Files
CoreStore/Sources/Internals.DiffableDataSourceSnapshot.swift
2019-10-11 07:47:49 +09:00

665 lines
22 KiB
Swift

//
// Internals.DiffableDataSourceSnapshot.swift
// CoreStore
//
// Copyright © 2018 John Rommel Estropia
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
#if canImport(UIKit) || canImport(AppKit)
import CoreData
#if canImport(UIKit)
import UIKit
#elseif canImport(AppKit)
import AppKit
#endif
// MARK: - Internals
extension Internals {
// MARK: - DiffableDataSourceSnapshot
// Implementation based on https://github.com/ra1028/DiffableDataSources
internal struct DiffableDataSourceSnapshot {
// MARK: Internal
internal let nextStateTag: UUID
init() {
self.structure = .init()
self.nextStateTag = .init()
}
init(sections: [NSFetchedResultsSectionInfo], previousStateTag: UUID, nextStateTag: UUID) {
self.structure = .init(sections: sections, previousStateTag: previousStateTag)
self.nextStateTag = nextStateTag
}
var numberOfItems: Int {
return self.structure.allItemIDs.count
}
var numberOfSections: Int {
return self.structure.allSectionIDs.count
}
var allSectionIDs: [String] {
return self.structure.allSectionIDs
}
var allSectionStateIDs: [SectionStateID] {
return self.structure.allSectionStateIDs
}
var allItemIDs: [NSManagedObjectID] {
return self.structure.allItemIDs
}
var allItemStateIDs: [ItemStateID] {
return self.structure.allItemStateIDs
}
func numberOfItems(inSection identifier: String) -> Int {
return self.itemIDs(inSection: identifier).count
}
func itemIDs(inSection identifier: String) -> [NSManagedObjectID] {
return self.structure.items(in: identifier)
}
func itemStateIDs(inSection identifier: String) -> [ItemStateID] {
return self.structure.itemStateIDs(in: identifier)
}
func sectionIDs(containingItem identifier: NSManagedObjectID) -> String? {
return self.structure.section(containing: identifier)
}
func sectionStateIDs(containingItem identifier: NSManagedObjectID) -> SectionStateID? {
return self.structure.sectionStateID(containing: identifier)
}
func indexOfItemID(_ identifier: NSManagedObjectID) -> Int? {
return self.structure.allItemIDs.firstIndex(of: identifier)
}
func indexOfSectionID(_ identifier: String) -> Int? {
return self.structure.allSectionIDs.firstIndex(of: identifier)
}
func itemIDs(where stateCondition: @escaping (UUID) -> Bool) -> [NSManagedObjectID] {
return self.structure.itemsIDs(where: stateCondition)
}
mutating func appendItems(_ identifiers: [NSManagedObjectID], toSection sectionIdentifier: String?, nextStateTag: UUID) {
self.structure.append(itemIDs: identifiers, to: sectionIdentifier, nextStateTag: nextStateTag)
}
mutating func insertItems(_ identifiers: [NSManagedObjectID], beforeItem beforeIdentifier: NSManagedObjectID, nextStateTag: UUID) {
self.structure.insert(itemIDs: identifiers, before: beforeIdentifier, nextStateTag: nextStateTag)
}
mutating func insertItems(_ identifiers: [NSManagedObjectID], afterItem afterIdentifier: NSManagedObjectID, nextStateTag: UUID) {
self.structure.insert(itemIDs: identifiers, after: afterIdentifier, nextStateTag: nextStateTag)
}
mutating func deleteItems(_ identifiers: [NSManagedObjectID]) {
self.structure.remove(itemIDs: identifiers)
}
mutating func deleteAllItems() {
self.structure.removeAllItems()
}
mutating func moveItem(_ identifier: NSManagedObjectID, beforeItem toIdentifier: NSManagedObjectID) {
self.structure.move(itemID: identifier, before: toIdentifier)
}
mutating func moveItem(_ identifier: NSManagedObjectID, afterItem toIdentifier: NSManagedObjectID) {
self.structure.move(itemID: identifier, after: toIdentifier)
}
mutating func reloadItems<S: Sequence>(_ identifiers: S, nextStateTag: UUID) where S.Element == NSManagedObjectID {
self.structure.update(itemIDs: identifiers, nextStateTag: nextStateTag)
}
mutating func appendSections(_ identifiers: [String], nextStateTag: UUID) {
