Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1077 insertions, 0 deletions

diff --git a/security/sandbox/chromium/base/logging.h b/security/sandbox/chromium/base/logging.h
new file mode 100644
index 0000000000..cb24b94833
--- /dev/null
+++ b/security/sandbox/chromium/base/logging.h
@@ -0,0 +1,1077 @@
+// 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_LOGGING_H_
+#define BASE_LOGGING_H_
+
+#include <stddef.h>
+
+#include <cassert>
+#include <cstdint>
+#include <cstring>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+#include "base/base_export.h"
+#include "base/callback_forward.h"
+#include "base/compiler_specific.h"
+#include "base/immediate_crash.h"
+#include "base/logging_buildflags.h"
+#include "base/macros.h"
+#include "base/scoped_clear_last_error.h"
+#include "base/strings/string_piece_forward.h"
+#include "base/template_util.h"
+#include "build/build_config.h"
+
+#if defined(OS_CHROMEOS)
+#include <cstdio>
+#endif
+
+//
+// Optional message capabilities
+// -----------------------------
+// Assertion failed messages and fatal errors are displayed in a dialog box
+// before the application exits. However, running this UI creates a message
+// loop, which causes application messages to be processed and potentially
+// dispatched to existing application windows. Since the application is in a
+// bad state when this assertion dialog is displayed, these messages may not
+// get processed and hang the dialog, or the application might go crazy.
+//
+// Therefore, it can be beneficial to display the error dialog in a separate
+// process from the main application. When the logging system needs to display
+// a fatal error dialog box, it will look for a program called
+// "DebugMessage.exe" in the same directory as the application executable. It
+// will run this application with the message as the command line, and will
+// not include the name of the application as is traditional for easier
+// parsing.
+//
+// The code for DebugMessage.exe is only one line. In WinMain, do:
+//   MessageBox(NULL, GetCommandLineW(), L"Fatal Error", 0);
+//
+// If DebugMessage.exe is not found, the logging code will use a normal
+// MessageBox, potentially causing the problems discussed above.
+
+// Instructions
+// ------------
+//
+// Make a bunch of macros for logging.  The way to log things is to stream
+// things to LOG(<a particular severity level>).  E.g.,
+//
+//   LOG(INFO) << "Found " << num_cookies << " cookies";
+//
+// You can also do conditional logging:
+//
+//   LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
+//
+// The CHECK(condition) macro is active in both debug and release builds and
+// effectively performs a LOG(FATAL) which terminates the process and
+// generates a crashdump unless a debugger is attached.
+//
+// There are also "debug mode" logging macros like the ones above:
+//
+//   DLOG(INFO) << "Found cookies";
+//
+//   DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
+//
+// All "debug mode" logging is compiled away to nothing for non-debug mode
+// compiles.  LOG_IF and development flags also work well together
+// because the code can be compiled away sometimes.
+//
+// We also have
+//
+//   LOG_ASSERT(assertion);
+//   DLOG_ASSERT(assertion);
+//
+// which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
+//
+// There are "verbose level" logging macros.  They look like
+//
+//   VLOG(1) << "I'm printed when you run the program with --v=1 or more";
+//   VLOG(2) << "I'm printed when you run the program with --v=2 or more";
+//
+// These always log at the INFO log level (when they log at all).
+// The verbose logging can also be turned on module-by-module.  For instance,
+//    --vmodule=profile=2,icon_loader=1,browser_*=3,*/chromeos/*=4 --v=0
+// will cause:
+//   a. VLOG(2) and lower messages to be printed from profile.{h,cc}
+//   b. VLOG(1) and lower messages to be printed from icon_loader.{h,cc}
+//   c. VLOG(3) and lower messages to be printed from files prefixed with
+//      "browser"
+//   d. VLOG(4) and lower messages to be printed from files under a
+//     "chromeos" directory.
+//   e. VLOG(0) and lower messages to be printed from elsewhere
+//
+// The wildcarding functionality shown by (c) supports both '*' (match
+// 0 or more characters) and '?' (match any single character)
+// wildcards.  Any pattern containing a forward or backward slash will
+// be tested against the whole pathname and not just the module.
+// E.g., "*/foo/bar/*=2" would change the logging level for all code
+// in source files under a "foo/bar" directory.
+//
+// There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
+//
+//   if (VLOG_IS_ON(2)) {
+//     // do some logging preparation and logging
+//     // that can't be accomplished with just VLOG(2) << ...;
+//   }
+//
+// There is also a VLOG_IF "verbose level" condition macro for sample
+// cases, when some extra computation and preparation for logs is not
+// needed.
+//
+//   VLOG_IF(1, (size > 1024))
+//      << "I'm printed when size is more than 1024 and when you run the "
+//         "program with --v=1 or more";
+//
+// We also override the standard 'assert' to use 'DLOG_ASSERT'.
+//
+// Lastly, there is:
+//
+//   PLOG(ERROR) << "Couldn't do foo";
+//   DPLOG(ERROR) << "Couldn't do foo";
+//   PLOG_IF(ERROR, cond) << "Couldn't do foo";
+//   DPLOG_IF(ERROR, cond) << "Couldn't do foo";
+//   PCHECK(condition) << "Couldn't do foo";
+//   DPCHECK(condition) << "Couldn't do foo";
+//
+// which append the last system error to the message in string form (taken from
+// GetLastError() on Windows and errno on POSIX).
+//
+// The supported severity levels for macros that allow you to specify one
+// are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
+//
+// Very important: logging a message at the FATAL severity level causes
+// the program to terminate (after the message is logged).
+//
+// There is the special severity of DFATAL, which logs FATAL in debug mode,
+// ERROR in normal mode.
