mirror of
https://github.com/Instagram/IGListKit
synced 2026-05-22 16:58:23 +00:00
5f3c7e0319
Summary: This diff introduces two experimental APIs to make `IGListKit` more usable with Swift values types: - The `ListIdentifiable` protocol, which provides the equivalent of the diff identifier half of `ListDiffable`. For equality, we just use Swift's native `Equatable`. - The `ListValueSectionController` base class, which provides a section controller interface for use with `ListIdentifiable` values. These two APIs work together through the use of a private box class. I'd like to keep this detail hidden from callers, so that product code only deals with native Swift types. Differential Revision: D23606413 fbshipit-source-id: 23718c508643f165c74550f1515d77448bd42d42
72 lines
2.3 KiB
Swift
72 lines
2.3 KiB
Swift
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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import IGListDiffKit
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/// The `ListIdentifiable` protocol is a subset of `ListDiffable`'s functionality,
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/// for use with Swift value types and `ListValueSectionController`.
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///
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/// `ListIdentifiable` is an experimental, under-development API, and may change without warning in the future.
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public protocol ListIdentifiable: Equatable {
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var diffIdentifier: NSObjectProtocol { get }
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}
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public extension ListIdentifiable {
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/// Provides an object version of the value that can be passed to Objective-C APIs from
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/// `IGListKit` that require objects.
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///
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/// The object class is a private implementation detail of `IGListSwiftKit`. Use of this
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/// API must be paired with the `ListValueSectionController` class, which unwraps the
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/// value for its subclasses.
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func diffable() -> ListDiffable {
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return ListDiffableValueBox(value: self)
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}
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/// Determines whether an arbitrary `Any` value is an object version of the identifiable value.
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static func isDiffable(_ value: Any) -> Bool {
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return value is ListDiffableValueBox<Self>
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}
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// TODO(natesm): Should this be a public API? It is for now.
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init?(diffable: Any) {
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if let value = (diffable as? ListDiffableValueBox<Self>)?.value {
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self = value
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} else {
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return nil
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}
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}
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}
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public extension Sequence where Element: ListIdentifiable {
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func diffables() -> [ListDiffable] {
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return map { $0.diffable() }
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}
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}
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/// An internal class for boxing Swift values, for use with the `ListValueSectionController` class.
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///
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/// The public boxing API is provided by a protocol extension of `ListIdentifiable`.
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private final class ListDiffableValueBox<Value: ListIdentifiable>: NSObject, ListDiffable {
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let value: Value
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init(value: Value) {
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self.value = value
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}
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// MARK: - ListDiffable
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func diffIdentifier() -> NSObjectProtocol {
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return value.diffIdentifier
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}
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func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
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if let other = object as? ListDiffableValueBox<Value> {
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return value == other.value
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} else {
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return false
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}
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}
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}
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