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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 /**
      6  * @fileoverview Base class for linux perf event parsers.
      7  *
      8  * The linux perf trace event importer depends on subclasses of
      9  * LinuxPerfParser to parse event data.  Each subclass corresponds
     10  * to a group of trace events; e.g. LinuxPerfSchedParser implements
     11  * parsing of sched:* kernel trace events.  Parser subclasses must
     12  * call LinuxPerfParser.registerSubtype to arrange to be instantiated
     13  * and their constructor must register their event handlers with the
     14  * importer.  For example,
     15  *
     16  * var LinuxPerfParser = tracing.LinuxPerfParser;
     17  *
     18  * function LinuxPerfWorkqueueParser(importer) {
     19  *   LinuxPerfParser.call(this, importer);
     20  *
     21  *   importer.registerEventHandler('workqueue_execute_start',
     22  *       LinuxPerfWorkqueueParser.prototype.executeStartEvent.bind(this));
     23  *   importer.registerEventHandler('workqueue_execute_end',
     24  *       LinuxPerfWorkqueueParser.prototype.executeEndEvent.bind(this));
     25  * }
     26  *
     27  * LinuxPerfParser.registerSubtype(LinuxPerfWorkqueueParser);
     28  *
     29  * When a registered event name is found in the data stream the associated
     30  * event handler is invoked:
     31  *
     32  *   executeStartEvent: function(eventName, cpuNumber, ts, eventBase)
     33  *
     34  * If the routine returns false the caller will generate an import error
     35  * saying there was a problem parsing it.  Handlers can also emit import
     36  * messages using this.importer.importError.  If this is done in lieu of
     37  * the generic import error it may be desirable for the handler to return
     38  * true.
     39  *
     40  * Trace events generated by writing to the trace_marker file are expected
     41  * to have a leading text marker followed by a ':'; e.g. the trace clock
     42  * synchronization event is:
     43  *
     44  *  tracing_mark_write: trace_event_clock_sync: parent_ts=0
     45  *
     46  * To register an event handler for these events, prepend the marker with
     47  * 'tracing_mark_write:'; e.g.
     48  *
     49  *    this.registerEventHandler('tracing_mark_write:trace_event_clock_sync',
     50  *
     51  * All subclasses should depend on linux_perf_parser, e.g.
     52  *
     53  * base.defineModule('linux_perf_workqueue_parser')
     54  *   .dependsOn('linux_perf_parser')
     55  *   .exportsTo('tracing', function()
     56  *
     57  * and be listed in the dependsOn of LinuxPerfImporter.  Beware that after
     58  * adding a new subclass you must run build/generate_about_tracing_contents.py
     59  * to regenerate about_tracing.*.
     60  */
     61 base.exportTo('tracing', function() {
     62 
     63   var subtypeConstructors = [];
     64 
     65   /**
     66    * Registers a subclass that will help parse linux perf events.
     67    * The importer will call createParsers (below) before importing
     68    * data so each subclass can register its handlers.
     69    *
     70    * @param {Function} subtypeConstructor The subtype's constructor function.
     71    */
     72   LinuxPerfParser.registerSubtype = function(subtypeConstructor) {
     73     subtypeConstructors.push(subtypeConstructor);
     74   };
     75 
     76   LinuxPerfParser.getSubtypeConstructors = function() {
     77     return subtypeConstructors;
     78   };
     79 
     80   /**
     81    * Parses linux perf events.
     82    * @constructor
     83    */
     84   function LinuxPerfParser(importer) {
     85     this.importer = importer;
     86   }
     87 
     88   LinuxPerfParser.prototype = {
     89     __proto__: Object.prototype
     90   };
     91 
     92   return {
     93     LinuxPerfParser: LinuxPerfParser
     94   };
     95 
     96 });
     97