import {
readID,
createID,
writeID,
GC,
nextID,
AbstractStructRef,
AbstractStruct,
replaceStruct,
addStruct,
addToDeleteSet,
ItemDeleted,
findRootTypeKey,
compareIDs,
getItem,
getItemType,
getItemCleanEnd,
getItemCleanStart,
YEvent, StructStore, ID, AbstractType, Y, Transaction // eslint-disable-line
} from '../internals.js'
import * as error from 'lib0/error.js'
import * as encoding from 'lib0/encoding.js'
import * as decoding from 'lib0/decoding.js'
import * as maplib from 'lib0/map.js'
import * as set from 'lib0/set.js'
import * as binary from 'lib0/binary.js'
/**
* Split leftItem into two items
* @param {Transaction} transaction
* @param {AbstractItem} leftItem
* @param {number} diff
* @return {AbstractItem}
*
* @function
* @private
*/
export const splitItem = (transaction, leftItem, diff) => {
const id = leftItem.id
// create rightItem
const rightItem = leftItem.copy(
createID(id.client, id.clock + diff),
leftItem,
createID(id.client, id.clock + diff - 1),
leftItem.right,
leftItem.rightOrigin,
leftItem.parent,
leftItem.parentSub
)
if (leftItem.deleted) {
rightItem.deleted = true
}
// update left (do not set leftItem.rightOrigin as it will lead to problems when syncing)
leftItem.right = rightItem
// update right
if (rightItem.right !== null) {
rightItem.right.left = rightItem
}
// right is more specific.
transaction._mergeStructs.add(rightItem.id)
return rightItem
}
/**
* Abstract class that represents any content.
*/
export class AbstractItem extends AbstractStruct {
/**
* @param {ID} id
* @param {AbstractItem | null} left
* @param {ID | null} origin
* @param {AbstractItem | null} right
* @param {ID | null} rightOrigin
* @param {AbstractType<any>} parent
* @param {string | null} parentSub
*/
constructor (id, left, origin, right, rightOrigin, parent, parentSub) {
super(id)
/**
* The item that was originally to the left of this item.
* @type {ID | null}
* @readonly
*/
this.origin = origin
/**
* The item that is currently to the left of this item.
* @type {AbstractItem | null}
*/
this.left = left
/**
* The item that is currently to the right of this item.
* @type {AbstractItem | null}
*/
this.right = right
/**
* The item that was originally to the right of this item.
* @readonly
* @type {ID | null}
*/
this.rightOrigin = rightOrigin
/**
* The parent type.
* @type {AbstractType<any>}
* @readonly
*/
this.parent = parent
/**
* If the parent refers to this item with some kind of key (e.g. YMap, the
* key is specified here. The key is then used to refer to the list in which
* to insert this item. If `parentSub = null` type._start is the list in
* which to insert to. Otherwise it is `parent._map`.
* @type {String | null}
* @readonly
*/
this.parentSub = parentSub
/**
* Whether this item was deleted or not.
* @type {Boolean}
*/
this.deleted = false
/**
* If this type's effect is reundone this type refers to the type that undid
* this operation.