self.structure.append(sectionIDs: identifiers, nextStateTag: nextStateTag)
}
mutating func insertSections(_ identifiers: [String], beforeSection toIdentifier: String, nextStateTag: UUID) {
self.structure.insert(sectionIDs: identifiers, before: toIdentifier, nextStateTag: nextStateTag)
}
mutating func insertSections(_ identifiers: [String], afterSection toIdentifier: String, nextStateTag: UUID) {
self.structure.insert(sectionIDs: identifiers, after: toIdentifier, nextStateTag: nextStateTag)
}
mutating func deleteSections(_ identifiers: [String]) {
self.structure.remove(sectionIDs: identifiers)
}
mutating func moveSection(_ identifier: String, beforeSection toIdentifier: String) {
self.structure.move(sectionID: identifier, before: toIdentifier)
}
mutating func moveSection(_ identifier: String, afterSection toIdentifier: String) {
self.structure.move(sectionID: identifier, after: toIdentifier)
}
mutating func reloadSections<S: Sequence>(_ identifiers: S, nextStateTag: UUID) where S.Element == String {
self.structure.update(sectionIDs: identifiers, nextStateTag: nextStateTag)
}
// MARK: Private
private var structure: BackingStructure
// MARK: - ItemStateID
internal struct ItemStateID: Identifiable, Equatable {
let stateTag: UUID
init(id: NSManagedObjectID, stateTag: UUID) {
self.id = id
self.stateTag = stateTag
}
func isContentEqual(to source: ItemStateID) -> Bool {
return self.id == source.id && self.stateTag == source.stateTag
}
// MARK: Identifiable
let id: NSManagedObjectID
}
// MARK: - SectionStateID
internal struct SectionStateID: Identifiable, Equatable {
let stateTag: UUID
init(id: String, stateTag: UUID) {
self.id = id
self.stateTag = stateTag
}
func isContentEqual(to source: SectionStateID) -> Bool {
return self.id == source.id && self.stateTag == source.stateTag
}
// MARK: Identifiable
let id: String
}
// MARK: - BackingStructure
fileprivate struct BackingStructure {
// MARK: Internal
var sections: [Section]
init() {
self.sections = []
}
init(sections: [NSFetchedResultsSectionInfo], previousStateTag: UUID) {
self.sections = sections.map {
Section(
id: $0.name,
items: $0.objects?
.compactMap({ ($0 as? NSManagedObject)?.objectID })
.map({ Item(id: $0, stateTag: previousStateTag) }) ?? [],
stateTag: previousStateTag
)
}
}
var allSectionIDs: [String] {
return self.sections.map({ $0.id })
}
var allSectionStateIDs: [SectionStateID] {
return self.sections.map({ $0.stateID })
}
var allItemIDs: [NSManagedObjectID] {
return self.sections.lazy.flatMap({ $0.elements }).map({ $0.id })
}
var allItemStateIDs: [ItemStateID] {
return self.sections.lazy.flatMap({ $0.elements }).map({ $0.stateID })
}
func items(in sectionID: String) -> [NSManagedObjectID] {
guard let sectionIndex = self.sectionIndex(of: sectionID) else {
Internals.abort("Section \"\(sectionID)\" does not exist")
}
return self.sections[sectionIndex].elements.map({ $0.id })
}
func itemsIDs(where stateCondition: @escaping (UUID) -> Bool) -> [NSManagedObjectID] {
return self.sections.lazy
.flatMap({ $0.elements.filter({ stateCondition($0.stateTag) }) })
.map({ $0.id })
}
func itemStateIDs(in sectionID: String) -> [ItemStateID] {
guard let sectionIndex = self.sectionIndex(of: sectionID) else {
Internals.abort("Section \"\(sectionID)\" does not exist")
}
return self.sections[sectionIndex].elements.map({ $0.stateID })
}
func section(containing itemID: NSManagedObjectID) -> String? {
return self.itemPositionMap()[itemID]?.section.id
}
func sectionStateID(containing itemID: NSManagedObjectID) -> SectionStateID? {
return self.itemPositionMap()[itemID]?.section.stateID
}
mutating func append(itemIDs: [NSManagedObjectID], to sectionID: String?, nextStateTag: UUID) {
let index: Array<Section>.Index
if let sectionID = sectionID {
guard let sectionIndex = self.sectionIndex(of: sectionID) else {
Internals.abort("Section \"\(sectionID)\" does not exist")
