.org

GObject
 +----GInitiallyUnowned
       +----GstObject
             +----GstElement
                   +----GstLibcameraSrc

Pad Templates:
  none

Element has no clocking capabilities.
Element has no URI handling capabilities.

Pads:
  none

Element Properties:
  name                : The name of the object
                        flags: accès en lecture, accès en écriture, 0x2000
                        String. Default: "libcamerasrc0"
  parent              : The parent of the object
                        flags: accès en lecture, accès en écriture, 0x2000
                        Object of type "GstObject"

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Silence -Wunused-function warning for older GLib versions]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/gstreamer/meson.build b/src/gstreamer/meson.build
new file mode 100644
index 00000000..490e030e
--- /dev/null
+++ b/src/gstreamer/meson.build
@@ -0,0 +1,32 @@
+libcamera_gst_sources = [
+    'gstlibcamera.c',
+    'gstlibcamerasrc.cpp',
+]
+
+libcamera_gst_c_args = [
+    '-DVERSION="@0@"'.format(libcamera_git_version),
+    '-DPACKAGE="@0@"'.format(meson.project_name()),
+]
+
+glib_dep = dependency('glib', required : get_option('gstreamer'))
+
+gst_dep = dependency('gstreamer-video-1.0', version : '>=1.14.0',
+                     required : get_option('gstreamer'))
+
+if glib_dep.found() and gst_dep.found()
+    # The G_DECLARE_FINAL_TYPE macro creates static inline functions that were
+    # not marked as possibly unused prior to GLib v2.63.0. This causes clang to
+    # complain about the ones we are not using. Silence the -Wunused-function
+    # warning in that case.
+    if cc.get_id() == 'clang' and glib_dep.version().version_compare('<2.63.0')
+        libcamera_gst_c_args += [ '-Wno-unused-function' ]
+    endif
+
+    libcamera_gst = shared_library('gstlibcamera',
+        libcamera_gst_sources,
+        c_args : libcamera_gst_c_args,
+        dependencies : [libcamera_dep, gst_dep],
+        install: true,
+        install_dir : '@0@/gstreamer-1.0'.format(get_option('libdir')),
+    )
+endif