yjs/src/structs/Item.js
2024-01-21 11:27:12 +01:00

814 lines
24 KiB
JavaScript

import {
GC,
getState,
AbstractStruct,
replaceStruct,
addStruct,
addToDeleteSet,
findRootTypeKey,
compareIDs,
getItem,
getItemCleanEnd,
getItemCleanStart,
readContentDeleted,
readContentBinary,
readContentJSON,
readContentAny,
readContentString,
readContentEmbed,
readContentDoc,
createID,
readContentFormat,
readContentType,
addChangedTypeToTransaction,
isDeleted,
StackItem, DeleteSet, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
} from '../internals.js'
import * as error from 'lib0/error'
import * as binary from 'lib0/binary'
import * as array from 'lib0/array'
/**
* @todo This should return several items
*
* @param {StructStore} store
* @param {ID} id
* @return {{item:Item, diff:number}}
*/
export const followRedone = (store, id) => {
/**
* @type {ID|null}
*/
let nextID = id
let diff = 0
let item
do {
if (diff > 0) {
nextID = createID(nextID.client, nextID.clock + diff)
}
item = getItem(store, nextID)
diff = nextID.clock - item.id.clock
nextID = item.redone
} while (nextID !== null && item instanceof Item)
return {
item, diff
}
}
/**
* Make sure that neither item nor any of its parents is ever deleted.
*
* This property does not persist when storing it into a database or when
* sending it to other peers
*
* @param {Item|null} item
* @param {boolean} keep
*/
export const keepItem = (item, keep) => {
while (item !== null && item.keep !== keep) {
item.keep = keep
item = /** @type {AbstractType<any>} */ (item.parent)._item
}
}
/**
* Split leftItem into two items
* @param {Transaction} transaction
* @param {Item} leftItem
* @param {number} diff
* @return {Item}
*
* @function
* @private
*/
export const splitItem = (transaction, leftItem, diff) => {
// create rightItem
const { client, clock } = leftItem.id
const rightItem = new Item(
createID(client, clock + diff),
leftItem,
createID(client, clock + diff - 1),
leftItem.right,
leftItem.rightOrigin,
leftItem.parent,
leftItem.parentSub,
leftItem.content.splice(diff)
)
if (leftItem.deleted) {
rightItem.markDeleted()
}
if (leftItem.keep) {
rightItem.keep = true
}
if (leftItem.redone !== null) {
rightItem.redone = createID(leftItem.redone.client, leftItem.redone.clock + diff)
}
// 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.push(rightItem)
// update parent._map
if (rightItem.parentSub !== null && rightItem.right === null) {
/** @type {AbstractType<any>} */ (rightItem.parent)._map.set(rightItem.parentSub, rightItem)
}
leftItem.length = diff
return rightItem
}
/**
* @param {Array<StackItem>} stack
* @param {ID} id
*/
const isDeletedByUndoStack = (stack, id) => array.some(stack, /** @param {StackItem} s */ s => isDeleted(s.deletions, id))
/**
* Redoes the effect of this operation.
*
* @param {Transaction} transaction The Yjs instance.
