1 // Copyright (c) 2006-2008 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 // Tracked is the base class for all tracked objects. During construction, it 7 // registers the fact that an instance was created, and at destruction time, it 8 // records that event. The instance may be tagged with a name, which is refered 9 // to as its Location. The Location is a file and line number, most 10 // typically indicated where the object was constructed. In some cases, as the 11 // object's significance is refined (for example, a Task object is augmented to 12 // do additonal things), its Location may be redefined to that later location. 13 14 // Tracking includes (for each instance) recording the birth thread, death 15 // thread, and duration of life (from construction to destruction). All this 16 // data is accumulated and filtered for review at about:objects. 17 18 #ifndef BASE_TRACKED_H_ 19 #define BASE_TRACKED_H_ 20 21 #include <string> 22 23 #include "base/time.h" 24 25 #ifndef NDEBUG 26 #ifndef TRACK_ALL_TASK_OBJECTS 27 #define TRACK_ALL_TASK_OBJECTS 28 #endif // TRACK_ALL_TASK_OBJECTS 29 #endif // NDEBUG 30 31 namespace tracked_objects { 32 33 //------------------------------------------------------------------------------ 34 // Location provides basic info where of an object was constructed, or was 35 // significantly brought to life. 36 37 class Location { 38 public: 39 // Constructor should be called with a long-lived char*, such as __FILE__. 40 // It assumes the provided value will persist as a global constant, and it 41 // will not make a copy of it. 42 Location(const char* function_name, const char* file_name, int line_number) 43 : function_name_(function_name), 44 file_name_(file_name), 45 line_number_(line_number) { } 46 47 // Provide a default constructor for easy of debugging. 48 Location() 49 : function_name_("Unknown"), 50 file_name_("Unknown"), 51 line_number_(-1) { } 52 53 // Comparison operator for insertion into a std::map<> hash tables. 54 // All we need is *some* (any) hashing distinction. Strings should already 55 // be unique, so we don't bother with strcmp or such. 56 // Use line number as the primary key (because it is fast, and usually gets us 57 // a difference), and then pointers as secondary keys (just to get some 58 // distinctions). 59 bool operator < (const Location& other) const { 60 if (line_number_ != other.line_number_) 61 return line_number_ < other.line_number_; 62 if (file_name_ != other.file_name_) 63 return file_name_ < other.file_name_; 64 return function_name_ < other.function_name_; 65 } 66 67 const char* function_name() const { return function_name_; } 68 const char* file_name() const { return file_name_; } 69 int line_number() const { return line_number_; } 70 71 void Write(bool display_filename, bool display_function_name, 72 std::string* output) const; 73 74 // Write function_name_ in HTML with '<' and '>' properly encoded. 75 void WriteFunctionName(std::string* output) const; 76 77 private: 78 const char* const function_name_; 79 const char* const file_name_; 80 const int line_number_; 81 }; 82 83 84 //------------------------------------------------------------------------------ 85 // Define a macro to record the current source location. 86 87 #define FROM_HERE tracked_objects::Location(__FUNCTION__, __FILE__, __LINE__) 88 89 90 //------------------------------------------------------------------------------ 91 92 93 class Births; 94 95 class Tracked { 96 public: 97 Tracked(); 98 virtual ~Tracked(); 99 100 // Used to record the FROM_HERE location of a caller. 101 void SetBirthPlace(const Location& from_here); 102 103 // When a task sits around a long time, such as in a timer, or object watcher, 104 // this method should be called when the task becomes active, and its 105 // significant lifetime begins (and its waiting to be woken up has passed). 106 void ResetBirthTime(); 107 108 bool MissingBirthplace() const; 109 110 private: 111 #ifdef TRACK_ALL_TASK_OBJECTS 112 113 // Pointer to instance were counts of objects with the same birth location 114 // (on the same thread) are stored. 115 Births* tracked_births_; 116 // The time this object was constructed. If its life consisted of a long 117 // waiting period, and then it became active, then this value is generally 118 // reset before the object begins it active life. 119 base::Time tracked_birth_time_; 120 121 #endif // TRACK_ALL_TASK_OBJECTS 122 123 DISALLOW_COPY_AND_ASSIGN(Tracked); 124 }; 125 126 } // namespace tracked_objects 127 128 #endif // BASE_TRACKED_H_ 129
