quotations: fix splitting quoted item and inserting new item in quoted range

src/structs/Item.js

@@ -24,7 +24,8 @@ import {
   addChangedTypeToTransaction,
   isDeleted,
   StackItem, DeleteSet, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction, // eslint-disable-line
-  YWeakLink
+  YWeakLink,
+  joinLinkedRange
 } from '../internals.js'
 
 import * as error from 'lib0/error'
@@ -106,6 +107,14 @@ export const splitItem = (transaction, leftItem, diff) => {
   if (leftItem.redone !== null) {
     rightItem.redone = createID(leftItem.redone.client, leftItem.redone.clock + diff)
   }
+  if (leftItem.linked) {
+    rightItem.linked = true
+    const allLinks = transaction.doc.store.linkedBy
+    const linkedBy = allLinks.get(leftItem)
+    if (linkedBy !== undefined) {
+      allLinks.set(rightItem, new Set(linkedBy))
+    }
+  }
   // update left (do not set leftItem.rightOrigin as it will lead to problems when syncing)
   leftItem.right = rightItem
   // update right
@@ -554,9 +563,15 @@ export class Item extends AbstractStruct {
           this.left.delete(transaction)
         }
       }
-      // adjust length of parent
-      if (this.parentSub === null && this.countable && !this.deleted) {
-        /** @type {AbstractType<any>} */ (this.parent)._length += this.length
+      if (this.parentSub === null && !this.deleted) {
+        if (this.countable) {
+          // adjust length of parent
+          /** @type {AbstractType<any>} */ (this.parent)._length += this.length
+        }
+        if (this.left && this.left.linked && this.right && this.right.linked) {
+          // this item exists within a quoted range
+          joinLinkedRange(transaction, this)
+        }
       }
       addStruct(transaction.doc.store, this)
       this.content.integrate(transaction, this)

src/types/YArray.js

@@ -212,7 +212,7 @@ export class YArray extends AbstractType {
    * @param {number} length The number of elements to include in returned weak link reference.
    * @return {YWeakLink<T>}
    */
-  quote(index, length = 1) {
+  quote (index, length = 1) {
     if (this.doc !== null) {
       return transact(this.doc, transaction => {
         return arrayWeakLink(transaction, this, index, length)

src/types/YMap.js

@@ -241,7 +241,7 @@ export class YMap extends AbstractType {
    * @param {string} key 
    * @return {YWeakLink<MapType>|undefined}
    */
-  link(key) {
+  link (key) {
     return mapWeakLink(this, key)
   }
 

src/types/YText.js

@@ -27,12 +27,14 @@ import {
   typeMapGetAll,
   updateMarkerChanges,
   ContentType,
-  ArraySearchMarker, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ID, Doc, Item, Snapshot, Transaction // eslint-disable-line
+  ArraySearchMarker, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ID, Doc, Item, Snapshot, Transaction, // eslint-disable-line
+  quoteText
 } from '../internals.js'
 
 import * as object from 'lib0/object'
 import * as map from 'lib0/map'
 import * as error from 'lib0/error'
+import { WeakLink } from 'yjs'
 
 /**
  * @param {any} a
@@ -1155,6 +1157,31 @@ export class YText extends AbstractType {
     }
   }
 
+  /**
+   * Returns a WeakLink representing a dynamic quotation of a range of elements.
+   * 
+   * In case when quotation happens in a middle of formatting range, formatting
+   * attributes will be split into before|within|after eg. quoting fragment of 
+   * `<i>hello world</i>` could result in `<i>he</i>"<i>llo wo</i>"<i>rld</i>`
+   * where `"<i>llo wo</i>"` represents quoted range.
+   *
+   * @param {number} index The index where quoted range should start
+   * @param {number} length Number of quoted elements
+   * @return {WeakLink<string>}
+   *
+   * @public
+   */
+  quote (index, length) {
+    const y = this.doc
+    if (y !== null) {
+      return transact(y, transaction => {
+        const pos = findPosition(transaction, this, index)
+        return quoteText(transaction, this, pos, length)
+      })
+    }
+    throw new Error('cannot quote YText which has not been integrated into any Doc')    
+  }
+
   /**
    * Deletes text starting from an index.
    *

src/types/YWeakLink.js

@@ -11,7 +11,9 @@ import {
   YWeakLinkRefID,
   writeID,
   readID,
-  RelativePosition
+  RelativePosition,
+  ItemTextListPosition,
+  ContentString
 } from "../internals.js"
 
