SQLTransactionBackend.h   [plain text]

/*
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 *     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
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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
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#ifndef SQLTransactionBackend_h
#define SQLTransactionBackend_h

#include "DatabaseBasicTypes.h"
#include "SQLTransactionStateMachine.h"
#include <memory>
#include <wtf/Deque.h>
#include <wtf/Forward.h>
#include <wtf/ThreadingPrimitives.h>
#include <wtf/text/WTFString.h>

namespace WebCore {

class Database;
class OriginLock;
class SQLError;
class SQLiteTransaction;
class SQLStatement;
class SQLStatementBackend;
class SQLTransaction;
class SQLTransactionBackend;
class SQLValue;

class SQLTransactionWrapper : public ThreadSafeRefCounted<SQLTransactionWrapper> {
public:
    virtual ~SQLTransactionWrapper() { }
    virtual bool performPreflight(SQLTransactionBackend*) = 0;
    virtual bool performPostflight(SQLTransactionBackend*) = 0;
    virtual SQLError* sqlError() const = 0;
    virtual void handleCommitFailedAfterPostflight(SQLTransactionBackend*) = 0;
};

class SQLTransactionBackend : public ThreadSafeRefCounted<SQLTransactionBackend>, public SQLTransactionStateMachine<SQLTransactionBackend> {
public:
    static Ref<SQLTransactionBackend> create(Database*, PassRefPtr<SQLTransaction>, PassRefPtr<SQLTransactionWrapper>, bool readOnly);

    virtual ~SQLTransactionBackend();

    void lockAcquired();
    void performNextStep();

#if PLATFORM(IOS)
    bool shouldPerformWhilePaused() const;
#endif

    Database* database() { return m_database.get(); }
    bool isReadOnly() { return m_readOnly; }
    void notifyDatabaseThreadIsShuttingDown();

    // APIs called from the frontend published via SQLTransactionBackend:
    void requestTransitToState(SQLTransactionState);
    PassRefPtr<SQLError> transactionError();
    SQLStatement* currentStatement();
    void setShouldRetryCurrentStatement(bool);
    void executeSQL(std::unique_ptr<SQLStatement>, const String& statement, const Vector<SQLValue>& arguments, int permissions);
    
private:
    SQLTransactionBackend(Database*, PassRefPtr<SQLTransaction>, PassRefPtr<SQLTransactionWrapper>, bool readOnly);

    void doCleanup();

    void enqueueStatementBackend(PassRefPtr<SQLStatementBackend>);

    // State Machine functions:
    virtual StateFunction stateFunctionFor(SQLTransactionState) override;
    void computeNextStateAndCleanupIfNeeded();

    // State functions:
    SQLTransactionState acquireLock();
    SQLTransactionState openTransactionAndPreflight();
    SQLTransactionState runStatements();
    SQLTransactionState postflightAndCommit();
    SQLTransactionState cleanupAndTerminate();
    SQLTransactionState cleanupAfterTransactionErrorCallback();

    SQLTransactionState unreachableState();
    SQLTransactionState sendToFrontendState();

    SQLTransactionState nextStateForCurrentStatementError();
    SQLTransactionState nextStateForTransactionError();
    SQLTransactionState runCurrentStatementAndGetNextState();

    void getNextStatement();

    void acquireOriginLock();
    void releaseOriginLockIfNeeded();

    RefPtr<SQLTransaction> m_frontend; // Has a reference cycle, and will break in doCleanup().
    RefPtr<SQLStatementBackend> m_currentStatementBackend;

    RefPtr<Database> m_database;
    RefPtr<SQLTransactionWrapper> m_wrapper;
    RefPtr<SQLError> m_transactionError;

    bool m_hasCallback;
    bool m_hasSuccessCallback;
    bool m_hasErrorCallback;
    bool m_shouldRetryCurrentStatement;
    bool m_modifiedDatabase;
    bool m_lockAcquired;
    bool m_readOnly;
    bool m_hasVersionMismatch;

    Mutex m_statementMutex;
    Deque<RefPtr<SQLStatementBackend>> m_statementQueue;

    std::unique_ptr<SQLiteTransaction> m_sqliteTransaction;
    RefPtr<OriginLock> m_originLock;
};

} // namespace WebCore

#endif // SQLTransactionBackend_h