+//
+// Output is of the format, for example:
+// [3816:3877:0812/234555.406952:VERBOSE1:drm_device_handle.cc(90)] Succeeded
+// authenticating /dev/dri/card0 in 0 ms with 1 attempt(s)
+//
+// The colon separated fields inside the brackets are as follows:
+// 0. An optional Logfile prefix (not included in this example)
+// 1. Process ID
+// 2. Thread ID
+// 3. The date/time of the log message, in MMDD/HHMMSS.Milliseconds format
+// 4. The log level
+// 5. The filename and line number where the log was instantiated
+//
+// Note that the visibility can be changed by setting preferences in
+// SetLogItems()
+
+namespace logging {
+
+// TODO(avi): do we want to do a unification of character types here?
+#if defined(OS_WIN)
+typedef wchar_t PathChar;
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+typedef char PathChar;
+#endif
+
+// A bitmask of potential logging destinations.
+using LoggingDestination = uint32_t;
+// Specifies where logs will be written. Multiple destinations can be specified
+// with bitwise OR.
+// Unless destination is LOG_NONE, all logs with severity ERROR and above will
+// be written to stderr in addition to the specified destination.
+enum : uint32_t {
+  LOG_NONE                = 0,
+  LOG_TO_FILE             = 1 << 0,
+  LOG_TO_SYSTEM_DEBUG_LOG = 1 << 1,
+  LOG_TO_STDERR           = 1 << 2,
+
+  LOG_TO_ALL = LOG_TO_FILE | LOG_TO_SYSTEM_DEBUG_LOG | LOG_TO_STDERR,
+
+// On Windows, use a file next to the exe.
+// On POSIX platforms, where it may not even be possible to locate the
+// executable on disk, use stderr.
+// On Fuchsia, use the Fuchsia logging service.
+#if defined(OS_FUCHSIA) || defined(OS_NACL)
+  LOG_DEFAULT = LOG_TO_SYSTEM_DEBUG_LOG,
+#elif defined(OS_WIN)
+  LOG_DEFAULT = LOG_TO_FILE,
+#elif defined(OS_POSIX)
+  LOG_DEFAULT = LOG_TO_SYSTEM_DEBUG_LOG | LOG_TO_STDERR,
+#endif
+};
+
+// Indicates that the log file should be locked when being written to.
+// Unless there is only one single-threaded process that is logging to
+// the log file, the file should be locked during writes to make each
+// log output atomic. Other writers will block.
+//
+// All processes writing to the log file must have their locking set for it to
+// work properly. Defaults to LOCK_LOG_FILE.
+enum LogLockingState { LOCK_LOG_FILE, DONT_LOCK_LOG_FILE };
+
+// On startup, should we delete or append to an existing log file (if any)?
+// Defaults to APPEND_TO_OLD_LOG_FILE.
+enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE };
+
+struct BASE_EXPORT LoggingSettings {
+  // Equivalent to logging destination enum, but allows for multiple
+  // destinations.
+  uint32_t logging_dest = LOG_DEFAULT;
+
+  // The four settings below have an effect only when LOG_TO_FILE is
+  // set in |logging_dest|.
+  const PathChar* log_file_path = nullptr;
+  LogLockingState lock_log = LOCK_LOG_FILE;
+  OldFileDeletionState delete_old = APPEND_TO_OLD_LOG_FILE;
+#if defined(OS_CHROMEOS)
+  // Contains an optional file that logs should be written to. If present,
+  // |log_file_path| will be ignored, and the logging system will take ownership
+  // of the FILE. If there's an error writing to this file, no fallback paths
+  // will be opened.
+  FILE* log_file = nullptr;
+#endif
+};
+
+// Define different names for the BaseInitLoggingImpl() function depending on
+// whether NDEBUG is defined or not so that we'll fail to link if someone tries
+// to compile logging.cc with NDEBUG but includes logging.h without defining it,
+// or vice versa.
+#if defined(NDEBUG)
+#define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG
+#else
+#define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG
+#endif
+
+// Implementation of the InitLogging() method declared below.  We use a
+// more-specific name so we can #define it above without affecting other code
+// that has named stuff "InitLogging".
+BASE_EXPORT bool BaseInitLoggingImpl(const LoggingSettings& settings);
+
+// Sets the log file name and other global logging state. Calling this function
+// is recommended, and is normally done at the beginning of application init.
+// If you don't call it, all the flags will be initialized to their default
+// values, and there is a race condition that may leak a critical section
+// object if two threads try to do the first log at the same time.
+// See the definition of the enums above for descriptions and default values.
+//
+// The default log file is initialized to "debug.log" in the application
+// directory. You probably don't want this, especially since the program
+// directory may not be writable on an enduser's system.
+//
+// This function may be called a second time to re-direct logging (e.g after
+// loging in to a user partition), however it should never be called more than
+// twice.
+inline bool InitLogging(const LoggingSettings& settings) {
+  return BaseInitLoggingImpl(settings);
+}
+
+// Sets the log level. Anything at or above this level will be written to the
+// log file/displayed to the user (if applicable). Anything below this level
+// will be silently ignored. The log level defaults to 0 (everything is logged
+// up to level INFO) if this function is not called.
+// Note that log messages for VLOG(x) are logged at level -x, so setting
+// the min log level to negative values enables verbose logging.
+BASE_EXPORT void SetMinLogLevel(int level);
+
+// Gets the current log level.
+BASE_EXPORT int GetMinLogLevel();
+
+// Used by LOG_IS_ON to lazy-evaluate stream arguments.
+BASE_EXPORT bool ShouldCreateLogMessage(int severity);
+
+// Gets the VLOG default verbosity level.
+BASE_EXPORT int GetVlogVerbosity();
+
+// Note that |N| is the size *with* the null terminator.
+BASE_EXPORT int GetVlogLevelHelper(const char* file_start, size_t N);
+
+// Gets the current vlog level for the given file (usually taken from __FILE__).
