weex_core/Source/include/wtf/LockedPrintStream.h

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
#pragma once

#include <wtf/PrintStream.h>
#include <wtf/RecursiveLockAdapter.h>
#include <wtf/WordLock.h>

namespace WTF {

// Makes every call to print() atomic.
class LockedPrintStream : public PrintStream {
public:
    LockedPrintStream(std::unique_ptr<PrintStream> target);
    virtual ~LockedPrintStream();
    
    void vprintf(const char* format, va_list) override WTF_ATTRIBUTE_PRINTF(2, 0);
    void flush() override;

protected:
    PrintStream& begin() override;
    void end() override;

private:
    // This needs to be a recursive lock because a printInternal or dump method could assert,
    // and that assert might want to log. Better to let it. This needs to be a WordLock so that
    // LockedPrintStream (i.e. cataLog) can be used to debug ParkingLot and Lock.
    RecursiveLockAdapter<WordLock> m_lock;
    std::unique_ptr<PrintStream> m_target;
};

} // namespace WTF

using WTF::LockedPrintStream;