Manage WebSQL callbacks with OwnPtr instead of refcounting

Source/modules/webdatabase/Database.cpp

 /*
  * 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
@@ skipping 122 matching lines @@
 void Database::closeImmediately()
 {
     ASSERT(m_executionContext->isContextThread());
     DatabaseThread* databaseThread = databaseContext()->databaseThread();
     if (databaseThread && !databaseThread->terminationRequested() && opened()) {
         logErrorMessage("forcibly closing database");
         databaseThread->scheduleTask(DatabaseCloseTask::create(this, 0));
     }
 }
 
-void Database::changeVersion(const String& oldVersion, const String& newVersion, PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<SQLVoidCallback> successCallback)
+void Database::changeVersion(const String& oldVersion, const String& newVersion, PassOwnPtr<SQLTransactionCallback> callback, PassOwnPtr<SQLTransactionErrorCallback> errorCallback, PassOwnPtr<SQLVoidCallback> successCallback)
 {
     ChangeVersionData data(oldVersion, newVersion);
     runTransaction(callback, errorCallback, successCallback, false, &data);
 }
 
-void Database::transaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<SQLVoidCallback> successCallback)
+void Database::transaction(PassOwnPtr<SQLTransactionCallback> callback, PassOwnPtr<SQLTransactionErrorCallback> errorCallback, PassOwnPtr<SQLVoidCallback> successCallback)
 {
     runTransaction(callback, errorCallback, successCallback, false);
 }
 
-void Database::readTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback, PassRefPtr<SQLVoidCallback> successCallback)
+void Database::readTransaction(PassOwnPtr<SQLTransactionCallback> callback, PassOwnPtr<SQLTransactionErrorCallback> errorCallback, PassOwnPtr<SQLVoidCallback> successCallback)
 {
     runTransaction(callback, errorCallback, successCallback, true);
 }
 
-static void callTransactionErrorCallback(ExecutionContext*, PassRefPtr<SQLTransactionErrorCallback> callback, PassRefPtr<SQLError> error)
+static void callTransactionErrorCallback(ExecutionContext*, PassOwnPtr<SQLTransactionErrorCallback> callback, PassRefPtr<SQLError> error)
 {
     callback->handleEvent(error.get());
 }
 
-void Database::runTransaction(PassRefPtr<SQLTransactionCallback> callback, PassRefPtr<SQLTransactionErrorCallback> errorCallback,
-    PassRefPtr<SQLVoidCallback> successCallback, bool readOnly, const ChangeVersionData* changeVersionData)
+void Database::runTransaction(PassOwnPtr<SQLTransactionCallback> callback, PassOwnPtr<SQLTransactionErrorCallback> errorCallback,
+    PassOwnPtr<SQLVoidCallback> successCallback, bool readOnly, const ChangeVersionData* changeVersionData)
 {
-    RefPtr<SQLTransactionErrorCallback> anotherRefToErrorCallback = errorCallback;
-    RefPtr<SQLTransaction> transaction = SQLTransaction::create(this, callback, successCallback, anotherRefToErrorCallback, readOnly);
-
+    RefPtr<SQLTransaction> transaction = SQLTransaction::create(this, callback, successCallback, errorCallback, 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");
-        executionContext()->postTask(createCallbackTask(&callTransactionErrorCallback, anotherRefToErrorCallback, error.release()));
+    transactionBackend = backend()->runTransaction(transaction, readOnly, changeVersionData);

[abarth-chromium, 2013/12/04 01:55:50]

Combine this line with the previous one?

[adamk, 2013/12/04 02:08:26]

Done.

+    if (!transactionBackend) {
+        if (OwnPtr<SQLTransactionErrorCallback> callback = transaction->releaseErrorCallback()) {

[abarth-chromium, 2013/12/04 01:55:50]

Will this always be non-zero if errorCallback was non-zero to start with?  That
was true in the old world.  Can we add an ASSERT to that effect?

[adamk, 2013/12/04 02:08:26]

Added an ASSERT, but it's ugly. Also added a FIXME; I think this whole function
should probably live in DatabaseBackend, but I can't figure out what that class
is even for (it's actually |this|).

+            RefPtr<SQLError> error = SQLError::create(SQLError::UNKNOWN_ERR, "database has been closed");
+            executionContext()->postTask(createCallbackTask(&callTransactionErrorCallback, callback.release(), error.release()));
+        }
     }
 }
 
 class DeliverPendingCallbackTask : public ExecutionContextTask {
 public:
     static PassOwnPtr<DeliverPendingCallbackTask> create(PassRefPtr<SQLTransaction> transaction)
     {
         return adoptPtr(new DeliverPendingCallbackTask(transaction));
     }
 
@@ skipping 75 matching lines @@
     backend()->reportStartTransactionResult(errorSite, webSqlErrorCode, sqliteErrorCode);
 }
 
 void Database::reportCommitTransactionResult(int errorSite, int webSqlErrorCode, int sqliteErrorCode)
 {
     backend()->reportCommitTransactionResult(errorSite, webSqlErrorCode, sqliteErrorCode);
 }
 
 
 } // namespace WebCore