[libcamera-devel] [PATCH v1] test: gstreamer: Factor out code into a base class

[Nicolas Dufresne]

Thanks for the patch,

see inline comment for possible improvements.

Le lundi 30 août 2021 à 02:36 +0530, Vedant Paranjape a écrit :
> Lot of code used in single stream test is boiler plate and common across
> every gstreamer test. Factored out this code into a base class called
> GstreamerTest.
> 
> Also updated the gstreamer_single_stream_test to use the GstreamerTest
> base class
> 
> Signed-off-by: Vedant Paranjape <vedantparanjape160201 at gmail.com>
> ---
>  .../gstreamer_single_stream_test.cpp          | 138 +++------------
>  test/gstreamer/gstreamer_test.cpp             | 157 ++++++++++++++++++
>  test/gstreamer/gstreamer_test.h               |  38 +++++
>  test/gstreamer/meson.build                    |   2 +-
>  4 files changed, 216 insertions(+), 119 deletions(-)
>  create mode 100644 test/gstreamer/gstreamer_test.cpp
>  create mode 100644 test/gstreamer/gstreamer_test.h
> 
> diff --git a/test/gstreamer/gstreamer_single_stream_test.cpp b/test/gstreamer/gstreamer_single_stream_test.cpp
> index 4c8d4804..021ac269 100644
> --- a/test/gstreamer/gstreamer_single_stream_test.cpp
> +++ b/test/gstreamer/gstreamer_single_stream_test.cpp
> @@ -14,86 +14,35 @@
>  
>  #include <gst/gst.h>
>  
> +#include "gstreamer_test.h"
>  #include "test.h"
>  
>  using namespace std;
>  
> -extern "C" {
> -const char *__asan_default_options()
> -{
> -	/*
> -	 * Disable leak detection due to a known global variable initialization
> -	 * leak in glib's g_quark_init(). This should ideally be handled by
> -	 * using a suppression file instead of disabling leak detection.
> -	 */
> -	return "detect_leaks=false";
> -}
> -}
> -
> -class GstreamerSingleStreamTest : public Test
> +class GstreamerSingleStreamTest : public GstreamerTest, public Test
>  {
> +public:
> +	GstreamerSingleStreamTest()
> +		: GstreamerTest()
> +	{
> +	}
> +
>  protected:
>  	int init() override
>  	{
> -		/*
> -		 * GStreamer by default spawns a process to run the
> -		 * gst-plugin-scanner helper. If libcamera is compiled with ASan
> -		 * enabled, and as GStreamer is most likely not, this causes the
> -		 * ASan link order check to fail when gst-plugin-scanner
> -		 * dlopen()s the plugin as many libraries will have already been
> -		 * loaded by then. Fix this issue by disabling spawning of a
> -		 * child helper process when scanning the build directory for
> -		 * plugins.
> -		 */
> -		gst_registry_fork_set_enabled(false);
> -
> -		/* Initialize GStreamer */
> -		g_autoptr(GError) errInit = NULL;
> -		if (!gst_init_check(nullptr, nullptr, &errInit)) {
> -			g_printerr("Could not initialize GStreamer: %s\n",
> -				   errInit ? errInit->message : "unknown error");
> -
> -			return TestFail;
> -		}
> -
> -		/*
> -		 * Remove the system libcamera plugin, if any, and add the
> -		 * plugin from the build directory.
> -		 */
> -		GstRegistry *registry = gst_registry_get();
> -		GstPlugin *plugin = gst_registry_lookup(registry, "libgstlibcamera.so");
> -		if (plugin) {
> -			gst_registry_remove_plugin(registry, plugin);
> -			gst_object_unref(plugin);
> -		}
> -
> -		std::string path = libcamera::utils::libcameraBuildPath()
> -				 + "src/gstreamer";
> -		if (!gst_registry_scan_path(registry, path.c_str())) {
> -			g_printerr("Failed to add plugin to registry\n");
> -			gst_deinit();
> -			return TestFail;
> -		}
> +		if (status_ != TestPass)
> +			return status_;
>  
> -		/* Create the elements */
> -		libcameraSrc_ = gst_element_factory_make("libcamerasrc", "libcamera");
>  		convert0_ = gst_element_factory_make("videoconvert", "convert0");
>  		sink0_ = gst_element_factory_make("fakesink", "sink0");
>  
> -		/* Create the empty pipeline_ */
> -		pipeline_ = gst_pipeline_new("test-pipeline");
> -
> -		if (!pipeline_ || !convert0_ || !sink0_ || !libcameraSrc_) {
> -			g_printerr("Not all elements could be created. %p.%p.%p.%p\n",
> -				   pipeline_, convert0_, sink0_, libcameraSrc_);
> -			if (pipeline_)
> -				gst_object_unref(pipeline_);
> +		if (!convert0_ || !sink0_) {
> +			g_printerr("Not all elements could be created. %p.%p\n",
> +				   convert0_, sink0_);
>  			if (convert0_)