* @param {Item} item
* @param {Set<Item>} redoitems
* @param {DeleteSet} itemsToDelete
* @param {boolean} ignoreRemoteMapChanges
* @param {import('../utils/UndoManager.js').UndoManager} um
*
* @return {Item|null}
*
* @private
*/
export const redoItem = (transaction, item, redoitems, itemsToDelete, ignoreRemoteMapChanges, um) => {
const doc = transaction.doc
const store = doc.store
const ownClientID = doc.clientID
const redone = item.redone
if (redone !== null) {
return getItemCleanStart(transaction, redone)
}
let parentItem = /** @type {AbstractType<any>} */ (item.parent)._item
/**
* @type {Item|null}
*/
let left = null
/**
* @type {Item|null}
*/
let right
// make sure that parent is redone
if (parentItem !== null && parentItem.deleted === true) {
// try to undo parent if it will be undone anyway
if (parentItem.redone === null && (!redoitems.has(parentItem) || redoItem(transaction, parentItem, redoitems, itemsToDelete, ignoreRemoteMapChanges, um) === null)) {
return null
}
while (parentItem.redone !== null) {
parentItem = getItemCleanStart(transaction, parentItem.redone)
}
}
const parentType = parentItem === null ? /** @type {AbstractType<any>} */ (item.parent) : /** @type {ContentType} */ (parentItem.content).type
if (item.parentSub === null) {
// Is an array item. Insert at the old position
left = item.left
right = item
// find next cloned_redo items
while (left !== null) {
/**
* @type {Item|null}
*/
let leftTrace = left
// trace redone until parent matches
while (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item !== parentItem) {
leftTrace = leftTrace.redone === null ? null : getItemCleanStart(transaction, leftTrace.redone)
}
if (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item === parentItem) {
left = leftTrace
break
}
left = left.left
}
while (right !== null) {
/**
* @type {Item|null}
*/
let rightTrace = right
// trace redone until parent matches
while (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item !== parentItem) {
rightTrace = rightTrace.redone === null ? null : getItemCleanStart(transaction, rightTrace.redone)
}
if (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item === parentItem) {
right = rightTrace
break
}
right = right.right
}
} else {
right = null
if (item.right && !ignoreRemoteMapChanges) {
left = item
// Iterate right while right is in itemsToDelete
// If it is intended to delete right while item is redone, we can expect that item should replace right.
while (left !== null && left.right !== null && (left.right.redone || isDeleted(itemsToDelete, left.right.id) || isDeletedByUndoStack(um.undoStack, left.right.id) || isDeletedByUndoStack(um.redoStack, left.right.id))) {
left = left.right
// follow redone
while (left.redone) left = getItemCleanStart(transaction, left.redone)
}
if (left && left.right !== null) {
// It is not possible to redo this item because it conflicts with a
// change from another client
return null
}
} else {
left = parentType._map.get(item.parentSub) || null
}
}
const nextClock = getState(store, ownClientID)
const nextId = createID(ownClientID, nextClock)
const redoneItem = new Item(
nextId,
left, left && left.lastId,
right, right && right.id,
parentType,
item.parentSub,
item.content.copy()
)
item.redone = nextId
keepItem(redoneItem, true)
redoneItem.integrate(transaction, 0)
return redoneItem
}
/**
* Abstract class that represents any content.
*/
export class Item extends AbstractStruct {
/**
* @param {ID} id
* @param {Item | null} left
* @param {ID | null} origin
* @param {Item | null} right
* @param {ID | null} rightOrigin
* @param {AbstractType<any>|ID|null} parent Is a type if integrated, is null if it is possible to copy parent from left or right, is ID before integration to search for it.
* @param {string | null} parentSub
* @param {AbstractContent} content
*/
constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
super(id, content.getLength())
/**
* The item that was originally to the left of this item.
* @type {ID | null}
*/
this.origin = origin
/**
* The item that is currently to the left of this item.
* @type {Item | null}
*/
this.left = left
/**
* The item that is currently to the right of this item.
* @type {Item | null}
*/
this.right = right
/**
* The item that was originally to the right of this item.
* @type {ID | null}
*/
this.rightOrigin = rightOrigin
/**
* @type {AbstractType<any>|ID|null}
*/
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}
*/
this.parentSub = parentSub
/**
* If this type's effect is redone this type refers to the type that undid
* this operation.
