[SCM] WebKit Debian packaging branch, webkit-1.1, updated. upstream/1.1.15.1-1414-gc69ee75

[eric at webkit.org]

The following commit has been merged in the webkit-1.1 branch:
commit 6276bb1213ac110f6165ed59078d11c116dc1af5
Author: eric at webkit.org <eric at webkit.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Date:   Tue Sep 29 20:05:11 2009 +0000

    2009-09-29  Dumitru Daniliuc  <dumi at chromium.org>
    
            Reviewed by Dimitri Glazkov.
    
            Starting all read-only transactions with an explicit BEGIN
            DEFERRED command instead of BEGIN, since some ports (chromium)
            might compile their own SQLite library and set BEGIN to BEGIN
            IMMEDIATE by default; which would result in a deadlock in case of
            two concurrent read-only transactions on the same DB, and would
            unnecessarily delay other potential transactions to the same DB.
    
            https://bugs.webkit.org/show_bug.cgi?id=29729
    
            * platform/sql/SQLiteTransaction.cpp:
            (WebCore::SQLiteTransaction::begin):
    
    git-svn-id: http://svn.webkit.org/repository/webkit/trunk@48894 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/WebCore/ChangeLog b/WebCore/ChangeLog
index 3938c9f..925a8d9 100644
--- a/WebCore/ChangeLog
+++ b/WebCore/ChangeLog
@@ -1,3 +1,19 @@
+2009-09-29  Dumitru Daniliuc  <dumi at chromium.org>
+
+        Reviewed by Dimitri Glazkov.
+
+        Starting all read-only transactions with an explicit BEGIN
+        DEFERRED command instead of BEGIN, since some ports (chromium)
+        might compile their own SQLite library and set BEGIN to BEGIN
+        IMMEDIATE by default; which would result in a deadlock in case of
+        two concurrent read-only transactions on the same DB, and would
+        unnecessarily delay other potential transactions to the same DB.
+
+        https://bugs.webkit.org/show_bug.cgi?id=29729
+
+        * platform/sql/SQLiteTransaction.cpp:
+        (WebCore::SQLiteTransaction::begin):
+
 2009-09-29  Kenneth Russell  <kbr at google.com>
 
         Reviewed by Dimitri Glazkov.
diff --git a/WebCore/platform/sql/SQLiteTransaction.cpp b/WebCore/platform/sql/SQLiteTransaction.cpp
index a4b2ac8..e0a8ff9 100644
--- a/WebCore/platform/sql/SQLiteTransaction.cpp
+++ b/WebCore/platform/sql/SQLiteTransaction.cpp
@@ -47,15 +47,21 @@ void SQLiteTransaction::begin()
 {
     if (!m_inProgress) {
         ASSERT(!m_db.m_transactionInProgress);
-        // Call BEGIN IMMEDIATE for a write transaction to acquire
-        // a RESERVED lock on the DB file. Otherwise, another write
-        // transaction (on another connection) could make changes
-        // to the same DB file before this transaction gets to execute
-        // any statements. If that happens, this transaction will fail.
+        // For read-only transactions, call BEGIN DEFERRED explicitly.
+        // Otherwise, a port might use a SQLite library that was build
+        // to interpret BEGIN as BEGIN IMMEDIATE, which would lead to
+        // a deadlock whenever two read transactions on the same DB
+        // are scheduled concurrently.
+        // For write transactions, call BEGIN IMMEDIATE to acquire
+        // a RESERVED lock on the DB file before the transaction
+        // callback is executed. Otherwise, another write transaction
+        // (on another connection) could make changes to the same DB file
+        // before this transaction gets to execute any statements.
+        // If that happens, this transaction will fail.
         // http://www.sqlite.org/lang_transaction.html
         // http://www.sqlite.org/lockingv3.html#locking
         if (m_readOnly)
-            m_inProgress = m_db.executeCommand("BEGIN;");
+            m_inProgress = m_db.executeCommand("BEGIN DEFERRED;");
         else
             m_inProgress = m_db.executeCommand("BEGIN IMMEDIATE;");
         m_db.m_transactionInProgress = m_inProgress;

-- 
WebKit Debian packaging