Changeset 143282 in webkit

Timestamp:

Feb 18, 2013 5:55:58 PM (11 years ago)

Author:

mark.lam@apple.com

Message:

Small follow up to r143271: Fix SQLTransaction leak.
​https://bugs.webkit.org/show_bug.cgi?id=110052.

Reviewed by Geoffrey Garen.

Applied Geoff's suggestion nullify m_frontend sooner for greater
code clarity. Also added some comments about m_frontend.

No new tests.

• Modules/webdatabase/SQLTransactionBackend.cpp:

(WebCore::SQLTransactionBackend::doCleanup):

• Modules/webdatabase/SQLTransactionBackend.h:

(SQLTransactionBackend):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• Modules/webdatabase/SQLTransactionBackend.cpp (modified) (3 diffs)
• Modules/webdatabase/SQLTransactionBackend.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-02-18  Mark Lam  <mark.lam@apple.com>
+
+        Small follow up to r143271: Fix SQLTransaction leak.
+        https://bugs.webkit.org/show_bug.cgi?id=110052.
+
+        Reviewed by Geoffrey Garen.
+
+        Applied Geoff's suggestion nullify m_frontend sooner for greater
+        code clarity. Also added some comments about m_frontend.
+
+        No new tests.
+
+        * Modules/webdatabase/SQLTransactionBackend.cpp:
+        (WebCore::SQLTransactionBackend::doCleanup):
+        * Modules/webdatabase/SQLTransactionBackend.h:
+        (SQLTransactionBackend):
+
 2013-02-18  Geoffrey Garen  <ggaren@apple.com>
 

trunk/Source/WebCore/Modules/webdatabase/SQLTransactionBackend.cpp

@@ -243 +243 @@
 //     Note: there's a circular reference between the SQLTransaction front-end and
 //     back-end. This circular reference is established in the constructor of the
-//     SQLTransactionBackend. The circular reference will only be broken at the end
-//     of the transaction's clean up state i.e. when the transaction should no
-//     longer be in use thereafter.
+//     SQLTransactionBackend. The circular reference will be broken by calling
+//     doCleanup() to nullify m_frontend. This is done at the end of the transaction's
+//     clean up state (i.e. when the transaction should no longer be in use thereafter),
+//     or if the database was interrupted. See comments on "What happens if a transaction
+//     is interrupted?" below for details.
 //
 //     After scheduling the transaction with the DatabaseThread (DatabaseBackendAsync::scheduleTransaction()):
@@ -381 +383 @@
     if (!m_frontend)
         return;
+    m_frontend = 0; // Break the reference cycle. See comment about the life-cycle above.
 
     ASSERT(currentThread() == database()->databaseContext()->databaseThread()->getThreadID());
@@ -399 +402 @@
     if (m_lockAcquired)
         m_database->transactionCoordinator()->releaseLock(this);
-
-    // Now that we're done, break the reference cycle that keeps us alive.
-    // See comment about the life-cycle above.
-    m_frontend = 0;
 
     // Do some aggresive clean up here except for m_database.

trunk/Source/WebCore/Modules/webdatabase/SQLTransactionBackend.h

@@ -110 +110 @@
     void getNextStatement();
 
-    RefPtr<SQLTransaction> m_frontend;
+    RefPtr<SQLTransaction> m_frontend; // Has a reference cycle, and will break in doCleanup().
     RefPtr<SQLStatementBackend> m_currentStatementBackend;