* @type {AbstractItem | null}
*/
this.redone = null
}
/**
* @param {Transaction} transaction
* @private
*/
integrate (transaction) {
const store = transaction.y.store
const id = this.id
const parent = this.parent
const parentSub = this.parentSub
const length = this.length
/**
* @type {AbstractItem|null}
*/
let o
// set o to the first conflicting item
if (this.left !== null) {
o = this.left.right
} else if (parentSub !== null) {
o = parent._map.get(parentSub) || null
while (o !== null && o.left !== null) {
o = o.left
}
} else {
o = parent._start
}
// TODO: use something like DeleteSet here (a tree implementation would be best)
/**
* @type {Set<AbstractItem>}
*/
const conflictingItems = new Set()
/**
* @type {Set<AbstractItem>}
*/
const itemsBeforeOrigin = new Set()
// Let c in conflictingItems, b in itemsBeforeOrigin
// ***{origin}bbbb{this}{c,b}{c,b}{o}***
// Note that conflictingItems is a subset of itemsBeforeOrigin
while (o !== null && o !== this.right) {
itemsBeforeOrigin.add(o)
conflictingItems.add(o)
if (compareIDs(this.origin, o.origin)) {
// case 1
if (o.id.client < id.client) {
this.left = o
conflictingItems.clear()
}
} else if (o.origin !== null && itemsBeforeOrigin.has(getItem(store, o.origin))) {
// case 2
if (o.origin === null || !conflictingItems.has(getItem(store, o.origin))) {
this.left = o
conflictingItems.clear()
}
} else {
break
}
o = o.right
}
// reconnect left/right + update parent map/start if necessary
if (this.left !== null) {
const right = this.left.right
this.right = right
this.left.right = this
} else {
let r
if (parentSub !== null) {
r = parent._map.get(parentSub) || null
while (r !== null && r.left !== null) {
r = r.left
}
} else {
r = parent._start
parent._start = this
}
this.right = r
}
if (this.right !== null) {
this.right.left = this
} else if (parentSub !== null) {
// set as current parent value if right === null and this is parentSub
parent._map.set(parentSub, this)
if (this.left !== null) {
// this is the current attribute value of parent. delete right
this.left.delete(transaction)
}
}
// adjust length of parent
if (parentSub === null && this.countable && !this.deleted) {
parent._length += length
}
addStruct(store, this)
maplib.setIfUndefined(transaction.changed, parent, set.create).add(parentSub)
// @ts-ignore
if ((parent._item !== null && parent._item.deleted) || (this.right !== null && parentSub !== null)) {
// delete if parent is deleted or if this is not the current attribute value of parent
this.delete(transaction)
}
}
/**
* Returns the next non-deleted item
* @private
*/
get next () {
let n = this.right
while (n !== null && n.deleted) {
n = n.right
}
return n
}
/**
* Returns the previous non-deleted item
* @private
*/
get prev () {
let n = this.left
while (n !== null && n.deleted) {
n = n.left
}
return n
}
/**
* Creates an Item with the same effect as this Item (without position effect)
*
* @param {ID} id
* @param {AbstractItem | null} left
* @param {ID | null} origin
* @param {AbstractItem | null} right
* @param {ID | null} rightOrigin
* @param {AbstractType<any>} parent
* @param {string | null} parentSub
* @return {AbstractItem}
*
* @private
*/
copy (id, left, origin, right, rightOrigin, parent, parentSub) {
throw new Error('unimplemented')
}
/**
* Redoes the effect of this operation.
*
* @param {Transaction} transaction The Yjs instance.
* @param {Set<AbstractItem>} redoitems
*
* @private
*/
redo (transaction, redoitems) {
if (this.redone !== null) {
return this.redone
}
/**
* @type {any}
*/
let parent = this.parent
if (parent === null) {
return
}
let left, right
if (this.parentSub === null) {
// Is an array item. Insert at the old position
left = this.left
right = this
} else {
// Is a map item. Insert as current value
left = parent.type._map.get(this.parentSub)
right = null
}
// make sure that parent is redone
if (parent._deleted === true && parent.redone === null) {
// try to undo parent if it will be undone anyway
if (!redoitems.has(parent) || !parent.redo(transaction, redoitems)) {
return false
}
}
if (parent.redone !== null) {
while (parent.redone !== null) {
parent = parent.redone
}
// find next cloned_redo items
while (left !== null) {
if (left.redone !== null && left.redone.parent === parent) {
left = left.redone
break
}
left = left.left
}
while (right !== null) {
if (right.redone !== null && right.redone.parent === parent) {
right = right.redone
}
right = right.right
}
}
this.redone = this.copy(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, this.parentSub)
this.redone.integrate(transaction)
return true
}
/**
* Computes the last content address of this Item.
