Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 322 insertions, 0 deletions

diff --git a/xpcom/base/Logging.h b/xpcom/base/Logging.h
new file mode 100644
index 0000000000..6ed2752315
--- /dev/null
+++ b/xpcom/base/Logging.h
@@ -0,0 +1,322 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_logging_h
+#define mozilla_logging_h
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Likely.h"
+
+// We normally have logging enabled everywhere, but measurements showed that
+// having logging enabled on Android is quite expensive (hundreds of kilobytes
+// for both the format strings for logging and the code to perform all the
+// logging calls).  Because retrieving logs from a mobile device is
+// comparatively more difficult for Android than it is for desktop and because
+// desktop machines tend to be less space/bandwidth-constrained than Android
+// devices, we've chosen to leave logging enabled on desktop, but disabled on
+// Android.  Given that logging can still be useful for development purposes,
+// however, we leave logging enabled on Android developer builds.
+#if !defined(ANDROID) || !defined(RELEASE_OR_BETA)
+#  define MOZ_LOGGING_ENABLED 1
+#else
+#  define MOZ_LOGGING_ENABLED 0
+#endif
+
+// The mandatory extension we add to log files.  Note that rotate will append
+// the file piece number still at the end.
+#define MOZ_LOG_FILE_EXTENSION ".moz_log"
+
+// Token for Process ID substitution.
+#define MOZ_LOG_PID_TOKEN "%PID"
+
+namespace mozilla {
+
+class TimeStamp;
+
+// While not a 100% mapping to PR_LOG's numeric values, mozilla::LogLevel does
+// maintain a direct mapping for the Disabled, Debug and Verbose levels.
+//
+// Mappings of LogLevel to PR_LOG's numeric values:
+//
+//   +---------+------------------+-----------------+
+//   | Numeric | NSPR Logging     | Mozilla Logging |
+//   +---------+------------------+-----------------+
+//   |       0 | PR_LOG_NONE      | Disabled        |
+//   |       1 | PR_LOG_ALWAYS    | Error           |
+//   |       2 | PR_LOG_ERROR     | Warning         |
+//   |       3 | PR_LOG_WARNING   | Info            |
+//   |       4 | PR_LOG_DEBUG     | Debug           |
+//   |       5 | PR_LOG_DEBUG + 1 | Verbose         |
+//   +---------+------------------+-----------------+
+//
+enum class LogLevel {
+  Disabled = 0,
+  Error,
+  Warning,
+  Info,
+  Debug,
+  Verbose,
+};
+
+/**
+ * Safely converts an integer into a valid LogLevel.
+ */
+LogLevel ToLogLevel(int32_t aLevel);
+
+class LogModule {
+ public:
+  ~LogModule() { ::free(mName); }
+
+  /**
+   * Retrieves the module with the given name. If it does not already exist
+   * it will be created.
+   *
+   * @param aName The name of the module.
+   * @return A log module for the given name. This may be shared.
+   */
+  static LogModule* Get(const char* aName);
+
+  /**
+   * Logging processes -MOZ_LOG and -MOZ_LOG_FILE command line arguments
+   * to override or set modules and the file as if passed through MOZ_LOG
+   * and MOZ_LOG_FILE env vars.  It's fine to pass (0, nullptr) if args
+   * are not accessible in the caller's context, it will just do nothing.
+   * Note that the args take effect (are processed) only when this function
+   * is called the first time.
+   */
+  static void Init(int argc, char* argv[]);
+
+  /**
+   * Sets the log file to the given filename.
+   */
+  static void SetLogFile(const char* aFilename);
+
+  /**
+   * @param aBuffer - pointer to a buffer
+   * @param aLength - the length of the buffer
+   *
+   * @return the actual length of the filepath.
+   */
+  static uint32_t GetLogFile(char* aBuffer, size_t aLength);
+
+  /**
+   * @param aAddTimestamp If we should log a time stamp with every message.
+   */
+  static void SetAddTimestamp(bool aAddTimestamp);
+
+  /**
+   * @param aIsSync If we should flush the file after every logged message.
