dmabufallocator: adds gst_dmabuf_allocator_alloc_with_flags

If we can guarantee the lifetime of the fd is longer than
the memory, we can use DONT_CLOSE flag not to close when release.
But it's not provided in gstdmabuf yet while gstfdmemory does.

For example, in case of using VA-API or MSDK, we would need this api.
Otherwise we should call dup to duplicate the fd.

https://bugzilla.gnome.org/show_bug.cgi?id=794829

docs/libs/gst-plugins-base-libs-sections.txt

@@ -7,6 +7,7 @@
 GST_CAPS_FEATURE_MEMORY_DMABUF
 gst_dmabuf_allocator_new
 gst_dmabuf_allocator_alloc
+gst_dmabuf_allocator_alloc_with_flags
 gst_dmabuf_memory_get_fd
 gst_is_dmabuf_memory
 <SUBSECTION Standard>

gst-libs/gst/allocators/gstdmabuf.c

@@ -157,6 +157,32 @@ gst_dmabuf_allocator_alloc (GstAllocator * allocator, gint fd, gsize size)
   return gst_fd_allocator_alloc (allocator, fd, size, GST_FD_MEMORY_FLAG_NONE);
 }
 
+/**
+ * gst_dmabuf_allocator_alloc_with_flags:
+ * @allocator: allocator to be used for this memory
+ * @fd: dmabuf file descriptor
+ * @size: memory size
+ * @flags: extra #GstFdMemoryFlags
+ *
+ * Return a %GstMemory that wraps a dmabuf file descriptor.
+ *
+ * Returns: (transfer full): a GstMemory based on @allocator.
+ *
+ * When the buffer will be released the allocator will close the @fd unless
+ * the %GST_FD_MEMORY_FLAG_DONT_CLOSE flag is specified.
+ * The memory is only mmapped on gst_buffer_mmap() request.
+ *
+ * Since: 1.16
+ */
+GstMemory *
+gst_dmabuf_allocator_alloc_with_flags (GstAllocator * allocator, gint fd,
+    gsize size, GstFdMemoryFlags flags)
+{
+  g_return_val_if_fail (GST_IS_DMABUF_ALLOCATOR (allocator), NULL);
+
+  return gst_fd_allocator_alloc (allocator, fd, size, flags);
+}
+
 /**
  * gst_dmabuf_memory_get_fd:
  * @mem: the memory to get the file descriptor

gst-libs/gst/allocators/gstdmabuf.h

@@ -104,6 +104,9 @@ GstAllocator * gst_dmabuf_allocator_new (void);
 GST_ALLOCATORS_API
 GstMemory    * gst_dmabuf_allocator_alloc (GstAllocator * allocator, gint fd, gsize size);
 
+GST_ALLOCATORS_API
+GstMemory    * gst_dmabuf_allocator_alloc_with_flags (GstAllocator * allocator, gint fd, gsize size, GstFdMemoryFlags flags);
+
 GST_ALLOCATORS_API
 gint           gst_dmabuf_memory_get_fd (GstMemory * mem);