>  				gst_object_unref(convert0_);
>  			if (sink0_)
>  				gst_object_unref(sink0_);
> -			if (libcameraSrc_)
> -				gst_object_unref(libcameraSrc_);
>  			gst_deinit();
>  
>  			return TestFail;
> @@ -102,16 +51,8 @@ protected:
>  		return TestPass;
>  	}
>  
> -	void cleanup() override
> -	{
> -		gst_object_unref(pipeline_);
> -		gst_deinit();
> -	}
> -
>  	int run() override
>  	{
> -		GstStateChangeReturn ret;
> -
>  		/* Build the pipeline */
>  		gst_bin_add_many(GST_BIN(pipeline_), libcameraSrc_, convert0_, sink0_, NULL);
>  		if (gst_element_link_many(libcameraSrc_, convert0_, sink0_, NULL) != TRUE) {
> @@ -119,57 +60,18 @@ protected:
>  			return TestFail;
>  		}
>  
> -		/* Start playing */
> -		ret = gst_element_set_state(pipeline_, GST_STATE_PLAYING);
> -		if (ret == GST_STATE_CHANGE_FAILURE) {
> -			g_printerr("Unable to set the pipeline to the playing state.\n");
> -			return TestFail;
> -		}
> +		gstreamer_start_pipeline();
> +		if (status_ != TestPass)
> +			return status_;
>  
> -		/* Wait until error or EOS or timeout after 2 seconds */
> -		constexpr GstMessageType msgType =
> -			static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
> -		constexpr GstClockTime timeout = 2 * GST_SECOND;
> -
> -		g_autoptr(GstBus) bus = gst_element_get_bus(pipeline_);
> -		g_autoptr(GstMessage) msg = gst_bus_timed_pop_filtered(bus, timeout, msgType);
> -
> -		gst_element_set_state(pipeline_, GST_STATE_NULL);
> -
> -		/* Parse error message */
> -		if (msg == NULL)
> -			return TestPass;
> -
> -		switch (GST_MESSAGE_TYPE(msg)) {
> -		case GST_MESSAGE_ERROR:
> -			gstreamer_print_error(msg);
> -			break;
> -		case GST_MESSAGE_EOS:
> -			g_print("End-Of-Stream reached.\n");
> -			break;
> -		default:
> -			g_printerr("Unexpected message received.\n");
> -			break;
> -		}
> +		gstreamer_wait_for_event();
> +		if (status_ != TestPass)
> +			return status_;
>  
> -		return TestFail;
> +		return TestPass;
>  	}
>  
>  private:
> -	void gstreamer_print_error(GstMessage *msg)
> -	{
> -		g_autoptr(GError) err = NULL;
> -		g_autofree gchar *debug_info = NULL;
> -
> -		gst_message_parse_error(msg, &err, &debug_info);
> -		g_printerr("Error received from element %s: %s\n",
> -			   GST_OBJECT_NAME(msg->src), err->message);
> -		g_printerr("Debugging information: %s\n",
> -			   debug_info ? debug_info : "none");
> -	}
> -
> -	GstElement *pipeline_;
> -	GstElement *libcameraSrc_;
>  	GstElement *convert0_;
>  	GstElement *sink0_;
>  };
> diff --git a/test/gstreamer/gstreamer_test.cpp b/test/gstreamer/gstreamer_test.cpp
> new file mode 100644
> index 00000000..34608a02
> --- /dev/null
> +++ b/test/gstreamer/gstreamer_test.cpp
> @@ -0,0 +1,157 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2021, Vedant Paranjape
> + *
> + * libcamera Gstreamer element API tests
> + */
> +
> +#include "gstreamer_test.h"
> +
> +#include "test.h"
> +
> +using namespace std;
> +
> +extern "C" {
> +const char *__asan_default_options()
> +{
> +	/*
> +	 * Disable leak detection due to a known global variable initialization
> +	 * leak in glib's g_quark_init(). This should ideally be handled by
> +	 * using a suppression file instead of disabling leak detection.
> +	 */
> +	return "detect_leaks=false";
> +}
> +}
> +
> +GstreamerTest::GstreamerTest()
> +{
> +	/*
> +	* GStreamer by default spawns a process to run the
> +	* gst-plugin-scanner helper. If libcamera is compiled with ASan
> +	* enabled, and as GStreamer is most likely not, this causes the
> +	* ASan link order check to fail when gst-plugin-scanner
> +	* dlopen()s the plugin as many libraries will have already been
> +	* loaded by then. Fix this issue by disabling spawning of a
> +	* child helper process when scanning the build directory for
> +	* plugins.
> +	*/
> +	gst_registry_fork_set_enabled(false);
> +
> +	/* Initialize GStreamer */
> +	g_autoptr(GError) errInit = NULL;
> +	if (!gst_init_check(nullptr, nullptr, &errInit)) {
> +		g_printerr("Could not initialize GStreamer: %s\n",
> +			   errInit ? errInit->message : "unknown error");
> +
> +		status_ = TestFail;
> +		return;
> +	}
> +
> +	/*
> +		* Remove the system libcamera plugin, if any, and add the
> +		* plugin from the build directory.
> +		*/

