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/*
This file is part of TALER
(C) 2016 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, If not, see <http://www.gnu.org/licenses/>
*/
/// <reference path="../decl/urijs/URIjs.d.ts" />
/**
* Database query abstractions.
* @module Query
* @author Florian Dold
*/
"use strict";
export function Query(db) {
return new QueryRoot(db);
}
/**
* Stream that can be filtered, reduced or joined
* with indices.
*/
export interface QueryStream<T> {
indexJoin<S>(storeName: string,
indexName: string,
keyFn: (obj: any) => any): QueryStream<[T,S]>;
filter(f: (any) => boolean): QueryStream<T>;
reduce<S>(f: (v: T, acc: S) => S, start?: S): Promise<S>;
}
/**
* Get an unresolved promise together with its extracted resolve / reject
* function.
*
* @returns {{resolve: any, reject: any, promise: Promise<T>}}
*/
function openPromise<T>() {
let resolve, reject;
const promise = new Promise<T>((res, rej) => {
resolve = res;
reject = rej;
});
return {resolve, reject, promise};
}
abstract class QueryStreamBase<T> implements QueryStream<T> {
abstract subscribe(f: (isDone: boolean,
value: any,
tx: IDBTransaction) => void);
root: QueryRoot;
constructor(root: QueryRoot) {
this.root = root;
}
indexJoin<S>(storeName: string,
indexName: string,
key: any): QueryStream<[T,S]> {
this.root.addWork(null, storeName, false);
return new QueryStreamIndexJoin(this, storeName, indexName, key);
}
filter(f: (any) => boolean): QueryStream<T> {
return new QueryStreamFilter(this, f);
}
reduce(f, acc?): Promise<any> {
let leakedResolve;
let p = new Promise((resolve, reject) => {
leakedResolve = resolve;
});
this.subscribe((isDone, value) => {
if (isDone) {
leakedResolve(acc);
return;
}
acc = f(value, acc);
});
return Promise.resolve()
.then(() => this.root.finish())
.then(() => p);
}
}
class QueryStreamFilter<T> extends QueryStreamBase<T> {
s: QueryStreamBase<T>;
filterFn;
constructor(s: QueryStreamBase<T>, filterFn) {
super(s.root);
this.s = s;
this.filterFn = filterFn;
}
subscribe(f) {
this.s.subscribe((isDone, value, tx) => {
if (isDone) {
f(true, undefined, tx);
return;
}
if (this.filterFn(value)) {
f(false, value, tx)
}
});
}
}
class QueryStreamIndexJoin<T> extends QueryStreamBase<T> {
s: QueryStreamBase<T>;
storeName;
key;
indexName;
constructor(s, storeName: string, indexName: string, key: any) {
super(s.root);
this.s = s;
this.storeName = storeName;
this.key = key;
this.indexName = indexName;
}
subscribe(f) {
this.s.subscribe((isDone, value, tx) => {
if (isDone) {
f(true, undefined, tx);
return;
}
let s = tx.objectStore(this.storeName).index(this.indexName);
let req = s.openCursor(IDBKeyRange.only(this.key(value)));
req.onsuccess = () => {
let cursor = req.result;
if (cursor) {
f(false, [value, cursor.value], tx);
cursor.continue();
} else {
f(true, undefined, tx);
}
}
});
}
}
class IterQueryStream<T> extends QueryStreamBase<T> {
private storeName;
private options;
constructor(qr, storeName, options) {
super(qr);
this.options = options;
this.storeName = storeName;
}
subscribe(f) {
let doIt = (tx) => {
const {indexName = void 0, only = void 0} = this.options;
let s;
if (indexName !== void 0) {
s = tx.objectStore(this.storeName)
.index(this.options.indexName);
} else {
s = tx.objectStore(this.storeName);
}
let kr = undefined;
if (only !== void 0) {
kr = IDBKeyRange.only(this.options.only);
}
let req = s.openCursor(kr);
req.onsuccess = (e) => {
let cursor: IDBCursorWithValue = req.result;
if (cursor) {
f(false, cursor.value, tx);
cursor.continue();
} else {
f(true, undefined, tx);
}
}
};
this.root.addWork(doIt, null, false);
}
}
class QueryRoot {
private work = [];
private db: IDBDatabase;
private stores = new Set();
private kickoffPromise;
/**
* Some operations is a write operation,
* and we need to do a "readwrite" transaction/
*/
private hasWrite;
constructor(db) {
this.db = db;
}
iter<T>(storeName, {only = void 0, indexName = void 0} = {}): QueryStream<T> {
this.stores.add(storeName);
return new IterQueryStream(this, storeName, {only, indexName});
}
/**
* Put an object into the given object store.
* Overrides if an existing object with the same key exists
* in the store.
*/
put(storeName, val): QueryRoot {
let doPut = (tx: IDBTransaction) => {
tx.objectStore(storeName).put(val);
};
this.addWork(doPut, storeName, true);
return this;
}
/**
* Add all object from an iterable to the given object store.
* Fails if the object's key is already present
* in the object store.
*/
putAll(storeName, iterable): QueryRoot {
const doPutAll = (tx: IDBTransaction) => {
for (const obj of iterable) {
tx.objectStore(storeName).put(obj);
}
};
this.addWork(doPutAll, storeName, true);
return this;
}
/**
* Add an object to the given object store.
* Fails if the object's key is already present
* in the object store.
*/
add(storeName, val): QueryRoot {
const doAdd = (tx: IDBTransaction) => {
tx.objectStore(storeName).add(val);
};
this.addWork(doAdd, storeName, true);
return this;
}
/**
* Get one object from a store by its key.
*/
get(storeName, key): Promise<any> {
const {resolve, promise} = openPromise();
const doGet = (tx) => {
const req = tx.objectStore(storeName).get(key);
req.onsuccess = (r) => {
resolve(req.result);
};
};
this.addWork(doGet, storeName, false);
return Promise.resolve()
.then(() => this.finish())
.then(() => promise);
}
/**
* Finish the query, and start the query in the first place if necessary.
*/
finish(): Promise<void> {
if (this.kickoffPromise) {
return this.kickoffPromise;
}
this.kickoffPromise = new Promise((resolve, reject) => {
const mode = this.hasWrite ? "readwrite" : "readonly";
const tx = this.db.transaction(Array.from(this.stores), mode);
tx.oncomplete = () => {
resolve();
};
for (let w of this.work) {
w(tx);
}
});
return this.kickoffPromise;
}
/**
* Delete an object by from the given object store.
*/
delete(storeName: string, key): QueryRoot {
const doDelete = (tx) => {
tx.objectStore(storeName).delete(key);
};
this.addWork(doDelete, storeName, true);
return this;
}
/**
* Low-level function to add a task to the internal work queue.
*/
addWork(workFn: (IDBTransaction) => void,
storeName: string,
isWrite: boolean) {
if (storeName) {
this.stores.add(storeName);
}
if (isWrite) {
this.hasWrite = true;
}
if (workFn) {
this.work.push(workFn);
}
}
}
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