/*
 * Copyright (C) 2007, 2008 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
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS 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.
 */

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

#include <wtf/StdLibExtras.h>

#if ENABLE(DATABASE)
#include "ChangeVersionWrapper.h"
#include "CString.h"
#include "DatabaseAuthorizer.h"
#include "DatabaseTask.h"
#include "DatabaseThread.h"
#include "DatabaseTracker.h"
#include "Document.h"
#include "ExceptionCode.h"
#include "Frame.h"
#include "InspectorController.h"
#include "Logging.h"
#include "NotImplemented.h"
#include "Page.h"
#include "OriginQuotaManager.h"
#include "ScriptController.h"
#include "SQLiteDatabase.h"
#include "SQLiteFileSystem.h"
#include "SQLiteStatement.h"
#include "SQLResultSet.h"
#include "SQLTransactionClient.h"
#include "SQLTransactionCoordinator.h"
#include <wtf/MainThread.h>
#endif

#if USE(JSC)
#include "JSDOMWindow.h"
#endif

namespace WebCore {

// If we sleep for more the 30 seconds while blocked on SQLITE_BUSY, give up.
static const int maxSqliteBusyWaitTime = 30000;

const String& Database::databaseInfoTableName()
{
    DEFINE_STATIC_LOCAL(String, name, ("__WebKitDatabaseInfoTable__"));
    return name;
}

#if ENABLE(DATABASE)

static Mutex& guidMutex()
{
    // Note: We don't have to use AtomicallyInitializedStatic here because
    // this function is called once in the constructor on the main thread
    // before any other threads that call this function are used.
    DEFINE_STATIC_LOCAL(Mutex, mutex, ());
    return mutex;
}

typedef HashMap<int, String> GuidVersionMap;
static GuidVersionMap& guidToVersionMap()
{
    DEFINE_STATIC_LOCAL(GuidVersionMap, map, ());
    return map;
}

// NOTE: Caller must lock guidMutex().
static inline void updateGuidVersionMap(int guid, String newVersion)
{
    // Ensure the the mutex is locked.
    ASSERT(!guidMutex().tryLock());

    // Note: It is not safe to put an empty string into the guidToVersionMap() map.
    // That's because the map is cross-thread, but empty strings are per-thread.
    // The copy() function makes a version of the string you can use on the current
    // thread, but we need a string we can keep in a cross-thread data structure.
    // FIXME: This is a quite-awkward restriction to have to program with.

    // Map null string to empty string (see comment above).
    guidToVersionMap().set(guid, newVersion.isEmpty() ? String() : newVersion.threadsafeCopy());
}

typedef HashMap<int, HashSet<Database*>*> GuidDatabaseMap;
static GuidDatabaseMap& guidToDatabaseMap()
{
    DEFINE_STATIC_LOCAL(GuidDatabaseMap, map, ());
    return map;
}

static const String& databaseVersionKey()
{
    DEFINE_STATIC_LOCAL(String, key, ("WebKitDatabaseVersionKey"));
    return key;
}

static int guidForOriginAndName(const String& origin, const String& name);

PassRefPtr<Database> Database::openDatabase(Document* document, const String& name, const String& expectedVersion, const String& displayName, unsigned long estimatedSize, ExceptionCode& e)
{
    if (!DatabaseTracker::tracker().canEstablishDatabase(document, name, displayName, estimatedSize)) {
        // FIXME: There should be an exception raised here in addition to returning a null Database object.  The question has been raised with the WHATWG.
        LOG(StorageAPI, "Database %s for origin %s not allowed to be established", name.ascii().data(), document->securityOrigin()->toString().ascii().data());
        return 0;
    }

    RefPtr<Database> database = adoptRef(new Database(document, name, expectedVersion, displayName, estimatedSize));

    if (!database->openAndVerifyVersion(e)) {
       LOG(StorageAPI, "Failed to open and verify version (expected %s) of database %s", expectedVersion.ascii().data(), database->databaseDebugName().ascii().data());
       return 0;
    }

    DatabaseTracker::tracker().setDatabaseDetails(document->securityOrigin(), name, displayName, estimatedSize);

    document->setHasOpenDatabases();