* @type {ID | null}
*/
this.redone = null
/**
* @type {AbstractContent}
*/
this.content = content
/**
* bit1: keep
* bit2: countable
* bit3: deleted
* bit4: mark - mark node as fast-search-marker
* @type {number} byte
*/
this.info = this.content.isCountable() ? binary.BIT2 : 0
}
/**
* This is used to mark the item as an indexed fast-search marker
*
* @type {boolean}
*/
set marker (isMarked) {
if (((this.info & binary.BIT4) > 0) !== isMarked) {
this.info ^= binary.BIT4
}
}
get marker () {
return (this.info & binary.BIT4) > 0
}
/**
* If true, do not garbage collect this Item.
*/
get keep () {
return (this.info & binary.BIT1) > 0
}
set keep (doKeep) {
if (this.keep !== doKeep) {
this.info ^= binary.BIT1
}
}
get countable () {
return (this.info & binary.BIT2) > 0
}
/**
* Whether this item was deleted or not.
* @type {Boolean}
*/
get deleted () {
return (this.info & binary.BIT3) > 0
}
set deleted (doDelete) {
if (this.deleted !== doDelete) {
this.info ^= binary.BIT3
}
}
markDeleted () {
this.info |= binary.BIT3
}
/**
* Return the creator clientID of the missing op or define missing items and return null.
*
* @param {Transaction} transaction
* @param {StructStore} store
* @return {null | number}
*/
getMissing (transaction, store) {
if (this.origin && this.origin.client !== this.id.client && this.origin.clock >= getState(store, this.origin.client)) {
return this.origin.client
}
if (this.rightOrigin && this.rightOrigin.client !== this.id.client && this.rightOrigin.clock >= getState(store, this.rightOrigin.client)) {
return this.rightOrigin.client
}
if (this.parent && this.parent.constructor === ID && this.id.client !== this.parent.client && this.parent.clock >= getState(store, this.parent.client)) {
return this.parent.client
}
// We have all missing ids, now find the items
if (this.origin) {
this.left = getItemCleanEnd(transaction, store, this.origin)
this.origin = this.left.lastId
}
if (this.rightOrigin) {
this.right = getItemCleanStart(transaction, this.rightOrigin)
this.rightOrigin = this.right.id
}
if ((this.left && this.left.constructor === GC) || (this.right && this.right.constructor === GC)) {
this.parent = null
} else if (!this.parent) {
// only set parent if this shouldn't be garbage collected
if (this.left && this.left.constructor === Item) {
this.parent = this.left.parent
this.parentSub = this.left.parentSub
}
if (this.right && this.right.constructor === Item) {
this.parent = this.right.parent
this.parentSub = this.right.parentSub
}
} else if (this.parent.constructor === ID) {
const parentItem = getItem(store, this.parent)
if (parentItem.constructor === GC) {
this.parent = null
} else {
this.parent = /** @type {ContentType} */ (parentItem.content).type
}
}
return null
}
/**
* @param {Transaction} transaction
* @param {number} offset
*/
integrate (transaction, offset) {
if (offset > 0) {
this.id.clock += offset
this.left = getItemCleanEnd(transaction, transaction.doc.store, createID(this.id.client, this.id.clock - 1))
this.origin = this.left.lastId
this.content = this.content.splice(offset)
this.length -= offset
}
if (this.parent) {
if ((!this.left && (!this.right || this.right.left !== null)) || (this.left && this.left.right !== this.right)) {
/**
* @type {Item|null}
*/
let left = this.left
/**
* @type {Item|null}
*/
let o
// set o to the first conflicting item
if (left !== null) {
o = left.right
} else if (this.parentSub !== null) {
o = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
while (o !== null && o.left !== null) {
o = o.left
}
} else {
o = /** @type {AbstractType<any>} */ (this.parent)._start
}
// TODO: use something like DeleteSet here (a tree implementation would be best)
// @todo use global set definitions
/**
* @type {Set<Item>}
*/
const conflictingItems = new Set()
/**
* @type {Set<Item>}
*/
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 < this.id.client) {
left = o
conflictingItems.clear()
} else if (compareIDs(this.rightOrigin, o.rightOrigin)) {
// this and o are conflicting and point to the same integration points. The id decides which item comes first.
