DatabaseTracker.cpp   [plain text]

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 * are met:
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 *     notice, this list of conditions and the following disclaimer.
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#include "config.h"
#include "DatabaseTracker.h"

#if ENABLE(SQL_DATABASE)

#include "Chrome.h"
#include "ChromeClient.h"
#include "DatabaseBackendBase.h"
#include "DatabaseBackendContext.h"
#include "DatabaseManager.h"
#include "DatabaseManagerClient.h"
#include "DatabaseThread.h"
#include "FileSystem.h"
#include "Logging.h"
#include "OriginLock.h"
#include "Page.h"
#include "SecurityOrigin.h"
#include "SecurityOriginHash.h"
#include "SQLiteFileSystem.h"
#include "SQLiteStatement.h"
#include <wtf/MainThread.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/CString.h>

using namespace std;

namespace WebCore {

static DatabaseTracker* staticTracker = 0;

void DatabaseTracker::initializeTracker(const String& databasePath)
{
    ASSERT(!staticTracker);
    if (staticTracker)
        return;

    staticTracker = new DatabaseTracker(databasePath);
}

DatabaseTracker& DatabaseTracker::tracker()
{
    if (!staticTracker)
        staticTracker = new DatabaseTracker("");

    return *staticTracker;
}

DatabaseTracker::DatabaseTracker(const String& databasePath)
    : m_client(0)
{
    setDatabaseDirectoryPath(databasePath);
}

void DatabaseTracker::setDatabaseDirectoryPath(const String& path)
{
    MutexLocker lockDatabase(m_databaseGuard);
    ASSERT(!m_database.isOpen());
    m_databaseDirectoryPath = path.isolatedCopy();
}

String DatabaseTracker::databaseDirectoryPath() const
{
    return m_databaseDirectoryPath.isolatedCopy();
}

String DatabaseTracker::trackerDatabasePath() const
{
    return SQLiteFileSystem::appendDatabaseFileNameToPath(m_databaseDirectoryPath.isolatedCopy(), "Databases.db");
}

void DatabaseTracker::openTrackerDatabase(TrackerCreationAction createAction)
{
    ASSERT(!m_databaseGuard.tryLock());

    if (m_database.isOpen())
        return;

    // If createIfDoesNotExist is false, SQLiteFileSystem::ensureDatabaseFileExists()
    // will return false if the database file does not exist.
    // If createIfDoesNotExist is true, SQLiteFileSystem::ensureDatabaseFileExists()
    // will attempt to create the path to the database file if it does not
    // exists yet. It'll return true if the path already exists, or if it
    // successfully creates the path. Else, it will return false.
    String databasePath = trackerDatabasePath();
    if (!SQLiteFileSystem::ensureDatabaseFileExists(databasePath, createAction == CreateIfDoesNotExist))
        return;

    if (!m_database.open(databasePath)) {
        // FIXME: What do do here?
        LOG_ERROR("Failed to open databasePath %s.", databasePath.ascii().data());
        return;
    }
    m_database.disableThreadingChecks();

    if (!m_database.tableExists("Origins")) {
        if (!m_database.executeCommand("CREATE TABLE Origins (origin TEXT UNIQUE ON CONFLICT REPLACE, quota INTEGER NOT NULL ON CONFLICT FAIL);")) {
            // FIXME: and here
            LOG_ERROR("Failed to create Origins table");
        }
    }

    if (!m_database.tableExists("Databases")) {
        if (!m_database.executeCommand("CREATE TABLE Databases (guid INTEGER PRIMARY KEY AUTOINCREMENT, origin TEXT, name TEXT, displayName TEXT, estimatedSize INTEGER, path TEXT);")) {
            // FIXME: and here
            LOG_ERROR("Failed to create Databases table");
        }
    }
}

bool DatabaseTracker::hasAdequateQuotaForOrigin(SecurityOrigin* origin, unsigned long estimatedSize, DatabaseError& err)
{
    ASSERT(!m_databaseGuard.tryLock());
    unsigned long long usage = usageForOrigin(origin);

    // If the database will fit, allow its creation.
    unsigned long long requirement = usage + max(1UL, estimatedSize);
    if (requirement < usage) {
        // The estimated size is so big it causes an overflow; don't allow creation.
        err = DatabaseError::DatabaseSizeOverflowed;
        return false;
    }
    if (requirement <= quotaForOriginNoLock(origin))
        return true;

    err = DatabaseError::DatabaseSizeExceededQuota;
    return false;
}

bool DatabaseTracker::canEstablishDatabase(DatabaseBackendContext* context, const String& name, unsigned long estimatedSize, DatabaseError& error)
{
    error = DatabaseError::None;

    MutexLocker lockDatabase(m_databaseGuard);
    SecurityOrigin* origin = context->securityOrigin();

    if (isDeletingDatabaseOrOriginFor(origin, name)) {
        error = DatabaseError::DatabaseIsBeingDeleted;
        return false;
    }

    recordCreatingDatabase(origin, name);

    // If a database already exists, ignore the passed-in estimated size and say it's OK.
    if (hasEntryForDatabase(origin, name))
        return true;

    if (hasAdequateQuotaForOrigin(origin, estimatedSize, error)) {
        ASSERT(error == DatabaseError::None);
        return true;
    }

