[libcamera-devel] [PATCH v1 17/23] gst: Add a pool and an allocator implementation

Nicolas Dufresne nicolas at ndufresne.ca
Wed Jan 29 04:32:04 CET 2020


From: Nicolas Dufresne <nicolas.dufresne at collabora.com>

This is needed to track the livetime of the FrameBufferAllocator in relation to
the GstBuffer/GstMemory objects travelling inside GStreamer.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
---
 src/gstreamer/gstlibcameraallocator.cpp | 240 ++++++++++++++++++++++++
 src/gstreamer/gstlibcameraallocator.h   |  29 +++
 src/gstreamer/gstlibcamerapool.cpp      | 109 +++++++++++
 src/gstreamer/gstlibcamerapool.h        |  27 +++
 src/gstreamer/meson.build               |  11 +-
 5 files changed, 413 insertions(+), 3 deletions(-)
 create mode 100644 src/gstreamer/gstlibcameraallocator.cpp
 create mode 100644 src/gstreamer/gstlibcameraallocator.h
 create mode 100644 src/gstreamer/gstlibcamerapool.cpp
 create mode 100644 src/gstreamer/gstlibcamerapool.h

diff --git a/src/gstreamer/gstlibcameraallocator.cpp b/src/gstreamer/gstlibcameraallocator.cpp
new file mode 100644
index 0000000..0f248b4
--- /dev/null
+++ b/src/gstreamer/gstlibcameraallocator.cpp
@@ -0,0 +1,240 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcameraallocator.cpp - GStreamer Custom Allocator
+ */
+
+#include "gstlibcameraallocator.h"
+#include "gstlibcamera-utils.h"
+
+#include <libcamera/camera.h>
+#include <libcamera/stream.h>
+#include <libcamera/framebuffer_allocator.h>
+
+using namespace libcamera;
+
+/***********************************************************************/
+/* Internal object for tracking memories associated with a FrameBuffer */
+/***********************************************************************/
+
+static gboolean gst_libcamera_allocator_release(GstMiniObject *mini_object);
+
+/* This internal object is used to track the outstanding GstMemory object that
+ * are part of a FrameBuffer. The allocator will only re-use a FrameBuffer when
+ * al all outstranging GstMemory have returned.
+ */
+struct FrameWrap {
+	FrameWrap(GstAllocator *allocator, FrameBuffer *buffer,
+		  gpointer stream);
+	~FrameWrap();
+
+	void AcquirePlane() { ++outstanding_planes_; }
+	bool ReleasePlane() { return --outstanding_planes_ == 0; }
+
+	gpointer stream_;
+	FrameBuffer *buffer_;
+	std::vector<GstMemory *> planes_;
+	gint outstanding_planes_;
+};
+
+static GQuark
+gst_libcamera_frame_quark(void)
+{
+	static gsize frame_quark = 0;
+
+	if (g_once_init_enter(&frame_quark)) {
+		GQuark quark = g_quark_from_string("GstLibCameraFrameWrap");
+		g_once_init_leave(&frame_quark, quark);
+	}
+
+	return frame_quark;
+}
+
+FrameWrap::FrameWrap(GstAllocator *allocator, FrameBuffer *buffer,
+		     gpointer stream)
+
+	: stream_(stream),
+	  buffer_(buffer),
+	  outstanding_planes_(0)
+{
+	for (const FrameBuffer::Plane &plane : buffer->planes()) {
+		GstMemory *mem = gst_fd_allocator_alloc(allocator,
+							plane.fd.fd(),
+							plane.length,
+							GST_FD_MEMORY_FLAG_DONT_CLOSE);
+		gst_mini_object_set_qdata(GST_MINI_OBJECT(mem),
+					  gst_libcamera_frame_quark(),
+					  this, NULL);
+		GST_MINI_OBJECT(mem)->dispose = gst_libcamera_allocator_release;
+		g_object_unref(mem->allocator);
+		planes_.push_back(mem);
+	}
+}
+
+FrameWrap::~FrameWrap()
+{
+	for (GstMemory *mem : planes_) {
+		GST_MINI_OBJECT(mem)->dispose = nullptr;
+		g_object_ref(mem->allocator);
+		gst_memory_unref(mem);
+	}
+}
+
+/***********************************/
+/* The GstAllocator implementation */
