125 lines
3.6 KiB
JavaScript
125 lines
3.6 KiB
JavaScript
import { StorageError } from "../common.js";
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// storage keys are defined to be unsigned 32bit numbers in WebPlatform.js, which is assumed by idb
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export function encodeUint32(n) {
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const hex = n.toString(16);
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return "0".repeat(8 - hex.length) + hex;
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}
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export function decodeUint32(str) {
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return parseInt(str, 16);
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}
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export function openDatabase(name, createObjectStore, version) {
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const req = window.indexedDB.open(name, version);
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req.onupgradeneeded = (ev) => {
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const db = ev.target.result;
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const oldVersion = ev.oldVersion;
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createObjectStore(db, oldVersion, version);
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};
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return reqAsPromise(req);
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}
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function wrapError(err) {
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return new StorageError(`wrapped DOMException`, err);
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}
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export function reqAsPromise(req) {
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return new Promise((resolve, reject) => {
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req.addEventListener("success", event => resolve(event.target.result));
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req.addEventListener("error", event => reject(wrapError(event.target.error)));
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});
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}
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export function txnAsPromise(txn) {
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return new Promise((resolve, reject) => {
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txn.addEventListener("complete", resolve);
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txn.addEventListener("abort", e => reject(wrapError(e)));
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});
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}
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export function iterateCursor(cursor, processValue) {
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// TODO: does cursor already have a value here??
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return new Promise((resolve, reject) => {
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cursor.onerror = (event) => {
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reject(new Error("Query failed: " + event.target.errorCode));
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};
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// collect results
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cursor.onsuccess = (event) => {
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const cursor = event.target.result;
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if (!cursor) {
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resolve(false);
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return; // end of results
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}
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const {done, jumpTo} = processValue(cursor.value, cursor.key);
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if (done) {
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resolve(true);
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} else if(jumpTo) {
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cursor.continue(jumpTo);
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} else {
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cursor.continue();
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}
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};
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}).catch(err => {
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throw new StorageError("iterateCursor failed", err);
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});
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}
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export async function fetchResults(cursor, isDone) {
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const results = [];
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await iterateCursor(cursor, (value) => {
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results.push(value);
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return {done: isDone(results)};
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});
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return results;
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}
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export async function select(db, storeName, toCursor, isDone) {
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if (!isDone) {
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isDone = () => false;
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}
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if (!toCursor) {
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toCursor = store => store.openCursor();
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}
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const tx = db.transaction([storeName], "readonly");
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const store = tx.objectStore(storeName);
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const cursor = toCursor(store);
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return await fetchResults(cursor, isDone);
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}
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export async function updateSingletonStore(db, storeName, value) {
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const tx = db.transaction([storeName], "readwrite");
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const store = tx.objectStore(storeName);
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const cursor = await reqAsPromise(store.openCursor());
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if (cursor) {
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return reqAsPromise(cursor.update(storeName));
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} else {
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return reqAsPromise(store.add(value));
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}
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}
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export async function findStoreValue(db, storeName, toCursor, matchesValue) {
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if (!matchesValue) {
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matchesValue = () => true;
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}
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if (!toCursor) {
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toCursor = store => store.openCursor();
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}
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const tx = db.transaction([storeName], "readwrite");
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const store = tx.objectStore(storeName);
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const cursor = await reqAsPromise(toCursor(store));
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let match;
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const matched = await iterateCursor(cursor, (value) => {
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if (matchesValue(value)) {
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match = value;
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return true;
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}
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});
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if (!matched) {
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throw new StorageError("Value not found");
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}
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return match;
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}
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