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// Copyright (c) 2012 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.
#ifndef BASE_LOCATION_H_
#define BASE_LOCATION_H_
#include <cassert>
#include <string>
#include "base/base_export.h"
#include "base/basictypes.h"
#include "base/containers/hash_tables.h"
namespace tracked_objects {
// Location provides basic info where of an object was constructed, or was
// significantly brought to life.
class BASE_EXPORT Location {
public:
// Constructor should be called with a long-lived char*, such as __FILE__.
// It assumes the provided value will persist as a global constant, and it
// will not make a copy of it.
Location(const char* function_name,
const char* file_name,
int line_number,
const void* program_counter);
// Provide a default constructor for easy of debugging.
Location();
// Copy constructor.
Location(const Location& other);
// Comparator for hash map insertion.
// No need to use |function_name_| since the other two fields uniquely
// identify this location.
bool operator==(const Location& other) const {
return line_number_ == other.line_number_ &&
file_name_ == other.file_name_;
}
const char* function_name() const { return function_name_; }
const char* file_name() const { return file_name_; }
int line_number() const { return line_number_; }
const void* program_counter() const { return program_counter_; }
std::string ToString() const;
// Hash operator for hash maps.
struct Hash {
size_t operator()(const Location& location) const {
// Compute the hash value using file name pointer and line number.
// No need to use |function_name_| since the other two fields uniquely
// identify this location.
// The file name will always be uniquely identified by its pointer since
// it comes from __FILE__, so no need to check the contents of the string.
// See the definition of FROM_HERE in location.h, and how it is used
// elsewhere.
// Due to inconsistent definitions of uint64_t and uintptr_t, casting the
// file name pointer to a uintptr_t causes a compiler error for some
// platforms. The solution is to explicitly cast it to a uint64_t.
return base::HashPair(reinterpret_cast<uint64_t>(location.file_name()),
location.line_number());
}
};
// Translate the some of the state in this instance into a human readable
// string with HTML characters in the function names escaped, and append that
// string to |output|. Inclusion of the file_name_ and function_name_ are
// optional, and controlled by the boolean arguments.
void Write(bool display_filename, bool display_function_name,
std::string* output) const;
// Write function_name_ in HTML with '<' and '>' properly encoded.
void WriteFunctionName(std::string* output) const;
private:
const char* function_name_;
const char* file_name_;
int line_number_;
const void* program_counter_;
};
// A "snapshotted" representation of the Location class that can safely be
// passed across process boundaries.
struct BASE_EXPORT LocationSnapshot {
// The default constructor is exposed to support the IPC serialization macros.
LocationSnapshot();
explicit LocationSnapshot(const tracked_objects::Location& location);
~LocationSnapshot();
std::string file_name;
std::string function_name;
int line_number;
};
BASE_EXPORT const void* GetProgramCounter();
// Define a macro to record the current source location.
#define FROM_HERE FROM_HERE_WITH_EXPLICIT_FUNCTION(__FUNCTION__)
#define FROM_HERE_WITH_EXPLICIT_FUNCTION(function_name) \
::tracked_objects::Location(function_name, \
__FILE__, \
__LINE__, \
::tracked_objects::GetProgramCounter())
} // namespace tracked_objects
#endif // BASE_LOCATION_H_