Divec has uploaded a new change for review.
https://gerrit.wikimedia.org/r/305438
Change subject: WIP: Function to rebase a transaction onto another
......................................................................
WIP: Function to rebase a transaction onto another
Change-Id: I2c83056b24e45edb35aceb78f8bf066866e6563f
---
M src/dm/ve.dm.Transaction.js
1 file changed, 128 insertions(+), 0 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/VisualEditor/VisualEditor
refs/changes/38/305438/1
diff --git a/src/dm/ve.dm.Transaction.js b/src/dm/ve.dm.Transaction.js
index 1b510fc..2cc0f26 100644
--- a/src/dm/ve.dm.Transaction.js
+++ b/src/dm/ve.dm.Transaction.js
@@ -1535,3 +1535,131 @@
}
return offset;
};
+
+/**
+ * Rebase this to happen after other
+ *
+ * @param {other} Transaction that acts on the document in the same start
state as this
+ * @returns {other|null}
+ */
+ve.dm.Transaction.prototype.rebaseOnto( other ) {
+ var i, len, r, range, opEnd,
+ changedRanges = other.getChangedRanges(),
+ // changedRange pointer
+ r = 0,
+ // cumulative range length diff
+ diff = 0,
+ tx = this.clone();
+
+ opLoop:
+ for ( i = 0, len = tx.operations.length; i < len; i++ ) {
+ op = tx.operations[ i ];
+ while ( true ) {
+ if ( r >= changedRanges.length ) {
+ op.start += diff;
+ continue opLoop;
+ }
+ range = changedRanges[ r ];
+ if ( range.end < op.start ) {
+ diff += range.diff;
+ r++;
+ continue;
+ }
+ break;
+ }
+ // Else op.start <= range.end
+
+ opEnd = ( op.type === 'replace' ? op.remove : op.type ===
'retain' ? op.length : 1 );
+ if ( opEnd < range.start ) {
+ op.start += diff;
+ continue;
+ }
+ // Else [ range.start, range.end ] overlaps with [ op.start,
op.end ]
+
+ if ( op.type === 'retain' && op.start <= range.start && opEnd
>= range.end ) {
+ op.start += diff;
+ op.length += range.diff;
+ }
+
+ // Else conflict
+ debugger;
+ console.log( 'Conflict:', [ range.start, range.end ], [
op.start, opEnd ] );
+ return null;
+ }
+ return tx;
+};
+
+
+/**
+ * @returns {Object[]} List of { start: x, end: x, diff: x } sorted by start
+ */
+ve.dm.Transaction.prototype.getChangedRanges = function () {
+ var i, len, op,
+ // List of { start: x, end: x, diff: x }
+ changedRanges = [],
+ // Number of annotation changes in force
+ annotating = 0,
+ // Data pointer
+ d = 0,
+ // Cumulative range length diff
+ diff = 0,
+ // Data pointer at the start of this run of annotation changes
+ annStart = null,
+ // Length diff at the start of this run of annotation changes
+ annStartDiff = null;
+
+ for ( i = 0, len = this.operations.length; i < len; i++ ) {
+ op = this.operations[ i ];
+ if ( op.type === 'retain' ) {
+ d += op.length;
+ } else if ( op.type === 'replaceMetadata' ) {
+ // Mark the current item as modified
+ if ( !annotating ) {
+ changedRanges.push( {
+ start: d,
+ end: d + 1,
+ diff: 0
+ } );
+ }
+ } else if ( op.type === 'replace' ) {
+ if ( !annotating ) {
+ changedRanges.push( {
+ start: d,
+ end: d + op.remove.length,
+ diff: op.insert.length -
op.remove.length
+ } );
+ }
+ d += op.remove.length;
+ diff += op.insert.length - op.remove.length;
+ } else if ( op.type === 'attribute' ) {
+ if ( !annotating ) {
+ changedRanges.push( {
+ start: d,
+ end: d + 1,
+ diff: 0
+ } );
+ }
+ } else if ( op.type === 'annotate' && ob.bias === 'start' ) {
+ if ( !annotating ) {
+ annStart = d;
+ annStartDiff = diff;
+ }
+ annotating++;
+ } else if ( op.type === 'annotate' && ob.bias === 'stop' ) {
+ annotating--;
+ if ( !annotating ) {
+ changedRanges.push( {
+ start: annStart,
+ end: d,
+ diff: diff - annStartDiff
+ } );
+ annStart = null;
+ annStartDiff = null;
+ }
+ } else {
+ debugger;
+ throw new Error( 'Weird operator', op );
+ }
+ }
+ return changedRanges;
+};
--
To view, visit https://gerrit.wikimedia.org/r/305438
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I2c83056b24e45edb35aceb78f8bf066866e6563f
Gerrit-PatchSet: 1
Gerrit-Project: VisualEditor/VisualEditor
Gerrit-Branch: master
Gerrit-Owner: Divec <da...@troi.org>
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