aboutsummaryrefslogtreecommitdiff
path: root/src/query.ts
blob: a284ef1b7be2792f46038d9ed134ad4571c56ac8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
/*
 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, see <http://www.gnu.org/licenses/>
 */


/**
 * Database query abstractions.
 * @module Query
 * @author Florian Dold
 */

"use strict";


export interface JoinResult<L,R> {
  left: L;
  right: R;
}

export interface JoinLeftResult<L,R> {
  left: L;
  right?: R;
}


export class Store<T> {
  name: string;
  validator?: (v: T) => T;
  storeParams: IDBObjectStoreParameters;

  constructor(name: string, storeParams: IDBObjectStoreParameters,
              validator?: (v: T) => T) {
    this.name = name;
    this.validator = validator;
    this.storeParams = storeParams;
  }
}

export class Index<S extends IDBValidKey,T> {
  indexName: string;
  storeName: string;
  keyPath: string | string[];

  constructor(s: Store<T>, indexName: string, keyPath: string | string[]) {
    this.storeName = s.name;
    this.indexName = indexName;
    this.keyPath = keyPath;
  }
}

/**
 * Stream that can be filtered, reduced or joined
 * with indices.
 */
export interface QueryStream<T> {
  indexJoin<S,I extends IDBValidKey>(index: Index<I,S>,
                                     keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>>;
  indexJoinLeft<S,I extends IDBValidKey>(index: Index<I,S>,
                                     keyFn: (obj: T) => I): QueryStream<JoinLeftResult<T, S>>;
  keyJoin<S,I extends IDBValidKey>(store: Store<S>,
                                   keyFn: (obj: T) => I): QueryStream<JoinResult<T,S>>;
  filter(f: (T: any) => boolean): QueryStream<T>;
  reduce<S>(f: (v: T, acc: S) => S, start?: S): Promise<S>;
  map<S>(f: (x:T) => S): QueryStream<S>;
  flatMap<S>(f: (x: T) => S[]): QueryStream<S>;
  toArray(): Promise<T[]>;

  then(onfulfill: any, onreject: any): any;
}

export let AbortTransaction = Symbol("abort_transaction");

/**
 * Get an unresolved promise together with its extracted resolve / reject
 * function.
 */
function openPromise<T>() {
  let resolve: ((value?: T | PromiseLike<T>) => void) | null = null;
  let reject: ((reason?: any) => void) | null = null;
  const promise = new Promise<T>((res, rej) => {
    resolve = res;
    reject = rej;
  });
  if (!(resolve && reject)) {
    // Never happens, unless JS implementation is broken
    throw Error();
  }
  return {resolve, reject, promise};
}


abstract class QueryStreamBase<T> implements QueryStream<T>, PromiseLike<void> {
  abstract subscribe(f: (isDone: boolean,
                         value: any,
                         tx: IDBTransaction) => void): void;

  root: QueryRoot;

  constructor(root: QueryRoot) {
    this.root = root;
  }

  then<R>(onfulfilled: (value: void) => R | PromiseLike<R>, onrejected: (reason: any) => R | PromiseLike<R>): PromiseLike<R>  {
    return this.root.then(onfulfilled, onrejected);
  }

  flatMap<S>(f: (x: T) => S[]): QueryStream<S> {
    return new QueryStreamFlatMap<T,S>(this, f);
  }

  map<S>(f: (x: T) => S): QueryStream<S> {
    return new QueryStreamMap(this, f);
  }

  indexJoin<S,I extends IDBValidKey>(index: Index<I,S>,
                                     keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>> {
    this.root.addStoreAccess(index.storeName, false);
    return new QueryStreamIndexJoin(this, index.storeName, index.indexName, keyFn);
  }

  indexJoinLeft<S,I extends IDBValidKey>(index: Index<I,S>,
                                     keyFn: (obj: T) => I): QueryStream<JoinLeftResult<T, S>> {
    this.root.addStoreAccess(index.storeName, false);
    return new QueryStreamIndexJoinLeft(this, index.storeName, index.indexName, keyFn);
  }

  keyJoin<S, I extends IDBValidKey>(store: Store<S>,
                                    keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>> {
    this.root.addStoreAccess(store.name, false);
    return new QueryStreamKeyJoin(this, store.name, keyFn);
  }