#if ENABLE(INSPECTOR)
    if (Page* page = document->frame()->page())
        page->inspectorController()->didOpenDatabase(database.get(), document->securityOrigin()->host(), name, expectedVersion);
#endif

    return database;
}

Database::Database(Document* document, const String& name, const String& expectedVersion, const String& displayName, unsigned long estimatedSize)
    : m_transactionInProgress(false)
    , m_isTransactionQueueEnabled(true)
    , m_document(document)
    , m_name(name.crossThreadString())
    , m_guid(0)
    , m_expectedVersion(expectedVersion.crossThreadString())
    , m_displayName(displayName.crossThreadString())
    , m_estimatedSize(estimatedSize)
    , m_deleted(false)
    , m_stopped(false)
    , m_opened(false)
{
    ASSERT(document);
    m_mainThreadSecurityOrigin = document->securityOrigin();
    m_databaseThreadSecurityOrigin = m_mainThreadSecurityOrigin->threadsafeCopy();

    if (m_name.isNull())
        m_name = "";

    ScriptController::initializeThreading();

    m_guid = guidForOriginAndName(m_mainThreadSecurityOrigin->toString(), name);

    {
        MutexLocker locker(guidMutex());

        HashSet<Database*>* hashSet = guidToDatabaseMap().get(m_guid);
        if (!hashSet) {
            hashSet = new HashSet<Database*>;
            guidToDatabaseMap().set(m_guid, hashSet);
        }

        hashSet->add(this);
    }

    ASSERT(m_document->databaseThread());

    m_filename = DatabaseTracker::tracker().fullPathForDatabase(m_mainThreadSecurityOrigin.get(), m_name);

    DatabaseTracker::tracker().addOpenDatabase(this);
    m_document->addOpenDatabase(this);
}

static void derefDocument(void* document)
{
    static_cast<Document*>(document)->deref();
}

Database::~Database()
{
    // Deref m_document on the main thread.
    callOnMainThread(derefDocument, m_document.release().releaseRef());
}

bool Database::openAndVerifyVersion(ExceptionCode& e)
{
    if (!m_document->databaseThread())
        return false;
    m_databaseAuthorizer = DatabaseAuthorizer::create();

    bool success = false;
    DatabaseTaskSynchronizer synchronizer;
    OwnPtr<DatabaseOpenTask> task = DatabaseOpenTask::create(this, &synchronizer, e, success);

    m_document->databaseThread()->scheduleImmediateTask(task.release());
    synchronizer.waitForTaskCompletion();

    return success;
}


static bool retrieveTextResultFromDatabase(SQLiteDatabase& db, const String& query, String& resultString)
{
    SQLiteStatement statement(db, query);
    int result = statement.prepare();

    if (result != SQLResultOk) {
        LOG_ERROR("Error (%i) preparing statement to read text result from database (%s)", result, query.ascii().data());
        return false;
    }

    result = statement.step();
    if (result == SQLResultRow) {
        resultString = statement.getColumnText(0);
        return true;
    } else if (result == SQLResultDone) {
        resultString = String();
        return true;
    } else {
        LOG_ERROR("Error (%i) reading text result from database (%s)", result, query.ascii().data());
        return false;
    }
}

bool Database::getVersionFromDatabase(String& version)
{
    DEFINE_STATIC_LOCAL(String, getVersionQuery, ("SELECT value FROM " + databaseInfoTableName() + " WHERE key = '" + databaseVersionKey() + "';"));

    m_databaseAuthorizer->disable();

    bool result = retrieveTextResultFromDatabase(m_sqliteDatabase, getVersionQuery.threadsafeCopy(), version);
    if (!result)
        LOG_ERROR("Failed to retrieve version from database %s", databaseDebugName().ascii().data());

    m_databaseAuthorizer->enable();

    return result;
}

static bool setTextValueInDatabase(SQLiteDatabase& db, const String& query, const String& value)
{
    SQLiteStatement statement(db, query);
    int result = statement.prepare();

    if (result != SQLResultOk) {
        LOG_ERROR("Failed to prepare statement to set value in database (%s)", query.ascii().data());
        return false;
    }

    statement.bindText(1, value);

    result = statement.step();
    if (result != SQLResultDone) {
        LOG_ERROR("Failed to step statement to set value in database (%s)", query.ascii().data());
        return false;
    }