    // If we get here, then we do not have enough quota for one of the
    // following reasons as indicated by the set error:
    //
    // If the error is DatabaseSizeOverflowed, then this means the requested
    // estimatedSize if so unreasonably large that it can cause an overflow in
    // the usage budget computation. In that case, there's nothing more we can
    // do, and there's no need for a retry. Hence, we should indicate that
    // we're done with our attempt to create the database.
    //
    // If the error is DatabaseSizeExceededQuota, then we'll give the client
    // a chance to update the quota and call retryCanEstablishDatabase() to try
    // again. Hence, we don't call doneCreatingDatabase() yet in that case.

    if (error == DatabaseError::DatabaseSizeOverflowed)
        doneCreatingDatabase(origin, name);
    else
        ASSERT(error == DatabaseError::DatabaseSizeExceededQuota);

    return false;
}

// Note: a thought about performance: hasAdequateQuotaForOrigin() was also
// called in canEstablishDatabase(), and hence, we're repeating some work within
// hasAdequateQuotaForOrigin(). However, retryCanEstablishDatabase() should only
// be called in the rare even if canEstablishDatabase() fails. Since it is rare,
// we should not bother optimizing it. It is more beneficial to keep
// hasAdequateQuotaForOrigin() simple and correct (i.e. bug free), and just
// re-use it. Also note that the path for opening a database involves IO, and
// hence should not be a performance critical path anyway. 
bool DatabaseTracker::retryCanEstablishDatabase(DatabaseBackendContext* context, const String& name, unsigned long estimatedSize, DatabaseError& error)
{
    error = DatabaseError::None;

    MutexLocker lockDatabase(m_databaseGuard);
    SecurityOrigin* origin = context->securityOrigin();

    // We have already eliminated other types of errors in canEstablishDatabase().
    // The only reason we're in retryCanEstablishDatabase() is because we gave
    // the client a chance to update the quota and are rechecking it here.
    // If we fail this check, the only possible reason this time should be due
    // to inadequate quota.
    if (hasAdequateQuotaForOrigin(origin, estimatedSize, error)) {
        ASSERT(error == DatabaseError::None);
        return true;
    }

    ASSERT(error == DatabaseError::DatabaseSizeExceededQuota);
    doneCreatingDatabase(origin, name);

    return false;
}

bool DatabaseTracker::hasEntryForOriginNoLock(SecurityOrigin* origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    openTrackerDatabase(DontCreateIfDoesNotExist);
    if (!m_database.isOpen())
        return false;

    SQLiteStatement statement(m_database, "SELECT origin FROM Origins where origin=?;");
    if (statement.prepare() != SQLResultOk) {
        LOG_ERROR("Failed to prepare statement.");
        return false;
    }

    statement.bindText(1, origin->databaseIdentifier());

    return statement.step() == SQLResultRow;
}

bool DatabaseTracker::hasEntryForOrigin(SecurityOrigin* origin)
{
    MutexLocker lockDatabase(m_databaseGuard);
    return hasEntryForOriginNoLock(origin);
}

bool DatabaseTracker::hasEntryForDatabase(SecurityOrigin* origin, const String& databaseIdentifier)
{
    ASSERT(!m_databaseGuard.tryLock());
    openTrackerDatabase(DontCreateIfDoesNotExist);
    if (!m_database.isOpen()) {
        // No "tracker database". Hence, no entry for the database of interest.
        return false;
    }

    // We've got a tracker database. Set up a query to ask for the db of interest:
    SQLiteStatement statement(m_database, "SELECT guid FROM Databases WHERE origin=? AND name=?;");

    if (statement.prepare() != SQLResultOk)
        return false;

    statement.bindText(1, origin->databaseIdentifier());
    statement.bindText(2, databaseIdentifier);

    return statement.step() == SQLResultRow;
}

unsigned long long DatabaseTracker::getMaxSizeForDatabase(const DatabaseBackendBase* database)
{
    // The maximum size for a database is the full quota for its origin, minus the current usage within the origin,
    // plus the current usage of the given database
    MutexLocker lockDatabase(m_databaseGuard);
    SecurityOrigin* origin = database->securityOrigin();

    unsigned long long quota = quotaForOriginNoLock(origin);
    unsigned long long diskUsage = usageForOrigin(origin);
    unsigned long long databaseFileSize = SQLiteFileSystem::getDatabaseFileSize(database->fileName());
    ASSERT(databaseFileSize <= diskUsage);

    if (diskUsage > quota)
        return databaseFileSize;

    // A previous error may have allowed the origin to exceed its quota, or may
    // have allowed this database to exceed our cached estimate of the origin
    // disk usage. Don't multiply that error through integer underflow, or the
    // effective quota will permanently become 2^64.
    unsigned long long maxSize = quota - diskUsage + databaseFileSize;
    if (maxSize > quota)
        maxSize = databaseFileSize;
    return maxSize;
}

void DatabaseTracker::interruptAllDatabasesForContext(const DatabaseBackendContext* context)
{
    Vector<RefPtr<DatabaseBackendBase> > openDatabases;
    {
        MutexLocker openDatabaseMapLock(m_openDatabaseMapGuard);

        if (!m_openDatabaseMap)
            return;