 /**
@@ -53,7 +55,7 @@ export class YWeakLink extends AbstractType {
    * 
    * @returns {boolean}
    */
-  isSingle() {
+  isSingle () {
     return this._quoteStart.item === this._quoteEnd.item
   }
   
@@ -62,7 +64,7 @@ export class YWeakLink extends AbstractType {
    * 
    * @return {T|undefined}
    */
-  deref() {
+  deref () {
     if (this._firstItem !== null) {
       let item = this._firstItem
       if (item.parentSub !== null) {
@@ -85,7 +87,7 @@ export class YWeakLink extends AbstractType {
    * 
    * @return {Array<any>}
    */
-  unqote() {
+  unqote () {
     let result = /** @type {Array<any>} */ ([])
     let item = this._firstItem
     const end = /** @type {ID} */ (this._quoteEnd.item)
@@ -182,6 +184,31 @@ export class YWeakLink extends AbstractType {
       writeID(encoder.restEncoder, /** @type {ID} */ (this._quoteEnd.item))
     }
   }
+
+  /**
+   * Returns the unformatted string representation of this quoted text range.
+   *
+   * @public
+   */
+  toString () {
+    let str = ''
+    /**
+     * @type {Item|null}
+     */
+    let n = this._firstItem
+    const end = /** @type {ID} */ (this._quoteEnd.item)
+    while (n !== null) {
+      if (!n.deleted && n.countable && n.content.constructor === ContentString) {
+        str += /** @type {ContentString} */ (n.content).str
+      }
+      const lastId = n.lastId
+      if (lastId.client === end.client && lastId.clock === end.clock) {
+        break;
+      }
+      n = n.right
+    }
+    return str
+  }
 }
 
   
@@ -259,6 +286,50 @@ export const arrayWeakLink = (transaction, parent, index, length = 1) => {
   throw invalidQuotedRange
 }
 
+/**
+ * Returns a {WeakLink} to an YMap element at given key.
+ * 
+ * @param {Transaction} transaction
+ * @param {AbstractType<any>} parent
+ * @param {ItemTextListPosition} pos
+ * @param {number} length
+ * @return {YWeakLink<string>}
+ */
+export const quoteText = (transaction, parent, pos, length) => {
+  if (pos.right !== null) {
+    const startItem = pos.right
+    const endIndex = pos.index + length
+    while (pos.index < endIndex) {
+      pos.forward()
+    }
+    if (pos.left !== null) {
+      let endItem = pos.left
+      if (pos.index > endIndex) {
+        const overflow = pos.index - endIndex
+        endItem = getItemCleanEnd(transaction, transaction.doc.store, createID(endItem.id.client, endItem.id.clock + endItem.length - overflow - 1))
+      }
+      const start = new RelativePosition(null, null, startItem.id, 0)
+      const end = new RelativePosition(null, null, endItem.lastId, -1)
+      const link = new YWeakLink(start, end, startItem)
+      if (parent.doc !== null) {
+        transact(parent.doc, (transaction) => {
+          const end = /** @type {ID} */ (link._quoteEnd.item)
+          for (let item = link._firstItem; item !== null; item = item = item.right) {
+            createLink(transaction, item, link)
+            const lastId = item.lastId
+            if (lastId.client === end.client && lastId.clock === end.clock) {
+              break;
+            }
+          }
+        })
+      }
+      return link
+    }
+  }
+  
+  throw invalidQuotedRange  
+}
+
 /**
  * Returns a {WeakLink} to an YMap element at given key.
  * 
@@ -319,4 +390,29 @@ export const unlinkFrom = (transaction, source, linkRef) => {
       }
     }
   }
+}
+
+/**
+ * Rebinds linkedBy links pointed between neighbours of a current item.
+ * This method expects that current item has both left and right neighbours.
+ * 
+ * @param {Transaction} transaction
+ * @param {Item} item
+ */
+export const joinLinkedRange = (transaction, item) => {
+  item.linked = true
+  const allLinks = transaction.doc.store.linkedBy
+  const leftLinks = allLinks.get(/** @type {Item} */ (item.left))
+  const rightLinks = allLinks.get(/** @type {Item} */ (item.right))
+  if (leftLinks && rightLinks) {
+    const common = new Set()
+    for (let link of leftLinks) {
+      if (rightLinks.has(link)) {
+        common.add(link)
+      }
+    }
+    if (common.size != 0) {
+      allLinks.set(item, common)
+    }
+  }
 }