}
index = sectionIndex
}
else {
let section = self.sections
guard !section.isEmpty else {
Internals.abort("No sections exist")
}
index = section.index(before: section.endIndex)
}
let items = itemIDs.lazy.map({ Item(id: $0, stateTag: nextStateTag) })
self.sections[index].elements.append(contentsOf: items)
}
mutating func insert(itemIDs: [NSManagedObjectID], before beforeItemID: NSManagedObjectID, nextStateTag: UUID) {
guard let itemPosition = self.itemPositionMap()[beforeItemID] else {
Internals.abort("Item \(beforeItemID) does not exist")
}
let items = itemIDs.lazy.map({ Item(id: $0, stateTag: nextStateTag) })
self.sections[itemPosition.sectionIndex].elements
.insert(contentsOf: items, at: itemPosition.itemRelativeIndex)
}
mutating func insert(itemIDs: [NSManagedObjectID], after afterItemID: NSManagedObjectID, nextStateTag: UUID) {
guard let itemPosition = self.itemPositionMap()[afterItemID] else {
Internals.abort("Item \(afterItemID) does not exist")
}
let itemIndex = self.sections[itemPosition.sectionIndex].elements
.index(after: itemPosition.itemRelativeIndex)
let items = itemIDs.lazy.map({ Item(id: $0, stateTag: nextStateTag) })
self.sections[itemPosition.sectionIndex].elements
.insert(contentsOf: items, at: itemIndex)
}
mutating func remove(itemIDs: [NSManagedObjectID]) {
let itemPositionMap = self.itemPositionMap()
var removeIndexSetMap: [Int: IndexSet] = [:]
for itemID in itemIDs {
guard let itemPosition = itemPositionMap[itemID] else {
continue
}
removeIndexSetMap[itemPosition.sectionIndex, default: []]
.insert(itemPosition.itemRelativeIndex)
}
for (sectionIndex, removeIndexSet) in removeIndexSetMap {
for range in removeIndexSet.rangeView.reversed() {
self.sections[sectionIndex].elements.removeSubrange(range)
}
}
}
mutating func removeAllItems() {
for sectionIndex in self.sections.indices {
self.sections[sectionIndex].elements.removeAll()
}
}
mutating func move(itemID: NSManagedObjectID, before beforeItemID: NSManagedObjectID) {
guard let removed = self.remove(itemID: itemID) else {
Internals.abort("Item \(itemID) does not exist")
}
guard let itemPosition = self.itemPositionMap()[beforeItemID] else {
Internals.abort("Item \(beforeItemID) does not exist")
}
self.sections[itemPosition.sectionIndex].elements
.insert(removed, at: itemPosition.itemRelativeIndex)
}
mutating func move(itemID: NSManagedObjectID, after afterItemID: NSManagedObjectID) {
guard let removed = self.remove(itemID: itemID) else {
Internals.abort("Item \(itemID) does not exist")
}
guard let itemPosition = self.itemPositionMap()[afterItemID] else {
Internals.abort("Item \(afterItemID) does not exist")
}
let itemIndex = self.sections[itemPosition.sectionIndex].elements
.index(after: itemPosition.itemRelativeIndex)
self.sections[itemPosition.sectionIndex].elements
.insert(removed, at: itemIndex)
}
mutating func update<S: Sequence>(itemIDs: S, nextStateTag: UUID) where S.Element == NSManagedObjectID {
let itemPositionMap = self.itemPositionMap()
for itemID in itemIDs {
guard let itemPosition = itemPositionMap[itemID] else {
continue
}
self.sections[itemPosition.sectionIndex]
.elements[itemPosition.itemRelativeIndex].stateTag = nextStateTag
}
}
mutating func append(sectionIDs: [String], nextStateTag: UUID) {
let newSections = sectionIDs.lazy.map({ Section(id: $0, stateTag: nextStateTag) })
self.sections.append(contentsOf: newSections)
}
mutating func insert(sectionIDs: [String], before beforeSectionID: String, nextStateTag: UUID) {
guard let sectionIndex = self.sectionIndex(of: beforeSectionID) else {
Internals.abort("Section \"\(beforeSectionID)\" does not exist")
}
let newSections = sectionIDs.lazy.map({ Section(id: $0, stateTag: nextStateTag) })
self.sections.insert(contentsOf: newSections, at: sectionIndex)
}
mutating func insert(sectionIDs: [String], after afterSectionID: String, nextStateTag: UUID) {