        DatabaseNameMap* nameMap = m_openDatabaseMap->get(context->securityOrigin());
        if (!nameMap)
            return;

        DatabaseNameMap::const_iterator dbNameMapEndIt = nameMap->end();
        for (DatabaseNameMap::const_iterator dbNameMapIt = nameMap->begin(); dbNameMapIt != dbNameMapEndIt; ++dbNameMapIt) {
            DatabaseSet* databaseSet = dbNameMapIt->value;
            DatabaseSet::const_iterator dbSetEndIt = databaseSet->end();
            for (DatabaseSet::const_iterator dbSetIt = databaseSet->begin(); dbSetIt != dbSetEndIt; ++dbSetIt) {
                if ((*dbSetIt)->databaseContext() == context)
                    openDatabases.append(*dbSetIt);
            }
        }
    }

    Vector<RefPtr<DatabaseBackendBase> >::const_iterator openDatabasesEndIt = openDatabases.end();
    for (Vector<RefPtr<DatabaseBackendBase> >::const_iterator openDatabasesIt = openDatabases.begin(); openDatabasesIt != openDatabasesEndIt; ++openDatabasesIt)
        (*openDatabasesIt)->interrupt();
}

String DatabaseTracker::originPath(SecurityOrigin* origin) const
{
    return SQLiteFileSystem::appendDatabaseFileNameToPath(m_databaseDirectoryPath.isolatedCopy(), origin->databaseIdentifier());
}

String DatabaseTracker::fullPathForDatabaseNoLock(SecurityOrigin* origin, const String& name, bool createIfNotExists)
{
    ASSERT(!m_databaseGuard.tryLock());

    String originIdentifier = origin->databaseIdentifier();
    String originPath = this->originPath(origin);

    // Make sure the path for this SecurityOrigin exists
    if (createIfNotExists && !SQLiteFileSystem::ensureDatabaseDirectoryExists(originPath))
        return String();

    // See if we have a path for this database yet
    if (!m_database.isOpen())
        return String();
    SQLiteStatement statement(m_database, "SELECT path FROM Databases WHERE origin=? AND name=?;");

    if (statement.prepare() != SQLResultOk)
        return String();

    statement.bindText(1, originIdentifier);
    statement.bindText(2, name);

    int result = statement.step();

    if (result == SQLResultRow)
        return SQLiteFileSystem::appendDatabaseFileNameToPath(originPath, statement.getColumnText(0));
    if (!createIfNotExists)
        return String();

    if (result != SQLResultDone) {
        LOG_ERROR("Failed to retrieve filename from Database Tracker for origin %s, name %s", originIdentifier.ascii().data(), name.ascii().data());
        return String();
    }
    statement.finalize();

    String fileName = SQLiteFileSystem::getFileNameForNewDatabase(originPath, name, originIdentifier, &m_database);
    if (!addDatabase(origin, name, fileName))
        return String();

    // If this origin's quota is being tracked (open handle to a database in this origin), add this new database
    // to the quota manager now
    String fullFilePath = SQLiteFileSystem::appendDatabaseFileNameToPath(originPath, fileName);

    return fullFilePath;
}

String DatabaseTracker::fullPathForDatabase(SecurityOrigin* origin, const String& name, bool createIfNotExists)
{
    MutexLocker lockDatabase(m_databaseGuard);
    return fullPathForDatabaseNoLock(origin, name, createIfNotExists).isolatedCopy();
}

void DatabaseTracker::origins(Vector<RefPtr<SecurityOrigin> >& originsResult)
{
    MutexLocker lockDatabase(m_databaseGuard);

    openTrackerDatabase(DontCreateIfDoesNotExist);
    if (!m_database.isOpen())
        return;

    SQLiteStatement statement(m_database, "SELECT origin FROM Origins");
    if (statement.prepare() != SQLResultOk) {
        LOG_ERROR("Failed to prepare statement.");
        return;
    }

    int result;
    while ((result = statement.step()) == SQLResultRow) {
        RefPtr<SecurityOrigin> origin = SecurityOrigin::createFromDatabaseIdentifier(statement.getColumnText(0));
        originsResult.append(origin->isolatedCopy());
    }
    originsResult.shrinkToFit();

    if (result != SQLResultDone)
        LOG_ERROR("Failed to read in all origins from the database.");
}

bool DatabaseTracker::databaseNamesForOriginNoLock(SecurityOrigin* origin, Vector<String>& resultVector)
{
    ASSERT(!m_databaseGuard.tryLock());
    openTrackerDatabase(DontCreateIfDoesNotExist);
    if (!m_database.isOpen())
        return false;

    SQLiteStatement statement(m_database, "SELECT name FROM Databases where origin=?;");

    if (statement.prepare() != SQLResultOk)
        return false;

    statement.bindText(1, origin->databaseIdentifier());

    int result;
    while ((result = statement.step()) == SQLResultRow)
        resultVector.append(statement.getColumnText(0));

    if (result != SQLResultDone) {
        LOG_ERROR("Failed to retrieve all database names for origin %s", origin->databaseIdentifier().ascii().data());
        return false;
    }

    return true;
}

bool DatabaseTracker::databaseNamesForOrigin(SecurityOrigin* origin, Vector<String>& resultVector)
{
    Vector<String> temp;
    {
        MutexLocker lockDatabase(m_databaseGuard);
        if (!databaseNamesForOriginNoLock(origin, temp))
          return false;
    }

    for (Vector<String>::iterator iter = temp.begin(); iter != temp.end(); ++iter)
        resultVector.append(iter->isolatedCopy());
    return true;
}