+template <size_t N>
+int GetVlogLevel(const char (&file)[N]) {
+  return GetVlogLevelHelper(file, N);
+}
+
+// Sets the common items you want to be prepended to each log message.
+// process and thread IDs default to off, the timestamp defaults to on.
+// If this function is not called, logging defaults to writing the timestamp
+// only.
+BASE_EXPORT void SetLogItems(bool enable_process_id, bool enable_thread_id,
+                             bool enable_timestamp, bool enable_tickcount);
+
+// Sets an optional prefix to add to each log message. |prefix| is not copied
+// and should be a raw string constant. |prefix| must only contain ASCII letters
+// to avoid confusion with PIDs and timestamps. Pass null to remove the prefix.
+// Logging defaults to no prefix.
+BASE_EXPORT void SetLogPrefix(const char* prefix);
+
+// Sets whether or not you'd like to see fatal debug messages popped up in
+// a dialog box or not.
+// Dialogs are not shown by default.
+BASE_EXPORT void SetShowErrorDialogs(bool enable_dialogs);
+
+// Sets the Log Assert Handler that will be used to notify of check failures.
+// Resets Log Assert Handler on object destruction.
+// The default handler shows a dialog box and then terminate the process,
+// however clients can use this function to override with their own handling
+// (e.g. a silent one for Unit Tests)
+using LogAssertHandlerFunction =
+    base::RepeatingCallback<void(const char* file,
+                                 int line,
+                                 const base::StringPiece message,
+                                 const base::StringPiece stack_trace)>;
+
+class BASE_EXPORT ScopedLogAssertHandler {
+ public:
+  explicit ScopedLogAssertHandler(LogAssertHandlerFunction handler);
+  ~ScopedLogAssertHandler();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedLogAssertHandler);
+};
+
+// Sets the Log Message Handler that gets passed every log message before
+// it's sent to other log destinations (if any).
+// Returns true to signal that it handled the message and the message
+// should not be sent to other log destinations.
+typedef bool (*LogMessageHandlerFunction)(int severity,
+    const char* file, int line, size_t message_start, const std::string& str);
+BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler);
+BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler();
+
+// The ANALYZER_ASSUME_TRUE(bool arg) macro adds compiler-specific hints
+// to Clang which control what code paths are statically analyzed,
+// and is meant to be used in conjunction with assert & assert-like functions.
+// The expression is passed straight through if analysis isn't enabled.
+//
+// ANALYZER_SKIP_THIS_PATH() suppresses static analysis for the current
+// codepath and any other branching codepaths that might follow.
+#if defined(__clang_analyzer__)
+
+inline constexpr bool AnalyzerNoReturn() __attribute__((analyzer_noreturn)) {
+  return false;
+}
+
+inline constexpr bool AnalyzerAssumeTrue(bool arg) {
+  // AnalyzerNoReturn() is invoked and analysis is terminated if |arg| is
+  // false.
+  return arg || AnalyzerNoReturn();
+}
+
+#define ANALYZER_ASSUME_TRUE(arg) logging::AnalyzerAssumeTrue(!!(arg))
+#define ANALYZER_SKIP_THIS_PATH() \
+  static_cast<void>(::logging::AnalyzerNoReturn())
+#define ANALYZER_ALLOW_UNUSED(var) static_cast<void>(var);
+
+#else  // !defined(__clang_analyzer__)
+
+#define ANALYZER_ASSUME_TRUE(arg) (arg)
+#define ANALYZER_SKIP_THIS_PATH()
+#define ANALYZER_ALLOW_UNUSED(var) static_cast<void>(var);
+
+#endif  // defined(__clang_analyzer__)
+
+typedef int LogSeverity;
+const LogSeverity LOG_VERBOSE = -1;  // This is level 1 verbosity
+// Note: the log severities are used to index into the array of names,
+// see log_severity_names.
+const LogSeverity LOG_INFO = 0;
+const LogSeverity LOG_WARNING = 1;
+const LogSeverity LOG_ERROR = 2;
+const LogSeverity LOG_FATAL = 3;
+const LogSeverity LOG_NUM_SEVERITIES = 4;
+
+// LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode
+#if defined(NDEBUG)
+const LogSeverity LOG_DFATAL = LOG_ERROR;
+#else
+const LogSeverity LOG_DFATAL = LOG_FATAL;
+#endif
+
+// A few definitions of macros that don't generate much code. These are used
+// by LOG() and LOG_IF, etc. Since these are used all over our code, it's
+// better to have compact code for these operations.
+#define COMPACT_GOOGLE_LOG_EX_INFO(ClassName, ...) \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_INFO, ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_EX_WARNING(ClassName, ...)              \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_WARNING, \
+                       ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_EX_ERROR(ClassName, ...) \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_ERROR, ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_EX_FATAL(ClassName, ...) \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_FATAL, ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ...) \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_DFATAL, ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
+  ::logging::ClassName(__FILE__, __LINE__, ::logging::LOG_DCHECK, ##__VA_ARGS__)
+
+#define COMPACT_GOOGLE_LOG_INFO COMPACT_GOOGLE_LOG_EX_INFO(LogMessage)
+#define COMPACT_GOOGLE_LOG_WARNING COMPACT_GOOGLE_LOG_EX_WARNING(LogMessage)
+#define COMPACT_GOOGLE_LOG_ERROR COMPACT_GOOGLE_LOG_EX_ERROR(LogMessage)
+#define COMPACT_GOOGLE_LOG_FATAL COMPACT_GOOGLE_LOG_EX_FATAL(LogMessage)
+#define COMPACT_GOOGLE_LOG_DFATAL COMPACT_GOOGLE_LOG_EX_DFATAL(LogMessage)
+#define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_EX_DCHECK(LogMessage)
+
+#if defined(OS_WIN)
+// wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets
+// substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us
+// to keep using this syntax, we define this macro to do the same thing
+// as COMPACT_GOOGLE_LOG_ERROR, and also define ERROR the same way that
+// the Windows SDK does for consistency.
