Merge webkit.org at R49305 : Automatic merge by git.

Change-Id: I8968561bc1bfd72b8923b7118d3728579c6dbcc7

1 files changed, 13 insertions, 2 deletions

diff --git a/WebCore/platform/sql/SQLiteTransaction.cpp b/WebCore/platform/sql/SQLiteTransaction.cpp
index 0a236be..a4b2ac8 100644
--- a/WebCore/platform/sql/SQLiteTransaction.cpp
+++ b/WebCore/platform/sql/SQLiteTransaction.cpp
@@ -30,9 +30,10 @@
 
 namespace WebCore {
 
-SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db)
+SQLiteTransaction::SQLiteTransaction(SQLiteDatabase& db, bool readOnly)
     : m_db(db)
     , m_inProgress(false)
+    , m_readOnly(readOnly)
 {
 }
 
@@ -46,7 +47,17 @@ void SQLiteTransaction::begin()
 {
     if (!m_inProgress) {
         ASSERT(!m_db.m_transactionInProgress);
-        m_inProgress = m_db.executeCommand("BEGIN;");
+        // 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.
+        // http://www.sqlite.org/lang_transaction.html
+        // http://www.sqlite.org/lockingv3.html#locking
+        if (m_readOnly)
+            m_inProgress = m_db.executeCommand("BEGIN;");
+        else
+            m_inProgress = m_db.executeCommand("BEGIN IMMEDIATE;");
         m_db.m_transactionInProgress = m_inProgress;
     }
 }