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 1419 : Location(const char* function_name, const char* file_name, int line_number)
43 : : function_name_(function_name),
44 : file_name_(file_name),
45 1419 : 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 0 : bool operator < (const Location& other) const {
60 0 : if (line_number_ != other.line_number_)
61 0 : return line_number_ < other.line_number_;
62 0 : if (file_name_ != other.file_name_)
63 0 : return file_name_ < other.file_name_;
64 0 : return function_name_ < other.function_name_;
65 : }
66 :
67 0 : const char* function_name() const { return function_name_; }
68 0 : const char* file_name() const { return file_name_; }
69 0 : 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_
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