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 <stddef.h> 9 10 #include <cassert> 11 #include <string> 12 13 #include "base/base_export.h" 14 #include "base/hash.h" 15 16 namespace tracked_objects { 17 18 // Location provides basic info where of an object was constructed, or was 19 // significantly brought to life. 20 class BASE_EXPORT Location { 21 public: 22 // Constructor should be called with a long-lived char*, such as __FILE__. 23 // It assumes the provided value will persist as a global constant, and it 24 // will not make a copy of it. 25 Location(const char* function_name, 26 const char* file_name, 27 int line_number, 28 const void* program_counter); 29 30 // Provide a default constructor for easy of debugging. 31 Location(); 32 33 // Copy constructor. 34 Location(const Location& other); 35 36 // Comparator for hash map insertion. 37 // No need to use |function_name_| since the other two fields uniquely 38 // identify this location. 39 bool operator==(const Location& other) const { 40 return line_number_ == other.line_number_ && 41 file_name_ == other.file_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 // Hash operator for hash maps. 52 struct Hash { 53 size_t operator()(const Location& location) const { 54 // Compute the hash value using file name pointer and line number. 55 // No need to use |function_name_| since the other two fields uniquely 56 // identify this location. 57 58 // The file name will always be uniquely identified by its pointer since 59 // it comes from __FILE__, so no need to check the contents of the string. 60 // See the definition of FROM_HERE in location.h, and how it is used 61 // elsewhere. 62 return base::HashInts(reinterpret_cast<uintptr_t>(location.file_name()), 63 location.line_number()); 64 } 65 }; 66 67 // Translate the some of the state in this instance into a human readable 68 // string with HTML characters in the function names escaped, and append that 69 // string to |output|. Inclusion of the file_name_ and function_name_ are 70 // optional, and controlled by the boolean arguments. 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* function_name_; 79 const char* file_name_; 80 int line_number_; 81 const void* program_counter_; 82 }; 83 84 // A "snapshotted" representation of the Location class that can safely be 85 // passed across process boundaries. 86 struct BASE_EXPORT LocationSnapshot { 87 // The default constructor is exposed to support the IPC serialization macros. 88 LocationSnapshot(); 89 explicit LocationSnapshot(const tracked_objects::Location& location); 90 ~LocationSnapshot(); 91 92 std::string file_name; 93 std::string function_name; 94 int line_number; 95 }; 96 97 BASE_EXPORT const void* GetProgramCounter(); 98 99 // Define a macro to record the current source location. 100 #define FROM_HERE FROM_HERE_WITH_EXPLICIT_FUNCTION(__func__) 101 102 #define FROM_HERE_WITH_EXPLICIT_FUNCTION(function_name) \ 103 ::tracked_objects::Location(function_name, \ 104 __FILE__, \ 105 __LINE__, \ 106 ::tracked_objects::GetProgramCounter()) 107 108 } // namespace tracked_objects 109 110 #endif // BASE_LOCATION_H_ 111
