Revert 107813 - add classes trace_analyzer::Query and TraceAnalyzer to make it easy to search thr...

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.
-// - Call TraceAnalyzer::AssociateBeginEndEvents (optional).
-// - Call TraceAnalyzer::AssociateEvents (zero or more times).
-// - Call TraceAnalyzer::FindEvents with queries to find specific events.
-//
-// A Query is a boolean expression tree that evaluates to true or false for a
-// given trace event. Queries can be combined into a tree using boolean,
-// arithmetic and comparison operators that refer to data of an individual trace
-// event.
-//
-// The events are returned as trace_analyzer::TraceEvent objects.
-// TraceEvent contains a single trace event's data, as well as a pointer to
-// a related trace event. The related trace event is typically the matching end
-// of a begin event or the matching begin of an end event.
-//
-// The following examples use this basic setup code to construct TraceAnalyzer
-// with the json trace string retrieved from TraceLog and construct an event
-// vector for retrieving events:
-//
-// TraceAnalyzer analyzer(json_events);
-// TraceEventVector events;
-//
-// During construction, TraceAnalyzer::SetDefaultAssociations is called to
-// associate all matching begin/end pairs similar to how they are shown in
-// about:tracing.
-//
-// EXAMPLE 1: Find events named "my_event".
-//
-// analyzer.FindEvents(Query(EVENT_NAME) == "my_event", &events);
-//
-// EXAMPLE 2: Find begin events named "my_event" with duration > 1 second.
-//
-// Query q = (Query(EVENT_NAME) == Query::String("my_event") &&
-//            Query(EVENT_PHASE) == Query::Phase(TRACE_EVENT_PHASE_BEGIN) &&
-//            Query(EVENT_DURATION) > Query::Double(1000000.0));
-// analyzer.FindEvents(q, &events);
-//
-// EXAMPLE 3: Associating event pairs across threads.
-//
-// If the test needs to analyze something that starts and ends on different
-// threads, the test needs to use INSTANT events. The typical procedure is to
-// specify the same unique ID as a TRACE_EVENT argument on both the start and
-// finish INSTANT events. Then use the following procedure to associate those
-// events.
-//
-// Step 1: instrument code with custom begin/end trace events.
-//   [Thread 1 tracing code]
-//   TRACE_EVENT_INSTANT1("test_latency", "timing1_begin", "id", 3);
-//   [Thread 2 tracing code]
-//   TRACE_EVENT_INSTANT1("test_latency", "timing1_end", "id", 3);
-//
-// Step 2: associate these custom begin/end pairs.
-//   Query begin(Query(EVENT_NAME) == Query::String("timing1_begin"));
-//   Query end(Query(EVENT_NAME) == Query::String("timing1_end"));
-//   Query match(Query(EVENT_ARG, "id") == Query(OTHER_ARG, "id"));
-//   analyzer.AssociateEvents(begin, end, match);
-//
-// Step 3: search for "timing1_begin" events with existing other event.
-//   Query q = (Query(EVENT_NAME) == Query::String("timing1_begin") &&
-//              Query(EVENT_HAS_OTHER));
-//   analyzer.FindEvents(q, &events);
-//
-// Step 4: analyze events, such as checking durations.
-//   for (size_t i = 0; i < events.size(); ++i) {
-//     double duration;
-//     EXPECT_TRUE(events[i].GetAbsTimeToOtherEvent(&duration));
-//     EXPECT_LT(duration, 1000000.0/60.0); // expect less than 1/60 second.
-//   }
-
-
-#ifndef BASE_TEST_TRACE_EVENT_ANALYZER_H_
-#define BASE_TEST_TRACE_EVENT_ANALYZER_H_
-#pragma once
-
-#include <map>
-
-#include "base/debug/trace_event.h"
-#include "base/memory/ref_counted_memory.h"
-#include "base/memory/scoped_ptr.h"
-
-namespace base {
-class Value;
-}
-
-namespace trace_analyzer {
-class QueryNode;
-
-// trace_analyzer::TraceEvent is a more convenient form of the
-// base::debug::TraceEvent class to make tracing-based tests easier to write.
-struct BASE_EXPORT TraceEvent {
-  // ProcessThreadID contains a Process ID and Thread ID.
-  struct ProcessThreadID {
-    ProcessThreadID() : process_id(0), thread_id(0) {}
-    ProcessThreadID(int process_id, int thread_id)
-        : process_id(process_id), thread_id(thread_id) {}
-    bool operator< (const ProcessThreadID& rhs) const {
-      if (process_id != rhs.process_id)
-        return process_id < rhs.process_id;
-      return thread_id < rhs.thread_id;
-    }
-    int process_id;
-    int thread_id;
-  };
-
-  TraceEvent();
-  ~TraceEvent();
-
-  bool SetFromJSON(const base::Value* event_value) WARN_UNUSED_RESULT;
-
-  bool operator< (const TraceEvent& rhs) const {
-    return timestamp < rhs.timestamp;
-  }
-
-  bool has_other_event() const { return other_event; }
-
-  // Returns absolute duration in microseconds between this event and other
-  // event. Returns false if has_other_event() is false.
