pw-profiler: add profiler tool

Add Profiler object and fields.
Add profiler extension API. It notifies Profiler objects with
real-time performance data.
Add module that implements the profiler extension.
Add pw-profiler tool that binds to the profiler API and dumps the
data into a log file, gnuplot files, a html page and a script to
generate svg graphs. This is almost the same as what JACK2
JackEngineProfiling does.

src/extensions/profiler.h

@@ -0,0 +1,83 @@
+/* PipeWire
+ *
+ * Copyright © 2020 Wim Taymans
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef PIPEWIRE_EXT_PROFILER_H
+#define PIPEWIRE_EXT_PROFILER_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <spa/utils/defs.h>
+
+#define PW_TYPE_INTERFACE_Profiler		PW_TYPE_INFO_INTERFACE_BASE "Profiler"
+
+#define PW_VERSION_PROFILER			3
+struct pw_profiler;
+
+#define PW_EXTENSION_MODULE_PROFILER		PIPEWIRE_MODULE_PREFIX "module-profiler"
+
+#define PW_PROFILER_EVENT_PROFILE		0
+#define PW_PROFILER_EVENT_NUM			1
+
+/** \ref pw_profiler events */
+struct pw_profiler_events {
+#define PW_VERSION_PROFILER_EVENTS		0
+	uint32_t version;
+
+	void (*profile) (void *object, const struct spa_pod *pod);
+};
+
+#define PW_PROFILER_METHOD_ADD_LISTENER		0
+#define PW_PROFILER_METHOD_NUM			1
+
+/** \ref pw_profiler methods */
+struct pw_profiler_methods {
+#define PW_VERSION_PROFILER_METHODS		0
+	uint32_t version;
+
+	int (*add_listener) (void *object,
+			struct spa_hook *listener,
+			const struct pw_profiler_events *events,
+			void *data);
+};
+
+#define pw_profiler_method(o,method,version,...)			\
+({									\
+	int _res = -ENOTSUP;						\
+	spa_interface_call_res((struct spa_interface*)o,		\
+			struct pw_profiler_methods, _res,		\
+			method, version, ##__VA_ARGS__);		\
+	_res;								\
+})
+
+#define pw_profiler_add_listener(c,...)		pw_profiler_method(c,add_listener,0,__VA_ARGS__)
+
+#define PW_KEY_PROFILER_NAME		"profiler.name"
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif /* PIPEWIRE_EXT_PROFILER_H */