Tools: add parser to extract event definitions in source & generate json output

Example definition:
			/* EVENT
			 * @description
			 * test description
			 * @arg1: test
			 */
			events::send<uint8_t>(events::ID("test_event"),
					"test message", events::Log::Error, 0);

Tools/px_process_events.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python
+############################################################################
+#
+#   Copyright (C) 2020 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+#
+# PX4 events processor (main executable file)
+#
+# This tool scans the PX4 source code for definitions of events.
+#
+
+import sys
+import os
+import argparse
+from px4events import srcscanner, srcparser, jsonout
+
+import re
+import codecs
+
+
+def main():
+    # Parse command line arguments
+    parser = argparse.ArgumentParser(description="Process events definitions.")
+    parser.add_argument("-s", "--src-path",
+                        default=["../src"],
+                        metavar="PATH",
+                        nargs='*',
+                        help="one or more paths/files to source files to scan for events")
+    parser.add_argument("-j", "--json",
+                        nargs='?',
+                        const="events.json",
+                        metavar="FILENAME",
+                        help="Create Json output file"
+                             " (default FILENAME: events.json)")
+    parser.add_argument('-v', '--verbose',
+                        action='store_true',
+                        help="verbose output")
+
+    args = parser.parse_args()
+
+    # Check for valid command
+    if not (args.json):
+        print("Error: You need to specify at least one output method!")
+        parser.print_usage()
+        sys.exit(1)
+
+    # Initialize source scanner and parser
+    scanner = srcscanner.SourceScanner()
+    parser = srcparser.SourceParser()
+
+    # Scan directories, and parse the files
+    if args.verbose:
+        print("Scanning source path " + str(args.src_path))
+
+    if not scanner.ScanDir(args.src_path, parser):
+        sys.exit(1)
+
+    events = parser.events
+
+    # Output to JSON file
+    if args.json:
+        if args.verbose: print("Creating Json file " + args.json)
+        cur_dir = os.path.dirname(os.path.realpath(__file__))
+        out = jsonout.JsonOutput(events)
+        out.save(args.json)
+
+if __name__ == "__main__":
+    main()