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// Copyright 2012 The Chromium Authors
// 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 <compare>
#include <string>
#include "base/base_export.h"
#include "base/memory/raw_ptr_exclusion.h"
#include "base/trace_event/base_tracing_forward.h"
#include "build/build_config.h"
namespace base {
// 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);
Location(Location&& other) noexcept;
Location& operator=(const Location& other);
static Location CreateForTesting(const char* function_name,
const char* file_name,
int line_number,
const void* program_counter) {
return Location(function_name, file_name, line_number, program_counter);
}
// Comparator for testing. The program counter should uniquely
// identify a location.
friend bool operator==(const Location& lhs, const Location& rhs) {
return lhs.program_counter_ == rhs.program_counter_;
}
// The program counter should uniquely identify a location. There is no
// guarantee that a program counter corresponds to unique function/file/line
// values, based on how it's constructed, and therefore equivalent locations
// could be distinguishable.
friend std::weak_ordering operator<=>(const Location& lhs,
const Location& rhs) {
return lhs.program_counter_ <=> rhs.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;
// Write a representation of this object into a trace.
void WriteIntoTrace(perfetto::TracedValue context) const;
static Location Current(const char* function_name = __builtin_FUNCTION(),
const char* file_name = __builtin_FILE(),
int line_number = __builtin_LINE());
private:
// 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);
const char* function_name_ = nullptr;
const char* file_name_ = nullptr;
int line_number_ = -1;
// `program_counter_` is not a raw_ptr<...> for performance reasons (based on
// analysis of sampling profiler data and tab_search:top100:2020).
RAW_PTR_EXCLUSION const void* program_counter_ = nullptr;
};
BASE_EXPORT const void* GetProgramCounter();
#define FROM_HERE ::base::Location::Current()
} // namespace base
#endif // BASE_LOCATION_H_
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