/*
 * Copyright (C) 2007, 2008, 2013 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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 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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 */

#include "config.h"
#include "Database.h"

#if ENABLE(SQL_DATABASE)

#include "ChangeVersionData.h"
#include "CrossThreadTask.h"
#include "DatabaseBackendContext.h"
#include "DatabaseCallback.h"
#include "DatabaseContext.h"
#include "DatabaseManager.h"
#include "DatabaseTask.h"
#include "DatabaseThread.h"
#include "DatabaseTracker.h"
#include "Document.h"
#include "JSDOMWindow.h"
#include "Logging.h"
#include "NotImplemented.h"
#include "Page.h"
#include "SQLError.h"
#include "SQLTransaction.h"
#include "SQLTransactionCallback.h"
#include "SQLTransactionErrorCallback.h"
#include "SQLiteStatement.h"
#include "ScriptExecutionContext.h"
#include "SecurityOrigin.h"
#include "VoidCallback.h"
#include <wtf/OwnPtr.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/CString.h>

namespace WebCore {

PassRefPtr<Database> Database::create(ScriptExecutionContext*, PassRefPtr<DatabaseBackendBase> backend)
    {
    // FIXME: Currently, we're only simulating the backend by return the
    // frontend database as its own the backend. When we split the 2 apart,
    // this create() function should be changed to be a factory method for
    // instantiating the backend.
    return static_cast<Database*>(backend.get());
    }

Database::Database(PassRefPtr<DatabaseBackendContext> databaseContext,
    const String& name, const String& expectedVersion, const String& displayName, unsigned long estimatedSize)
    : DatabaseBase(databaseContext->scriptExecutionContext())
    , DatabaseBackend(databaseContext, name, expectedVersion, displayName, estimatedSize)
    , m_databaseContext(DatabaseBackend::databaseContext()->frontend())
    , m_deleted(false)
{
    m_databaseThreadSecurityOrigin = m_contextThreadSecurityOrigin->isolatedCopy();
    setFrontend(this);

    ASSERT(m_databaseContext->databaseThread());
}

class DerefContextTask : public ScriptExecutionContext::Task {
public:
    static PassOwnPtr<DerefContextTask> create(PassRefPtr<ScriptExecutionContext> context)
    {
        return adoptPtr(new DerefContextTask(context));
    }

    virtual void performTask(ScriptExecutionContext* context)
    {
        ASSERT_UNUSED(context, context == m_context);
        m_context.clear();
    }

    virtual bool isCleanupTask() const { return true; }

private:
    DerefContextTask(PassRefPtr<ScriptExecutionContext> context)
        : m_context(context)
    {
    }
    
    RefPtr<ScriptExecutionContext> m_context;
};

Database::~Database()
{
    // The reference to the ScriptExecutionContext needs to be cleared on the JavaScript thread.  If we're on that thread already, we can just let the RefPtr's destruction do the dereffing.
    if (!m_scriptExecutionContext->isContextThread()) {
        // Grab a pointer to the script execution here because we're releasing it when we pass it to
        // DerefContextTask::create.
        ScriptExecutionContext* scriptExecutionContext = m_scriptExecutionContext.get();
        
        scriptExecutionContext->postTask(DerefContextTask::create(m_scriptExecutionContext.release()));
    }
}

Database* Database::from(DatabaseBackend* backend)
{
    return static_cast<Database*>(backend->m_frontend);
}

PassRefPtr<DatabaseBackend> Database::backend()
{
    return this;
}

String Database::version() const
{
    if (m_deleted)
        return String();
    return DatabaseBackendBase::version();
}

void Database::markAsDeletedAndClose()
{
    if (m_deleted || !databaseContext()->databaseThread())
        return;

    LOG(StorageAPI, "Marking %s (%p) as deleted", stringIdentifier().ascii().data(), this);
    m_deleted = true;

    DatabaseTaskSynchronizer synchronizer;
    if (databaseContext()->databaseThread()->terminationRequested(&synchronizer)) {
        LOG(StorageAPI, "Database handle %p is on a terminated DatabaseThread, cannot be marked for normal closure\n", this);
        return;
    }