+#define ERROR 0
+#define COMPACT_GOOGLE_LOG_EX_0(ClassName, ...) \
+  COMPACT_GOOGLE_LOG_EX_ERROR(ClassName , ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR
+// Needed for LOG_IS_ON(ERROR).
+const LogSeverity LOG_0 = LOG_ERROR;
+#endif
+
+// As special cases, we can assume that LOG_IS_ON(FATAL) always holds. Also,
+// LOG_IS_ON(DFATAL) always holds in debug mode. In particular, CHECK()s will
+// always fire if they fail.
+#define LOG_IS_ON(severity) \
+  (::logging::ShouldCreateLogMessage(::logging::LOG_##severity))
+
+// We don't do any caching tricks with VLOG_IS_ON() like the
+// google-glog version since it increases binary size.  This means
+// that using the v-logging functions in conjunction with --vmodule
+// may be slow.
+#define VLOG_IS_ON(verboselevel) \
+  ((verboselevel) <= ::logging::GetVlogLevel(__FILE__))
+
+// Helper macro which avoids evaluating the arguments to a stream if
+// the condition doesn't hold. Condition is evaluated once and only once.
+#define LAZY_STREAM(stream, condition)                                  \
+  !(condition) ? (void) 0 : ::logging::LogMessageVoidify() & (stream)
+
+// We use the preprocessor's merging operator, "##", so that, e.g.,
+// LOG(INFO) becomes the token COMPACT_GOOGLE_LOG_INFO.  There's some funny
+// subtle difference between ostream member streaming functions (e.g.,
+// ostream::operator<<(int) and ostream non-member streaming functions
+// (e.g., ::operator<<(ostream&, string&): it turns out that it's
+// impossible to stream something like a string directly to an unnamed
+// ostream. We employ a neat hack by calling the stream() member
+// function of LogMessage which seems to avoid the problem.
+#define LOG_STREAM(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
+
+#define LOG(severity) LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity))
+#define LOG_IF(severity, condition) \
+  LAZY_STREAM(LOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
+
+// The VLOG macros log with negative verbosities.
+#define VLOG_STREAM(verbose_level) \
+  ::logging::LogMessage(__FILE__, __LINE__, -verbose_level).stream()
+
+#define VLOG(verbose_level) \
+  LAZY_STREAM(VLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
+
+#define VLOG_IF(verbose_level, condition) \
+  LAZY_STREAM(VLOG_STREAM(verbose_level), \
+      VLOG_IS_ON(verbose_level) && (condition))
+
+#if defined (OS_WIN)
+#define VPLOG_STREAM(verbose_level) \
+  ::logging::Win32ErrorLogMessage(__FILE__, __LINE__, -verbose_level, \
+    ::logging::GetLastSystemErrorCode()).stream()
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+#define VPLOG_STREAM(verbose_level) \
+  ::logging::ErrnoLogMessage(__FILE__, __LINE__, -verbose_level, \
+    ::logging::GetLastSystemErrorCode()).stream()
+#endif
+
+#define VPLOG(verbose_level) \
+  LAZY_STREAM(VPLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
+
+#define VPLOG_IF(verbose_level, condition) \
+  LAZY_STREAM(VPLOG_STREAM(verbose_level), \
+    VLOG_IS_ON(verbose_level) && (condition))
+
+// TODO(akalin): Add more VLOG variants, e.g. VPLOG.
+
+#define LOG_ASSERT(condition)                       \
+  LOG_IF(FATAL, !(ANALYZER_ASSUME_TRUE(condition))) \
+      << "Assert failed: " #condition ". "
+
+#if defined(OS_WIN)
+#define PLOG_STREAM(severity) \
+  COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \
+      ::logging::GetLastSystemErrorCode()).stream()
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+#define PLOG_STREAM(severity) \
+  COMPACT_GOOGLE_LOG_EX_ ## severity(ErrnoLogMessage, \
+      ::logging::GetLastSystemErrorCode()).stream()
+#endif
+
+#define PLOG(severity)                                          \
+  LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity))
+
+#define PLOG_IF(severity, condition) \
+  LAZY_STREAM(PLOG_STREAM(severity), LOG_IS_ON(severity) && (condition))
+
+BASE_EXPORT extern std::ostream* g_swallow_stream;
+
+// Note that g_swallow_stream is used instead of an arbitrary LOG() stream to
+// avoid the creation of an object with a non-trivial destructor (LogMessage).
+// On MSVC x86 (checked on 2015 Update 3), this causes a few additional
+// pointless instructions to be emitted even at full optimization level, even
+// though the : arm of the ternary operator is clearly never executed. Using a
+// simpler object to be &'d with Voidify() avoids these extra instructions.
+// Using a simpler POD object with a templated operator<< also works to avoid
+// these instructions. However, this causes warnings on statically defined
+// implementations of operator<<(std::ostream, ...) in some .cc files, because
+// they become defined-but-unreferenced functions. A reinterpret_cast of 0 to an
+// ostream* also is not suitable, because some compilers warn of undefined
+// behavior.
+#define EAT_STREAM_PARAMETERS \
+  true ? (void)0              \
+       : ::logging::LogMessageVoidify() & (*::logging::g_swallow_stream)
+
+// Captures the result of a CHECK_EQ (for example) and facilitates testing as a
+// boolean.
+class CheckOpResult {
+ public:
+  // |message| must be non-null if and only if the check failed.
+  constexpr CheckOpResult(std::string* message) : message_(message) {}
+  // Returns true if the check succeeded.
+  constexpr operator bool() const { return !message_; }
+  // Returns the message.
