Implement a dynamically growing memory log buffer with an upper limit.

src/log-utils.cc

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "log-utils.h"
+
+namespace v8 {
+namespace internal {
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+
+LogDynamicBuffer::LogDynamicBuffer(int block_size, int max_size)
+    : block_size_(block_size),
+      max_size_(max_size - (max_size % block_size_)),
+      blocks_(max_size_ / block_size_ + 1),
+      write_pos_(0), block_index_(0), block_write_pos_(0) {
+  ASSERT(BlocksCount() > 0);
+  blocks_[0] = NewArray<char>(block_size_);

[Søren Thygesen Gjesse, 2009/05/27 12:00:40]

Maybe add a private method AllocateBlock.

[Mikhail Naganov, 2009/05/28 07:05:35]

Done.

+  for (int i = 1; i < BlocksCount(); ++i) {
+    blocks_[i] = NULL;
+  }
+}
+
+
+LogDynamicBuffer::~LogDynamicBuffer() {
+  for (int i = 0; i < BlocksCount(); ++i) {
+    DeleteArray(blocks_[i]);
+  }
+}
+
+
+int LogDynamicBuffer::Read(int from_pos, char* dest_buf, int buf_size) {
+  if (buf_size == 0) return 0;
+  int read_pos = from_pos;
+  int block_read_index = BlockIndex(from_pos);
+  int block_read_pos = PosInBlock(from_pos);
+  int dest_buf_pos = 0;
+  // Read until dest_buf is filled, or write_pos_ encountered.
+  while (read_pos < write_pos_ && dest_buf_pos < buf_size) {
+    const int read_size = Min(write_pos_ - read_pos,
+        Min(buf_size - dest_buf_pos, block_size_ - block_read_pos));
+    memcpy(dest_buf + dest_buf_pos,
+           blocks_[block_read_index] + block_read_pos, read_size);
+    block_read_pos += read_size;
+    dest_buf_pos += read_size;
+    read_pos += read_size;
+    if (block_read_pos == block_size_) {
+      block_read_pos = 0;
+      ++block_read_index;
+    }
+  }
+  return dest_buf_pos;
+}
+
+
+int LogDynamicBuffer::Write(const char* data, int data_size) {
+  if ((write_pos_ + data_size) > max_size_) return 0;
+  int data_pos = 0;
+  while (data_pos < data_size) {
+    const int write_size =
+        Min(data_size - data_pos, block_size_ - block_write_pos_);
+    memcpy(blocks_[block_index_] + block_write_pos_, data + data_pos,
+           write_size);
+    block_write_pos_ += write_size;
+    data_pos += write_size;
+    if (block_write_pos_ == block_size_) {
+      block_write_pos_ = 0;
+      blocks_[++block_index_] = NewArray<char>(block_size_);

[Søren Thygesen Gjesse, 2009/05/27 12:00:40]

Ditto.

[Mikhail Naganov, 2009/05/28 07:05:35]

Done.

