Avoid data race on Database::m_opened.

third_party/WebKit/Source/modules/webdatabase/Database.cpp

 /*
  * Copyright (C) 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
@@ skipping 35 matching lines @@
 #include "modules/webdatabase/SQLTransactionClient.h"
 #include "modules/webdatabase/SQLTransactionCoordinator.h"
 #include "modules/webdatabase/SQLTransactionErrorCallback.h"
 #include "modules/webdatabase/sqlite/SQLiteStatement.h"
 #include "modules/webdatabase/sqlite/SQLiteTransaction.h"
 #include "platform/Logging.h"
 #include "platform/heap/SafePoint.h"
 #include "platform/weborigin/DatabaseIdentifier.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebDatabaseObserver.h"
+#include "wtf/Atomics.h"
 
 // Registering "opened" databases with the DatabaseTracker
 // =======================================================
 // The DatabaseTracker maintains a list of databases that have been
 // "opened" so that the client can call interrupt or delete on every database
 // associated with a DatabaseContext.
 //
 // We will only call DatabaseTracker::addOpenDatabase() to add the database
 // to the tracker as opened when we've succeeded in opening the database,
 // and will set m_opened to true. Similarly, we only call
@@ skipping 135 matching lines @@
     return guid;
 }
 
 Database::Database(DatabaseContext* databaseContext, const String& name, const String& expectedVersion, const String& displayName, unsigned long estimatedSize)
     : m_databaseContext(databaseContext)
     , m_name(name.isolatedCopy())
     , m_expectedVersion(expectedVersion.isolatedCopy())
     , m_displayName(displayName.isolatedCopy())
     , m_estimatedSize(estimatedSize)
     , m_guid(0)
-    , m_opened(false)
+    , m_opened(0)
     , m_new(false)
     , m_transactionInProgress(false)
     , m_isTransactionQueueEnabled(true)
 {
     m_contextThreadSecurityOrigin = m_databaseContext->securityOrigin()->isolatedCopy();
 
     m_databaseAuthorizer = DatabaseAuthorizer::create(infoTableName);
 
     if (m_name.isNull())
         m_name = "";
@@ skipping 140 matching lines @@
 const char* Database::databaseInfoTableName()
 {
     return infoTableName;
 }
 
 void Database::closeDatabase()
 {
     if (!m_opened)
         return;
 
+    releaseStore(&m_opened, 0);
     m_sqliteDatabase.close();
-    m_opened = false;
     // See comment at the top this file regarding calling removeOpenDatabase().
     DatabaseTracker::tracker().removeOpenDatabase(this);
     {
         SafePointAwareMutexLocker locker(guidMutex());
 
         ASSERT(guidCount().contains(m_guid));
         if (guidCount().remove(m_guid)) {
             guidToVersionMap().remove(m_guid);
         }
     }
@@ skipping 139 matching lines @@
         errorMessage = "unable to open database, version mismatch, '" + m_expectedVersion + "' does not match the currentVersion of '" + currentVersion + "'";
         m_sqliteDatabase.close();
         return false;
     }
 
     ASSERT(m_databaseAuthorizer);
     m_sqliteDatabase.setAuthorizer(m_databaseAuthorizer.get());
 
     // See comment at the top this file regarding calling addOpenDatabase().
     DatabaseTracker::tracker().addOpenDatabase(this);
-    m_opened = true;
+    m_opened = 1;
 
     // Declare success:
     error = DatabaseError::None; // Clear the presumed error from above.
     onExitCaller.setOpenSucceeded();
 
     if (m_new && !shouldSetVersionInNewDatabase) {
         // The caller provided a creationCallback which will set the expected
         // version.
         m_expectedVersion = "";
     }
@@ skipping 350 matching lines @@
 
 SecurityOrigin* Database::securityOrigin() const
 {
     if (executionContext()->isContextThread())
         return m_contextThreadSecurityOrigin.get();
     if (databaseContext()->databaseThread()->isDatabaseThread())
         return m_databaseThreadSecurityOrigin.get();
     return 0;
 }
 
+bool Database::opened()
+{
+    return static_cast<bool>(acquireLoad(&m_opened));
+}
+
 } // namespace blink