  filter(f: (x: any) => boolean): QueryStream<T> {
    return new QueryStreamFilter(this, f);
  }

  toArray(): Promise<T[]> {
    let {resolve, promise} = openPromise();
    let values: T[] = [];

    this.subscribe((isDone, value) => {
      if (isDone) {
        resolve(values);
        return;
      }
      values.push(value);
    });

    return Promise.resolve()
                  .then(() => this.root.finish())
                  .then(() => promise);
  }

  reduce<A>(f: (x: any, acc?: A) => A, init?: A): Promise<any> {
    let {resolve, promise} = openPromise();
    let acc = init;

    this.subscribe((isDone, value) => {
      if (isDone) {
        resolve(acc);
        return;
      }
      acc = f(value, acc);
    });

    return Promise.resolve()
                  .then(() => this.root.finish())
                  .then(() => promise);
  }
}

type FilterFn = (e: any) => boolean;
type SubscribeFn = (done: boolean, value: any, tx: IDBTransaction) => void;

interface FlatMapFn<T> {
  (v: T): T[];
}

class QueryStreamFilter<T> extends QueryStreamBase<T> {
  s: QueryStreamBase<T>;
  filterFn: FilterFn;

  constructor(s: QueryStreamBase<T>, filterFn: FilterFn) {
    super(s.root);
    this.s = s;
    this.filterFn = filterFn;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      if (this.filterFn(value)) {
        f(false, value, tx);
      }
    });
  }
}


class QueryStreamFlatMap<T,S> extends QueryStreamBase<S> {
  s: QueryStreamBase<T>;
  flatMapFn: (v: T) => S[];

  constructor(s: QueryStreamBase<T>, flatMapFn: (v: T) => S[]) {
    super(s.root);
    this.s = s;
    this.flatMapFn = flatMapFn;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      let values = this.flatMapFn(value);
      for (let v in values) {
        f(false, value, tx)
      }
    });
  }
}


class QueryStreamMap<S,T> extends QueryStreamBase<T> {
  s: QueryStreamBase<S>;
  mapFn: (v: S) => T;

  constructor(s: QueryStreamBase<S>, mapFn: (v: S) => T) {
    super(s.root);
    this.s = s;
    this.mapFn = mapFn;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      let mappedValue = this.mapFn(value);
      f(false, mappedValue, tx);
    });
  }
}


class QueryStreamIndexJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
  s: QueryStreamBase<T>;
  storeName: string;
  key: any;
  indexName: string;

  constructor(s: QueryStreamBase<T>, storeName: string, indexName: string,
              key: any) {
    super(s.root);
    this.s = s;
    this.storeName = storeName;
    this.key = key;
    this.indexName = indexName;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      console.log("joining on", this.key(value));
      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, {left: value, right: cursor.value}, tx);
          cursor.continue();
        }
      }
    });
  }
}


class QueryStreamIndexJoinLeft<T, S> extends QueryStreamBase<JoinLeftResult<T, S>> {
  s: QueryStreamBase<T>;
  storeName: string;
  key: any;
  indexName: string;

  constructor(s: QueryStreamBase<T>, storeName: string, indexName: string,
              key: any) {
    super(s.root);
    this.s = s;
    this.storeName = storeName;
    this.key = key;
    this.indexName = indexName;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      console.log("joining on", this.key(value));
      const s = tx.objectStore(this.storeName).index(this.indexName);
      const req = s.openCursor(IDBKeyRange.only(this.key(value)));
      let gotMatch = false;
      req.onsuccess = () => {
        let cursor = req.result;
        if (cursor) {
          gotMatch = true;
          f(false, {left: value, right: cursor.value}, tx);
          cursor.continue();
        } else {
          if (!gotMatch) {
            f(false, {left: value}, tx);
          }
        }
      }
    });
  }
}


class QueryStreamKeyJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
  s: QueryStreamBase<T>;
  storeName: string;
  key: any;

  constructor(s: QueryStreamBase<T>, storeName: string,
              key: any) {
    super(s.root);
    this.s = s;
    this.storeName = storeName;
    this.key = key;
  }