+/***********************************/
+struct _GstLibcameraAllocator {
+	GstDmaBufAllocator parent;
+	FrameBufferAllocator *fb_allocator;
+	/* A hash table using Stream pointer as key and returning a GQueue of
+	 * FrameWrap. */
+	GHashTable *pools;
+};
+
+G_DEFINE_TYPE(GstLibcameraAllocator, gst_libcamera_allocator,
+	      GST_TYPE_DMABUF_ALLOCATOR);
+
+static gboolean
+gst_libcamera_allocator_release(GstMiniObject *mini_object)
+{
+	GstMemory *mem = GST_MEMORY_CAST(mini_object);
+	GstLibcameraAllocator *self = GST_LIBCAMERA_ALLOCATOR(mem->allocator);
+	GST_OBJECT_LOCKER(self);
+	gpointer data = gst_mini_object_get_qdata(mini_object,
+						  gst_libcamera_frame_quark());
+	auto *frame = (FrameWrap *)data;
+
+	gst_memory_ref(mem);
+
+	if (frame->ReleasePlane()) {
+		auto *pool = (GQueue *)g_hash_table_lookup(self->pools, frame->stream_);
+		g_return_val_if_fail(pool, TRUE);
+		g_queue_push_tail(pool, frame);
+	}
+
+	/* Keep last in case we are holding on the last allocator ref */
+	g_object_unref(mem->allocator);
+
+	/* Rreturns FALSE so that our mini object isn't freed */
+	return FALSE;
+}
+
+static void
+gst_libcamera_allocator_free_pool(gpointer data)
+{
+	GQueue *queue = (GQueue *)data;
+	FrameWrap *frame;
+
+	while ((frame = (FrameWrap *)g_queue_pop_head(queue))) {
+		g_warn_if_fail(frame->outstanding_planes_ == 0);
+		delete frame;
+	}
+
+	g_queue_free(queue);
+}
+
+static void
+gst_libcamera_allocator_init(GstLibcameraAllocator *self)
+{
+	self->pools = g_hash_table_new_full(NULL, NULL, NULL,
+					    gst_libcamera_allocator_free_pool);
+	GST_OBJECT_FLAG_SET(self, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
+}
+
+static void
+gst_libcamera_allocator_dispose(GObject *object)
+{
+	GstLibcameraAllocator *self = GST_LIBCAMERA_ALLOCATOR(object);
+
+	if (self->pools) {
+		g_hash_table_unref(self->pools);
+		self->pools = NULL;
+	}
+
+	G_OBJECT_CLASS(gst_libcamera_allocator_parent_class)->dispose(object);
+}
+
+static void
+gst_libcamera_allocator_finalize(GObject *object)
+{
+	GstLibcameraAllocator *self = GST_LIBCAMERA_ALLOCATOR(object);
+
+	delete self->fb_allocator;
+
+	G_OBJECT_CLASS(gst_libcamera_allocator_parent_class)->finalize(object);
+}
+
+static void
+gst_libcamera_allocator_class_init(GstLibcameraAllocatorClass *klass)
+{
+	auto *allocator_class = GST_ALLOCATOR_CLASS(klass);
+	auto *object_class = G_OBJECT_CLASS(klass);
+
+	object_class->dispose = gst_libcamera_allocator_dispose;
+	object_class->finalize = gst_libcamera_allocator_finalize;
+	allocator_class->alloc = NULL;
+}
+
+GstLibcameraAllocator *
+gst_libcamera_allocator_new(std::shared_ptr<Camera> camera)
+{
+	auto *self = (GstLibcameraAllocator *)g_object_new(GST_TYPE_LIBCAMERA_ALLOCATOR,
+							   nullptr);
+
+	self->fb_allocator = FrameBufferAllocator::create(camera);
+	for (Stream *stream : camera->streams()) {
+		gint ret;
+
+		ret = self->fb_allocator->allocate(stream);
+		if (ret == 0)
+			return nullptr;
+
+		GQueue *pool = g_queue_new();
+		for (const std::unique_ptr<FrameBuffer> &buffer :
+		     self->fb_allocator->buffers(stream)) {
+			auto *fb = new FrameWrap(GST_ALLOCATOR(self),
+						 buffer.get(), stream);
+			g_queue_push_tail(pool, fb);
+		}
+
+		g_hash_table_insert(self->pools, stream, pool);
+	}
+
+	return self;
+}
+
+bool
+gst_libcamera_allocator_prepare_buffer(GstLibcameraAllocator *self,
+				       Stream *stream, GstBuffer *buffer)
+{
+	GST_OBJECT_LOCKER(self);
+
+	auto *pool = (GQueue *)g_hash_table_lookup(self->pools, stream);