+   */
+  static void SetIsSync(bool aIsSync);
+
+  /**
+   * @param aCaptureStacks If we should capture stacks for the Firefox
+   * Profiler markers that are recorded for for each log entry.
+   */
+  static void SetCaptureStacks(bool aCaptureStacks);
+
+  /**
+   * Indicates whether or not the given log level is enabled.
+   */
+  bool ShouldLog(LogLevel aLevel) const { return mLevel >= aLevel; }
+
+  /**
+   * Retrieves the log module's current level.
+   */
+  LogLevel Level() const { return mLevel; }
+
+  /**
+   * Sets the log module's level.
+   */
+  void SetLevel(LogLevel level);
+
+  /**
+   * Print a log message for this module.
+   */
+  void Printv(LogLevel aLevel, const char* aFmt, va_list aArgs) const
+      MOZ_FORMAT_PRINTF(3, 0);
+
+  void Printv(LogLevel aLevel, const TimeStamp* aStart, const char* aFmt,
+              va_list aArgs) const MOZ_FORMAT_PRINTF(4, 0);
+
+  /**
+   * Retrieves the module name.
+   */
+  const char* Name() const { return mName; }
+
+ private:
+  friend class LogModuleManager;
+
+  explicit LogModule(const char* aName, LogLevel aLevel)
+      : mName(strdup(aName)), mLevel(aLevel) {}
+
+  LogModule(LogModule&) = delete;
+  LogModule& operator=(const LogModule&) = delete;
+
+  char* mName;
+
+  Atomic<LogLevel, Relaxed> mLevel;
+};
+
+/**
+ * Helper class that lazy loads the given log module. This is safe to use for
+ * declaring static references to log modules and can be used as a replacement
+ * for accessing a LogModule directly.
+ *
+ * Example usage:
+ *   static LazyLogModule sLayoutLog("layout");
+ *
+ *   void Foo() {
+ *     MOZ_LOG(sLayoutLog, LogLevel::Verbose, ("Entering foo"));
+ *   }
+ */
+class LazyLogModule final {
+ public:
+  explicit constexpr LazyLogModule(const char* aLogName)
+      : mLogName(aLogName), mLog(nullptr) {}
+
+  MOZ_NEVER_INLINE_DEBUG operator LogModule*() {
+    // NB: The use of an atomic makes the reading and assignment of mLog
+    //     thread-safe. There is a small chance that mLog will be set more
+    //     than once, but that's okay as it will be set to the same LogModule
+    //     instance each time. Also note LogModule::Get is thread-safe.
+    LogModule* tmp = mLog;
+    if (MOZ_UNLIKELY(!tmp)) {
+      tmp = LogModule::Get(mLogName);
+      mLog = tmp;
+    }
+
+    return tmp;
+  }
+
+ private:
+  const char* const mLogName;
+
+  Atomic<LogModule*, ReleaseAcquire> mLog;
+};
+
+namespace detail {
+
+inline bool log_test(const LogModule* module, LogLevel level) {
+  MOZ_ASSERT(level != LogLevel::Disabled);
+  return module && module->ShouldLog(level);
+}
+
+void log_print(const LogModule* aModule, LogLevel aLevel, const char* aFmt, ...)
+    MOZ_FORMAT_PRINTF(3, 4);
+
+void log_print(const LogModule* aModule, LogLevel aLevel, TimeStamp* aStart,
+               const char* aFmt, ...) MOZ_FORMAT_PRINTF(4, 5);
+}  // namespace detail
+
+}  // namespace mozilla
+
+// Helper macro used convert MOZ_LOG's third parameter, |_args|, from a
+// parenthesized form to a varargs form. For example:
+//   ("%s", "a message") => "%s", "a message"
+#define MOZ_LOG_EXPAND_ARGS(...) __VA_ARGS__
+
+#if MOZ_LOGGING_ENABLED
+#  define MOZ_LOG_TEST(_module, _level) \
+    MOZ_UNLIKELY(mozilla::detail::log_test(_module, _level))
+#else
+// Define away MOZ_LOG_TEST here so the compiler will fold away entire
+// logging blocks via dead code elimination, e.g.:
+//
+//   if (MOZ_LOG_TEST(...)) {
+//     ...compute things to log and log them...
