Source/WebCore/Modules/webdatabase/DatabaseTask.h

/*
 * Copyright (C) 2007, 2008, 2013, 2015 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  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.
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 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS 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
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 */

#pragma once

#include "ExceptionOr.h"
#include <wtf/Condition.h>
#include <wtf/Forward.h>
#include <wtf/Lock.h>

namespace WebCore {

class Database;
class SQLTransaction;

// Can be used to wait until DatabaseTask is completed.
// Has to be passed into DatabaseTask::create to be associated with the task.
class DatabaseTaskSynchronizer {
    WTF_MAKE_NONCOPYABLE(DatabaseTaskSynchronizer);
public:
    DatabaseTaskSynchronizer();

    // Called from main thread to wait until task is completed.
    void waitForTaskCompletion();

    // Called by the task.
    void taskCompleted();

#if ASSERT_ENABLED
    bool hasCheckedForTermination() const { return m_hasCheckedForTermination; }
    void setHasCheckedForTermination() { m_hasCheckedForTermination = true; }
#endif

private:
    bool m_taskCompleted WTF_GUARDED_BY_LOCK(m_synchronousLock) { false };
    Lock m_synchronousLock;
    Condition m_synchronousCondition;
#if ASSERT_ENABLED
    bool m_hasCheckedForTermination { false };
#endif
};

class DatabaseTask {
    WTF_MAKE_FAST_ALLOCATED;
public:
    virtual ~DatabaseTask();

    void performTask();

    Database& database() const { return m_database; }

#if ASSERT_ENABLED
    bool hasSynchronizer() const { return m_synchronizer; }
    bool hasCheckedForTermination() const { return m_synchronizer->hasCheckedForTermination(); }
#endif

protected:
    DatabaseTask(Database&, DatabaseTaskSynchronizer*);

private:
    virtual void doPerformTask() = 0;

    Database& m_database;
    DatabaseTaskSynchronizer* m_synchronizer;

#if !LOG_DISABLED
    virtual const char* debugTaskName() const = 0;
#endif

#if ASSERT_ENABLED
    bool m_complete { false };
#endif
};

class DatabaseOpenTask final : public DatabaseTask {
public:
    DatabaseOpenTask(Database&, bool setVersionInNewDatabase, DatabaseTaskSynchronizer&, ExceptionOr<void>& result);

private:
    void doPerformTask() final;

#if !LOG_DISABLED
    const char* debugTaskName() const final;
#endif

    bool m_setVersionInNewDatabase;
    ExceptionOr<void>& m_result;
};

class DatabaseCloseTask final : public DatabaseTask {
public:
    DatabaseCloseTask(Database&, DatabaseTaskSynchronizer&);

private:
    void doPerformTask() final;

#if !LOG_DISABLED
    const char* debugTaskName() const final;
#endif
};

class DatabaseTransactionTask final : public DatabaseTask {
public:
    explicit DatabaseTransactionTask(RefPtr<SQLTransaction>&&);
    virtual ~DatabaseTransactionTask();

    SQLTransaction* transaction() const { return m_transaction.get(); }

private:
    void doPerformTask() final;

#if !LOG_DISABLED
    const char* debugTaskName() const final;
#endif

    RefPtr<SQLTransaction> m_transaction;
    bool m_didPerformTask;
};

class DatabaseTableNamesTask final : public DatabaseTask {
public:
    DatabaseTableNamesTask(Database&, DatabaseTaskSynchronizer&, Vector<String>& result);

private:
    void doPerformTask() final;

#if !LOG_DISABLED
    const char* debugTaskName() const override;
#endif

    Vector<String>& m_result;
};

} // namespace WebCore