Convert LCStoreDB to using startAtomic/endAtomic

* This avoids throwing atomic section errors when recache()
  is triggered in the middle of transactions.
* Also made the read-only checks handle $wgReadOnly mode.

Change-Id: Ie00cf8454656a6dc3b1862475a959b2af3b472f0

diff --git a/includes/cache/LocalisationCache.php b/includes/cache/LocalisationCache.php
index 03841d6..fad8ee8 100644 (file)
--- a/includes/cache/LocalisationCache.php
+++ b/includes/cache/LocalisationCache.php
@@ -1147,29 +1147,32 @@ interface LCStore {
  * This will work on any MediaWiki installation.
  */
 class LCStoreDB implements LCStore {
+       /** @var string */
        private $currentLang;
+       /** @var bool */
        private $writesDone = false;
-
-       /** @var DatabaseBase */
+       /** @var IDatabase */
        private $dbw;
        /** @var array */
        private $batch = array();
-
+       /** @var bool */
        private $readOnly = false;
 
        public function get( $code, $key ) {
-               if ( $this->writesDone ) {
-                       $db = wfGetDB( DB_MASTER );
+               if ( $this->writesDone && $this->dbw ) {
+                       $db = $this->dbw; // see the changes in finishWrite()
                } else {
                        $db = wfGetDB( DB_SLAVE );
                }
-               $row = $db->selectRow( 'l10n_cache', array( 'lc_value' ),
-                       array( 'lc_lang' => $code, 'lc_key' => $key ), __METHOD__ );
-               if ( $row ) {
-                       return unserialize( $db->decodeBlob( $row->lc_value ) );
-               } else {
-                       return null;
-               }
+
+               $value = $db->selectField(
+                       'l10n_cache',
+                       'lc_value',
+                       array( 'lc_lang' => $code, 'lc_key' => $key ),
+                       __METHOD__
+               );
+
+               return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
        }
 
        public function startWrite( $code ) {
@@ -1180,6 +1183,7 @@ class LCStoreDB implements LCStore {
                }
 
                $this->dbw = wfGetDB( DB_MASTER );
+               $this->readOnly = $this->dbw->isReadOnly();
 
                $this->currentLang = $code;
                $this->batch = array();
@@ -1192,10 +1196,13 @@ class LCStoreDB implements LCStore {
                        throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
                }
 
-               $this->dbw->begin( __METHOD__ );
+               $this->dbw->startAtomic( __METHOD__ );
                try {
-                       $this->dbw->delete( 'l10n_cache',
-                               array( 'lc_lang' => $this->currentLang ), __METHOD__ );
+                       $this->dbw->delete(
+                               'l10n_cache',
+                               array( 'lc_lang' => $this->currentLang ),
+                               __METHOD__
+                       );
                        foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
                                $this->dbw->insert( 'l10n_cache', $rows, __METHOD__ );
                        }
@@ -1207,7 +1214,7 @@ class LCStoreDB implements LCStore {
                                throw $e;
                        }
                }
-               $this->dbw->commit( __METHOD__ );
+               $this->dbw->endAtomic( __METHOD__ );
 
                $this->currentLang = null;
                $this->batch = array();
@@ -1223,7 +1230,8 @@ class LCStoreDB implements LCStore {
                $this->batch[] = array(
                        'lc_lang' => $this->currentLang,
                        'lc_key' => $key,
-                       'lc_value' => $this->dbw->encodeBlob( serialize( $value ) ) );
+                       'lc_value' => $this->dbw->encodeBlob( serialize( $value ) )
+               );
        }
 }