kopia lustrzana https://github.com/Tldraw/Tldraw
106 wiersze
2.4 KiB
TypeScript
106 wiersze
2.4 KiB
TypeScript
import { StyleProp } from '@tldraw/tlschema'
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import { exhaustiveSwitchError } from '@tldraw/utils'
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/** @public */
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export type SharedStyle<T> =
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| { readonly type: 'mixed' }
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| { readonly type: 'shared'; readonly value: T }
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function sharedStyleEquals<T>(a: SharedStyle<T>, b: SharedStyle<T> | undefined) {
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if (!b) return false
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switch (a.type) {
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case 'mixed':
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return b.type === 'mixed'
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case 'shared':
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return b.type === 'shared' && a.value === b.value
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default:
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throw exhaustiveSwitchError(a)
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}
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}
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/** @public */
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export class ReadonlySharedStyleMap {
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protected map: Map<StyleProp<unknown>, SharedStyle<unknown>>
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constructor(entries?: Iterable<[StyleProp<unknown>, SharedStyle<unknown>]>) {
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this.map = new Map(entries)
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}
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get<T>(prop: StyleProp<T>): SharedStyle<T> | undefined {
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return this.map.get(prop) as SharedStyle<T> | undefined
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}
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getAsKnownValue<T>(prop: StyleProp<T>): T | undefined {
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const value = this.get(prop)
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if (!value) return undefined
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if (value.type === 'mixed') return undefined
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return value.value
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}
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get size() {
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return this.map.size
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}
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equals(other: ReadonlySharedStyleMap) {
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if (this.size !== other.size) return false
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const checkedKeys = new Set()
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for (const [styleProp, value] of this) {
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if (!sharedStyleEquals(value, other.get(styleProp))) return false
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checkedKeys.add(styleProp)
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}
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for (const [styleProp, value] of other) {
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if (checkedKeys.has(styleProp)) continue
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if (!sharedStyleEquals(value, this.get(styleProp))) return false
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}
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return true
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}
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keys() {
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return this.map.keys()
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}
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values() {
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return this.map.values()
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}
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entries() {
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return this.map.entries()
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}
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[Symbol.iterator]() {
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return this.map[Symbol.iterator]()
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}
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}
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/** @internal */
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export class SharedStyleMap extends ReadonlySharedStyleMap {
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set<T>(prop: StyleProp<T>, value: SharedStyle<T>) {
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this.map.set(prop, value)
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}
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applyValue<T>(prop: StyleProp<T>, value: T) {
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const existingValue = this.get(prop)
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// if we don't have a value yet, set it
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if (!existingValue) {
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this.set(prop, { type: 'shared', value })
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return
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}
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switch (existingValue.type) {
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case 'mixed':
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// we're already mixed, adding new values won't help
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return
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case 'shared':
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if (existingValue.value !== value) {
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// if the value is different, we're now mixed:
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this.set(prop, { type: 'mixed' })
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}
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return
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default:
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exhaustiveSwitchError(existingValue, 'type')
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}
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}
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}
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