Indent looks wrong, did you enable the commit hooks ?

> +	GstRegistry *registry = gst_registry_get();
> +	GstPlugin *plugin = gst_registry_lookup(registry, "libgstlibcamera.so");
> +	if (plugin) {
> +		gst_registry_remove_plugin(registry, plugin);
> +		gst_object_unref(plugin);

nit: Perhaps use a g_autoptr() instead ?

> +	}
> +
> +	std::string path = libcamera::utils::libcameraBuildPath() + "src/gstreamer";
> +	if (!gst_registry_scan_path(registry, path.c_str())) {
> +		g_printerr("Failed to add plugin to registry\n");
> +		gst_deinit();

Move this in the destructor ? Note that gst_deinit() can only be run once per
process live-time. So if you have multiple test in the same process, make sure
this happens only once.

> +		status_ = TestFail;
> +		return;
> +	}
> +
> +	/* Create the elements */
> +	libcameraSrc_ = gst_element_factory_make("libcamerasrc", "libcamera");
> +	pipeline_ = gst_pipeline_new("test-pipeline");

Personally, I would entirely defer this, and create a virtual func to create the
pipeline. This way test can use gst_parse_launch() instead of handcrafting test
pipelines.

> +
> +	if (!pipeline_ || !libcameraSrc_) {
> +		g_printerr("Not all elements could be created. %p.%p\n",
> +			   pipeline_, libcameraSrc_);
> +		if (pipeline_)
> +			gst_object_unref(pipeline_);
> +		if (libcameraSrc_)
> +			gst_object_unref(libcameraSrc_);
To avoid this overhead, use local g_autoptr() and then blabla_ =
g_steal_pointer() to save it.
> +		gst_deinit();
> +		status_ = TestFail;
> +		return;
> +	}
> +
> +	status_ = TestPass;

I peaked at the usage, and I'm not big fan, have you considered adding an init()
function with a proper return value? The C++ way is to use exception, not sure
what the libcamera project thinks about it.

> +}
> +
> +GstreamerTest::~GstreamerTest()
> +{
> +	gst_object_unref(pipeline_);
> +	if (status_ == TestFail) {
> +		gst_object_unref(libcameraSrc_);
> +	}
> +
> +	gst_deinit();

As you already do this here, and destructor get called regardless if the
constructor worked or not, I think ou can remove all the duplicates in the
constructor.