*/
get lastId () {
return createID(this.id.client, this.id.clock + this.length - 1)
}
/**
* Computes the length of this Item.
*/
get length () {
return 1
}
/**
* Should return false if this Item is some kind of meta information
* (e.g. format information).
*
* * Whether this Item should be addressable via `yarray.get(i)`
* * Whether this Item should be counted when computing yarray.length
*/
get countable () {
return true
}
/**
* Do not call directly. Always split via StructStore!
*
* Splits this Item so that another Item can be inserted in-between.
* This must be overwritten if _length > 1
* Returns right part after split
*
* (see {@link ItemJSON}/{@link ItemString} for implementation)
*
* Does not integrate the struct, nor store it in struct store.
*
* This method should only be cally by StructStore.
*
* @param {Transaction} transaction
* @param {number} diff
* @return {AbstractItem}
*
* @private
*/
splitAt (transaction, diff) {
throw new Error('unimplemented')
}
/**
* @param {AbstractItem} right
* @return {boolean}
*
* @private
*/
mergeWith (right) {
if (compareIDs(right.origin, this.lastId) && this.right === right && compareIDs(this.rightOrigin, right.rightOrigin)) {
this.right = right.right
if (this.right !== null) {
this.right.left = this
}
return true
}
return false
}
/**
* Mark this Item as deleted.
*
* @param {Transaction} transaction
*/
delete (transaction) {
if (!this.deleted) {
const parent = this.parent
// adjust the length of parent
if (this.countable && this.parentSub === null) {
parent._length -= this.length
}
this.deleted = true
addToDeleteSet(transaction.deleteSet, this.id, this.length)
maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
}
}
/**
* @param {Transaction} transaction
* @param {StructStore} store
*
* @private
*/
gcChildren (transaction, store) { }
/**
* @param {Transaction} transaction
* @param {StructStore} store
*
* @private
*/
gc (transaction, store) {
let r
if (this.parent._item !== null && this.parent._item.deleted) {
r = new GC(this.id, this.length)
} else {
r = new ItemDeleted(this.id, this.left, this.origin, this.right, this.rightOrigin, this.parent, this.parentSub, this.length)
if (r.right !== null) {
r.right.left = r
} else if (r.parentSub !== null) {
r.parent._map.set(r.parentSub, r)
}
if (r.left !== null) {
r.left.right = r
} else if (r.parentSub === null) {
r.parent._start = r
}
}
replaceStruct(store, this, r)
transaction._mergeStructs.add(r.id)
}
/**
* @return {Array<any>}
*/
getContent () {
throw error.methodUnimplemented()
}
/**
* 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 {encoding.Encoder} encoder The encoder to write data to.
* @param {number} offset
* @param {number} encodingRef
*
* @private
*/
write (encoder, offset, encodingRef) {
const origin = offset > 0 ? createID(this.id.client, this.id.clock + offset - 1) : this.origin
const rightOrigin = this.rightOrigin
const parentSub = this.parentSub
const info = (encodingRef & binary.BITS5) |
(origin === null ? 0 : binary.BIT8) | // origin is defined
(rightOrigin === null ? 0 : binary.BIT7) | // right origin is defined
(parentSub === null ? 0 : binary.BIT6) // parentSub is non-null
encoding.writeUint8(encoder, info)
if (origin !== null) {
writeID(encoder, origin)
}
if (rightOrigin !== null) {
writeID(encoder, rightOrigin)
}
if (origin === null && rightOrigin === null) {
const parent = this.parent
if (parent._item === null) {
// parent type on y._map
// find the correct key
// @ts-ignore we know that y exists
const ykey = findRootTypeKey(parent)
encoding.writeVarUint(encoder, 1) // write parentYKey
encoding.writeVarString(encoder, ykey)
} else {
encoding.writeVarUint(encoder, 0) // write parent id
// @ts-ignore _item is defined because parent is integrated
writeID(encoder, parent._item.id)
}
if (parentSub !== null) {
encoding.writeVarString(encoder, parentSub)
}
}
}
}
/**
* @private
*/
export class AbstractItemRef extends AbstractStructRef {
/**
* @param {decoding.Decoder} decoder
* @param {ID} id
* @param {number} info
*/
constructor (decoder, id, info) {
super(id)
/**
* The item that was originally to the left of this item.
