videoio: refactor GStreamer backend

- exception safe smart pointers, fixed many memory leaks
- fixed errors handling
- fixed strings handling
- fixed file existence check
- fixed toFraction() implementation
- add 'drop=true' for v4l2 input
- avoid overriding custom pipelines sink's 'max-buffers' value
- updated valgrind supression rules
- added support for GStreamer native leaks tracking (via gst_deinit() call)
- repaired capturing through GStreamer0.10 (fixed CV_8UC1)

modules/videoio/src/precomp.hpp

@@ -154,8 +154,11 @@ CvVideoWriter* cvCreateVideoWriter_AVFoundation( const char* filename, int fourc
 
 CvCapture * cvCreateCameraCapture_Unicap  (const int     index);
 CvCapture * cvCreateCameraCapture_PvAPI  (const int     index);
+
+namespace cv {
 CvVideoWriter* cvCreateVideoWriter_GStreamer( const char* filename, int fourcc,
                                             double fps, CvSize frameSize, int is_color );
+}
 
 
 namespace cv

platforms/scripts/valgrind.supp

@@ -218,6 +218,14 @@
    fun:__itt_*create*
 }
 
+{
+   OpenCV-gtk_init
+   Memcheck:Leak
+   ...
+   fun:gtk_init
+   fun:cvInitSystem
+}
+
 {
    OpenCV-FFmpeg-swsscale
    Memcheck:Addr16
@@ -227,6 +235,35 @@
    fun:cvWriteFrame_FFMPEG
 }
 
+{
+   OpenCV-GStreamer-gst_init
+   Memcheck:Leak
+   ...
+   fun:gst_init
+}
+
+{
+   OpenCV-GStreamer-gst_deinit
+   Memcheck:Leak
+   ...
+   fun:gst_deinit
+}
+
+{
+   OpenCV-GStreamer-gst_init_check
+   Memcheck:Leak
+   ...
+   fun:gst_init_check
+}
+
+{
+   OpenCV-GStreamer-gst_parse_launch_full-reachable
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   ...
+   fun:gst_parse_launch_full
+}
+
 {
    OpenCV-OpenEXR-ThreadPool
    Memcheck:Leak

platforms/scripts/valgrind_3rdparty.supp

@@ -18,6 +18,15 @@
    fun:_ZN7testing8internal11CmpHelperLEIddEENS_15AssertionResultEPKcS4_RKT_RKT0_
 }
 
+{
+   GTest-RegisterTests
+   Memcheck:Leak
+   ...
+   fun:RegisterTests
+   ...
+   fun:_ZN7testing14InitGoogleTestEPiPPc
+}
+
 {
    OpenCL
    Memcheck:Cond
@@ -55,10 +64,10 @@
 }
 
 {
-   glib
+   GTK-css
    Memcheck:Leak
-   fun:*alloc
-   obj:*/libglib*
+   ...
+   fun:gtk_css_provider*
 }
 
 {
@@ -120,3 +129,78 @@
    ...
    fun:cvWriteFrame_FFMPEG
 }
+
+{
+   GStreamer-orc_program_compile_full
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   ...
+   fun:orc_program_compile_full
+   ...
+   fun:clone
+}
+
+{
+   GStreamer-orc_program_new_from_static_bytecode
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   ...
+   fun:orc_program_new_from_static_bytecode
+   ...
+   fun:clone
+}
+
+{
+   GStreamer-matroska-other
+   Memcheck:Leak
+   ...
+   fun:gst*
+   obj:*gstmatroska*
+   ...
+   obj:*glib*
+   fun:start_thread
+   fun:clone
+}
+
+{
+   GStreamer-matroska-gst_riff_create_video_caps
+   Memcheck:Leak
+   ...
+   fun:gst_riff_create_video_caps
+   obj:*gstmatroska*
+   ...
+   fun:clone
+}
+
+
+{
+   GStreamer-tls
+   Memcheck:Leak
+   match-leak-kinds: possible
+   fun:calloc
+   fun:allocate_dtv
+   fun:_dl_allocate_tls
+}
+
+{
+   GStreamer-registry
+   Memcheck:Leak
+   ...
+   fun:gst_update_registry
+}
+
+{
+   GStreamer-plugin_load
+   Memcheck:Leak
+   ...
+   fun:gst_plugin_load_by_name
+}
+
+{
+   GStreamer-separate-threads
+   Memcheck:Leak
+   ...
+   obj:*/libglib*
+   fun:start_thread
+   fun:clone
+}