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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 'use strict';
      6 
      7 /**
      8  * @fileoverview Base class for linux perf event parsers.
      9  *
     10  * The linux perf trace event importer depends on subclasses of
     11  * Parser to parse event data.  Each subclass corresponds
     12  * to a group of trace events; e.g. SchedParser implements
     13  * parsing of sched:* kernel trace events.  Parser subclasses must
     14  * call Parser.registerSubtype to arrange to be instantiated
     15  * and their constructor must register their event handlers with the
     16  * importer.  For example,
     17  *
     18  * var Parser = tracing.importer.linux_perf.Parser;
     19  *
     20  * function WorkqueueParser(importer) {
     21  *   Parser.call(this, importer);
     22  *
     23  *   importer.registerEventHandler('workqueue_execute_start',
     24  *       WorkqueueParser.prototype.executeStartEvent.bind(this));
     25  *   importer.registerEventHandler('workqueue_execute_end',
     26  *       WorkqueueParser.prototype.executeEndEvent.bind(this));
     27  * }
     28  *
     29  * Parser.registerSubtype(WorkqueueParser);
     30  *
     31  * When a registered event name is found in the data stream the associated
     32  * event handler is invoked:
     33  *
     34  *   executeStartEvent: function(eventName, cpuNumber, ts, eventBase)
     35  *
     36  * If the routine returns false the caller will generate an import error
     37  * saying there was a problem parsing it.  Handlers can also emit import
     38  * messages using this.importer.importError.  If this is done in lieu of
     39  * the generic import error it may be desirable for the handler to return
     40  * true.
     41  *
     42  * Trace events generated by writing to the trace_marker file are expected
     43  * to have a leading text marker followed by a ':'; e.g. the trace clock
     44  * synchronization event is:
     45  *
     46  *  tracing_mark_write: trace_event_clock_sync: parent_ts=0
     47  *
     48  * To register an event handler for these events, prepend the marker with
     49  * 'tracing_mark_write:'; e.g.
     50  *
     51  *    this.registerEventHandler('tracing_mark_write:trace_event_clock_sync',
     52  *
     53  * All subclasses should depend on importer.linux_perf.parser, e.g.
     54  *
     55  * base.defineModule('importer.linux_perf.workqueue_parser')
     56  *   .dependsOn('importer.linux_perf.parser')
     57  *   .exportsTo('tracing', function()
     58  *
     59  * and be listed in the dependsOn of LinuxPerfImporter.  Beware that after
     60  * adding a new subclass you must run build/generate_about_tracing_contents.py
     61  * to regenerate about_tracing.*.
     62  */
     63 base.exportTo('tracing.importer.linux_perf', function() {
     64 
     65   var subtypeConstructors = [];
     66 
     67   /**
     68    * Registers a subclass that will help parse linux perf events.
     69    * The importer will call createParsers (below) before importing
     70    * data so each subclass can register its handlers.
     71    *
     72    * @param {Function} subtypeConstructor The subtype's constructor function.
     73    */
     74   Parser.registerSubtype = function(subtypeConstructor) {
     75     subtypeConstructors.push(subtypeConstructor);
     76   };
     77 
     78   Parser.getSubtypeConstructors = function() {
     79     return subtypeConstructors;
     80   };
     81 
     82   /**
     83    * Parses linux perf events.
     84    * @constructor
     85    */
     86   function Parser(importer) {
     87     this.importer = importer;
     88     this.model = importer.model;
     89   }
     90 
     91   Parser.prototype = {
     92     __proto__: Object.prototype
     93   };
     94 
     95   return {
     96     Parser: Parser
     97   };
     98 
     99 });
    100