guard let beforeIndex = self.sectionIndex(of: afterSectionID) else {
Internals.abort("Section \"\(afterSectionID)\" does not exist")
}
let sectionIndex = self.sections.index(after: beforeIndex)
let newSections = sectionIDs.lazy.map({ Section(id: $0, stateTag: nextStateTag) })
self.sections.insert(contentsOf: newSections, at: sectionIndex)
}
mutating func remove(sectionIDs: [String]) {
for sectionID in sectionIDs {
self.remove(sectionID: sectionID)
}
}
mutating func move(sectionID: String, before beforeSectionID: String) {
guard let removed = self.remove(sectionID: sectionID) else {
Internals.abort("Section \"\(sectionID)\" does not exist")
}
guard let sectionIndex = self.sectionIndex(of: beforeSectionID) else {
Internals.abort("Section \"\(beforeSectionID)\" does not exist")
}
self.sections.insert(removed, at: sectionIndex)
}
mutating func move(sectionID: String, after afterSectionID: String) {
guard let removed = self.remove(sectionID: sectionID) else {
Internals.abort("Section \"\(sectionID)\" does not exist")
}
guard let beforeIndex = self.sectionIndex(of: afterSectionID) else {
Internals.abort("Section \"\(afterSectionID)\" does not exist")
}
let sectionIndex = self.sections.index(after: beforeIndex)
self.sections.insert(removed, at: sectionIndex)
}
mutating func update<S: Sequence>(sectionIDs: S, nextStateTag: UUID) where S.Element == String {
for sectionID in sectionIDs {
guard let sectionIndex = self.sectionIndex(of: sectionID) else {
continue
}
self.sections[sectionIndex].stateTag = nextStateTag
}
}
// MARK: Private
private static let zeroUUID: UUID = .init(uuid: (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
private func sectionIndex(of sectionID: String) -> Array<Section>.Index? {
return self.sections.firstIndex(where: { $0.id == sectionID })
}
@discardableResult
private mutating func remove(itemID: NSManagedObjectID) -> Item? {
guard let itemPosition = self.itemPositionMap()[itemID] else {
return nil
}
return self.sections[itemPosition.sectionIndex].elements
.remove(at: itemPosition.itemRelativeIndex)
}
@discardableResult
private mutating func remove(sectionID: String) -> Section? {
guard let sectionIndex = self.sectionIndex(of: sectionID) else {
return nil
}
return self.sections.remove(at: sectionIndex)
}
private func itemPositionMap() -> [NSManagedObjectID: ItemPosition] {
return self.sections.enumerated().reduce(into: [:]) { result, section in
for (itemRelativeIndex, item) in section.element.elements.enumerated() {
result[item.id] = ItemPosition(
item: item,
itemRelativeIndex: itemRelativeIndex,
section: section.element,
sectionIndex: section.offset
)
}
}
}
// MARK: - Item
fileprivate struct Item: Identifiable, Equatable {
var stateTag: UUID
init(id: NSManagedObjectID, stateTag: UUID) {
self.id = id
self.stateTag = stateTag
}
var stateID: ItemStateID {
return .init(id: self.id, stateTag: self.stateTag)
}
func isContentEqual(to source: Item) -> Bool {
return self.id == source.id && self.stateTag == source.stateTag
}
// MARK: Identifiable
let id: NSManagedObjectID
}
// MARK: - Section
fileprivate struct Section: Identifiable, Equatable {
var elements: [Item] = []
var stateTag: UUID
init(id: String, items: [Item] = [], stateTag: UUID) {
self.id = id
self.elements = items
self.stateTag = stateTag
}
init<S: Sequence>(source: Section, elements: S) where S.Element == Item {
self.init(id: source.id, items: Array(elements), stateTag: source.stateTag)
}
var stateID: SectionStateID {
return .init(id: self.id, stateTag: self.stateTag)
}
func isContentEqual(to source: Section) -> Bool {
return self.id == source.id && self.stateTag == source.stateTag
}
// MARK: Identifiable
let id: String
}
// MARK: - ItemPosition
fileprivate struct ItemPosition {
let item: Item
let itemRelativeIndex: Int
let section: Section
let sectionIndex: Int
}
}
}
}
#endif