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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.
#include "base/location.h"
#include "base/compiler_specific.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/trace_event/trace_event.h"
#if defined(COMPILER_MSVC)
#include <intrin.h>
#endif
namespace base {
namespace {
// Returns the length of the given null terminated c-string.
constexpr size_t StrLen(const char* str) {
size_t str_len = 0;
for (str_len = 0; UNSAFE_TODO(str[str_len]) != '\0'; ++str_len)
;
return str_len;
}
// Finds the length of the build folder prefix from the file path.
// TODO(ssid): Strip prefixes from stored strings in the binary. This code only
// skips the prefix while reading the file name strings at runtime.
constexpr size_t StrippedFilePathPrefixLength() {
constexpr char path[] = __FILE__;
// Only keep the file path starting from the src directory.
#if defined(__clang__) && defined(_MSC_VER)
constexpr char stripped[] = "base\\location.cc";
#else
constexpr char stripped[] = "base/location.cc";
#endif
constexpr size_t path_len = StrLen(path);
constexpr size_t stripped_len = StrLen(stripped);
static_assert(path_len >= stripped_len,
"Invalid file path for base/location.cc.");
return path_len - stripped_len;
}
constexpr size_t kStrippedPrefixLength = StrippedFilePathPrefixLength();
// Returns true if the |name| string has |prefix_len| characters in the prefix
// and the suffix matches the |expected| string.
// TODO(ssid): With C++20 we can make base::EndsWith() constexpr and use it
// instead.
constexpr bool StrEndsWith(const char* name,
size_t prefix_len,
const char* expected) {
const size_t name_len = StrLen(name);
const size_t expected_len = StrLen(expected);
if (name_len != prefix_len + expected_len) {
return false;
}
for (size_t i = 0; i < expected_len; ++i) {
if (UNSAFE_TODO(name[i + prefix_len] != expected[i])) {
return false;
}
}
return true;
}
#if defined(__clang__) && defined(_MSC_VER)
static_assert(StrEndsWith(__FILE__, kStrippedPrefixLength, "base\\location.cc"),
"The file name does not match the expected prefix format.");
#else
static_assert(StrEndsWith(__FILE__, kStrippedPrefixLength, "base/location.cc"),
"The file name does not match the expected prefix format.");
#endif
} // namespace
Location::Location() = default;
Location::Location(const Location& other) = default;
Location::Location(Location&& other) noexcept = default;
Location& Location::operator=(const Location& other) = default;
Location::Location(const char* file_name, const void* program_counter)
: file_name_(file_name), program_counter_(program_counter) {}
Location::Location(const char* function_name,
const char* file_name,
int line_number,
const void* program_counter)
: function_name_(function_name),
file_name_(file_name),
line_number_(line_number),
program_counter_(program_counter) {
#if !BUILDFLAG(IS_NACL)
// The program counter should not be null except in a default constructed
// (empty) Location object. This value is used for identity, so if it doesn't
// uniquely identify a location, things will break.
//
// The program counter isn't supported in NaCl so location objects won't work
// properly in that context.
DCHECK(program_counter);
#endif
}
std::string Location::ToString() const {
if (has_source_info()) {
return std::string(function_name_) + "@" + file_name_ + ":" +
NumberToString(line_number_);
}
return StringPrintf("pc:%p", program_counter_);
}
void Location::WriteIntoTrace(perfetto::TracedValue context) const {
auto dict = std::move(context).WriteDictionary();
dict.Add("function_name", function_name_);
dict.Add("file_name", file_name_);
dict.Add("line_number", line_number_);
}
#if defined(COMPILER_MSVC)
#define RETURN_ADDRESS() _ReturnAddress()
#elif defined(COMPILER_GCC) && !BUILDFLAG(IS_NACL)
#define RETURN_ADDRESS() \
__builtin_extract_return_addr(__builtin_return_address(0))
#else
#define RETURN_ADDRESS() nullptr
#endif
// static
NOINLINE Location Location::Current(const char* function_name,
const char* file_name,
int line_number) {
return Location(function_name, UNSAFE_TODO(file_name + kStrippedPrefixLength),
line_number, RETURN_ADDRESS());
}
// static
NOINLINE Location Location::CurrentWithoutFunctionName(const char* file_name,
int line_number) {
return Location(nullptr, UNSAFE_TODO(file_name + kStrippedPrefixLength),
line_number, RETURN_ADDRESS());
}
//------------------------------------------------------------------------------
NOINLINE const void* GetProgramCounter() {
return RETURN_ADDRESS();
}
} // namespace base
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