+  std::string* message() { return message_; }
+
+ private:
+  std::string* message_;
+};
+
+// CHECK dies with a fatal error if condition is not true.  It is *not*
+// controlled by NDEBUG, so the check will be executed regardless of
+// compilation mode.
+//
+// We make sure CHECK et al. always evaluates their arguments, as
+// doing CHECK(FunctionWithSideEffect()) is a common idiom.
+
+#if defined(OFFICIAL_BUILD) && defined(NDEBUG)
+
+// Make all CHECK functions discard their log strings to reduce code bloat, and
+// improve performance, for official release builds.
+//
+// This is not calling BreakDebugger since this is called frequently, and
+// calling an out-of-line function instead of a noreturn inline macro prevents
+// compiler optimizations.
+#define CHECK(condition) \
+  UNLIKELY(!(condition)) ? IMMEDIATE_CRASH() : EAT_STREAM_PARAMETERS
+
+// PCHECK includes the system error code, which is useful for determining
+// why the condition failed. In official builds, preserve only the error code
+// message so that it is available in crash reports. The stringified
+// condition and any additional stream parameters are dropped.
+#define PCHECK(condition)                                  \
+  LAZY_STREAM(PLOG_STREAM(FATAL), UNLIKELY(!(condition))); \
+  EAT_STREAM_PARAMETERS
+
+#define CHECK_OP(name, op, val1, val2) CHECK((val1) op (val2))
+
+#else  // !(OFFICIAL_BUILD && NDEBUG)
+
+// Do as much work as possible out of line to reduce inline code size.
+#define CHECK(condition)                                                      \
+  LAZY_STREAM(::logging::LogMessage(__FILE__, __LINE__, #condition).stream(), \
+              !ANALYZER_ASSUME_TRUE(condition))
+
+#define PCHECK(condition)                                           \
+  LAZY_STREAM(PLOG_STREAM(FATAL), !ANALYZER_ASSUME_TRUE(condition)) \
+      << "Check failed: " #condition ". "
+
+// Helper macro for binary operators.
+// Don't use this macro directly in your code, use CHECK_EQ et al below.
+// The 'switch' is used to prevent the 'else' from being ambiguous when the
+// macro is used in an 'if' clause such as:
+// if (a == 1)
+//   CHECK_EQ(2, a);
+#define CHECK_OP(name, op, val1, val2)                                         \
+  switch (0) case 0: default:                                                  \
+  if (::logging::CheckOpResult true_if_passed =                                \
+      ::logging::Check##name##Impl((val1), (val2),                             \
+                                   #val1 " " #op " " #val2))                   \
+   ;                                                                           \
+  else                                                                         \
+    ::logging::LogMessage(__FILE__, __LINE__, true_if_passed.message()).stream()
+
+#endif  // !(OFFICIAL_BUILD && NDEBUG)
+
+// This formats a value for a failing CHECK_XX statement.  Ordinarily,
+// it uses the definition for operator<<, with a few special cases below.
+template <typename T>
+inline typename std::enable_if<
+    base::internal::SupportsOstreamOperator<const T&>::value &&
+        !std::is_function<typename std::remove_pointer<T>::type>::value,
+    void>::type
+MakeCheckOpValueString(std::ostream* os, const T& v) {
+  (*os) << v;
+}
+
+// Overload for types that no operator<< but do have .ToString() defined.
+template <typename T>
+inline typename std::enable_if<
+    !base::internal::SupportsOstreamOperator<const T&>::value &&
+        base::internal::SupportsToString<const T&>::value,
+    void>::type
+MakeCheckOpValueString(std::ostream* os, const T& v) {
+  (*os) << v.ToString();
+}
+
+// Provide an overload for functions and function pointers. Function pointers
+// don't implicitly convert to void* but do implicitly convert to bool, so
+// without this function pointers are always printed as 1 or 0. (MSVC isn't
+// standards-conforming here and converts function pointers to regular
+// pointers, so this is a no-op for MSVC.)
+template <typename T>
+inline typename std::enable_if<
+    std::is_function<typename std::remove_pointer<T>::type>::value,
+    void>::type
+MakeCheckOpValueString(std::ostream* os, const T& v) {
+  (*os) << reinterpret_cast<const void*>(v);
+}
+
+// We need overloads for enums that don't support operator<<.
+// (i.e. scoped enums where no operator<< overload was declared).
+template <typename T>
+inline typename std::enable_if<
+    !base::internal::SupportsOstreamOperator<const T&>::value &&
+        std::is_enum<T>::value,
+    void>::type
+MakeCheckOpValueString(std::ostream* os, const T& v) {
+  (*os) << static_cast<typename std::underlying_type<T>::type>(v);
+}
+
+// We need an explicit overload for std::nullptr_t.
+BASE_EXPORT void MakeCheckOpValueString(std::ostream* os, std::nullptr_t p);
+
+// Build the error message string.  This is separate from the "Impl"
+// function template because it is not performance critical and so can
+// be out of line, while the "Impl" code should be inline.  Caller
+// takes ownership of the returned string.
+template<class t1, class t2>
+std::string* MakeCheckOpString(const t1& v1, const t2& v2, const char* names) {
+  std::ostringstream ss;
+  ss << names << " (";
+  MakeCheckOpValueString(&ss, v1);
+  ss << " vs. ";
+  MakeCheckOpValueString(&ss, v2);
+  ss << ")";
+  std::string* msg = new std::string(ss.str());
+  return msg;
+}
+
+// Commonly used instantiations of MakeCheckOpString<>. Explicitly instantiated
+// in logging.cc.