DatabaseDetails DatabaseTracker::detailsForNameAndOrigin(const String& name, SecurityOrigin* origin)
{
    String originIdentifier = origin->databaseIdentifier();
    String displayName;
    int64_t expectedUsage;

    {
        MutexLocker lockDatabase(m_databaseGuard);

        openTrackerDatabase(DontCreateIfDoesNotExist);
        if (!m_database.isOpen())
            return DatabaseDetails();
        SQLiteStatement statement(m_database, "SELECT displayName, estimatedSize FROM Databases WHERE origin=? AND name=?");
        if (statement.prepare() != SQLResultOk)
            return DatabaseDetails();

        statement.bindText(1, originIdentifier);
        statement.bindText(2, name);

        int result = statement.step();
        if (result == SQLResultDone)
            return DatabaseDetails();

        if (result != SQLResultRow) {
            LOG_ERROR("Error retrieving details for database %s in origin %s from tracker database", name.ascii().data(), originIdentifier.ascii().data());
            return DatabaseDetails();
        }
        displayName = statement.getColumnText(0);
        expectedUsage = statement.getColumnInt64(1);
    }

    return DatabaseDetails(name, displayName, expectedUsage, usageForDatabase(name, origin));
}

void DatabaseTracker::setDatabaseDetails(SecurityOrigin* origin, const String& name, const String& displayName, unsigned long estimatedSize)
{
    String originIdentifier = origin->databaseIdentifier();
    int64_t guid = 0;

    MutexLocker lockDatabase(m_databaseGuard);

    openTrackerDatabase(CreateIfDoesNotExist);
    if (!m_database.isOpen())
        return;
    SQLiteStatement statement(m_database, "SELECT guid FROM Databases WHERE origin=? AND name=?");
    if (statement.prepare() != SQLResultOk)
        return;

    statement.bindText(1, originIdentifier);
    statement.bindText(2, name);

    int result = statement.step();
    if (result == SQLResultRow)
        guid = statement.getColumnInt64(0);
    statement.finalize();

    if (guid == 0) {
        if (result != SQLResultDone)
            LOG_ERROR("Error to determing existence of database %s in origin %s in tracker database", name.ascii().data(), originIdentifier.ascii().data());
        else {
            // This case should never occur - we should never be setting database details for a database that doesn't already exist in the tracker
            // But since the tracker file is an external resource not under complete control of our code, it's somewhat invalid to make this an ASSERT case
            // So we'll print an error instead
            LOG_ERROR("Could not retrieve guid for database %s in origin %s from the tracker database - it is invalid to set database details on a database that doesn't already exist in the tracker",
                       name.ascii().data(), originIdentifier.ascii().data());
        }
        return;
    }

    SQLiteStatement updateStatement(m_database, "UPDATE Databases SET displayName=?, estimatedSize=? WHERE guid=?");
    if (updateStatement.prepare() != SQLResultOk)
        return;

    updateStatement.bindText(1, displayName);
    updateStatement.bindInt64(2, estimatedSize);
    updateStatement.bindInt64(3, guid);

    if (updateStatement.step() != SQLResultDone) {
        LOG_ERROR("Failed to update details for database %s in origin %s", name.ascii().data(), originIdentifier.ascii().data());
        return;
    }

    if (m_client)
        m_client->dispatchDidModifyDatabase(origin, name);
}

unsigned long long DatabaseTracker::usageForDatabase(const String& name, SecurityOrigin* origin)
{
    String path = fullPathForDatabase(origin, name, false);
    if (path.isEmpty())
        return 0;

    return SQLiteFileSystem::getDatabaseFileSize(path);
}

void DatabaseTracker::doneCreatingDatabase(DatabaseBackendBase* database)
{
    MutexLocker lockDatabase(m_databaseGuard);
    doneCreatingDatabase(database->securityOrigin(), database->stringIdentifier());
}

void DatabaseTracker::addOpenDatabase(DatabaseBackendBase* database)
{
    if (!database)
        return;

    {
        MutexLocker openDatabaseMapLock(m_openDatabaseMapGuard);

        if (!m_openDatabaseMap)
            m_openDatabaseMap = adoptPtr(new DatabaseOriginMap);

        String name(database->stringIdentifier());
        DatabaseNameMap* nameMap = m_openDatabaseMap->get(database->securityOrigin());
        if (!nameMap) {
            nameMap = new DatabaseNameMap;
            m_openDatabaseMap->set(database->securityOrigin()->isolatedCopy(), nameMap);
        }

        DatabaseSet* databaseSet = nameMap->get(name);
        if (!databaseSet) {
            databaseSet = new DatabaseSet;
            nameMap->set(name.isolatedCopy(), databaseSet);
        }

        databaseSet->add(database);