    return true;
}

bool Database::setVersionInDatabase(const String& version)
{
    // The INSERT will replace an existing entry for the database with the new version number, due to the UNIQUE ON CONFLICT REPLACE
    // clause in the CREATE statement (see Database::performOpenAndVerify()).
    DEFINE_STATIC_LOCAL(String, setVersionQuery, ("INSERT INTO " + databaseInfoTableName() + " (key, value) VALUES ('" + databaseVersionKey() + "', ?);"));

    m_databaseAuthorizer->disable();

    bool result = setTextValueInDatabase(m_sqliteDatabase, setVersionQuery.threadsafeCopy(), version);
    if (!result)
        LOG_ERROR("Failed to set version %s in database (%s)", version.ascii().data(), setVersionQuery.ascii().data());

    m_databaseAuthorizer->enable();

    return result;
}

bool Database::versionMatchesExpected() const
{
    if (!m_expectedVersion.isEmpty()) {
        MutexLocker locker(guidMutex());
        return m_expectedVersion == guidToVersionMap().get(m_guid);
    }

    return true;
}

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

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

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

    m_document->databaseThread()->unscheduleDatabaseTasks(this);

    DatabaseTaskSynchronizer synchronizer;
    OwnPtr<DatabaseCloseTask> task = DatabaseCloseTask::create(this, &synchronizer);

    m_document->databaseThread()->scheduleImmediateTask(task.release());
    synchronizer.waitForTaskCompletion();
}

static void documentRemoveOpenDatabase(void* context)
{
    ASSERT(isMainThread());
    Database* database = static_cast<Database*>(context);
    database->document()->removeOpenDatabase(database);
    database->deref();
}

void Database::close()
{
    if (!m_opened)
        return;

    ASSERT(m_document->databaseThread());
    ASSERT(currentThread() == document()->databaseThread()->getThreadID());
    m_sqliteDatabase.close();
    m_document->databaseThread()->recordDatabaseClosed(this);
    m_opened = false;

    {
        MutexLocker locker(guidMutex());

        HashSet<Database*>* hashSet = guidToDatabaseMap().get(m_guid);
        ASSERT(hashSet);
        ASSERT(hashSet->contains(this));
        hashSet->remove(this);
        if (hashSet->isEmpty()) {
            guidToDatabaseMap().remove(m_guid);
            delete hashSet;
            guidToVersionMap().remove(m_guid);
        }
    }

    m_document->databaseThread()->unscheduleDatabaseTasks(this);

    DatabaseTracker::tracker().removeOpenDatabase(this);
    ref();  // deref() called in documentRemoveOpenDatabase()
    callOnMainThread(documentRemoveOpenDatabase, this);
}

void Database::stop()
{
    // FIXME: The net effect of the following code is to remove all pending transactions and statements, but allow the current statement
    // to run to completion.  In the future we can use the sqlite3_progress_handler or sqlite3_interrupt interfaces to cancel the current
    // statement in response to close(), as well.

    // This method is meant to be used as an analog to cancelling a loader, and is used when a document is shut down as the result of
    // a page load or closing the page
    m_stopped = true;

    {
        MutexLocker locker(m_transactionInProgressMutex);
        m_isTransactionQueueEnabled = false;
        m_transactionInProgress = false;
    }
}

unsigned long long Database::maximumSize() const
{
    return DatabaseTracker::tracker().getMaxSizeForDatabase(this);
}

void Database::disableAuthorizer()
{
    ASSERT(m_databaseAuthorizer);
    m_databaseAuthorizer->disable();
}

void Database::enableAuthorizer()
{
    ASSERT(m_databaseAuthorizer);
    m_databaseAuthorizer->enable();
}

void Database::setAuthorizerReadOnly()
{
    ASSERT(m_databaseAuthorizer);
    m_databaseAuthorizer->setReadOnly();
}

static int guidForOriginAndName(const String& origin, const String& name)
{
    String stringID;
    if (origin.endsWith("/"))
        stringID = origin + name;
    else
        stringID = origin + "/" + name;