+extern template BASE_EXPORT std::string* MakeCheckOpString<int, int>(
+    const int&, const int&, const char* names);
+extern template BASE_EXPORT
+std::string* MakeCheckOpString<unsigned long, unsigned long>(
+    const unsigned long&, const unsigned long&, const char* names);
+extern template BASE_EXPORT
+std::string* MakeCheckOpString<unsigned long, unsigned int>(
+    const unsigned long&, const unsigned int&, const char* names);
+extern template BASE_EXPORT
+std::string* MakeCheckOpString<unsigned int, unsigned long>(
+    const unsigned int&, const unsigned long&, const char* names);
+extern template BASE_EXPORT
+std::string* MakeCheckOpString<std::string, std::string>(
+    const std::string&, const std::string&, const char* name);
+
+// Helper functions for CHECK_OP macro.
+// The (int, int) specialization works around the issue that the compiler
+// will not instantiate the template version of the function on values of
+// unnamed enum type - see comment below.
+//
+// The checked condition is wrapped with ANALYZER_ASSUME_TRUE, which under
+// static analysis builds, blocks analysis of the current path if the
+// condition is false.
+#define DEFINE_CHECK_OP_IMPL(name, op)                                 \
+  template <class t1, class t2>                                        \
+  constexpr std::string* Check##name##Impl(const t1& v1, const t2& v2, \
+                                           const char* names) {        \
+    if (ANALYZER_ASSUME_TRUE(v1 op v2))                                \
+      return nullptr;                                                  \
+    else                                                               \
+      return ::logging::MakeCheckOpString(v1, v2, names);              \
+  }                                                                    \
+  constexpr std::string* Check##name##Impl(int v1, int v2,             \
+                                           const char* names) {        \
+    if (ANALYZER_ASSUME_TRUE(v1 op v2))                                \
+      return nullptr;                                                  \
+    else                                                               \
+      return ::logging::MakeCheckOpString(v1, v2, names);              \
+  }
+DEFINE_CHECK_OP_IMPL(EQ, ==)
+DEFINE_CHECK_OP_IMPL(NE, !=)
+DEFINE_CHECK_OP_IMPL(LE, <=)
+DEFINE_CHECK_OP_IMPL(LT, < )
+DEFINE_CHECK_OP_IMPL(GE, >=)
+DEFINE_CHECK_OP_IMPL(GT, > )
+#undef DEFINE_CHECK_OP_IMPL
+
+#define CHECK_EQ(val1, val2) CHECK_OP(EQ, ==, val1, val2)
+#define CHECK_NE(val1, val2) CHECK_OP(NE, !=, val1, val2)
+#define CHECK_LE(val1, val2) CHECK_OP(LE, <=, val1, val2)
+#define CHECK_LT(val1, val2) CHECK_OP(LT, < , val1, val2)
+#define CHECK_GE(val1, val2) CHECK_OP(GE, >=, val1, val2)
+#define CHECK_GT(val1, val2) CHECK_OP(GT, > , val1, val2)
+
+#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
+#define DCHECK_IS_ON() false
+#else
+#define DCHECK_IS_ON() true
+#endif
+
+// Definitions for DLOG et al.
+
+#if DCHECK_IS_ON()
+
+#define DLOG_IS_ON(severity) LOG_IS_ON(severity)
+#define DLOG_IF(severity, condition) LOG_IF(severity, condition)
+#define DLOG_ASSERT(condition) LOG_ASSERT(condition)
+#define DPLOG_IF(severity, condition) PLOG_IF(severity, condition)
+#define DVLOG_IF(verboselevel, condition) VLOG_IF(verboselevel, condition)
+#define DVPLOG_IF(verboselevel, condition) VPLOG_IF(verboselevel, condition)
+
+#else  // DCHECK_IS_ON()
+
+// If !DCHECK_IS_ON(), we want to avoid emitting any references to |condition|
+// (which may reference a variable defined only if DCHECK_IS_ON()).
+// Contrast this with DCHECK et al., which has different behavior.
+
+#define DLOG_IS_ON(severity) false
+#define DLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
+#define DLOG_ASSERT(condition) EAT_STREAM_PARAMETERS
+#define DPLOG_IF(severity, condition) EAT_STREAM_PARAMETERS
+#define DVLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
+#define DVPLOG_IF(verboselevel, condition) EAT_STREAM_PARAMETERS
+
+#endif  // DCHECK_IS_ON()
+
+#define DLOG(severity)                                          \
+  LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
+
+#define DPLOG(severity)                                         \
+  LAZY_STREAM(PLOG_STREAM(severity), DLOG_IS_ON(severity))
+
+#define DVLOG(verboselevel) DVLOG_IF(verboselevel, true)
+
+#define DVPLOG(verboselevel) DVPLOG_IF(verboselevel, true)
+
+// Definitions for DCHECK et al.
+
+#if DCHECK_IS_ON()
+
+#if defined(DCHECK_IS_CONFIGURABLE)
+BASE_EXPORT extern LogSeverity LOG_DCHECK;
+#else
+const LogSeverity LOG_DCHECK = LOG_FATAL;
+#endif  // defined(DCHECK_IS_CONFIGURABLE)
+
+#else  // DCHECK_IS_ON()
+
+// There may be users of LOG_DCHECK that are enabled independently
+// of DCHECK_IS_ON(), so default to FATAL logging for those.
+const LogSeverity LOG_DCHECK = LOG_FATAL;
+
+#endif  // DCHECK_IS_ON()
+
+// DCHECK et al. make sure to reference |condition| regardless of
+// whether DCHECKs are enabled; this is so that we don't get unused
+// variable warnings if the only use of a variable is in a DCHECK.
+// This behavior is different from DLOG_IF et al.
+//
+// Note that the definition of the DCHECK macros depends on whether or not
+// DCHECK_IS_ON() is true. When DCHECK_IS_ON() is false, the macros use
+// EAT_STREAM_PARAMETERS to avoid expressions that would create temporaries.