+//   }
+#  define MOZ_LOG_TEST(_module, _level) false
+#endif
+
+// The natural definition of the MOZ_LOG macro would expand to:
+//
+//   do {
+//     if (MOZ_LOG_TEST(_module, _level)) {
+//       mozilla::detail::log_print(_module, ...);
+//     }
+//   } while (0)
+//
+// However, since _module is a LazyLogModule, and we need to call
+// LazyLogModule::operator() to get a LogModule* for the MOZ_LOG_TEST
+// macro and for the logging call, we'll wind up doing *two* calls, one
+// for each, rather than a single call.  The compiler is not able to
+// fold the two calls into one, and the extra call can have a
+// significant effect on code size.  (Making LazyLogModule::operator() a
+// `const` function does not have any effect.)
+//
+// Therefore, we will have to make a single call ourselves.  But again,
+// the natural definition:
+//
+//   do {
+//     ::mozilla::LogModule* real_module = _module;
+//     if (MOZ_LOG_TEST(real_module, _level)) {
+//       mozilla::detail::log_print(real_module, ...);
+//     }
+//   } while (0)
+//
+// also has a problem: if logging is disabled, then we will call
+// LazyLogModule::operator() unnecessarily, and the compiler will not be
+// able to optimize away the call as dead code.  We would like to avoid
+// such a scenario, as the whole point of disabling logging is for the
+// logging statements to not generate any code.
+//
+// Therefore, we need different definitions of MOZ_LOG, depending on
+// whether logging is enabled or not.  (We need an actual definition of
+// MOZ_LOG even when logging is disabled to ensure the compiler sees that
+// variables only used during logging code are actually used, even if the
+// code will never be executed.)  Hence, the following code.
+//
+// MOZ_LOG_DURATION takes a start time, and will generate a time range
+// in the logs.  Also, if the Firefox Profiler is running,
+// MOZ_LOG_DURATION will generate a marker with a time duration
+// instead of a single point in time.
+#if MOZ_LOGGING_ENABLED
+#  define MOZ_LOG(_module, _level, _args)                      \
+    do {                                                       \
+      const ::mozilla::LogModule* moz_real_module = _module;   \
+      if (MOZ_LOG_TEST(moz_real_module, _level)) {             \
+        mozilla::detail::log_print(moz_real_module, _level,    \
+                                   MOZ_LOG_EXPAND_ARGS _args); \
+      }                                                        \
+    } while (0)
+#  define MOZ_LOG_DURATION(_module, _level, start, _args)          \
+    do {                                                           \
+      const ::mozilla::LogModule* moz_real_module = _module;       \
+      if (MOZ_LOG_TEST(moz_real_module, _level)) {                 \
+        mozilla::detail::log_print(moz_real_module, _level, start, \
+                                   MOZ_LOG_EXPAND_ARGS _args);     \
+      }                                                            \
+    } while (0)
+#else
+#  define MOZ_LOG(_module, _level, _args)                      \
+    do {                                                       \
+      if (MOZ_LOG_TEST(_module, _level)) {                     \
+        mozilla::detail::log_print(_module, _level,            \
+                                   MOZ_LOG_EXPAND_ARGS _args); \
+      }                                                        \
+    } while (0)
+#  define MOZ_LOG_DURATION(_module, _level, start, _args)      \
+    do {                                                       \
+      if (MOZ_LOG_TEST(_module, _level)) {                     \
+        mozilla::detail::log_print(_module, _level, start,     \
+                                   MOZ_LOG_EXPAND_ARGS _args); \
+      }                                                        \
+    } while (0)
+#endif
+
+// This #define is a Logging.h-only knob!  Don't encourage people to get fancy
+// with their log definitions by exporting it outside of Logging.h.
+#undef MOZ_LOGGING_ENABLED
+
+#endif  // mozilla_logging_h