Add searching features to new TraceEventVector class for tests.

base/test/trace_event_analyzer.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Use trace_analyzer::Query and trace_analyzer::TraceAnalyzer to search for
 // specific trace events that were generated by the trace_event.h API.
 //
 // Basic procedure:
 // - Get trace events JSON string from base::debug::TraceLog.
 // - Create TraceAnalyzer with JSON string.
@@ skipping 397 matching lines @@
   explicit QueryNode(const Query& query);
   const Query& query() const { return query_; }
 
  private:
   friend class base::RefCounted<QueryNode>;
   ~QueryNode();
 
   Query query_;
 };
 
-// TraceAnalyzer helps tests search for trace events.
-class TraceAnalyzer {
+class TraceEventVector : public std::vector<const TraceEvent*> {

[Paweł Hajdan Jr., 2011/12/12 17:21:51]

Inheritance from std::vector? I'm suspicious. Could you explain more why you're
doing that?

[jbates, 2011/12/12 22:00:32]

Done.

  public:
-  typedef std::vector<const TraceEvent*> TraceEventVector;
-
-  struct Stats {
+  struct RateStats {
     double min_us;
     double max_us;
     double mean_us;
     double standard_deviation_us;
   };
 
+  // Calculate min/max/mean and standard deviation from the times between
+  // adjacent events.
+  bool GetRateStats(RateStats* stats);
+
+  // Starting from |position|, find the first event that matches |query|.
+  // Returns true if found, false otherwise.
+  bool FindFirstOf(Query query,
+                   size_t position,
+                   size_t* return_index) const;
+
+  // Starting from |position|, find the last event that matches |query|.
+  // Returns true if found, false otherwise.
+  bool FindLastOf(Query query,
+                  size_t position,
+                  size_t* return_index) const;
+
+  // Find the closest events to |position| in time that match |query|.
+  // return_second_closest may be NULL. Closeness is determined by comparing
+  // with the event timestamp.
+  // Returns true if found, false otherwise. If both return parameters are
+  // requested, both must be found for a successful result.
+  bool FindClosest(Query query,
+                   size_t position,
+                   size_t* return_closest,
+                   size_t* return_second_closest) const;

[Paweł Hajdan Jr., 2011/12/12 17:21:51]

nit: If second_closest is there, why not third_closest and so on? Would it help
to have a method like that to only return the first value, and then another one
to return a sorted vector?

[jbates, 2011/12/12 22:00:32]

Returning a sorted vector did occur to me, but one or two satisfies all the use
cases I can think of. Basically, the second one is just to find out if the event
was very close to the closest, or if it was closer to the mid-point between two
events. Going from 2 to n adds some complexity, so I didn't think it was worth
it without some use cases.

+
+  // Count matches, inclusive of |begin_position|, exclusive of |end_position|.
+  int CountMatches(Query query,

[Paweł Hajdan Jr., 2011/12/12 17:21:51]

nit: If size_t is generally used, why this and method below return int?

[jbates, 2011/12/12 22:00:32]

Done.

+                   size_t begin_position,
+                   size_t end_position) const;
+
+  // Count all matches.
+  int CountMatches(Query query) const {
+    return CountMatches(query, 0, size());
+  }
+};
+
+// TraceAnalyzer helps tests search for trace events.
+class TraceAnalyzer {
+ public:
   ~TraceAnalyzer();
 
   // Use trace events from JSON string generated by tracing API.
   // Returns non-NULL if the JSON is successfully parsed.
   static TraceAnalyzer* Create(const std::string& json_events)
                                WARN_UNUSED_RESULT;
 
   // Associate BEGIN and END events with each other. This allows Query(OTHER_*)
   // to access the associated event and enables Query(EVENT_DURATION).
   // An end event will match the most recent begin event with the same name,
@@ skipping 27 matching lines @@
   //
   // NOTE: AssociateEvents will overwrite existing other_event associations if
   // the queries pass for events that already had a previous association.
   //
   // After calling FindEvents or FindOneEvent, it is not allowed to call
   // AssociateEvents again.
   void AssociateEvents(const Query& first,
                        const Query& second,
                        const Query& match);
 
+  // For each event, copy its arguments to the other_event argument map. If
+  // argument name already exists, it will not be overwritten.
+  void MergeAssociatedEventArgs();
+
   // Find all events that match query and replace output vector.
   size_t FindEvents(const Query& query, TraceEventVector* output);
 
   // Helper method: find first event that matches query
   const TraceEvent* FindOneEvent(const Query& query);
 
   const std::string& GetThreadName(const TraceEvent::ProcessThreadID& thread);
 
-  // Calculate min/max/mean and standard deviation from the times between
-  // adjacent events.
-  static bool GetRateStats(const TraceEventVector& events, Stats* stats);
-
  private:
   TraceAnalyzer();
 
   bool SetEvents(const std::string& json_events) WARN_UNUSED_RESULT;
 
   // Read metadata (thread names, etc) from events.
   void ParseMetadata();
 
   std::map<TraceEvent::ProcessThreadID, std::string> thread_names_;
   std::vector<TraceEvent> raw_events_;
   bool allow_assocation_changes_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceAnalyzer);
 };
 
 }  // namespace trace_analyzer
 
 #endif  // BASE_TEST_TRACE_EVENT_ANALYZER_H_