src/third_party/WebKit/Source/modules/webdatabase/SQLTransactionCoordinator.cpp

   1 /*
   2  * Copyright (C) 2009 Google Inc. All rights reserved.
   3  * Copyright (C) 2013 Apple Inc. All rights reserved.
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   6  * modification, are permitted provided that the following conditions are
   7  * met:
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   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
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  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include "config.h"
  33 #include "modules/webdatabase/SQLTransactionCoordinator.h"
  34
  35 #include "modules/webdatabase/Database.h"
  36 #include "modules/webdatabase/SQLTransactionBackend.h"
  37
  38 namespace blink {
  39
  40 static String getDatabaseIdentifier(SQLTransactionBackend* transaction)
  41 {
  42     Database* database = transaction->database();
  43     ASSERT(database);
  44     return database->stringIdentifier();
  45 }
  46
  47 SQLTransactionCoordinator::SQLTransactionCoordinator()
  48     : m_isShuttingDown(false)
  49 {
  50 }
  51
  52 void SQLTransactionCoordinator::trace(Visitor* visitor)
  53 {
  54 #if ENABLE(OILPAN)
  55     visitor->trace(m_coordinationInfoMap);
  56 #endif
  57 }
  58
  59 void SQLTransactionCoordinator::processPendingTransactions(CoordinationInfo& info)
  60 {
  61     if (info.activeWriteTransaction || info.pendingTransactions.isEmpty())
  62         return;
  63
  64     RefPtrWillBeRawPtr<SQLTransactionBackend> firstPendingTransaction = info.pendingTransactions.first();
  65     if (firstPendingTransaction->isReadOnly()) {
  66         do {
  67             firstPendingTransaction = info.pendingTransactions.takeFirst();
  68             info.activeReadTransactions.add(firstPendingTransaction);
  69             firstPendingTransaction->lockAcquired();
  70         } while (!info.pendingTransactions.isEmpty() && info.pendingTransactions.first()->isReadOnly());
  71     } else if (info.activeReadTransactions.isEmpty()) {
  72         info.pendingTransactions.removeFirst();
  73         info.activeWriteTransaction = firstPendingTransaction;
  74         firstPendingTransaction->lockAcquired();
  75     }
  76 }
  77
  78 void SQLTransactionCoordinator::acquireLock(SQLTransactionBackend* transaction)
  79 {
  80     ASSERT(!m_isShuttingDown);
  81
  82     String dbIdentifier = getDatabaseIdentifier(transaction);
  83
  84     CoordinationInfoHeapMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier);
  85     if (coordinationInfoIterator == m_coordinationInfoMap.end()) {
  86         // No pending transactions for this DB
  87         CoordinationInfo& info = m_coordinationInfoMap.add(dbIdentifier, CoordinationInfo()).storedValue->value;
  88         info.pendingTransactions.append(transaction);
  89         processPendingTransactions(info);
  90     } else {
  91         CoordinationInfo& info = coordinationInfoIterator->value;
  92         info.pendingTransactions.append(transaction);
  93         processPendingTransactions(info);
  94     }
  95
  96 }
  97
  98 void SQLTransactionCoordinator::releaseLock(SQLTransactionBackend* transaction)
  99 {
 100     if (m_isShuttingDown)
 101         return;
 102
 103     String dbIdentifier = getDatabaseIdentifier(transaction);
 104
 105     CoordinationInfoHeapMap::iterator coordinationInfoIterator = m_coordinationInfoMap.find(dbIdentifier);
 106     ASSERT_WITH_SECURITY_IMPLICATION(coordinationInfoIterator != m_coordinationInfoMap.end());
 107     CoordinationInfo& info = coordinationInfoIterator->value;
 108
 109     if (transaction->isReadOnly()) {
 110         ASSERT(info.activeReadTransactions.contains(transaction));
 111         info.activeReadTransactions.remove(transaction);
 112     } else {
 113         ASSERT(info.activeWriteTransaction == transaction);
 114         info.activeWriteTransaction = nullptr;
 115     }
 116
 117     processPendingTransactions(info);
 118 }
 119
 120 void SQLTransactionCoordinator::shutdown()
 121 {
 122     // Prevent releaseLock() from accessing / changing the coordinationInfo
 123     // while we're shutting down.
 124     m_isShuttingDown = true;
 125
 126     // Notify all transactions in progress that the database thread is shutting down
 127     for (CoordinationInfoHeapMap::iterator coordinationInfoIterator = m_coordinationInfoMap.begin();
 128          coordinationInfoIterator != m_coordinationInfoMap.end(); ++coordinationInfoIterator) {
 129         CoordinationInfo& info = coordinationInfoIterator->value;
 130
 131         // Clean up transactions that have reached "lockAcquired":
 132         // Transaction phase 4 cleanup. See comment on "What happens if a
 133         // transaction is interrupted?" at the top of SQLTransactionBackend.cpp.
 134         if (info.activeWriteTransaction)
 135             info.activeWriteTransaction->notifyDatabaseThreadIsShuttingDown();
 136         for (WillBeHeapHashSet<RefPtrWillBeMember<SQLTransactionBackend> >::iterator activeReadTransactionsIterator =
 137                      info.activeReadTransactions.begin();
 138              activeReadTransactionsIterator != info.activeReadTransactions.end();
 139              ++activeReadTransactionsIterator) {
 140             (*activeReadTransactionsIterator)->notifyDatabaseThreadIsShuttingDown();
 141         }
 142
 143         // Clean up transactions that have NOT reached "lockAcquired":
 144         // Transaction phase 3 cleanup. See comment on "What happens if a
 145         // transaction is interrupted?" at the top of SQLTransactionBackend.cpp.
 146         while (!info.pendingTransactions.isEmpty()) {
 147             RefPtrWillBeRawPtr<SQLTransactionBackend> transaction = info.pendingTransactions.takeFirst();
 148             transaction->notifyDatabaseThreadIsShuttingDown();
 149         }
 150     }
 151
 152     // Clean up all pending transactions for all databases
 153     m_coordinationInfoMap.clear();
 154 }
 155
 156 } // namespace blink