// Since this is to the left of o, we can break here
break
} // else, o might be integrated before an item that this conflicts with. If so, we will find it in the next iterations
} else if (o.origin !== null && itemsBeforeOrigin.has(getItem(transaction.doc.store, o.origin))) { // use getItem instead of getItemCleanEnd because we don't want / need to split items.
// case 2
if (!conflictingItems.has(getItem(transaction.doc.store, o.origin))) {
left = o
conflictingItems.clear()
}
} else {
break
}
o = o.right
}
this.left = left
}
// 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 (this.parentSub !== null) {
r = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
while (r !== null && r.left !== null) {
r = r.left
}
} else {
r = /** @type {AbstractType<any>} */ (this.parent)._start
;/** @type {AbstractType<any>} */ (this.parent)._start = this
}
this.right = r
}
if (this.right !== null) {
this.right.left = this
} else if (this.parentSub !== null) {
// set as current parent value if right === null and this is parentSub
/** @type {AbstractType<any>} */ (this.parent)._map.set(this.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 (this.parentSub === null && this.countable && !this.deleted) {
/** @type {AbstractType<any>} */ (this.parent)._length += this.length
}
addStruct(transaction.doc.store, this)
this.content.integrate(transaction, this)
// add parent to transaction.changed
addChangedTypeToTransaction(transaction, /** @type {AbstractType<any>} */ (this.parent), this.parentSub)
if ((/** @type {AbstractType<any>} */ (this.parent)._item !== null && /** @type {AbstractType<any>} */ (this.parent)._item.deleted) || (this.parentSub !== null && this.right !== null)) {
// delete if parent is deleted or if this is not the current attribute value of parent
this.delete(transaction)
}
} else {
// parent is not defined. Integrate GC struct instead
new GC(this.id, this.length).integrate(transaction, 0)
}
}
/**
* Returns the next non-deleted item
*/
get next () {
let n = this.right
while (n !== null && n.deleted) {
n = n.right
}
return n
}
/**
* Returns the previous non-deleted item
*/
get prev () {
let n = this.left
while (n !== null && n.deleted) {
n = n.left
}
return n
}
/**
* Computes the last content address of this Item.
*/
get lastId () {
// allocating ids is pretty costly because of the amount of ids created, so we try to reuse whenever possible
return this.length === 1 ? this.id : createID(this.id.client, this.id.clock + this.length - 1)
}
/**
* Try to merge two items
*
* @param {Item} right
* @return {boolean}
*/
mergeWith (right) {
if (
this.constructor === right.constructor &&
compareIDs(right.origin, this.lastId) &&
this.right === right &&
compareIDs(this.rightOrigin, right.rightOrigin) &&
this.id.client === right.id.client &&
this.id.clock + this.length === right.id.clock &&
this.deleted === right.deleted &&
this.redone === null &&
right.redone === null &&
this.content.constructor === right.content.constructor &&
this.content.mergeWith(right.content)
) {
const searchMarker = /** @type {AbstractType<any>} */ (this.parent)._searchMarker
if (searchMarker) {
searchMarker.forEach(marker => {
if (marker.p === right) {
// right is going to be "forgotten" so we need to update the marker
marker.p = this
// adjust marker index
if (!this.deleted && this.countable) {
marker.index -= this.length
}
}
})
}
if (right.keep) {
this.keep = true
}
this.right = right.right
if (this.right !== null) {
this.right.left = this
}
this.length += right.length
return true
}
return false
}
/**
* Mark this Item as deleted.
