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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 <stddef.h>
#include <cassert>
#include <functional>
#include <string>
#include "base/base_export.h"
#include "base/debug/debugging_buildflags.h"
#include "base/hash/hash.h"
#include "build/build_config.h"
namespace base {
#if defined(__has_builtin)
// Clang allows detection of these builtins.
#define SUPPORTS_LOCATION_BUILTINS \
(__has_builtin(__builtin_FUNCTION) && __has_builtin(__builtin_FILE) && \
__has_builtin(__builtin_LINE))
#elif defined(COMPILER_GCC) && __GNUC__ >= 7
// GCC has supported these for a long time, but they point at the function
// declaration in the case of default arguments, rather than at the call site.
#define SUPPORTS_LOCATION_BUILTINS 1
#else
#define SUPPORTS_LOCATION_BUILTINS 0
#endif
// Location provides basic info where of an object was constructed, or was
// significantly brought to life.
class BASE_EXPORT Location {
public:
Location();
Location(const Location& other);
// Only initializes the file name and program counter, the source information
// will be null for the strings, and -1 for the line number.
// TODO(http://crbug.com/760702) remove file name from this constructor.
Location(const char* file_name, const void* program_counter);
// 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);
// Comparator for hash map insertion. The program counter should uniquely
// identify a location.
bool operator==(const Location& other) const {
return program_counter_ == other.program_counter_;
}
// Returns true if there is source code location info. If this is false,
// the Location object only contains a program counter or is
// default-initialized (the program counter is also null).
bool has_source_info() const { return function_name_ && file_name_; }
// Will be nullptr for default initialized Location objects and when source
// names are disabled.
const char* function_name() const { return function_name_; }
// Will be nullptr for default initialized Location objects and when source
// names are disabled.
const char* file_name() const { return file_name_; }
// Will be -1 for default initialized Location objects and when source names
// are disabled.
int line_number() const { return line_number_; }
// The address of the code generating this Location object. Should always be
// valid except for default initialized Location objects, which will be
// nullptr.
const void* program_counter() const { return program_counter_; }
// Converts to the most user-readable form possible. If function and filename
// are not available, this will return "pc:<hex address>".
std::string ToString() const;
static Location CreateFromHere(const char* file_name);
static Location CreateFromHere(const char* function_name,
const char* file_name,
int line_number);
#if SUPPORTS_LOCATION_BUILTINS && BUILDFLAG(ENABLE_LOCATION_SOURCE)
static Location Current(const char* function_name = __builtin_FUNCTION(),
const char* file_name = __builtin_FILE(),
int line_number = __builtin_LINE());
#elif SUPPORTS_LOCATION_BUILTINS
static Location Current(const char* file_name = __builtin_FILE());
#else
static Location Current();
#endif
private:
const char* function_name_ = nullptr;
const char* file_name_ = nullptr;
int line_number_ = -1;
const void* program_counter_ = nullptr;
};
BASE_EXPORT const void* GetProgramCounter();
// The macros defined here will expand to the current function.
#if BUILDFLAG(ENABLE_LOCATION_SOURCE)
// Full source information should be included.
#define FROM_HERE FROM_HERE_WITH_EXPLICIT_FUNCTION(__func__)
#define FROM_HERE_WITH_EXPLICIT_FUNCTION(function_name) \
::base::Location::CreateFromHere(function_name, __FILE__, __LINE__)
#else
// TODO(http://crbug.com/760702) remove the __FILE__ argument from these calls.
#define FROM_HERE ::base::Location::CreateFromHere(__FILE__)
#define FROM_HERE_WITH_EXPLICIT_FUNCTION(function_name) \
::base::Location::CreateFromHere(function_name, __FILE__, -1)
#endif
} // namespace base
namespace std {
// Specialization for using Location in hash tables.
template <>
struct hash<::base::Location> {
std::size_t operator()(const ::base::Location& loc) const {
const void* program_counter = loc.program_counter();
return base::FastHash(base::as_bytes(base::make_span(&program_counter, 1)));
}
};
} // namespace std
#endif // BASE_LOCATION_H_
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