        LOG(StorageAPI, "Added open Database %s (%p)\n", database->stringIdentifier().ascii().data(), database);
    }
}

void DatabaseTracker::removeOpenDatabase(DatabaseBackendBase* database)
{
    if (!database)
        return;

    {
        MutexLocker openDatabaseMapLock(m_openDatabaseMapGuard);

        if (!m_openDatabaseMap) {
            ASSERT_NOT_REACHED();
            return;
        }

        String name(database->stringIdentifier());
        DatabaseNameMap* nameMap = m_openDatabaseMap->get(database->securityOrigin());
        if (!nameMap) {
            ASSERT_NOT_REACHED();
            return;
        }

        DatabaseSet* databaseSet = nameMap->get(name);
        if (!databaseSet) {
            ASSERT_NOT_REACHED();
            return;
        }

        databaseSet->remove(database);

        LOG(StorageAPI, "Removed open Database %s (%p)\n", database->stringIdentifier().ascii().data(), database);

        if (!databaseSet->isEmpty())
            return;

        nameMap->remove(name);
        delete databaseSet;

        if (!nameMap->isEmpty())
            return;

        m_openDatabaseMap->remove(database->securityOrigin());
        delete nameMap;
    }
}

void DatabaseTracker::getOpenDatabases(SecurityOrigin* origin, const String& name, HashSet<RefPtr<DatabaseBackendBase> >* databases)
{
    MutexLocker openDatabaseMapLock(m_openDatabaseMapGuard);
    if (!m_openDatabaseMap)
        return;

    DatabaseNameMap* nameMap = m_openDatabaseMap->get(origin);
    if (!nameMap)
        return;

    DatabaseSet* databaseSet = nameMap->get(name);
    if (!databaseSet)
        return;

    for (DatabaseSet::iterator it = databaseSet->begin(); it != databaseSet->end(); ++it)
        databases->add(*it);
}

PassRefPtr<OriginLock> DatabaseTracker::originLockFor(SecurityOrigin* origin)
{
    MutexLocker lockDatabase(m_databaseGuard);
    String databaseIdentifier = origin->databaseIdentifier();

    // The originLockMap is accessed from multiple DatabaseThreads since
    // different script contexts can be writing to different databases from
    // the same origin. Hence, the databaseIdentifier key needs to be an
    // isolated copy. An isolated copy gives us a value whose refCounting is
    // thread-safe, since our copy is guarded by the m_databaseGuard mutex.
    databaseIdentifier = databaseIdentifier.isolatedCopy();

    OriginLockMap::AddResult addResult =
        m_originLockMap.add(databaseIdentifier, RefPtr<OriginLock>());
    if (!addResult.isNewEntry)
        return addResult.iterator->value;

    String path = originPath(origin);
    RefPtr<OriginLock> lock = adoptRef(new OriginLock(path));
    ASSERT(lock);
    addResult.iterator->value = lock;

    return lock.release();
}

void DatabaseTracker::deleteOriginLockFor(SecurityOrigin* origin)
{
    ASSERT(!m_databaseGuard.tryLock());

    // There is not always an instance of an OriginLock associated with an origin.
    // For example, if the OriginLock lock file was created by a previous run of
    // the browser which has now terminated, and the current browser process
    // has not executed any database transactions from this origin that would
    // have created the OriginLock instance in memory. In this case, we will have
    // a lock file but not an OriginLock instance in memory.

    // This function is only called if we are already deleting all the database
    // files in this origin. We'll give the OriginLock one chance to do an
    // orderly clean up first when we remove its ref from the m_originLockMap.
    // This may or may not be possible depending on whether other threads are
    // also using the OriginLock at the same time. After that, we will go ahead
    // and delete the lock file.

    m_originLockMap.remove(origin->databaseIdentifier());
    OriginLock::deleteLockFile(originPath(origin));
}

unsigned long long DatabaseTracker::usageForOrigin(SecurityOrigin* origin)
{
    String originPath = this->originPath(origin);
    unsigned long long diskUsage = 0;
    Vector<String> fileNames = listDirectory(originPath, String("*.db"));
    Vector<String>::iterator fileName = fileNames.begin();
    Vector<String>::iterator lastFileName = fileNames.end();
    for (; fileName != lastFileName; ++fileName) {
        long long size;
        getFileSize(*fileName, size);
        diskUsage += size;
    }
    return diskUsage;
}

unsigned long long DatabaseTracker::quotaForOriginNoLock(SecurityOrigin* origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    unsigned long long quota = 0;

    openTrackerDatabase(DontCreateIfDoesNotExist);
    if (!m_database.isOpen())
        return quota;