+	g_return_val_if_fail(pool, false);
+
+	auto *frame = (FrameWrap *)g_queue_pop_head(pool);
+	if (!frame)
+		return false;
+
+	for (GstMemory *mem : frame->planes_) {
+		frame->AcquirePlane();
+		gst_buffer_append_memory(buffer, mem);
+		g_object_ref(mem->allocator);
+	}
+
+	return true;
+}
+
+gsize
+gst_libcamera_allocator_get_pool_size(GstLibcameraAllocator *self,
+				      Stream *stream)
+{
+	GST_OBJECT_LOCKER(self);
+
+	auto *pool = (GQueue *)g_hash_table_lookup(self->pools, stream);
+	g_return_val_if_fail(pool, false);
+
+	return pool->length;
+}
diff --git a/src/gstreamer/gstlibcameraallocator.h b/src/gstreamer/gstlibcameraallocator.h
new file mode 100644
index 0000000..f2a0f58
--- /dev/null
+++ b/src/gstreamer/gstlibcameraallocator.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcameraallocator.h - GStreamer Custom Allocator
+ */
+
+#include <gst/gst.h>
+#include <gst/allocators/allocators.h>
+#include <libcamera/stream.h>
+
+#ifndef __GST_LIBCAMERA_ALLOCATOR_H__
+#define __GST_LIBCAMERA_ALLOCATOR_H__
+
+#define GST_TYPE_LIBCAMERA_ALLOCATOR gst_libcamera_allocator_get_type()
+G_DECLARE_FINAL_TYPE(GstLibcameraAllocator, gst_libcamera_allocator,
+		     GST_LIBCAMERA, ALLOCATOR, GstDmaBufAllocator)
+
+GstLibcameraAllocator *gst_libcamera_allocator_new(std::shared_ptr<libcamera::Camera> camera);
+
+bool gst_libcamera_allocator_prepare_buffer(GstLibcameraAllocator *self,
+					    libcamera::Stream *stream,
+					    GstBuffer *buffer);
+
+gsize gst_libcamera_allocator_get_pool_size(GstLibcameraAllocator *allocator,
+					    libcamera::Stream *stream);
+
+#endif /* __GST_LIBCAMERA_ALLOCATOR_H__ */
diff --git a/src/gstreamer/gstlibcamerapool.cpp b/src/gstreamer/gstlibcamerapool.cpp
new file mode 100644
index 0000000..f84d1d6
--- /dev/null
+++ b/src/gstreamer/gstlibcamerapool.cpp
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcamerapool.cpp - GStreamer Buffer Pool
+ */
+
+#include "gstlibcamerapool.h"
+#include "gstlibcamera-utils.h"
+
+#include <libcamera/stream.h>
+
+using namespace libcamera;
+
+struct _GstLibcameraPool {
+	GstBufferPool parent;
+
+	GstAtomicQueue *queue;
+	GstLibcameraAllocator *allocator;
+	Stream *stream;
+};
+
+G_DEFINE_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_TYPE_BUFFER_POOL);
+
+static GstFlowReturn
+gst_libcamera_pool_acquire_buffer(GstBufferPool *pool, GstBuffer **buffer,
+				  GstBufferPoolAcquireParams *params)
+{
+	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
+	GstBuffer *buf = (GstBuffer *)gst_atomic_queue_pop(self->queue);
+	if (!buf)
+		return GST_FLOW_ERROR;
+
+	if (!gst_libcamera_allocator_prepare_buffer(self->allocator, self->stream, buf))
+		return GST_FLOW_ERROR;
+
+	*buffer = buf;
+	return GST_FLOW_OK;
+}
+
+static void
+gst_libcamera_pool_reset_buffer(GstBufferPool *pool, GstBuffer *buffer)
+{
+	GstBufferPoolClass *klass = GST_BUFFER_POOL_CLASS(gst_libcamera_pool_parent_class);
+
+	/* Clears all the memories and only pool the GstBuffer objects */
+	gst_buffer_remove_all_memory(buffer);
+	klass->reset_buffer(pool, buffer);
+	GST_BUFFER_FLAGS(buffer) = 0;
+}
+
+static void
+gst_libcamera_pool_release_buffer(GstBufferPool *pool, GstBuffer *buffer)
+{
+	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
+	gst_atomic_queue_push(self->queue, (gpointer)buffer);
+}
+
+static void
+gst_libcamera_pool_init(GstLibcameraPool *self)
+{
+	self->queue = gst_atomic_queue_new(4);
+}
+
+static void
+gst_libcamera_pool_finalize(GObject *object)
+{
