fixed pos.rel cases

src/types/AbstractType.js

@@ -55,11 +55,19 @@ export const useSearchMarker = (tr, yarray, index, f) => {
     searchMarker.push(fsm)
   }
   const diff = fsm.index - index
+  // @todo create fresh marker if diff > index
   if (diff > 0) {
     fsm.backward(tr, diff)
   } else {
     fsm.forward(tr, -diff)
   }
+  // @todo remove this tests
+  const otherTesting = new ListIterator(yarray)
+  otherTesting.forward(tr, index)
+  if (otherTesting.nextItem !== fsm.nextItem || otherTesting.index !== fsm.index || otherTesting.reachedEnd !== fsm.reachedEnd) {
+    throw new Error('udtirane')
+  }
+
   const result = f(fsm)
   if (fsm.reachedEnd) {
     fsm.reachedEnd = false
@@ -93,7 +101,7 @@ export const useSearchMarker = (tr, yarray, index, f) => {
  * @param {Array<ListIterator>} searchMarker
  * @param {number} index
  * @param {number} len If insertion, len is positive. If deletion, len is negative.
- * @param {ListIterator} origSearchMarker Do not update this searchmarker because it is the one we used to manipulate.
+ * @param {ListIterator|null} origSearchMarker Do not update this searchmarker because it is the one we used to manipulate. @todo !=null for improved perf in ytext
  */
 export const updateMarkerChanges = (searchMarker, index, len, origSearchMarker) => {
   for (let i = searchMarker.length - 1; i >= 0; i--) {

src/types/YText.js

@@ -27,6 +27,7 @@ import {
   updateMarkerChanges,
   ContentType,
   useSearchMarker,
+  findIndexCleanStart,
   ListIterator, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ID, Doc, Item, Snapshot, Transaction // eslint-disable-line
 } from '../internals.js'
 
@@ -127,9 +128,27 @@ const findPosition = (transaction, parent, index) => {
   const currentAttributes = new Map()
   if (parent._searchMarker) {
     return useSearchMarker(transaction, parent, index, listIter => {
+      let left, right
+      if (listIter.rel > 0) {
+        // must exist because rel > 0
+        const nextItem = /** @type {Item} */ (listIter.nextItem)
+        if (listIter.rel === nextItem.length) {
+          left = nextItem
+          right = left.right
+        } else {
+          const structs = /** @type {Array<Item|GC>} */ (transaction.doc.store.clients.get(nextItem.id.client))
+          const after = /** @type {Item} */ (structs[findIndexCleanStart(transaction, structs, nextItem.id.clock + listIter.rel)])
+          listIter.nextItem = after
+          listIter.rel = 0
+          left = listIter.left
+          right = listIter.right
+        }
+      } else {
+        left = listIter.left
+        right = listIter.right
+      }
       // @todo this should simply split if .rel > 0
-      const pos = new ItemTextListPosition(listIter.left, listIter.right, listIter.index, currentAttributes)
-      return findNextPosition(transaction, pos, index - listIter.index + listIter.rel)
+      return new ItemTextListPosition(left, right, index, currentAttributes)
     })
   } else {
     const pos = new ItemTextListPosition(null, parent._start, 0, currentAttributes)
@@ -266,7 +285,7 @@ const insertText = (transaction, parent, currPos, text, attributes) => {
   const content = text.constructor === String ? new ContentString(/** @type {string} */ (text)) : (text instanceof AbstractType ? new ContentType(text) : new ContentEmbed(text))
   let { left, right, index } = currPos
   if (parent._searchMarker) {
-    updateMarkerChanges(transaction, parent._searchMarker, currPos.index, content.getLength())
+    updateMarkerChanges(parent._searchMarker, currPos.index, content.getLength(), null)
   }
   right = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, content)
   right.integrate(transaction, 0)
@@ -471,7 +490,7 @@ const deleteText = (transaction, currPos, length) => {
   }
   const parent = /** @type {AbstractType<any>} */ (/** @type {Item} */ (currPos.left || currPos.right).parent)
   if (parent._searchMarker) {
-    updateMarkerChanges(transaction, parent._searchMarker, currPos.index, -startLength + length)
+    updateMarkerChanges(parent._searchMarker, currPos.index, -startLength + length, null)
   }
   return currPos
 }

src/utils/ListIterator.js

@@ -162,13 +162,18 @@ export class ListIterator {
   /**
    * @param {Transaction} tr
    * @param {number} len
+   * @return {ListIterator}
    */
   backward (tr, len) {
     if (this.index - len < 0) {
       throw lengthExceeded
     }
-    let item = this.nextItem && this.nextItem.left
     this.index -= len
+    if (this.rel > len) {
+      this.rel -= len
+      return this
+    }
+    let item = this.nextItem && this.nextItem.left
     if (this.rel) {
       len -= this.rel
       this.rel = 0
@@ -177,8 +182,10 @@ export class ListIterator {
       if (item.countable && !item.deleted && item.moved === this.currMove) {
         len -= item.length
         if (len < 0) {
-          this.rel = item.length + len
+          this.rel = -len
           len = 0
+        }
+        if (len === 0) {
           break
         }
       } else if (item.content.constructor === ContentMove && item.moved === this.currMove) {
@@ -201,8 +208,7 @@ export class ListIterator {
       }
       item = item.left
     }
-    this.index -= len
-    this.nextItem = item && item.right
+    this.nextItem = item
     return this
   }
 

tests/testHelper.js

@@ -373,6 +373,29 @@ export const compare = users => {
     t.compare(Y.encodeStateVector(users[i]), Y.encodeStateVector(users[i + 1]))
     compareDS(Y.createDeleteSetFromStructStore(users[i].store), Y.createDeleteSetFromStructStore(users[i + 1].store))
     compareStructStores(users[i].store, users[i + 1].store)
+    // test list-iterator
+    {
+      const user = users[0]
+      user.transact(tr => {
+        const type = user.getArray('array')
+        Y.useSearchMarker(tr, type, type.length, walker => {
+          for (let i = type.length; i >= 0; i--) {
+            const otherWalker = new Y.ListIterator(type)
+            otherWalker.forward(tr, walker.index)
+            otherWalker.forward(tr, 0)
+            walker.forward(tr, 0)
+            t.assert(walker.index === i)
+            t.assert(walker.left === otherWalker.left)
+            t.assert(walker.right === otherWalker.right)
+            t.assert(walker.nextItem === otherWalker.nextItem)
+            t.assert(walker.reachedEnd === otherWalker.reachedEnd)
+            if (i > 0) {
+              walker.backward(tr, 1)
+            }
+          }
+        })
+      })
+    }
   }
   users.map(u => u.destroy())
 }