* @type {ID | null}
*/
this.left = (info & binary.BIT8) === binary.BIT8 ? readID(decoder) : null
/**
* The item that was originally to the right of this item.
* @type {ID | null}
*/
this.right = (info & binary.BIT7) === binary.BIT7 ? readID(decoder) : null
const canCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
const hasParentYKey = canCopyParentInfo ? decoding.readVarUint(decoder) === 1 : false
/**
* If parent = null and neither left nor right are defined, then we know that `parent` is child of `y`
* and we read the next string as parentYKey.
* It indicates how we store/retrieve parent from `y.share`
* @type {string|null}
*/
this.parentYKey = canCopyParentInfo && hasParentYKey ? decoding.readVarString(decoder) : null
/**
* The parent type.
* @type {ID | null}
*/
this.parent = canCopyParentInfo && !hasParentYKey ? readID(decoder) : null
/**
* If the parent refers to this item with some kind of key (e.g. YMap, the
* key is specified here. The key is then used to refer to the list in which
* to insert this item. If `parentSub = null` type._start is the list in
* which to insert to. Otherwise it is `parent._map`.
* @type {String | null}
*/
this.parentSub = canCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoding.readVarString(decoder) : null
const missing = this._missing
if (this.left !== null) {
missing.push(this.left)
}
if (this.right !== null) {
missing.push(this.right)
}
if (this.parent !== null) {
missing.push(this.parent)
}
}
}
/**
* @param {AbstractItemRef} item
* @param {number} offset
*
* @function
* @private
*/
export const changeItemRefOffset = (item, offset) => {
item.id = createID(item.id.client, item.id.clock + offset)
item.left = createID(item.id.client, item.id.clock - 1)
}
export class ItemParams {
/**
* @param {AbstractItem?} left
* @param {AbstractItem?} right
* @param {AbstractType<YEvent>?} parent
* @param {string|null} parentSub
*/
constructor (left, right, parent, parentSub) {
this.left = left
this.right = right
this.parent = parent
this.parentSub = parentSub
}
}
/**
* Outsourcing some of the logic of computing the item params from a received struct.
* If parent === null, it is expected to gc the read struct. Otherwise apply it.
*
* @param {Transaction} transaction
* @param {StructStore} store
* @param {ID|null} leftid
* @param {ID|null} rightid
* @param {ID|null} parentid
* @param {string|null} parentSub
* @param {string|null} parentYKey
* @return {ItemParams}
*
* @private
* @function
*/
export const computeItemParams = (transaction, store, leftid, rightid, parentid, parentSub, parentYKey) => {
const left = leftid === null ? null : getItemCleanEnd(transaction, store, leftid)
const right = rightid === null ? null : getItemCleanStart(transaction, store, rightid)
let parent = null
if (parentid !== null) {
const parentItem = getItemType(store, parentid)
switch (parentItem.constructor) {
case ItemDeleted:
case GC:
break
default:
parent = parentItem.type
}
} else if (parentYKey !== null) {
parent = transaction.y.get(parentYKey)
} else if (left !== null) {
if (left.constructor !== GC) {
parent = left.parent
parentSub = left.parentSub
}
} else if (right !== null) {
if (right.constructor !== GC) {
parent = right.parent
parentSub = right.parentSub
}
} else {
throw error.unexpectedCase()
}
return new ItemParams(left, right, parent, parentSub)
}