-  bool GetAbsTimeToOtherEvent(double* duration) const;
-
-  // Return the argument value if it exists and it is a string.
-  bool GetArgAsString(const std::string& name, std::string* arg) const;
-  // Return the argument value if it exists and it is a number.
-  bool GetArgAsNumber(const std::string& name, double* arg) const;
-
-  // Process ID and Thread ID.
-  ProcessThreadID thread;
-
-  // Time since epoch in microseconds.
-  // Stored as double to match its JSON representation.
-  double timestamp;
-
-  base::debug::TraceEventPhase phase;
-
-  std::string category;
-
-  std::string name;
-
-  // All numbers and bool values from TraceEvent args are cast to double.
-  // bool becomes 1.0 (true) or 0.0 (false).
-  std::map<std::string, double> arg_numbers;
-
-  std::map<std::string, std::string> arg_strings;
-
-  // The other event associated with this event (or NULL).
-  const TraceEvent* other_event;
-};
-
-// Pass these values to Query to compare with the corresponding member of a
-// TraceEvent.
-enum TraceEventMember {
-  EVENT_INVALID,
-  // Use these to access the event members:
-  EVENT_PID,
-  EVENT_TID,
-  // Return the timestamp of the event in microseconds since epoch.
-  EVENT_TIME,
-  // Return the absolute time between event and other event in microseconds.
-  // Only works for events with associated BEGIN/END: Query(EVENT_HAS_OTHER).
-  EVENT_DURATION,
-  EVENT_PHASE,
-  EVENT_CATEGORY,
-  EVENT_NAME,
-  EVENT_HAS_ARG,
-  EVENT_ARG,
-  // Return true if associated event exists.
-  // (Typically BEGIN for END or END for BEGIN).
-  EVENT_HAS_OTHER,
-  // Use these to access the associated event's members:
-  OTHER_PID,
-  OTHER_TID,
-  OTHER_TIME,
-  OTHER_PHASE,
-  OTHER_CATEGORY,
-  OTHER_NAME,
-  OTHER_HAS_ARG,
-  OTHER_ARG
-};
-
-class BASE_EXPORT Query {
- public:
-  // Compare with the given member.
-  Query(TraceEventMember member);
-
-  // Compare with the given member argument value.
-  Query(TraceEventMember member, const std::string& arg_name);
-
-  Query(const Query& query);
-
-  ~Query();
-
-  // Compare with the given string.
-  static Query String(const std::string& str);
-
-  // Compare with the given number.
-  static Query Double(double num);
-  static Query Int(int32 num);
-  static Query Uint(uint32 num);
-
-  // Compare with the given bool.
-  static Query Bool(bool boolean);
-
-  // Compare with the given phase.
-  static Query Phase(base::debug::TraceEventPhase phase);
-
-  // Compare with the given string pattern. Only works with == and != operators.
-  // Example: Query(EVENT_NAME) == Query::Pattern("MyEvent*")
-  static Query Pattern(const std::string& pattern);
-
-  // Common queries:
-
-  // Find BEGIN events that have a corresponding END event.
-  static Query MatchBeginWithEnd() {
-    return (Query(EVENT_PHASE) ==
-            Query::Phase(base::debug::TRACE_EVENT_PHASE_BEGIN)) &&
-           Query(EVENT_HAS_OTHER);
-  }
-
-  // Find BEGIN events of given |name| which also have associated END events.
-  static Query MatchBeginName(const std::string& name) {
-    return (Query(EVENT_NAME) == name) && MatchBeginWithEnd();
-  }
-
-  // Match given Process ID and Thread ID.
-  static Query MatchThread(const TraceEvent::ProcessThreadID& thread) {
-    return (Query(EVENT_PID) == Query::Int(thread.process_id)) &&
-           (Query(EVENT_TID) == Query::Int(thread.thread_id));
-  }
-
-  // Match event pair that spans multiple threads.
-  static Query MatchCrossThread() {
-    return (Query(EVENT_PID) != Query(OTHER_PID)) ||
-           (Query(EVENT_TID) != Query(OTHER_TID));
-  }
-
-  // Boolean operators:
-  Query operator==(const Query& rhs) const;
-  Query operator!=(const Query& rhs) const;
-  Query operator< (const Query& rhs) const;
-  Query operator<=(const Query& rhs) const;
-  Query operator> (const Query& rhs) const;
-  Query operator>=(const Query& rhs) const;
-  Query operator&&(const Query& rhs) const;
-  Query operator||(const Query& rhs) const;
-  Query operator!() const;
-
-  // Arithmetic operators:
-  // Following operators are applied to double arguments:
-  Query operator+(const Query& rhs) const;
-  Query operator-(const Query& rhs) const;
-  Query operator*(const Query& rhs) const;
-  Query operator/(const Query& rhs) const;
-  Query operator-() const;
-  // Mod operates on int64 args (doubles are casted to int64 beforehand):
-  Query operator%(const Query& rhs) const;
-
-  // Return true if the given event matches this query tree.
