forked from MapComplete/MapComplete
81 lines
2.7 KiB
TypeScript
81 lines
2.7 KiB
TypeScript
import { IdbLocalStorage } from "../../Web/IdbLocalStorage"
|
|
import { UIEventSource } from "../../UIEventSource"
|
|
|
|
/**
|
|
* A class which allows to read/write a tile to local storage.
|
|
*
|
|
* Does the heavy lifting for LocalStorageFeatureSource and SaveFeatureToLocalStorage.
|
|
*
|
|
* Note: OSM-features with a negative id are ignored
|
|
*/
|
|
export default class TileLocalStorage<T> {
|
|
private static perLayer: Record<string, TileLocalStorage<any>> = {}
|
|
private readonly _layername: string
|
|
private readonly inUse = new UIEventSource(false)
|
|
private readonly cachedSources: Record<number, UIEventSource<T> & { flush: () => void }> = {}
|
|
|
|
private static readonly useIndexedDb = typeof indexedDB !== "undefined"
|
|
private constructor(layername: string) {
|
|
this._layername = layername
|
|
}
|
|
|
|
public static construct<T>(backend: string, layername: string): TileLocalStorage<T> {
|
|
const key = backend + "_" + layername
|
|
const cached = TileLocalStorage.perLayer[key]
|
|
if (cached) {
|
|
return cached
|
|
}
|
|
|
|
const tls = new TileLocalStorage<T>(key)
|
|
TileLocalStorage.perLayer[key] = tls
|
|
return tls
|
|
}
|
|
|
|
/**
|
|
* Constructs a UIEventSource element which is synced with localStorage.
|
|
* Supports 'flush'
|
|
*/
|
|
public getTileSource(tileIndex: number): UIEventSource<T> & { flush: () => void } {
|
|
const cached = this.cachedSources[tileIndex]
|
|
if (cached) {
|
|
return cached
|
|
}
|
|
const src = <UIEventSource<T> & { flush: () => void }>(
|
|
UIEventSource.FromPromise(this.GetIdb(tileIndex))
|
|
)
|
|
src.flush = () => this.SetIdb(tileIndex, src.data)
|
|
src.addCallbackD((data) => this.SetIdb(tileIndex, data))
|
|
this.cachedSources[tileIndex] = src
|
|
return src
|
|
}
|
|
|
|
private async SetIdb(tileIndex: number, data: any): Promise<void> {
|
|
if(!TileLocalStorage.useIndexedDb){
|
|
return
|
|
}
|
|
try {
|
|
await this.inUse.AsPromise((inUse) => !inUse)
|
|
this.inUse.setData(true)
|
|
await IdbLocalStorage.SetDirectly(this._layername + "_" + tileIndex, data)
|
|
this.inUse.setData(false)
|
|
} catch (e) {
|
|
console.error(
|
|
"Could not save tile to indexed-db: ",
|
|
e,
|
|
"tileIndex is:",
|
|
tileIndex,
|
|
"for layer",
|
|
this._layername,
|
|
"data is",
|
|
data
|
|
)
|
|
}
|
|
}
|
|
|
|
private GetIdb(tileIndex: number): Promise<any> {
|
|
if(!TileLocalStorage.useIndexedDb){
|
|
return undefined
|
|
}
|
|
return IdbLocalStorage.GetDirectly(this._layername + "_" + tileIndex)
|
|
}
|
|
}
|