From 13cd29ea6263eeb1f7139504c34b662cb63a3e96 Mon Sep 17 00:00:00 2001
From: Roan Kattouw <roan.kattouw@gmail.com>
Date: Wed, 4 Sep 2013 13:14:02 -0700
Subject: [PATCH] Allow replace operations to replace metadata as well

This was already possible in the operation structure by using
removeMetadata and insertMetadata, but no transaction builders
generated transactions like that.

With this change, pushReplace() can be instructed to overwrite the
metadata with arbitrary data rather than collapsing it by passing the
optional insertMeta parameter.

Change-Id: I0272fe38e053161c738591cf0a7b447a0827d4dc
---
 modules/ve/dm/ve.dm.Transaction.js | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/modules/ve/dm/ve.dm.Transaction.js b/modules/ve/dm/ve.dm.Transaction.js
index 67191102d0..5db0fd1bf7 100644
--- a/modules/ve/dm/ve.dm.Transaction.js
+++ b/modules/ve/dm/ve.dm.Transaction.js
@@ -890,22 +890,24 @@ ve.dm.Transaction.prototype.addSafeRemoveOps = function ( doc, removeStart, remo
  * @param {number} offset Offset to start at
  * @param {number} removeLength Number of data items to remove
  * @param {Array} insert Data to insert
+ * @param {Array} [insertMetadata] Overwrite the metadata with this data, rather than collapsing it
  */
-ve.dm.Transaction.prototype.pushReplace = function ( doc, offset, removeLength, insert ) {
+ve.dm.Transaction.prototype.pushReplace = function ( doc, offset, removeLength, insert, insertMetadata ) {
 	if ( removeLength === 0 && insert.length === 0 ) {
 		// Don't push no-ops
 		return;
 	}
 
-	var op, end = this.operations.length - 1,
+	var op, extraMetadata, end = this.operations.length - 1,
 		lastOp = end >= 0 ? this.operations[end] : null,
 		penultOp = end >= 1 ? this.operations[ end - 1 ] : null,
 		range = new ve.Range( offset, offset + removeLength ),
 		remove = doc.getData( range ),
 		removeMetadata = doc.getMetadata( range ),
-		insertMetadata, extraMetadata;
+		isRemoveEmpty = ve.compare( removeMetadata, new Array( removeMetadata.length ) ),
+		isInsertEmpty = insertMetadata && ve.compare( insertMetadata, new Array( insertMetadata.length ) );
 
-	if ( !ve.compare( removeMetadata, new Array( removeMetadata.length ) ) ) {
+	if ( !insertMetadata && !isRemoveEmpty ) {
 		// if we are removing a range which includes metadata, we need to
 		// collapse it.  If there's nothing to insert, we also need to add
 		// an extra `replaceMetadata` operation later in order to insert the
@@ -918,6 +920,9 @@ ve.dm.Transaction.prototype.pushReplace = function ( doc, offset, removeLength,
 			// pad out at end so insert metadata is the same length as insert data
 			ve.batchSplice( insertMetadata, 1, 0, new Array( insert.length - 1 ) );
 		}
+	} else if ( isInsertEmpty && isRemoveEmpty ) {
+		// No metadata changes, don't pollute the transaction with [undefined, undefined, ...]
+		insertMetadata = undefined;
 	}
 
 	// simple replaces can be combined