-  // This is a recursive method that walks the query tree.
-  bool Evaluate(const TraceEvent& event) const;
-
- private:
-  enum Operator {
-    OP_INVALID,
-    // Boolean operators:
-    OP_EQ,
-    OP_NE,
-    OP_LT,
-    OP_LE,
-    OP_GT,
-    OP_GE,
-    OP_AND,
-    OP_OR,
-    OP_NOT,
-    // Arithmetic operators:
-    OP_ADD,
-    OP_SUB,
-    OP_MUL,
-    OP_DIV,
-    OP_MOD,
-    OP_NEGATE
-  };
-
-  enum QueryType {
-    QUERY_BOOLEAN_OPERATOR,
-    QUERY_ARITHMETIC_OPERATOR,
-    QUERY_EVENT_MEMBER,
-    QUERY_NUMBER,
-    QUERY_STRING
-  };
-
-  // Compare with the given string.
-  Query(const std::string& str);
-
-  // Compare with the given number.
-  Query(double num);
-
-  // Construct a boolean Query that returns (left <binary_op> right).
-  Query(const Query& left, const Query& right, Operator binary_op);
-
-  // Construct a boolean Query that returns (<binary_op> left).
-  Query(const Query& left, Operator unary_op);
-
-  // Try to compare left_ against right_ based on operator_.
-  // If either left or right does not convert to double, false is returned.
-  // Otherwise, true is returned and |result| is set to the comparison result.
-  bool CompareAsDouble(const TraceEvent& event, bool* result) const;
-
-  // Try to compare left_ against right_ based on operator_.
-  // If either left or right does not convert to string, false is returned.
-  // Otherwise, true is returned and |result| is set to the comparison result.
-  bool CompareAsString(const TraceEvent& event, bool* result) const;
-
-  // Attempt to convert this Query to a double. On success, true is returned
-  // and the double value is stored in |num|.
-  bool GetAsDouble(const TraceEvent& event, double* num) const;
-
-  // Attempt to convert this Query to a string. On success, true is returned
-  // and the string value is stored in |str|.
-  bool GetAsString(const TraceEvent& event, std::string* str) const;
-
-  // Evaluate this Query as an arithmetic operator on left_ and right_.
-  bool EvaluateArithmeticOperator(const TraceEvent& event,
-                                  double* num) const;
-
-  // For QUERY_EVENT_MEMBER Query: attempt to get the value of the Query.
-  // The TraceValue will either be TRACE_TYPE_DOUBLE, TRACE_TYPE_STRING,
-  // or if requested member does not exist, it will be TRACE_TYPE_UNDEFINED.
-  base::debug::TraceValue GetMemberValue(const TraceEvent& event) const;
-
-  // Does this Query represent a value?
-  bool is_value() const { return type_ != QUERY_BOOLEAN_OPERATOR; }
-
-  bool is_unary_operator() const {
-    return operator_ == OP_NOT || operator_ == OP_NEGATE;
-  }
-
-  bool is_comparison_operator() const {
-    return operator_ != OP_INVALID && operator_ < OP_AND;
-  }
-
-  const Query& left() const;
-  const Query& right() const;
-
-  QueryType type_;
-  Operator operator_;
-  scoped_refptr<QueryNode> left_;
-  scoped_refptr<QueryNode> right_;
-  TraceEventMember member_;
-  double number_;
-  std::string string_;
-  bool is_pattern_;
-};
-
-// Implementation detail:
-// QueryNode allows Query to store a ref-counted query tree.
-class QueryNode : public base::RefCounted<QueryNode> {
- public:
-  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 BASE_EXPORT TraceAnalyzer {
- public:
-  typedef std::vector<const TraceEvent*> TraceEventVector;
-
-  ~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,
-  // category, process ID and thread ID. This matches what is shown in
-  // about:tracing.
-  void AssociateBeginEndEvents();
-
-  // AssociateEvents can be used to customize event associations by setting the
-  // other_event member of TraceEvent. This should be used to associate two
-  // INSTANT events.
-  //
-  // The assumptions are:
-  // - |first| events occur before |second| events.
-  // - the closest matching |second| event is the correct match.
-  //
-  // |first|  - Eligible |first| events match this query.
-  // |second| - Eligible |second| events match this query.
-  // |match|  - This query is run on the |first| event. The OTHER_* EventMember
-  //            queries will point to an eligible |second| event. The query
-  //            should evaluate to true if the |first|/|second| pair is a match.
-  //
-  // When a match is found, the pair will be associated by having their
-  // other_event member point to each other. AssociateEvents does not clear
-  // previous associations, so it is possible to associate multiple pairs of
-  // events by calling AssociateEvents more than once with different queries.
-  //
-  // 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);
-
-  // 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);
-
- 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_