src/net/instaweb/http/sync_fetcher_adapter_callback.cc

// Copyright 2010 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Author: jmarantz@google.com (Joshua Marantz)
//         lsong@google.com (Libo Song)

#include "net/instaweb/http/public/sync_fetcher_adapter_callback.h"

#include "base/logging.h"
#include "pagespeed/kernel/base/abstract_mutex.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/condvar.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/base/thread_system.h"
#include "pagespeed/kernel/base/writer.h"

namespace net_instaweb {

class MessageHandler;

bool SyncFetcherAdapterCallback::ProtectedWriter::Write(
    const StringPiece& buf, MessageHandler* handler) {
  bool ret = true;

  // If the callback has not timed out and been released, then pass
  // the data through.
  if (callback_->LockIfNotReleased()) {
    ret = orig_writer_->Write(buf, handler);
    callback_->Unlock();
  }
  return ret;
}

bool SyncFetcherAdapterCallback::ProtectedWriter::Flush(
    MessageHandler* handler) {
  bool ret = true;

  // If the callback has not timed out and been released, then pass
  // the flush through.
  if (callback_->LockIfNotReleased()) {
    ret = orig_writer_->Flush(handler);
    callback_->Unlock();
  }
  return ret;
}

SyncFetcherAdapterCallback::SyncFetcherAdapterCallback(
    ThreadSystem* thread_system, Writer* writer,
    const RequestContextPtr& request_context)
    : AsyncFetch(request_context),
      mutex_(thread_system->NewMutex()),
      cond_(mutex_->NewCondvar()),
      done_(false),
      success_(false),
      released_(false),
      writer_(new ProtectedWriter(this, writer)) {
}

SyncFetcherAdapterCallback::~SyncFetcherAdapterCallback() {
}

void SyncFetcherAdapterCallback::HandleDone(bool success) {
  mutex_->Lock();
  done_ = true;
  success_ = success;
  if (released_) {
    mutex_->Unlock();
    delete this;
  } else {
    cond_->Signal();
    mutex_->Unlock();
  }
}

void SyncFetcherAdapterCallback::Release() {
  mutex_->Lock();
  DCHECK(!released_);
  released_ = true;
  if (done_) {
    mutex_->Unlock();
    delete this;
  } else {
    mutex_->Unlock();
  }
}

bool SyncFetcherAdapterCallback::IsDone() const {
  ScopedMutex hold_lock(mutex_.get());
  return done_;
}

bool SyncFetcherAdapterCallback::IsDoneLockHeld() const {
  mutex_->DCheckLocked();
  return done_;
}

bool SyncFetcherAdapterCallback::success() const {
  ScopedMutex hold_lock(mutex_.get());
  return success_;
}

bool SyncFetcherAdapterCallback::released() const {
  ScopedMutex hold_lock(mutex_.get());
  return released_;
}

bool SyncFetcherAdapterCallback::LockIfNotReleased() {
  mutex_->Lock();
  if (!released_) {
    return true;
  } else {
    mutex_->Unlock();
    return false;
  }
}

void SyncFetcherAdapterCallback::Unlock() {
  mutex_->Unlock();
}

void SyncFetcherAdapterCallback::TimedWait(int64 timeout_ms) {
  mutex_->DCheckLocked();
  DCHECK(!released_);
  cond_->TimedWait(timeout_ms);
}

}  // namespace net_instaweb