+	GstLibcameraPool *self = GST_LIBCAMERA_POOL(object);
+	GstBuffer *buf;
+
+	while ((buf = (GstBuffer *)gst_atomic_queue_pop(self->queue)))
+		gst_buffer_unref(buf);
+
+	gst_atomic_queue_unref(self->queue);
+	g_object_unref(self->allocator);
+
+	G_OBJECT_CLASS(gst_libcamera_pool_parent_class)->finalize(object);
+}
+
+static void
+gst_libcamera_pool_class_init(GstLibcameraPoolClass *klass)
+{
+	auto *object_class = G_OBJECT_CLASS(klass);
+	auto *pool_class = GST_BUFFER_POOL_CLASS(klass);
+
+	object_class->finalize = gst_libcamera_pool_finalize;
+	pool_class->start = nullptr;
+	pool_class->acquire_buffer = gst_libcamera_pool_acquire_buffer;
+	pool_class->reset_buffer = gst_libcamera_pool_reset_buffer;
+	pool_class->release_buffer = gst_libcamera_pool_release_buffer;
+}
+
+GstLibcameraPool *
+gst_libcamera_pool_new(GstLibcameraAllocator *allocator, Stream *stream)
+{
+	auto *pool = (GstLibcameraPool *)g_object_new(GST_TYPE_LIBCAMERA_POOL, nullptr);
+
+	pool->allocator = (GstLibcameraAllocator *)g_object_ref(allocator);
+	pool->stream = stream;
+
+	gsize pool_size = gst_libcamera_allocator_get_pool_size(allocator, stream);
+	for (gsize i = 0; i < pool_size; i++) {
+		GstBuffer *buffer = gst_buffer_new();
+		gst_atomic_queue_push(pool->queue, buffer);
+	}
+
+	return pool;
+}
diff --git a/src/gstreamer/gstlibcamerapool.h b/src/gstreamer/gstlibcamerapool.h
new file mode 100644
index 0000000..ca6b299
--- /dev/null
+++ b/src/gstreamer/gstlibcamerapool.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcamerapool.h - GStreamer Buffer Pool
+ *
+ * This is a partial implementation of GstBufferPool intended for internal use
+ * only. This pool cannot be configured or activated.
+ */
+
+#include <gst/gst.h>
+#include <libcamera/stream.h>
+
+#include "gstlibcameraallocator.h"
+
+#ifndef __GST_LIBCAMERA_POOL_H__
+#define __GST_LIBCAMERA_POOL_H__
+
+#define GST_TYPE_LIBCAMERA_POOL gst_libcamera_pool_get_type()
+G_DECLARE_FINAL_TYPE(GstLibcameraPool, gst_libcamera_pool,
+		     GST_LIBCAMERA, POOL, GstBufferPool)
+
+GstLibcameraPool *gst_libcamera_pool_new(GstLibcameraAllocator *allocator,
+					 libcamera::Stream *stream);
+
+#endif /* __GST_LIBCAMERA_POOL_H__ */
diff --git a/src/gstreamer/meson.build b/src/gstreamer/meson.build
index e497bf4..346910f 100644
--- a/src/gstreamer/meson.build
+++ b/src/gstreamer/meson.build
@@ -4,6 +4,8 @@ libcamera_gst_sources = [
     'gstlibcamerasrc.cpp',
     'gstlibcameraprovider.cpp',
     'gstlibcamerapad.cpp',
+    'gstlibcameraallocator.cpp',
+    'gstlibcamerapool.cpp'
 ]
 
 libcamera_gst_c_args = [
@@ -11,15 +13,18 @@ libcamera_gst_c_args = [
     '-DPACKAGE="@0@"'.format(meson.project_name()),
 ]
 
-gst_dep = dependency('gstreamer-video-1.0', version : '>=1.16.1',
+gst_req = '>=1.16.1'
+gstvideo_dep = dependency('gstreamer-video-1.0', version : gst_req,
+    required : get_option('gstreamer'))
+gstallocator_dep = dependency('gstreamer-allocators-1.0', version : gst_req,
     required : get_option('gstreamer'))
 
-if gst_dep.found()
+if gstvideo_dep.found() and gstallocator_dep.found()
   libcamera_gst = shared_library('gstlibcamera',
       libcamera_gst_sources,
       c_args : libcamera_gst_c_args,
       include_directories : [],
-      dependencies : [libcamera_dep, gst_dep],
+      dependencies : [libcamera_dep, gstvideo_dep, gstallocator_dep],
       install: true,
       install_dir : '@0@/gstreamer-1.0'.format(get_option('libdir')),
   )
-- 
2.24.1



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