+
+#if DCHECK_IS_ON()
+
+#define DCHECK(condition)                                           \
+  LAZY_STREAM(LOG_STREAM(DCHECK), !ANALYZER_ASSUME_TRUE(condition)) \
+      << "Check failed: " #condition ". "
+#define DPCHECK(condition)                                           \
+  LAZY_STREAM(PLOG_STREAM(DCHECK), !ANALYZER_ASSUME_TRUE(condition)) \
+      << "Check failed: " #condition ". "
+
+#else  // DCHECK_IS_ON()
+
+#define DCHECK(condition) EAT_STREAM_PARAMETERS << !(condition)
+#define DPCHECK(condition) EAT_STREAM_PARAMETERS << !(condition)
+
+#endif  // DCHECK_IS_ON()
+
+// Helper macro for binary operators.
+// Don't use this macro directly in your code, use DCHECK_EQ et al below.
+// The 'switch' is used to prevent the 'else' from being ambiguous when the
+// macro is used in an 'if' clause such as:
+// if (a == 1)
+//   DCHECK_EQ(2, a);
+#if DCHECK_IS_ON()
+
+#define DCHECK_OP(name, op, val1, val2)                                \
+  switch (0) case 0: default:                                          \
+  if (::logging::CheckOpResult true_if_passed =                        \
+      ::logging::Check##name##Impl((val1), (val2),                     \
+                                   #val1 " " #op " " #val2))           \
+   ;                                                                   \
+  else                                                                 \
+    ::logging::LogMessage(__FILE__, __LINE__, ::logging::LOG_DCHECK,   \
+                          true_if_passed.message()).stream()
+
+#else  // DCHECK_IS_ON()
+
+// When DCHECKs aren't enabled, DCHECK_OP still needs to reference operator<<
+// overloads for |val1| and |val2| to avoid potential compiler warnings about
+// unused functions. For the same reason, it also compares |val1| and |val2|
+// using |op|.
+//
+// Note that the contract of DCHECK_EQ, etc is that arguments are only evaluated
+// once. Even though |val1| and |val2| appear twice in this version of the macro
+// expansion, this is OK, since the expression is never actually evaluated.
+#define DCHECK_OP(name, op, val1, val2)                             \
+  EAT_STREAM_PARAMETERS << (::logging::MakeCheckOpValueString(      \
+                                ::logging::g_swallow_stream, val1), \
+                            ::logging::MakeCheckOpValueString(      \
+                                ::logging::g_swallow_stream, val2), \
+                            (val1)op(val2))
+
+#endif  // DCHECK_IS_ON()
+
+// Equality/Inequality checks - compare two values, and log a
+// LOG_DCHECK message including the two values when the result is not
+// as expected.  The values must have operator<<(ostream, ...)
+// defined.
+//
+// You may append to the error message like so:
+//   DCHECK_NE(1, 2) << "The world must be ending!";
+//
+// We are very careful to ensure that each argument is evaluated exactly
+// once, and that anything which is legal to pass as a function argument is
+// legal here.  In particular, the arguments may be temporary expressions
+// which will end up being destroyed at the end of the apparent statement,
+// for example:
+//   DCHECK_EQ(string("abc")[1], 'b');
+//
+// WARNING: These don't compile correctly if one of the arguments is a pointer
+// and the other is NULL.  In new code, prefer nullptr instead.  To
+// work around this for C++98, simply static_cast NULL to the type of the
+// desired pointer.
+
+#define DCHECK_EQ(val1, val2) DCHECK_OP(EQ, ==, val1, val2)
+#define DCHECK_NE(val1, val2) DCHECK_OP(NE, !=, val1, val2)
+#define DCHECK_LE(val1, val2) DCHECK_OP(LE, <=, val1, val2)
+#define DCHECK_LT(val1, val2) DCHECK_OP(LT, < , val1, val2)
+#define DCHECK_GE(val1, val2) DCHECK_OP(GE, >=, val1, val2)
+#define DCHECK_GT(val1, val2) DCHECK_OP(GT, > , val1, val2)
+
+#if BUILDFLAG(ENABLE_LOG_ERROR_NOT_REACHED)
+// Implement logging of NOTREACHED() as a dedicated function to get function
+// call overhead down to a minimum.
+void LogErrorNotReached(const char* file, int line);
+#define NOTREACHED()                                       \
+  true ? ::logging::LogErrorNotReached(__FILE__, __LINE__) \
+       : EAT_STREAM_PARAMETERS
+#else
+#define NOTREACHED() DCHECK(false)
+#endif
+
+// Redefine the standard assert to use our nice log files
+#undef assert
+#define assert(x) DLOG_ASSERT(x)
+
+// This class more or less represents a particular log message.  You
+// create an instance of LogMessage and then stream stuff to it.
+// When you finish streaming to it, ~LogMessage is called and the
+// full message gets streamed to the appropriate destination.
+//
+// You shouldn't actually use LogMessage's constructor to log things,
+// though.  You should use the LOG() macro (and variants thereof)
+// above.
+class BASE_EXPORT LogMessage {
+ public:
+  // Used for LOG(severity).
+  LogMessage(const char* file, int line, LogSeverity severity);
+
+  // Used for CHECK().  Implied severity = LOG_FATAL.
+  LogMessage(const char* file, int line, const char* condition);
+
+  // Used for CHECK_EQ(), etc. Takes ownership of the given string.
+  // Implied severity = LOG_FATAL.
+  LogMessage(const char* file, int line, std::string* result);
+
+  // Used for DCHECK_EQ(), etc. Takes ownership of the given string.
+  LogMessage(const char* file, int line, LogSeverity severity,
+             std::string* result);
+
+  ~LogMessage();
+
+  std::ostream& stream() { return stream_; }
+
+  LogSeverity severity() { return severity_; }
+  std::string str() { return stream_.str(); }
+
+ private:
+  void Init(const char* file, int line);
+
+  LogSeverity severity_;
+  std::ostringstream stream_;
+  size_t message_start_;  // Offset of the start of the message (past prefix
+                          // info).