    // Note: We don't have to use AtomicallyInitializedStatic here because
    // this function is called once in the constructor on the main thread
    // before any other threads that call this function are used.
    DEFINE_STATIC_LOCAL(Mutex, stringIdentifierMutex, ());
    MutexLocker locker(stringIdentifierMutex);
    typedef HashMap<String, int> IDGuidMap;
    DEFINE_STATIC_LOCAL(IDGuidMap, stringIdentifierToGUIDMap, ());
    int guid = stringIdentifierToGUIDMap.get(stringID);
    if (!guid) {
        static int currentNewGUID = 1;
        guid = currentNewGUID++;
        stringIdentifierToGUIDMap.set(stringID, guid);
    }

    return guid;
}

void Database::resetAuthorizer()
{
    if (m_databaseAuthorizer)
        m_databaseAuthorizer->reset();
}

void Database::performPolicyChecks()
{
    // FIXME: Code similar to the following will need to be run to enforce the per-origin size limit the spec mandates.
    // Additionally, we might need a way to pause the database thread while the UA prompts the user for permission to
    // increase the size limit

    /*
    if (m_databaseAuthorizer->lastActionIncreasedSize())
        DatabaseTracker::scheduleFileSizeCheckOnMainThread(this);
    */

    notImplemented();
}

bool Database::performOpenAndVerify(ExceptionCode& e)
{
    if (!m_sqliteDatabase.open(m_filename)) {
        LOG_ERROR("Unable to open database at path %s", m_filename.ascii().data());
        e = INVALID_STATE_ERR;
        return false;
    }

    m_opened = true;
    if (m_document->databaseThread())
        m_document->databaseThread()->recordDatabaseOpen(this);

    ASSERT(m_databaseAuthorizer);
    m_sqliteDatabase.setAuthorizer(m_databaseAuthorizer);
    m_sqliteDatabase.setBusyTimeout(maxSqliteBusyWaitTime);

    String currentVersion;
    {
        MutexLocker locker(guidMutex());

        GuidVersionMap::iterator entry = guidToVersionMap().find(m_guid);
        if (entry != guidToVersionMap().end()) {
            // Map null string to empty string (see updateGuidVersionMap()).
            currentVersion = entry->second.isNull() ? String("") : entry->second;
            LOG(StorageAPI, "Current cached version for guid %i is %s", m_guid, currentVersion.ascii().data());
        } else {
            LOG(StorageAPI, "No cached version for guid %i", m_guid);

            if (!m_sqliteDatabase.tableExists(databaseInfoTableName())) {
                if (!m_sqliteDatabase.executeCommand("CREATE TABLE " + databaseInfoTableName() + " (key TEXT NOT NULL ON CONFLICT FAIL UNIQUE ON CONFLICT REPLACE,value TEXT NOT NULL ON CONFLICT FAIL);")) {
                    LOG_ERROR("Unable to create table %s in database %s", databaseInfoTableName().ascii().data(), databaseDebugName().ascii().data());
                    e = INVALID_STATE_ERR;
                    return false;
                }
            }

            if (!getVersionFromDatabase(currentVersion)) {
                LOG_ERROR("Failed to get current version from database %s", databaseDebugName().ascii().data());
                e = INVALID_STATE_ERR;
                return false;
            }
            if (currentVersion.length()) {
                LOG(StorageAPI, "Retrieved current version %s from database %s", currentVersion.ascii().data(), databaseDebugName().ascii().data());
            } else {
                LOG(StorageAPI, "Setting version %s in database %s that was just created", m_expectedVersion.ascii().data(), databaseDebugName().ascii().data());
                if (!setVersionInDatabase(m_expectedVersion)) {
                    LOG_ERROR("Failed to set version %s in database %s", m_expectedVersion.ascii().data(), databaseDebugName().ascii().data());
                    e = INVALID_STATE_ERR;
                    return false;
                }
                currentVersion = m_expectedVersion;
            }

            updateGuidVersionMap(m_guid, currentVersion);
        }
    }

    if (currentVersion.isNull()) {
        LOG(StorageAPI, "Database %s does not have its version set", databaseDebugName().ascii().data());
        currentVersion = "";
    }

    // If the expected version isn't the empty string, ensure that the current database version we have matches that version. Otherwise, set an exception.
    // If the expected version is the empty string, then we always return with whatever version of the database we have.
    if (m_expectedVersion.length() && m_expectedVersion != currentVersion) {
        LOG(StorageAPI, "page expects version %s from database %s, which actually has version name %s - openDatabase() call will fail", m_expectedVersion.ascii().data(),
            databaseDebugName().ascii().data(), currentVersion.ascii().data());
        e = INVALID_STATE_ERR;
        return false;
    }