+    }
+  }
+  write_pos_ += data_size;
+  return data_size;
+}
+
+
+Log::WritePtr Log::Write = NULL;
+FILE* Log::output_handle_ = NULL;
+LogDynamicBuffer* Log::output_buffer_ = NULL;
+Mutex* Log::mutex_ = NULL;
+char* Log::message_buffer_ = NULL;
+
+
+void Log::Init() {
+  mutex_ = OS::CreateMutex();
+  message_buffer_ = NewArray<char>(kMessageBufferSize);
+}
+
+
+void Log::OpenStdout() {
+  ASSERT(!IsEnabled());
+  output_handle_ = stdout;
+  Write = WriteToFile;
+  Init();
+}
+
+
+void Log::OpenFile(const char* name) {
+  ASSERT(!IsEnabled());
+  output_handle_ = OS::FOpen(name, OS::LogFileOpenMode);
+  Write = WriteToFile;
+  Init();
+}
+
+
+void Log::OpenMemoryBuffer() {
+  ASSERT(!IsEnabled());
+  output_buffer_ = new LogDynamicBuffer(
+      kDynamicBufferBlockSize, kMaxDynamicBufferSize);
+  Write = WriteToMemory;
+  Init();
+}
+
+
+void Log::Close() {
+  if (Write == WriteToFile) {
+    fclose(output_handle_);
+    output_handle_ = NULL;
+  } else if (Write == WriteToMemory) {
+    delete output_buffer_;
+    output_buffer_ = NULL;
+  } else {
+    ASSERT(Write == NULL);
+  }
+  Write = NULL;
+
+  delete mutex_;
+  mutex_ = NULL;
+}
+
+
+int Log::GetLogLines(int from_pos, char* dest_buf, int max_size) {
+  if (Write != WriteToMemory) return 0;
+  ASSERT(output_buffer_ != NULL);
+  ASSERT(from_pos >= 0);
+  ASSERT(max_size >= 0);
+  int actual_size = output_buffer_->Read(from_pos, dest_buf, max_size);
+  ASSERT(actual_size <= max_size);
+  if (actual_size == 0) return 0;
+
+  // Find previous log line boundary.
+  char* end_pos = dest_buf + actual_size - 1;
+  while (end_pos >= dest_buf && *end_pos != '\n') --end_pos;
+  actual_size = end_pos - dest_buf + 1;
+  ASSERT(actual_size <= max_size);
+  return actual_size;
+}
+
+
+LogMessageBuilder::LogMessageBuilder(): sl(Log::mutex_), pos_(0) {
+  ASSERT(Log::message_buffer_ != NULL);
+}
+
+
+void LogMessageBuilder::Append(const char* format, ...) {
+  Vector<char> buf(Log::message_buffer_ + pos_,
+                   Log::kMessageBufferSize - pos_);
+  va_list args;
+  va_start(args, format);
+  Append(format, args);
+  va_end(args);
+  ASSERT(pos_ <= Log::kMessageBufferSize);
+}
+
+
+void LogMessageBuilder::Append(const char* format, va_list args) {
+  Vector<char> buf(Log::message_buffer_ + pos_,
+                   Log::kMessageBufferSize - pos_);
+  int result = v8::internal::OS::VSNPrintF(buf, format, args);
+
+  // Result is -1 if output was truncated.
+  if (result >= 0) {
+    pos_ += result;
+  } else {
+    pos_ = Log::kMessageBufferSize;
+  }
+  ASSERT(pos_ <= Log::kMessageBufferSize);
+}
+
+
+void LogMessageBuilder::Append(const char c) {
+  if (pos_ < Log::kMessageBufferSize) {
+    Log::message_buffer_[pos_++] = c;
+  }
+  ASSERT(pos_ <= Log::kMessageBufferSize);
+}
+
+
+void LogMessageBuilder::Append(String* str) {
+  AssertNoAllocation no_heap_allocation;  // Ensure string stay valid.
+  int length = str->length();
+  for (int i = 0; i < length; i++) {
+    Append(static_cast<char>(str->Get(i)));
+  }
+}
+
+
+void LogMessageBuilder::AppendDetailed(String* str, bool show_impl_info) {
+  AssertNoAllocation no_heap_allocation;  // Ensure string stay valid.
+  int len = str->length();
+  if (len > 0x1000)
+    len = 0x1000;
+  if (show_impl_info) {
+    Append(str->IsAsciiRepresentation() ? 'a' : '2');
+    if (StringShape(str).IsExternal())
+      Append('e');
+    if (StringShape(str).IsSymbol())
+      Append('#');
+    Append(":%i:", str->length());
+  }
+  for (int i = 0; i < len; i++) {
+    uc32 c = str->Get(i);
+    if (c > 0xff) {
+      Append("\\u%04x", c);
+    } else if (c < 32 || c > 126) {
+      Append("\\x%02x", c);
+    } else if (c == ',') {
+      Append("\\,");
+    } else if (c == '\\') {
+      Append("\\\\");
+    } else {
+      Append("%lc", c);
+    }
+  }
+}
+
+
+void LogMessageBuilder::WriteToLogFile() {
+  ASSERT(pos_ <= Log::kMessageBufferSize);
+  Log::Write(Log::message_buffer_, pos_);
+}
+
+
+void LogMessageBuilder::WriteCStringToLogFile(const char* str) {
+  int len = strlen(str);
+  Log::Write(str, len);
+}
+
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+} }  // namespace v8::internal