1 files changed, 57 insertions, 0 deletions
diff --git a/src/rocksdb/logging/log_buffer.h b/src/rocksdb/logging/log_buffer.h
new file mode 100644
index 000000000..92d38d10d
--- /dev/null
+++ b/src/rocksdb/logging/log_buffer.h
@@ -0,0 +1,57 @@
+// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include <ctime>
+
+#include "memory/arena.h"
+#include "port/sys_time.h"
+#include "rocksdb/env.h"
+#include "util/autovector.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class Logger;
+
+// A class to buffer info log entries and flush them in the end.
+class LogBuffer {
+ public:
+  // log_level: the log level for all the logs
+  // info_log:  logger to write the logs to
+  LogBuffer(const InfoLogLevel log_level, Logger* info_log);
+
+  // Add a log entry to the buffer. Use default max_log_size.
+  // max_log_size indicates maximize log size, including some metadata.
+  void AddLogToBuffer(size_t max_log_size, const char* format, va_list ap);
+
+  size_t IsEmpty() const { return logs_.empty(); }
+
+  // Flush all buffered log to the info log.
+  void FlushBufferToLog();
+  static const size_t kDefaultMaxLogSize = 512;
+
+ private:
+  // One log entry with its timestamp
+  struct BufferedLog {
+    port::TimeVal now_tv;  // Timestamp of the log
+    char message[1];       // Beginning of log message
+  };
+
+  const InfoLogLevel log_level_;
+  Logger* info_log_;
+  Arena arena_;
+  autovector<BufferedLog*> logs_;
+};
+
+// Add log to the LogBuffer for a delayed info logging. It can be used when
+// we want to add some logs inside a mutex.
+// max_log_size indicates maximize log size, including some metadata.
+extern void LogToBuffer(LogBuffer* log_buffer, size_t max_log_size,
+                        const char* format, ...);
+// Same as previous function, but with default max log size.
+extern void LogToBuffer(LogBuffer* log_buffer, const char* format, ...);
+
+}  // namespace ROCKSDB_NAMESPACE