fixed a condition where re-uploading a file that's already stashed causes breakage...

diff --git a/includes/upload/UploadStash.php b/includes/upload/UploadStash.php
index 9c526b4..66bf33f 100644 (file)
--- a/includes/upload/UploadStash.php
+++ b/includes/upload/UploadStash.php
@@ -238,6 +238,30 @@ class UploadStash {
                // insert the file metadata into the db.
                wfDebug( __METHOD__ . " inserting $stashPath under $key\n" );
                $dbw = $this->repo->getMasterDb();
+
+               // select happens on the master so this can all be in a transaction, which
+               // avoids a race condition that's likely with multiple people uploading from the same
+               // set of files
+               $dbw->begin();
+               // first, check to see if it's already there.
+               $row = $dbw->selectRow(
+                       'uploadstash',
+                       'us_user, us_timestamp',
+                       array('us_key' => $key),
+                       __METHOD__
+               );
+               
+               // The current user can't have this key if:
+               // - the key is owned by someone else and
+               // - the age of the key is less than REPO_AGE
+               if( is_object( $row ) ) {
+                       if( $row->us_user != $this->userId &&
+                               $row->wfTimestamp( TS_UNIX, $row->us_timestamp ) > time() - UploadStash::REPO_AGE * 3600
+                       ) {
+                               $dbw->rollback();
+                               throw new UploadStashWrongOwnerException( "Attempting to upload a duplicate of a file that someone else has stashed" );
+                       }
+               }
                
                $this->fileMetadata[$key] = array(
                        'us_user' => $this->userId,
@@ -255,13 +279,15 @@ class UploadStash {
                        'us_timestamp' => $dbw->timestamp(),
                        'us_status' => 'finished'
                );
-                               
-
-               $dbw->insert(
+               
+               // if a row exists but previous checks on it passed, let the current user take over this key.   
+               $dbw->replace(
                        'uploadstash',
+                       'us_key',
                        $this->fileMetadata[$key],
                        __METHOD__      
                );
+               $dbw->commit();
 
                // store the insertid in the class variable so immediate retrieval (possibly laggy) isn't necesary.
                $this->fileMetadata[$key]['us_id'] = $dbw->insertId();