--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/logging/logMessageBuffer.cpp	Mon May 09 15:46:12 2016 +0200
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+#include "precompiled.hpp"
+#include "logging/logMessageBuffer.hpp"
+#include "memory/allocation.inline.hpp"
+#include "runtime/thread.inline.hpp"
+
+template <typename T>
+static void grow(T*& buffer, size_t& capacity, size_t minimum_length = 0) {
+  size_t new_size = capacity * 2;
+  if (new_size < minimum_length) {
+    new_size = minimum_length;
+  }
+  buffer = REALLOC_C_HEAP_ARRAY(T, buffer, new_size, mtLogging);
+  capacity = new_size;
+}
+
+LogMessageBuffer::LogMessageBuffer() : _message_buffer_size(0),
+                                       _message_buffer_capacity(0),
+                                       _message_buffer(NULL),
+                                       _line_count(0),
+                                       _line_capacity(0),
+                                       _lines(NULL),
+                                       _allocated(false),
+                                       _least_detailed_level(LogLevel::Off),
+                                       _prefix_fn(NULL) {
+}
+
+LogMessageBuffer::~LogMessageBuffer() {
+  if (_allocated) {
+    FREE_C_HEAP_ARRAY(char, _message_buffer);
+    FREE_C_HEAP_ARRAY(LogLine, _lines);
+  }
+}
+
+void LogMessageBuffer::reset() {
+  _message_buffer_size = 0;
+  _line_count = 0;
+}
+
+void LogMessageBuffer::initialize_buffers() {
+  assert(!_allocated, "buffer already initialized/allocated");
+  _allocated = true;
+  _message_buffer = NEW_C_HEAP_ARRAY(char, InitialMessageBufferCapacity, mtLogging);
+  _lines = NEW_C_HEAP_ARRAY(LogLine, InitialLineCapacity, mtLogging);
+  _message_buffer_capacity = InitialMessageBufferCapacity;
+  _line_capacity = InitialLineCapacity;
+}
+
+void LogMessageBuffer::Iterator::skip_messages_with_finer_level() {
+  for (; _current_line_index < _message._line_count; _current_line_index++) {
+    if (_message._lines[_current_line_index].level >= _level) {
+      break;
+    }
+  }
+}
+
+void LogMessageBuffer::write(LogLevelType level, const char* fmt, ...) {
+  va_list args;
+  va_start(args, fmt);
+  vwrite(level, fmt, args);
+  va_end(args);
+};
+
+void LogMessageBuffer::vwrite(LogLevelType level, const char* fmt, va_list args) {
+  if (!_allocated) {
+    initialize_buffers();
+  }
+
+  if (level > _least_detailed_level) {
+    _least_detailed_level = level;
+  }
+
+  size_t written;
+  for (int attempts = 0; attempts < 2; attempts++) {
+    written = 0;
+    size_t remaining_buffer_length = _message_buffer_capacity - _message_buffer_size;
+    char* current_buffer_position = _message_buffer + _message_buffer_size;
+
+    if (_prefix_fn != NULL) {
+      written += _prefix_fn(current_buffer_position, remaining_buffer_length);
+      current_buffer_position += written;
+      if (remaining_buffer_length < written) {
+        remaining_buffer_length = 0;
+      } else {
+        remaining_buffer_length -= written;
+      }
+    }
+
+    va_list copy;
+    va_copy(copy, args);
+    written += (size_t)os::log_vsnprintf(current_buffer_position, remaining_buffer_length, fmt, copy) + 1;
+    va_end(copy);
+    if (written > _message_buffer_capacity - _message_buffer_size) {
+      assert(attempts == 0, "Second attempt should always have a sufficiently large buffer (resized to fit).");
+      grow(_message_buffer, _message_buffer_capacity, _message_buffer_size + written);
+      continue;
+    }
+    break;
+  }
+
+  if (_line_count == _line_capacity) {
+    grow(_lines, _line_capacity);
+  }
+
+  _lines[_line_count].level = level;
+  _lines[_line_count].message_offset = _message_buffer_size;
+  _message_buffer_size += written;
+  _line_count++;
+}
+
+#define LOG_LEVEL(level, name) \
+LogMessageBuffer& LogMessageBuffer::v##name(const char* fmt, va_list args) { \
+  vwrite(LogLevel::level, fmt, args); \
+  return *this; \
+} \
+LogMessageBuffer& LogMessageBuffer::name(const char* fmt, ...) { \
+  va_list args; \
+  va_start(args, fmt); \
+  vwrite(LogLevel::level, fmt, args); \
+  va_end(args); \
+  return *this; \
+}
+LOG_LEVEL_LIST
+#undef LOG_LEVEL