    OwnPtr<DatabaseCloseTask> task = DatabaseCloseTask::create(this, &synchronizer);
    databaseContext()->databaseThread()->scheduleImmediateTask(task.release());
    synchronizer.waitForTaskCompletion();
}

void Database::closeImmediately()
{
    ASSERT(m_scriptExecutionContext->isContextThread());
    DatabaseThread* databaseThread = databaseContext()->databaseThread();
    if (databaseThread && !databaseThread->terminationRequested() && opened()) {
        logErrorMessage("forcibly closing database");
        databaseThread->scheduleImmediateTask(DatabaseCloseTask::create(this, 0));
    }
}

void Database::changeVersion(const String& oldVersion, const String& newVersion,
                             PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
                             PassRefPtr<VoidCallback> successCallback)
{
    ChangeVersionData data(oldVersion, newVersion);
    runTransaction(callback, errorCallback, successCallback, false, &data);
}

void Database::transaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<VoidCallback> successCallback)
{
    runTransaction(callback, errorCallback, successCallback, false);
}

void Database::readTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<VoidCallback> successCallback)
{
    runTransaction(callback, errorCallback, successCallback, true);
}

static void callTransactionErrorCallback(ScriptExecutionContext*, PassRefPtr<SQLTransactionErrorCallback> callback, PassRefPtr<SQLError> error)
{
    callback->handleEvent(error.get());
}

void Database::runTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
    PassRefPtr<VoidCallback> successCallback, bool readOnly, const ChangeVersionData* changeVersionData)
{
    RefPtr<SQLTransactionErrorCallback> anotherRefToErrorCallback = errorCallback;
    RefPtr<SQLTransaction> transaction = SQLTransaction::create(this, callback, successCallback, anotherRefToErrorCallback, readOnly);

    RefPtr<SQLTransactionBackend> transactionBackend;
    transactionBackend = backend()->runTransaction(transaction.release(), readOnly, changeVersionData);
    if (!transactionBackend && anotherRefToErrorCallback) {
            RefPtr<SQLError> error = SQLError::create(SQLError::UNKNOWN_ERR, "database has been closed");
        scriptExecutionContext()->postTask(createCallbackTask(&callTransactionErrorCallback, anotherRefToErrorCallback, error.release()));
        }
}

class DeliverPendingCallbackTask : public ScriptExecutionContext::Task {
public:
    static PassOwnPtr<DeliverPendingCallbackTask> create(PassRefPtr<SQLTransaction> transaction)
    {
        return adoptPtr(new DeliverPendingCallbackTask(transaction));
    }

    virtual void performTask(ScriptExecutionContext*)
    {
        m_transaction->performPendingCallback();
    }

private:
    DeliverPendingCallbackTask(PassRefPtr<SQLTransaction> transaction)
        : m_transaction(transaction)
    {
    }

    RefPtr<SQLTransaction> m_transaction;
};

void Database::scheduleTransactionCallback(SQLTransaction* transaction)
{
    m_scriptExecutionContext->postTask(DeliverPendingCallbackTask::create(transaction));
}

Vector<String> Database::performGetTableNames()
{
    disableAuthorizer();

    SQLiteStatement statement(sqliteDatabase(), "SELECT name FROM sqlite_master WHERE type='table';");
    if (statement.prepare() != SQLResultOk) {
        LOG_ERROR("Unable to retrieve list of tables for database %s", databaseDebugName().ascii().data());
        enableAuthorizer();
        return Vector<String>();
    }

    Vector<String> tableNames;
    int result;
    while ((result = statement.step()) == SQLResultRow) {
        String name = statement.getColumnText(0);
        if (name != databaseInfoTableName())
            tableNames.append(name);
    }

    enableAuthorizer();

    if (result != SQLResultDone) {
        LOG_ERROR("Error getting tables for database %s", databaseDebugName().ascii().data());
        return Vector<String>();
    }

    return tableNames;
}

Vector<String> Database::tableNames()
{
    // FIXME: Not using isolatedCopy on these strings looks ok since threads take strict turns
    // in dealing with them. However, if the code changes, this may not be true anymore.
    Vector<String> result;
    DatabaseTaskSynchronizer synchronizer;
    if (!databaseContext()->databaseThread() || databaseContext()->databaseThread()->terminationRequested(&synchronizer))
        return result;

    OwnPtr<DatabaseTableNamesTask> task = DatabaseTableNamesTask::create(this, &synchronizer, result);
    databaseContext()->databaseThread()->scheduleImmediateTask(task.release());
    synchronizer.waitForTaskCompletion();

    return result;
}

SecurityOrigin* Database::securityOrigin() const
{
    if (m_scriptExecutionContext->isContextThread())
        return m_contextThreadSecurityOrigin.get();
    if (currentThread() == databaseContext()->databaseThread()->getThreadID())
        return m_databaseThreadSecurityOrigin.get();
    return 0;
}

} // namespace WebCore

#endif // ENABLE(SQL_DATABASE)