    SQLiteStatement statement(m_database, "SELECT quota FROM Origins where origin=?;");
    if (statement.prepare() != SQLResultOk) {
        LOG_ERROR("Failed to prepare statement.");
        return quota;
    }
    statement.bindText(1, origin->databaseIdentifier());

    if (statement.step() == SQLResultRow)
        quota = statement.getColumnInt64(0);

    return quota;
}

unsigned long long DatabaseTracker::quotaForOrigin(SecurityOrigin* origin)
{
    MutexLocker lockDatabase(m_databaseGuard);
    return quotaForOriginNoLock(origin);
}

void DatabaseTracker::setQuota(SecurityOrigin* origin, unsigned long long quota)
{
    MutexLocker lockDatabase(m_databaseGuard);

    if (quotaForOriginNoLock(origin) == quota)
        return;

    openTrackerDatabase(CreateIfDoesNotExist);
    if (!m_database.isOpen())
        return;

    bool originEntryExists = hasEntryForOriginNoLock(origin);
    if (!originEntryExists) {
        SQLiteStatement statement(m_database, "INSERT INTO Origins VALUES (?, ?)");
        if (statement.prepare() != SQLResultOk) {
            LOG_ERROR("Unable to establish origin %s in the tracker", origin->databaseIdentifier().ascii().data());
        } else {
            statement.bindText(1, origin->databaseIdentifier());
            statement.bindInt64(2, quota);

            if (statement.step() != SQLResultDone)
                LOG_ERROR("Unable to establish origin %s in the tracker", origin->databaseIdentifier().ascii().data());
        }
    } else {
        SQLiteStatement statement(m_database, "UPDATE Origins SET quota=? WHERE origin=?");
        bool error = statement.prepare() != SQLResultOk;
        if (!error) {
            statement.bindInt64(1, quota);
            statement.bindText(2, origin->databaseIdentifier());

            error = !statement.executeCommand();
        }

        if (error)
#if OS(WINDOWS)
            LOG_ERROR("Failed to set quota %I64u in tracker database for origin %s", quota, origin->databaseIdentifier().ascii().data());
#else
            LOG_ERROR("Failed to set quota %llu in tracker database for origin %s", quota, origin->databaseIdentifier().ascii().data());
#endif
    }

    if (m_client)
        m_client->dispatchDidModifyOrigin(origin);
}

bool DatabaseTracker::addDatabase(SecurityOrigin* origin, const String& name, const String& path)
{
    ASSERT(!m_databaseGuard.tryLock());
    openTrackerDatabase(CreateIfDoesNotExist);
    if (!m_database.isOpen())
        return false;

    // New database should never be added until the origin has been established
    ASSERT(hasEntryForOriginNoLock(origin));

    SQLiteStatement statement(m_database, "INSERT INTO Databases (origin, name, path) VALUES (?, ?, ?);");

    if (statement.prepare() != SQLResultOk)
        return false;

    statement.bindText(1, origin->databaseIdentifier());
    statement.bindText(2, name);
    statement.bindText(3, path);

    if (!statement.executeCommand()) {
        LOG_ERROR("Failed to add database %s to origin %s: %s\n", name.ascii().data(), origin->databaseIdentifier().ascii().data(), m_database.lastErrorMsg());
        return false;
    }

    if (m_client)
        m_client->dispatchDidModifyOrigin(origin);

    return true;
}

void DatabaseTracker::deleteAllDatabases()
{
    Vector<RefPtr<SecurityOrigin> > originsCopy;
    origins(originsCopy);

    for (unsigned i = 0; i < originsCopy.size(); ++i)
        deleteOrigin(originsCopy[i].get());
}

// It is the caller's responsibility to make sure that nobody is trying to create, delete, open, or close databases in this origin while the deletion is
// taking place.
bool DatabaseTracker::deleteOrigin(SecurityOrigin* origin)
{
    Vector<String> databaseNames;
    {
        MutexLocker lockDatabase(m_databaseGuard);
        openTrackerDatabase(DontCreateIfDoesNotExist);
        if (!m_database.isOpen())
            return false;

        if (!databaseNamesForOriginNoLock(origin, databaseNames)) {
            LOG_ERROR("Unable to retrieve list of database names for origin %s", origin->databaseIdentifier().ascii().data());
            return false;
        }
        if (!canDeleteOrigin(origin)) {
            LOG_ERROR("Tried to delete an origin (%s) while either creating database in it or already deleting it", origin->databaseIdentifier().ascii().data());
            ASSERT_NOT_REACHED();
            return false;
        }
        recordDeletingOrigin(origin);
    }

    // We drop the lock here because holding locks during a call to deleteDatabaseFile will deadlock.
    for (unsigned i = 0; i < databaseNames.size(); ++i) {
        if (!deleteDatabaseFile(origin, databaseNames[i])) {
            // Even if the file can't be deleted, we want to try and delete the rest, don't return early here.
            LOG_ERROR("Unable to delete file for database %s in origin %s", databaseNames[i].ascii().data(), origin->databaseIdentifier().ascii().data());
        }
    }

    {
        MutexLocker lockDatabase(m_databaseGuard);
        deleteOriginLockFor(origin);
        doneDeletingOrigin(origin);

        SQLiteStatement statement(m_database, "DELETE FROM Databases WHERE origin=?");
        if (statement.prepare() != SQLResultOk) {
            LOG_ERROR("Unable to prepare deletion of databases from origin %s from tracker", origin->databaseIdentifier().ascii().data());
            return false;
        }

        statement.bindText(1, origin->databaseIdentifier());

        if (!statement.executeCommand()) {
            LOG_ERROR("Unable to execute deletion of databases from origin %s from tracker", origin->databaseIdentifier().ascii().data());
            return false;
        }

