root/third_party/leveldatabase/port/port_chromium.cc

DEFINITIONS

1. Lock
2. Unlock
3. AssertHeld
4. Wait
5. Signal
6. SignalAll
7. InitOnceImpl
8. Snappy_Compress
9. Snappy_GetUncompressedLength
10. Snappy_Uncompress

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "port/port_chromium.h"

#include "base/threading/platform_thread.h"
#include "util/logging.h"

#if defined(USE_SNAPPY)
#  include "third_party/snappy/src/snappy.h"
#endif

namespace leveldb {
namespace port {

Mutex::Mutex() {
}

Mutex::~Mutex() {
}

void Mutex::Lock() {
  mu_.Acquire();
}

void Mutex::Unlock() {
  mu_.Release();
}

void Mutex::AssertHeld() {
  mu_.AssertAcquired();
}

CondVar::CondVar(Mutex* mu)
    : cv_(&mu->mu_) {
}

CondVar::~CondVar() { }

void CondVar::Wait() {
  cv_.Wait();
}

void CondVar::Signal(){
  cv_.Signal();
}

void CondVar::SignalAll() {
  cv_.Broadcast();
}

void InitOnceImpl(OnceType* once, void (*initializer)()) {
  OnceType state = ::base::subtle::Acquire_Load(once);
  if (state == ONCE_STATE_DONE)
    return;

  state = ::base::subtle::NoBarrier_CompareAndSwap(
              once,
              ONCE_STATE_UNINITIALIZED,
              ONCE_STATE_EXECUTING_CLOSURE);

  if (state == ONCE_STATE_UNINITIALIZED) {
    // We are the first thread, we have to call the closure.
    (*initializer)();
    ::base::subtle::Release_Store(once, ONCE_STATE_DONE);
  } else {
    // Another thread is running the closure, wait until completion.
    while (state == ONCE_STATE_EXECUTING_CLOSURE) {
      ::base::PlatformThread::YieldCurrentThread();
      state = ::base::subtle::Acquire_Load(once);
    }
  }
}

bool Snappy_Compress(const char* input, size_t input_length,
                     std::string* output) {
#if defined(USE_SNAPPY)
  output->resize(snappy::MaxCompressedLength(input_length));
  size_t outlen;
  snappy::RawCompress(input, input_length, &(*output)[0], &outlen);
  output->resize(outlen);
  return true;
#else
  return false;
#endif
}

bool Snappy_GetUncompressedLength(const char* input_data,
                                  size_t input_length,
                                  size_t* result) {
#if defined(USE_SNAPPY)
  return snappy::GetUncompressedLength(input_data, input_length, result);
#else
  return false;
#endif
}

bool Snappy_Uncompress(const char* input_data, size_t input_length,
                       char* output) {
#if defined(USE_SNAPPY)
  return snappy::RawUncompress(input_data, input_length, output);
#else
  return false;
#endif
}

}
}