Source/modules/filesystem/SyncCallbackHelper.h

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 * Copyright (C) 2013 Samsung Electronics. 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.
 */

#ifndef SyncCallbackHelper_h
#define SyncCallbackHelper_h

#include "bindings/v8/ExceptionState.h"
#include "core/fileapi/FileError.h"
#include "core/html/VoidCallback.h"
#include "modules/filesystem/DirectoryEntry.h"
#include "modules/filesystem/DirectoryReaderSync.h"
#include "modules/filesystem/EntriesCallback.h"
#include "modules/filesystem/EntryCallback.h"
#include "modules/filesystem/EntrySync.h"
#include "modules/filesystem/ErrorCallback.h"
#include "modules/filesystem/FileEntry.h"
#include "modules/filesystem/FileSystemCallback.h"
#include "modules/filesystem/MetadataCallback.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefCounted.h"

namespace WebCore {

template <typename ResultType, typename CallbackArg>
struct HelperResultType {
    typedef PassRefPtr<ResultType> ReturnType;
    typedef RefPtr<ResultType> StorageType;

    static ReturnType createFromCallbackArg(CallbackArg argument)
    {
        return ResultType::create(argument);
    }
};

template <>
struct HelperResultType<EntrySyncVector, const EntryVector&> {
    typedef EntrySyncVector ReturnType;
    typedef EntrySyncVector StorageType;

    static EntrySyncVector createFromCallbackArg(const EntryVector& entries)
    {
        EntrySyncVector result;
        size_t entryCount = entries.size();
        result.reserveInitialCapacity(entryCount);
        for (size_t i = 0; i < entryCount; ++i)
            result.uncheckedAppend(EntrySync::create(entries[i].get()));
        return result;
    }
};

// A helper template for FileSystemSync implementation.
template <typename SuccessCallback, typename CallbackArg, typename ResultType>
class SyncCallbackHelper {
    WTF_MAKE_NONCOPYABLE(SyncCallbackHelper);
public:
    typedef SyncCallbackHelper<SuccessCallback, CallbackArg, ResultType> HelperType;
    typedef HelperResultType<ResultType, CallbackArg> ResultTypeTrait;
    typedef typename ResultTypeTrait::StorageType ResultStorageType;
    typedef typename ResultTypeTrait::ReturnType ResultReturnType;

    SyncCallbackHelper()
        : m_errorCode(FileError::OK)
        , m_completed(false)
    {
    }

    ResultReturnType getResult(ExceptionState& exceptionState)
    {
        if (m_errorCode)
            FileError::throwDOMException(exceptionState, m_errorCode);

        return m_result;
    }

    PassOwnPtr<SuccessCallback> successCallback() { return SuccessCallbackImpl::create(this); }
    PassOwnPtr<ErrorCallback> errorCallback() { return ErrorCallbackImpl::create(this); }

private:
    class SuccessCallbackImpl : public SuccessCallback {
    public:
        static PassOwnPtr<SuccessCallbackImpl> create(HelperType* helper)
        {
            return adoptPtr(new SuccessCallbackImpl(helper));
        }

        virtual bool handleEvent()
        {
            m_helper->setError(FileError::OK);
            return true;
        }

        virtual bool handleEvent(CallbackArg arg)
        {
            m_helper->setResult(arg);
            return true;
        }

    private:
        explicit SuccessCallbackImpl(HelperType* helper)
            : m_helper(helper)
        {
        }
        HelperType* m_helper;
    };

    class ErrorCallbackImpl : public ErrorCallback {
    public:
        static PassOwnPtr<ErrorCallbackImpl> create(HelperType* helper)
        {
            return adoptPtr(new ErrorCallbackImpl(helper));
        }

        virtual bool handleEvent(FileError* error)
        {
            ASSERT(error);
            m_helper->setError(error->code());
            return true;
        }

    private:
        explicit ErrorCallbackImpl(HelperType* helper)
            : m_helper(helper)
        {
        }
        HelperType* m_helper;
    };

    void setError(FileError::ErrorCode code)
    {
        m_errorCode = code;
        m_completed = true;
    }

    void setResult(CallbackArg result)
    {
        m_result = ResultTypeTrait::createFromCallbackArg(result);
        m_completed = true;
    }

    ResultStorageType m_result;
    FileError::ErrorCode m_errorCode;
    bool m_completed;
};

struct EmptyType : public RefCounted<EmptyType> {
    static PassRefPtr<EmptyType> create(EmptyType*)
    {
        return 0;
    }
};

typedef SyncCallbackHelper<EntryCallback, Entry*, EntrySync> EntrySyncCallbackHelper;
typedef SyncCallbackHelper<EntriesCallback, const EntryVector&, EntrySyncVector> EntriesSyncCallbackHelper;
typedef SyncCallbackHelper<MetadataCallback, Metadata*, Metadata> MetadataSyncCallbackHelper;
typedef SyncCallbackHelper<VoidCallback, EmptyType*, EmptyType> VoidSyncCallbackHelper;
typedef SyncCallbackHelper<FileSystemCallback, DOMFileSystem*, DOMFileSystemSync> FileSystemSyncCallbackHelper;

} // namespace WebCore

#endif // SyncCallbackHelper_h