+  // The file and line information passed in to the constructor.
+  const char* file_;
+  const int line_;
+  const char* file_basename_;
+
+  // This is useful since the LogMessage class uses a lot of Win32 calls
+  // that will lose the value of GLE and the code that called the log function
+  // will have lost the thread error value when the log call returns.
+  base::internal::ScopedClearLastError last_error_;
+
+  DISALLOW_COPY_AND_ASSIGN(LogMessage);
+};
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros.  This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+class LogMessageVoidify {
+ public:
+  LogMessageVoidify() = default;
+  // This has to be an operator with a precedence lower than << but
+  // higher than ?:
+  void operator&(std::ostream&) { }
+};
+
+#if defined(OS_WIN)
+typedef unsigned long SystemErrorCode;
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+typedef int SystemErrorCode;
+#endif
+
+// Alias for ::GetLastError() on Windows and errno on POSIX. Avoids having to
+// pull in windows.h just for GetLastError() and DWORD.
+BASE_EXPORT SystemErrorCode GetLastSystemErrorCode();
+BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code);
+
+#if defined(OS_WIN)
+// Appends a formatted system message of the GetLastError() type.
+class BASE_EXPORT Win32ErrorLogMessage {
+ public:
+  Win32ErrorLogMessage(const char* file,
+                       int line,
+                       LogSeverity severity,
+                       SystemErrorCode err);
+
+  // Appends the error message before destructing the encapsulated class.
+  ~Win32ErrorLogMessage();
+
+  std::ostream& stream() { return log_message_.stream(); }
+
+ private:
+  SystemErrorCode err_;
+  LogMessage log_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(Win32ErrorLogMessage);
+};
+#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
+// Appends a formatted system message of the errno type
+class BASE_EXPORT ErrnoLogMessage {
+ public:
+  ErrnoLogMessage(const char* file,
+                  int line,
+                  LogSeverity severity,
+                  SystemErrorCode err);
+
+  // Appends the error message before destructing the encapsulated class.
+  ~ErrnoLogMessage();
+
+  std::ostream& stream() { return log_message_.stream(); }
+
+ private:
+  SystemErrorCode err_;
+  LogMessage log_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(ErrnoLogMessage);
+};
+#endif  // OS_WIN
+
+// Closes the log file explicitly if open.
+// NOTE: Since the log file is opened as necessary by the action of logging
+//       statements, there's no guarantee that it will stay closed
+//       after this call.
+BASE_EXPORT void CloseLogFile();
+
+#if defined(OS_CHROMEOS)
+// Returns a new file handle that will write to the same destination as the
+// currently open log file. Returns nullptr if logging to a file is disabled,
+// or if opening the file failed. This is intended to be used to initialize
+// logging in child processes that are unable to open files.
+BASE_EXPORT FILE* DuplicateLogFILE();
+#endif
+
+// Async signal safe logging mechanism.
+BASE_EXPORT void RawLog(int level, const char* message);
+
+#define RAW_LOG(level, message) \
+  ::logging::RawLog(::logging::LOG_##level, message)
+
+#define RAW_CHECK(condition)                               \
+  do {                                                     \
+    if (!(condition))                                      \
+      ::logging::RawLog(::logging::LOG_FATAL,              \
+                        "Check failed: " #condition "\n"); \
+  } while (0)
+
+#if defined(OS_WIN)
+// Returns true if logging to file is enabled.
+BASE_EXPORT bool IsLoggingToFileEnabled();
+
+// Returns the default log file path.
+BASE_EXPORT std::wstring GetLogFileFullPath();
+#endif
+
+}  // namespace logging
+
+// Note that "The behavior of a C++ program is undefined if it adds declarations
+// or definitions to namespace std or to a namespace within namespace std unless
+// otherwise specified." --C++11[namespace.std]
+//
+// We've checked that this particular definition has the intended behavior on
+// our implementations, but it's prone to breaking in the future, and please
+// don't imitate this in your own definitions without checking with some
+// standard library experts.
+namespace std {
+// These functions are provided as a convenience for logging, which is where we
+// use streams (it is against Google style to use streams in other places). It
+// is designed to allow you to emit non-ASCII Unicode strings to the log file,
+// which is normally ASCII. It is relatively slow, so try not to use it for
+// common cases. Non-ASCII characters will be converted to UTF-8 by these
+// operators.
+BASE_EXPORT std::ostream& operator<<(std::ostream& out, const wchar_t* wstr);
+inline std::ostream& operator<<(std::ostream& out, const std::wstring& wstr) {
+  return out << wstr.c_str();
+}
+}  // namespace std
+
+// The NOTIMPLEMENTED() macro annotates codepaths which have not been
+// implemented yet. If output spam is a serious concern,
+// NOTIMPLEMENTED_LOG_ONCE can be used.
+
+#if defined(COMPILER_GCC)
+// On Linux, with GCC, we can use __PRETTY_FUNCTION__ to get the demangled name
+// of the current function in the NOTIMPLEMENTED message.
+#define NOTIMPLEMENTED_MSG "Not implemented reached in " << __PRETTY_FUNCTION__
+#else
+#define NOTIMPLEMENTED_MSG "NOT IMPLEMENTED"
+#endif
+
+#define NOTIMPLEMENTED() DLOG(ERROR) << NOTIMPLEMENTED_MSG
+#define NOTIMPLEMENTED_LOG_ONCE()                       \
+  do {                                                  \
+    static bool logged_once = false;                    \
+    DLOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG; \
+    logged_once = true;                                 \
+  } while (0);                                          \
+  EAT_STREAM_PARAMETERS
+
+#endif  // BASE_LOGGING_H_