tests/y-weak-links.tests.js

@@ -472,6 +472,75 @@ export const testDeepObserveArray = tc => { //FIXME
   t.compare(events.length, 1)
   t.compare(events[0].target, link)
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testDeepObserveNewElementWithinQuotedRange = tc => {
+  const { testConnector, users, array0, array1 } = init(tc, { users: 2 })
+  const m1 = new Y.Map()
+  const m3 = new Y.Map()
+  array0.insert(0, [1,m1,m3,2])
+  const link0 = array0.quote(1, 2)
+  array0.insert(0, [link0])
+
+  testConnector.flushAllMessages()
+
+  /**
+   * @type {Array<any>}
+   */
+  let e0 = []
+  link0.observeDeep((evts) => {
+    e0 = []
+    for (let e of evts) {
+      switch (e.constructor) {
+        case Y.YMapEvent:
+          e0.push({target: e.target, keys: e.keys})
+          break;
+        case Y.YWeakLinkEvent:
+          e0.push({target: e.target})
+          break;
+        default: throw new Error('unexpected event type ' + e.constructor)
+      }
+    }
+  })
+
+  const link1 = /** @type {Y.WeakLink<any>} */ (array1.get(0))
+  /**
+   * @type {Array<any>}
+   */
+  let e1 = []
+  link1.observeDeep((evts) => {
+    e1 = []
+    for (let e of evts) {
+      switch (e.constructor) {
+        case Y.YMapEvent:
+          e1.push({target: e.target, keys: e.keys})
+          break;
+        case Y.YWeakLinkEvent:
+          e1.push({target: e.target})
+          break;
+        default: throw new Error('unexpected event type ' + e.constructor)
+      }
+    }
+  })
+
+  const m20 = new Y.Map()
+  array0.insert(3, [m20])
+
+  m20.set('key', 'value')
+  t.compare(e0.length, 1)
+  t.compare(e0[0].target, m20)
+  t.compare(e0[0].keys, new Map([['key', {action:'add', oldValue: undefined}]]))
+
+  testConnector.flushAllMessages()
+
+  const m21 = array1.get(3)
+  t.compare(e1.length, 1)
+  t.compare(e1[0].target, m21)
+  t.compare(e1[0].keys, new Map([['key', {action:'add', oldValue: undefined}]]))
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -608,4 +677,56 @@ export const testRemoteMapUpdate = tc => {
   t.compare(link0.deref(), 3)
   t.compare(link1.deref(), 3)
   t.compare(link2.deref(), 3)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testTextBasic = tc => {
+  const { testConnector, text0, array0, text1 } = init(tc, { users: 2 })
+
+  text0.insert(0, 'abcd')
+  const link0 = text0.quote(1, 2)
+  t.compare(link0.toString(), 'bc')
+  text0.insert(2, 'ef')
+  t.compare(link0.toString(), 'befc')
+  text0.delete(3, 3)
+  t.compare(link0.toString(), 'be')
+  text0.insertEmbed(3, link0)
+  
+  testConnector.flushAllMessages()
+
+  const delta = text1.toDelta()
+  const { insert } = delta[1]
+  t.compare(insert.toString(), 'be')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+const testQuoteFormattedText = tc => {
+  const doc = new Y.Doc()
+  const text = /** @type {Y.XmlText} */ (doc.get('text', Y.XmlText))
+  const text2 = /** @type {Y.XmlText} */ (doc.get('text2', Y.XmlText))
+
+  text.insert(0, 'abcde')
+  text.format(1, 3, {i:true}) // 'a<i>bcd</i>e'
+  const l1 = text.quote(0, 2) // 'a<i>b</i>'
+  const l2 = text.quote(2, 1) // '<i>c</i>'
+  const l3 = text.quote(3, 2) // '<i>d</i>e'
+
+  t.compare(l1.toString(), 'a<i>b</i>')
+  t.compare(l2.toString(), '<i>c</i>')
+  t.compare(l3.toString(), '<i>d</i>e')
+
+  text2.insertEmbed(0, l1)
+  text2.insertEmbed(1, l2)
+  text2.insertEmbed(2, l3)
+
+  const delta = text2.toDelta()
+  t.compare(delta, [
+    {insert: l1},
+    {insert: l2},
+    {insert: l3},
+  ])
 }