        SQLiteStatement originStatement(m_database, "DELETE FROM Origins WHERE origin=?");
        if (originStatement.prepare() != SQLResultOk) {
            LOG_ERROR("Unable to prepare deletion of origin %s from tracker", origin->databaseIdentifier().ascii().data());
            return false;
        }

        originStatement.bindText(1, origin->databaseIdentifier());

        if (!originStatement.executeCommand()) {
            LOG_ERROR("Unable to execute deletion of databases from origin %s from tracker", origin->databaseIdentifier().ascii().data());
            return false;
        }

        SQLiteFileSystem::deleteEmptyDatabaseDirectory(originPath(origin));

        RefPtr<SecurityOrigin> originPossiblyLastReference = origin;
        bool isEmpty = true;

        openTrackerDatabase(DontCreateIfDoesNotExist);
        if (m_database.isOpen()) {
            SQLiteStatement statement(m_database, "SELECT origin FROM Origins");
            if (statement.prepare() != SQLResultOk)
                LOG_ERROR("Failed to prepare statement.");
            else if (statement.step() == SQLResultRow)
                isEmpty = false;
        }

        // If we removed the last origin, do some additional deletion.
        if (isEmpty) {
            if (m_database.isOpen())
                m_database.close();
           SQLiteFileSystem::deleteDatabaseFile(trackerDatabasePath());
           SQLiteFileSystem::deleteEmptyDatabaseDirectory(m_databaseDirectoryPath);
        }

        if (m_client) {
            m_client->dispatchDidModifyOrigin(origin);
            for (unsigned i = 0; i < databaseNames.size(); ++i)
                m_client->dispatchDidModifyDatabase(origin, databaseNames[i]);
        }
    }
    return true;
}

bool DatabaseTracker::isDeletingDatabaseOrOriginFor(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    // Can't create a database while someone else is deleting it; there's a risk of leaving untracked database debris on the disk.
    return isDeletingDatabase(origin, name) || isDeletingOrigin(origin);
}

void DatabaseTracker::recordCreatingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    NameCountMap* nameMap = m_beingCreated.get(origin);
    if (!nameMap) {
        nameMap = new NameCountMap();
        m_beingCreated.set(origin->isolatedCopy(), nameMap);
    }
    long count = nameMap->get(name);
    nameMap->set(name.isolatedCopy(), count + 1);
}

void DatabaseTracker::doneCreatingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    NameCountMap* nameMap = m_beingCreated.get(origin);
    ASSERT(nameMap);
    if (!nameMap)
        return;

    long count = nameMap->get(name);
    ASSERT(count > 0);
    if (count <= 1) {
        nameMap->remove(name);
        if (nameMap->isEmpty()) {
            m_beingCreated.remove(origin);
            delete nameMap;
        }
    } else
        nameMap->set(name, count - 1);
}

bool DatabaseTracker::creatingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    NameCountMap* nameMap = m_beingCreated.get(origin);
    return nameMap && nameMap->get(name);
}

bool DatabaseTracker::canDeleteDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    return !creatingDatabase(origin, name) && !isDeletingDatabase(origin, name);
}

void DatabaseTracker::recordDeletingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    ASSERT(canDeleteDatabase(origin, name));
    NameSet* nameSet = m_beingDeleted.get(origin);
    if (!nameSet) {
        nameSet = new NameSet();
        m_beingDeleted.set(origin->isolatedCopy(), nameSet);
    }
    ASSERT(!nameSet->contains(name));
    nameSet->add(name.isolatedCopy());
}

void DatabaseTracker::doneDeletingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    NameSet* nameSet = m_beingDeleted.get(origin);
    ASSERT(nameSet);
    if (!nameSet)
        return;

    ASSERT(nameSet->contains(name));
    nameSet->remove(name);
    if (nameSet->isEmpty()) {
        m_beingDeleted.remove(origin);
        delete nameSet;
    }
}

bool DatabaseTracker::isDeletingDatabase(SecurityOrigin *origin, const String& name)
{
    ASSERT(!m_databaseGuard.tryLock());
    NameSet* nameSet = m_beingDeleted.get(origin);
    return nameSet && nameSet->contains(name);
}

bool DatabaseTracker::canDeleteOrigin(SecurityOrigin *origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    return !(isDeletingOrigin(origin) || m_beingCreated.get(origin));
}

bool DatabaseTracker::isDeletingOrigin(SecurityOrigin *origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    return m_originsBeingDeleted.contains(origin);
}

void DatabaseTracker::recordDeletingOrigin(SecurityOrigin *origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    ASSERT(!isDeletingOrigin(origin));
    m_originsBeingDeleted.add(origin->isolatedCopy());
}

void DatabaseTracker::doneDeletingOrigin(SecurityOrigin *origin)
{
    ASSERT(!m_databaseGuard.tryLock());
    ASSERT(isDeletingOrigin(origin));
    m_originsBeingDeleted.remove(origin);
}

bool DatabaseTracker::deleteDatabase(SecurityOrigin* origin, const String& name)
{
    {
        MutexLocker lockDatabase(m_databaseGuard);
        openTrackerDatabase(DontCreateIfDoesNotExist);
        if (!m_database.isOpen())
            return false;

        if (!canDeleteDatabase(origin, name)) {
            ASSERT_NOT_REACHED();
            return false;
        }
        recordDeletingDatabase(origin, name);
    }