> +}
> +
> +void GstreamerTest::gstreamer_start_pipeline()
> +{
> +	GstStateChangeReturn ret;
> +
> +	/* Start playing */
> +	ret = gst_element_set_state(pipeline_, GST_STATE_PLAYING);
> +	if (ret == GST_STATE_CHANGE_FAILURE) {
> +		g_printerr("Unable to set the pipeline to the playing state.\n");
> +		status_ = TestFail;
> +		return;
> +	}
> +
> +	status_ = TestPass;

Why not use a return value ?

> +}
> +
> +void GstreamerTest::gstreamer_wait_for_event()
> +{
> +	/* Wait until error or EOS or timeout after 2 seconds */
> +	constexpr GstMessageType msgType =
> +		static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
> +	constexpr GstClockTime timeout = 2 * GST_SECOND;
> +
> +	g_autoptr(GstBus) bus = gst_element_get_bus(pipeline_);
> +	g_autoptr(GstMessage) msg = gst_bus_timed_pop_filtered(bus, timeout, msgType);

Can we make the msgType a optional argument here ? IIRC C++ allow for default
value.

> +
> +	gst_element_set_state(pipeline_, GST_STATE_NULL);

The method is called "wait_for_event", having it stop the pipeline is a bit
unexpected.

> +
> +	/* Parse error message */
> +	if (msg == NULL) {
> +		status_ = TestPass;
> +		return;
> +	}
> +
> +	switch (GST_MESSAGE_TYPE(msg)) {
> +	case GST_MESSAGE_ERROR:
> +		gstreamer_print_error(msg);
> +		break;
> +	case GST_MESSAGE_EOS:
> +		g_print("End-Of-Stream reached.\n");
> +		break;
> +	default:
> +		g_printerr("Unexpected message received.\n");
> +		break;
> +	}
> +
> +	status_ = TestPass;
> +}
> +
> +void GstreamerTest::gstreamer_print_error(GstMessage *msg)
> +{
> +	g_autoptr(GError) err = NULL;
> +	g_autofree gchar *debug_info = NULL;
> +
> +	gst_message_parse_error(msg, &err, &debug_info);
> +	g_printerr("Error received from element %s: %s\n",
> +		   GST_OBJECT_NAME(msg->src), err->message);
> +	g_printerr("Debugging information: %s\n",
> +		   debug_info ? debug_info : "none");
> +}
> +
> diff --git a/test/gstreamer/gstreamer_test.h b/test/gstreamer/gstreamer_test.h
> new file mode 100644
> index 00000000..8e117166
> --- /dev/null
> +++ b/test/gstreamer/gstreamer_test.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2021, Vedant Paranjape
> + *
> + * gstreamer_test.cpp - GStreamer test base class
> + */
> +
> +#ifndef __LIBCAMERA_GSTREAMER_TEST_H__
> +#define __LIBCAMERA_GSTREAMER_TEST_H__
> +
> +#include <iostream>
> +#include <unistd.h>
> +
> +#include <libcamera/base/utils.h>
> +
> +#include "libcamera/internal/source_paths.h"
> +
> +#include <gst/gst.h>
> +
> +using namespace std;
> +
> +class GstreamerTest
> +{
> +public:
> +	GstreamerTest();
> +	~GstreamerTest();
> +
> +protected:
> +	void gstreamer_start_pipeline();
> +	void gstreamer_wait_for_event();
> +	void gstreamer_print_error(GstMessage *msg);
> +
> +	GstElement *pipeline_;
> +	GstElement *libcameraSrc_;
> +	int status_;
> +};
> +
> +#endif /* __LIBCAMERA_GSTREAMER_TEST_H__ */
> \ No newline at end of file
> diff --git a/test/gstreamer/meson.build b/test/gstreamer/meson.build
> index b99aa0da..aca53b92 100644
> --- a/test/gstreamer/meson.build
> +++ b/test/gstreamer/meson.build
> @@ -10,7 +10,7 @@ gstreamer_tests = [
>  gstreamer_dep = dependency('gstreamer-1.0', required: true)
>  
>  foreach t : gstreamer_tests
> -    exe = executable(t[0], t[1],
> +    exe = executable(t[0], t[1], 'gstreamer_test.cpp',
>                       dependencies : [libcamera_private, gstreamer_dep],
>                       link_with : test_libraries,
>                       include_directories : test_includes_internal)