    return true;
}

void Database::changeVersion(const String& oldVersion, const String& newVersion,
                             PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
                             PassRefPtr<VoidCallback> successCallback)
{
    m_transactionQueue.append(SQLTransaction::create(this, callback, errorCallback, successCallback, ChangeVersionWrapper::create(oldVersion, newVersion)));
    MutexLocker locker(m_transactionInProgressMutex);
    if (!m_transactionInProgress)
        scheduleTransaction();
}

void Database::transaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
                           PassRefPtr<VoidCallback> successCallback, bool readOnly)
{
    m_transactionQueue.append(SQLTransaction::create(this, callback, errorCallback, successCallback, 0, readOnly));
    MutexLocker locker(m_transactionInProgressMutex);
    if (!m_transactionInProgress)
        scheduleTransaction();
}

void Database::scheduleTransaction()
{
    ASSERT(!m_transactionInProgressMutex.tryLock()); // Locked by caller.
    RefPtr<SQLTransaction> transaction;

    if (m_isTransactionQueueEnabled && !m_transactionQueue.isEmpty()) {
        transaction = m_transactionQueue.first();
        m_transactionQueue.removeFirst();
    }

    if (transaction && m_document->databaseThread()) {
        OwnPtr<DatabaseTransactionTask> task = DatabaseTransactionTask::create(transaction);
        LOG(StorageAPI, "Scheduling DatabaseTransactionTask %p for transaction %p\n", task.get(), task->transaction());
        m_transactionInProgress = true;
        m_document->databaseThread()->scheduleTask(task.release());
    } else
        m_transactionInProgress = false;
}

void Database::scheduleTransactionStep(SQLTransaction* transaction, bool immediately)
{
    if (!m_document->databaseThread())
        return;

    OwnPtr<DatabaseTransactionTask> task = DatabaseTransactionTask::create(transaction);
    LOG(StorageAPI, "Scheduling DatabaseTransactionTask %p for the transaction step\n", task.get());
    if (immediately)
        m_document->databaseThread()->scheduleImmediateTask(task.release());
    else
        m_document->databaseThread()->scheduleTask(task.release());
}

void Database::scheduleTransactionCallback(SQLTransaction* transaction)
{
    transaction->ref();
    callOnMainThread(deliverPendingCallback, transaction);
}

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

    SQLiteStatement statement(m_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;
}

SQLTransactionClient* Database::transactionClient() const
{
    return m_document->databaseThread()->transactionClient();
}

SQLTransactionCoordinator* Database::transactionCoordinator() const
{
    return m_document->databaseThread()->transactionCoordinator();
}

String Database::version() const
{
    if (m_deleted)
        return String();
    MutexLocker locker(guidMutex());
    return guidToVersionMap().get(m_guid).threadsafeCopy();
}

void Database::deliverPendingCallback(void* context)
{
    SQLTransaction* transaction = static_cast<SQLTransaction*>(context);
    transaction->performPendingCallback();
    transaction->deref(); // Was ref'd in scheduleTransactionCallback().
}

Vector<String> Database::tableNames()
{
    // FIXME: Not using threadsafeCopy 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;
    if (!m_document->databaseThread())
        return result;

    DatabaseTaskSynchronizer synchronizer;
    OwnPtr<DatabaseTableNamesTask> task = DatabaseTableNamesTask::create(this, &synchronizer, result);

    m_document->databaseThread()->scheduleImmediateTask(task.release());
    synchronizer.waitForTaskCompletion();

    return result;
}

void Database::setExpectedVersion(const String& version)
{
    m_expectedVersion = version.threadsafeCopy();
    // Update the in memory database version map.
    MutexLocker locker(guidMutex());
    updateGuidVersionMap(m_guid, version);
}

SecurityOrigin* Database::securityOrigin() const
{
    if (isMainThread())
        return m_mainThreadSecurityOrigin.get();
    if (currentThread() == document()->databaseThread()->getThreadID())
        return m_databaseThreadSecurityOrigin.get();
    return 0;
}

String Database::stringIdentifier() const
{
    // Return a deep copy for ref counting thread safety
    return m_name.threadsafeCopy();
}

String Database::displayName() const
{
    // Return a deep copy for ref counting thread safety
    return m_displayName.threadsafeCopy();
}

unsigned long Database::estimatedSize() const
{
    return m_estimatedSize;
}

String Database::fileName() const
{
    // Return a deep copy for ref counting thread safety
    return m_filename.threadsafeCopy();
}

#endif

}