*
* @param {Transaction} transaction
*/
delete (transaction) {
if (!this.deleted) {
const parent = /** @type {AbstractType<any>} */ (this.parent)
// adjust the length of parent
if (this.countable && this.parentSub === null) {
parent._length -= this.length
}
this.markDeleted()
addToDeleteSet(transaction.deleteSet, this.id.client, this.id.clock, this.length)
addChangedTypeToTransaction(transaction, parent, this.parentSub)
this.content.delete(transaction)
}
}
/**
* @param {StructStore} store
* @param {boolean} parentGCd
*/
gc (store, parentGCd) {
if (!this.deleted) {
throw error.unexpectedCase()
}
this.content.gc(store)
if (parentGCd) {
replaceStruct(store, this, new GC(this.id, this.length))
} else {
this.content = new ContentDeleted(this.length)
}
}
/**
* 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 {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
* @param {number} offset
*/
write (encoder, offset) {
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 = (this.content.getRef() & 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
encoder.writeInfo(info)
if (origin !== null) {
encoder.writeLeftID(origin)
}
if (rightOrigin !== null) {
encoder.writeRightID(rightOrigin)
}
if (origin === null && rightOrigin === null) {
const parent = /** @type {AbstractType<any>} */ (this.parent)
if (parent._item !== undefined) {
const parentItem = parent._item
if (parentItem === null) {
// parent type on y._map
// find the correct key
const ykey = findRootTypeKey(parent)
encoder.writeParentInfo(true) // write parentYKey
encoder.writeString(ykey)
} else {
encoder.writeParentInfo(false) // write parent id
encoder.writeLeftID(parentItem.id)
}
} else if (parent.constructor === String) { // this edge case was added by differential updates
encoder.writeParentInfo(true) // write parentYKey
encoder.writeString(parent)
} else if (parent.constructor === ID) {
encoder.writeParentInfo(false) // write parent id
encoder.writeLeftID(parent)
} else {
error.unexpectedCase()
}
if (parentSub !== null) {
encoder.writeString(parentSub)
}
}
this.content.write(encoder, offset)
}
}
/**
* @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
* @param {number} info
*/
export const readItemContent = (decoder, info) => contentRefs[info & binary.BITS5](decoder)
/**
* A lookup map for reading Item content.
*
* @type {Array<function(UpdateDecoderV1 | UpdateDecoderV2):AbstractContent>}
*/
export const contentRefs = [
() => { error.unexpectedCase() }, // GC is not ItemContent
readContentDeleted, // 1
readContentJSON, // 2
readContentBinary, // 3
readContentString, // 4
readContentEmbed, // 5
readContentFormat, // 6
readContentType, // 7
readContentAny, // 8
readContentDoc, // 9
() => { error.unexpectedCase() } // 10 - Skip is not ItemContent
]
/**
* Do not implement this class!
*/
export class AbstractContent {
/**
* @return {number}
*/
getLength () {
throw error.methodUnimplemented()
}
/**
* @return {Array<any>}
*/
getContent () {
throw error.methodUnimplemented()
}
/**
* 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
*
* @return {boolean}
*/
isCountable () {
throw error.methodUnimplemented()
}
/**
* @return {AbstractContent}
*/
copy () {
throw error.methodUnimplemented()
}
/**
* @param {number} _offset
* @return {AbstractContent}
*/
splice (_offset) {
throw error.methodUnimplemented()
}
/**
* @param {AbstractContent} _right
* @return {boolean}
*/
mergeWith (_right) {
throw error.methodUnimplemented()
}
/**
* @param {Transaction} _transaction
* @param {Item} _item
*/
integrate (_transaction, _item) {
throw error.methodUnimplemented()
}
/**
* @param {Transaction} _transaction
*/
delete (_transaction) {
throw error.methodUnimplemented()
}
/**
* @param {StructStore} _store
*/
gc (_store) {
throw error.methodUnimplemented()
}
/**
* @param {UpdateEncoderV1 | UpdateEncoderV2} _encoder
* @param {number} _offset
*/
write (_encoder, _offset) {
throw error.methodUnimplemented()
}
/**
* @return {number}
*/
getRef () {
throw error.methodUnimplemented()
}
}