prelim gc

src/Struct/Delete.js

@@ -13,18 +13,18 @@ export function deleteItemRange (y, user, clock, range) {
   if (item !== null) {
     if (!item._deleted) {
       item._splitAt(y, range)
-      item._delete(y, createDelete)
+      item._delete(y, createDelete, true)
     }
     let itemLen = item._length
     range -= itemLen
     clock += itemLen
     if (range > 0) {
       let node = y.os.findNode(new ID(user, clock))
-      while (node !== null && range > 0 && node.val._id.equals(new ID(user, clock))) {
+      while (node !== null && node.val !== null && range > 0 && node.val._id.equals(new ID(user, clock))) {
         const nodeVal = node.val
         if (!nodeVal._deleted) {
           nodeVal._splitAt(y, range)
-          nodeVal._delete(y, createDelete)
+          nodeVal._delete(y, createDelete, true)
         }
         const nodeLen = nodeVal._length
         range -= nodeLen

src/Struct/GC.js

@@ -0,0 +1,44 @@
+
+export default class GC {
+  constructor () {
+    this._id = null
+    this._length = 0
+  }
+
+  get _deleted () {
+    return true
+  }
+
+  integrate () {
+  }
+
+  /**
+   * Transform the properties of this type to binary and write it to an
+   * BinaryEncoder.
+   *
+   * This is called when this Item is sent to a remote peer.
+   *
+   * @param {BinaryEncoder} encoder The encoder to write data to.
+   * @private
+   */
+  _toBinary (encoder) {
+    encoder.writeUint8(getStructReference(this.constructor))
+    encoder.writeID(this._id)
+    encoder.writeVarUint(this._length)
+  }
+
+  /**
+   * Read the next Item in a Decoder and fill this Item with the read data.
+   *
+   * This is called when data is received from a remote peer.
+   *
+   * @param {Y} y The Yjs instance that this Item belongs to.
+   * @param {BinaryDecoder} decoder The decoder object to read data from.
+   * @private
+   */
+  _fromBinary (y, decoder) {
+    this._id = decoder.readID()
+    this._length = decoder.readVarUint()
+    return []
+  }  
+}

src/Struct/Item.js

@@ -3,6 +3,7 @@ import ID from '../Util/ID/ID.js'
 import { RootFakeUserID } from '../Util/ID/RootID.js'
 import Delete from './Delete.js'
 import { transactionTypeChanged } from '../Transaction.js'
+import GC from './GC.js'
 
 /**
  * @private
@@ -220,7 +221,7 @@ export default class Item {
   _delete (y, createDelete = true) {
     if (!this._deleted) {
       this._deleted = true
-      y.ds.markDeleted(this._id, this._length)
+      y.ds.mark(this._id, this._length, false)
       let del = new Delete()
       del._targetID = this._id
       del._length = this._length
@@ -236,6 +237,32 @@ export default class Item {
     }
   }
 
+  _gcChildren (y) {}
+  
+  _gc (y) {
+    y.ds.mark(this._id, this._length, true)
+    const gc = new GC()
+    gc._id = this._id
+    gc._length = this._length
+    y.os.delete(this._id)
+    let n = y.os.put(gc)
+    const prev = n.prev().val
+    if (prev !== null && prev.constructor === GC && prev._id.user === n.val._id.user && prev._id.clock + prev._length === n.val._id.clock) {
+      // TODO: do merging for all items!
+      prev._length += n.val._length
+      y.os.delete(n.val._id)
+      n = prev
+    }
+    if (n.val) {
+      n = n.val
+    }
+    const next = y.os.findNext(n._id)
+    if (next !== null && next.constructor === GC && next._id.user === n._id.user && next._id.clock === n._id.clock + n._length) {
+      n._length += next._length
+      y.os.delete(n._id)
+    }
+  }
+
   /**
    * This is called right before this Item receives any children.
    * It can be overwritten to apply pending changes before applying remote changes

src/Struct/Type.js

@@ -30,6 +30,14 @@ export function getListItemIDByPosition (type, i) {
   }
 }
 
+function gcChildren (y, item) {
+  while (item !== null) {
+    item._delete(y, false, true)
+    item._gc(y)
+    item = item._right
+  }
+}
+
 /**
  * Abstract Yjs Type class
  */
@@ -184,6 +192,20 @@ export default class Type extends Item {
     }
   }
 
+  _gcChildren (y) {
+    gcChildren(y, this._start)
+    this._start = null
+    this._map.forEach(item => {
+      gcChildren(y, item)
+    })
+    this._map = new Map()
+  }
+
+  _gc (y) {
+    this._gcChildren(y)
+    super._gc(y)
+  }
+
   /**
    * @private
    * Mark this Item as deleted.
@@ -192,22 +214,25 @@ export default class Type extends Item {
    * @param {boolean} createDelete Whether to propagate a message that this
    *                               Type was deleted.
    */
-  _delete (y, createDelete) {
+  _delete (y, createDelete, gcChildren = true) {
-    super._delete(y, createDelete)
+    super._delete(y, createDelete, gcChildren)
     y._transaction.changedTypes.delete(this)
     // delete map types
     for (let value of this._map.values()) {
       if (value instanceof Item && !value._deleted) {
-        value._delete(y, false)
+        value._delete(y, false, gcChildren)
       }
     }
     // delete array types
     let t = this._start
     while (t !== null) {
       if (!t._deleted) {
-        t._delete(y, false)
+        t._delete(y, false, gcChildren)
       }
       t = t._right
     }
+    if (gcChildren) {
+      this._gcChildren(y)
+    }
   }
 }

src/Types/YXml/YXmlFragment.js

@@ -126,8 +126,8 @@ export default class YXmlFragment extends YArray {
    *
    * @private
    */
-  _delete (y, createDelete) {
+  _delete (y, createDelete, gcChildren) {
-    super._delete(y, createDelete)
+    super._delete(y, createDelete, gcChildren)
   }
 
   /**

src/Types/YXml/YXmlText.js

@@ -36,7 +36,7 @@ export default class YXmlText extends YText {
    *
    * @private
    */
-  _delete (y, createDelete) {
+  _delete (y, createDelete, gcChildren) {
-    super._delete(y, createDelete)
+    super._delete(y, createDelete, gcChildren)
   }
 }

src/Util/structReferences.js

@@ -8,6 +8,7 @@ import ItemJSON from '../Struct/ItemJSON.js'
 import ItemString from '../Struct/ItemString.js'
 import ItemFormat from '../Struct/ItemFormat.js'
 import ItemEmbed from '../Struct/ItemEmbed.js'
+import GC from '../Struct/GC.js'
 
 const structs = new Map()
 const references = new Map()
@@ -54,3 +55,5 @@ registerStruct(6, YXmlFragment)
 registerStruct(7, YXmlElement)
 registerStruct(8, YXmlText)
 registerStruct(9, YXmlHook)
+
+registerStruct(12, GC)