    // We drop the lock here because holding locks during a call to deleteDatabaseFile will deadlock.
    if (!deleteDatabaseFile(origin, name)) {
        LOG_ERROR("Unable to delete file for database %s in origin %s", name.ascii().data(), origin->databaseIdentifier().ascii().data());
        MutexLocker lockDatabase(m_databaseGuard);
        doneDeletingDatabase(origin, name);
        return false;
    }

    MutexLocker lockDatabase(m_databaseGuard);

    SQLiteStatement statement(m_database, "DELETE FROM Databases WHERE origin=? AND name=?");
    if (statement.prepare() != SQLResultOk) {
        LOG_ERROR("Unable to prepare deletion of database %s from origin %s from tracker", name.ascii().data(), origin->databaseIdentifier().ascii().data());
        doneDeletingDatabase(origin, name);
        return false;
    }

    statement.bindText(1, origin->databaseIdentifier());
    statement.bindText(2, name);

    if (!statement.executeCommand()) {
        LOG_ERROR("Unable to execute deletion of database %s from origin %s from tracker", name.ascii().data(), origin->databaseIdentifier().ascii().data());
        doneDeletingDatabase(origin, name);
        return false;
    }

    if (m_client) {
        m_client->dispatchDidModifyOrigin(origin);
        m_client->dispatchDidModifyDatabase(origin, name);
    }
    doneDeletingDatabase(origin, name);
    
    return true;
}

// deleteDatabaseFile has to release locks between looking up the list of databases to close and closing them.  While this is in progress, the caller
// is responsible for making sure no new databases are opened in the file to be deleted.
bool DatabaseTracker::deleteDatabaseFile(SecurityOrigin* origin, const String& name)
{
    String fullPath = fullPathForDatabase(origin, name, false);
    if (fullPath.isEmpty())
        return true;

#ifndef NDEBUG
    {
        MutexLocker lockDatabase(m_databaseGuard);
        ASSERT(isDeletingDatabaseOrOriginFor(origin, name));
    }
#endif

    Vector<RefPtr<DatabaseBackendBase> > deletedDatabases;

    // Make sure not to hold the any locks when calling
    // Database::markAsDeletedAndClose(), since that can cause a deadlock
    // during the synchronous DatabaseThread call it triggers.
    {
        MutexLocker openDatabaseMapLock(m_openDatabaseMapGuard);
        if (m_openDatabaseMap) {
            // There are some open databases, lets check if they are for this origin.
            DatabaseNameMap* nameMap = m_openDatabaseMap->get(origin);
            if (nameMap && nameMap->size()) {
                // There are some open databases for this origin, let's check
                // if they are this database by name.
                DatabaseSet* databaseSet = nameMap->get(name);
                if (databaseSet && databaseSet->size()) {
                    // We have some database open with this name. Mark them as deleted.
                    DatabaseSet::const_iterator end = databaseSet->end();
                    for (DatabaseSet::const_iterator it = databaseSet->begin(); it != end; ++it)
                        deletedDatabases.append(*it);
                }
            }
        }
    }

    for (unsigned i = 0; i < deletedDatabases.size(); ++i)
        deletedDatabases[i]->markAsDeletedAndClose();

    return SQLiteFileSystem::deleteDatabaseFile(fullPath);
}

void DatabaseTracker::setClient(DatabaseManagerClient* client)
{
    m_client = client;
}

static Mutex& notificationMutex()
{
    DEFINE_STATIC_LOCAL(Mutex, mutex, ());
    return mutex;
}

typedef Vector<pair<RefPtr<SecurityOrigin>, String> > NotificationQueue;

static NotificationQueue& notificationQueue()
{
    DEFINE_STATIC_LOCAL(NotificationQueue, queue, ());
    return queue;
}

void DatabaseTracker::scheduleNotifyDatabaseChanged(SecurityOrigin* origin, const String& name)
{
    MutexLocker locker(notificationMutex());

    notificationQueue().append(pair<RefPtr<SecurityOrigin>, String>(origin->isolatedCopy(), name.isolatedCopy()));
    scheduleForNotification();
}

static bool notificationScheduled = false;

void DatabaseTracker::scheduleForNotification()
{
    ASSERT(!notificationMutex().tryLock());

    if (!notificationScheduled) {
        callOnMainThread(DatabaseTracker::notifyDatabasesChanged, 0);
        notificationScheduled = true;
    }
}

void DatabaseTracker::notifyDatabasesChanged(void*)
{
    // Note that if DatabaseTracker ever becomes non-singleton, we'll have to amend this notification
    // mechanism to include which tracker the notification goes out on as well.
    DatabaseTracker& theTracker(tracker());

    NotificationQueue notifications;
    {
        MutexLocker locker(notificationMutex());

        notifications.swap(notificationQueue());

        notificationScheduled = false;
    }

    if (!theTracker.m_client)
        return;

    for (unsigned i = 0; i < notifications.size(); ++i)
        theTracker.m_client->dispatchDidModifyDatabase(notifications[i].first.get(), notifications[i].second);
}


} // namespace WebCore
#endif