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#ifndef BASE_LOCATION_H_
6#define BASE_LOCATION_H_
7
8#include <string>
9
10#include "base/base_export.h"
11#include "base/basictypes.h"
12
13namespace tracked_objects {
14
15// Location provides basic info where of an object was constructed, or was
16// significantly brought to life.
17class BASE_EXPORT Location {
18 public:
19  // Constructor should be called with a long-lived char*, such as __FILE__.
20  // It assumes the provided value will persist as a global constant, and it
21  // will not make a copy of it.
22  Location(const char* function_name,
23           const char* file_name,
24           int line_number,
25           const void* program_counter);
26
27  // Provide a default constructor for easy of debugging.
28  Location();
29
30  // Comparison operator for insertion into a std::map<> hash tables.
31  // All we need is *some* (any) hashing distinction.  Strings should already
32  // be unique, so we don't bother with strcmp or such.
33  // Use line number as the primary key (because it is fast, and usually gets us
34  // a difference), and then pointers as secondary keys (just to get some
35  // distinctions).
36  bool operator < (const Location& other) const {
37    if (line_number_ != other.line_number_)
38      return line_number_ < other.line_number_;
39    if (file_name_ != other.file_name_)
40      return file_name_ < other.file_name_;
41    return function_name_ < other.function_name_;
42  }
43
44  const char* function_name()   const { return function_name_; }
45  const char* file_name()       const { return file_name_; }
46  int line_number()             const { return line_number_; }
47  const void* program_counter() const { return program_counter_; }
48
49  std::string ToString() const;
50
51  // Translate the some of the state in this instance into a human readable
52  // string with HTML characters in the function names escaped, and append that
53  // string to |output|.  Inclusion of the file_name_ and function_name_ are
54  // optional, and controlled by the boolean arguments.
55  void Write(bool display_filename, bool display_function_name,
56             std::string* output) const;
57
58  // Write function_name_ in HTML with '<' and '>' properly encoded.
59  void WriteFunctionName(std::string* output) const;
60
61 private:
62  const char* function_name_;
63  const char* file_name_;
64  int line_number_;
65  const void* program_counter_;
66};
67
68// A "snapshotted" representation of the Location class that can safely be
69// passed across process boundaries.
70struct BASE_EXPORT LocationSnapshot {
71  // The default constructor is exposed to support the IPC serialization macros.
72  LocationSnapshot();
73  explicit LocationSnapshot(const tracked_objects::Location& location);
74  ~LocationSnapshot();
75
76  std::string file_name;
77  std::string function_name;
78  int line_number;
79};
80
81BASE_EXPORT const void* GetProgramCounter();
82
83// Define a macro to record the current source location.
84#define FROM_HERE FROM_HERE_WITH_EXPLICIT_FUNCTION(__FUNCTION__)
85
86#define FROM_HERE_WITH_EXPLICIT_FUNCTION(function_name)                        \
87    ::tracked_objects::Location(function_name,                                 \
88                                __FILE__,                                      \
89                                __LINE__,                                      \
90                                ::tracked_objects::GetProgramCounter())
91
92}  // namespace tracked_objects
93
94#endif  // BASE_LOCATION_H_
95