  subscribe(f: SubscribeFn) {
    this.s.subscribe((isDone, value, tx) => {
      if (isDone) {
        f(true, undefined, tx);
        return;
      }
      console.log("joining on", this.key(value));
      let s = tx.objectStore(this.storeName);
      let req = s.openCursor(IDBKeyRange.only(this.key(value)));
      req.onsuccess = () => {
        let cursor = req.result;
        if (cursor) {
          f(false, {left:value, right: cursor.value}, tx);
          cursor.continue();
        } else {
          f(true, undefined, tx);
        }
      }
    });
  }
}


class IterQueryStream<T> extends QueryStreamBase<T> {
  private storeName: string;
  private options: any;
  private subscribers: SubscribeFn[];

  constructor(qr: QueryRoot, storeName: string, options: any) {
    super(qr);
    this.options = options;
    this.storeName = storeName;
    this.subscribers = [];

    let doIt = (tx: IDBTransaction) => {
      const {indexName = void 0, only = void 0} = this.options;
      let s: any;
      if (indexName !== void 0) {
        s = tx.objectStore(this.storeName)
              .index(this.options.indexName);
      } else {
        s = tx.objectStore(this.storeName);
      }
      let kr: IDBKeyRange | undefined = undefined;
      if (only !== undefined) {
        kr = IDBKeyRange.only(this.options.only);
      }
      let req = s.openCursor(kr);
      req.onsuccess = () => {
        let cursor: IDBCursorWithValue = req.result;
        if (cursor) {
          for (let f of this.subscribers) {
            f(false, cursor.value, tx);
          }
          cursor.continue();
        } else {
          for (let f of this.subscribers) {
            f(true, undefined, tx);
          }
        }
      }
    };

    this.root.addWork(doIt);
  }

  subscribe(f: SubscribeFn) {
    this.subscribers.push(f);
  }
}


export class QueryRoot implements PromiseLike<void> {
  private work: ((t: IDBTransaction) => void)[] = [];
  private db: IDBDatabase;
  private stores = new Set();
  private kickoffPromise: Promise<void>;

  /**
   * Some operations is a write operation,
   * and we need to do a "readwrite" transaction/
   */
  private hasWrite: boolean;

  private finishScheduled: boolean;

  constructor(db: IDBDatabase) {
    this.db = db;
  }

  then<R>(onfulfilled: (value: void) => R | PromiseLike<R>, onrejected: (reason: any) => R | PromiseLike<R>): PromiseLike<R> {
    return this.finish().then(onfulfilled, onrejected);
  }

  iter<T>(store: Store<T>): QueryStream<T> {
    this.stores.add(store.name);
    this.scheduleFinish();
    return new IterQueryStream(this, store.name, {});
  }

  iterIndex<S extends IDBValidKey,T>(index: Index<S,T>,
                                     only?: S): QueryStream<T> {
    this.stores.add(index.storeName);
    this.scheduleFinish();
    return new IterQueryStream(this, index.storeName, {
      only,
      indexName: index.indexName
    });
  }

  /**
   * Put an object into the given object store.
   * Overrides if an existing object with the same key exists
   * in the store.
   */
  put<T>(store: Store<T>, val: T): QueryRoot {
    let doPut = (tx: IDBTransaction) => {
      tx.objectStore(store.name).put(val);
    };
    this.scheduleFinish();
    this.addWork(doPut, store.name, true);
    return this;
  }


  putWithResult<T>(store: Store<T>, val: T): Promise<IDBValidKey> {
    const {resolve, promise} = openPromise();
    let doPutWithResult = (tx: IDBTransaction) => {
      let req = tx.objectStore(store.name).put(val);
      req.onsuccess = () => {
        resolve(req.result);
      }
      this.scheduleFinish();
    };
    this.addWork(doPutWithResult, store.name, true);
    return Promise.resolve()
                  .then(() => this.finish())
                  .then(() => promise);
  }


  mutate<T>(store: Store<T>, key: any, f: (v: T) => T): QueryRoot {
    let doPut = (tx: IDBTransaction) => {
      let reqGet = tx.objectStore(store.name).get(key);
      reqGet.onsuccess = () => {
        let r = reqGet.result;
        let m: T;
        try {
          m = f(r);
        } catch (e) {
          if (e == AbortTransaction) {
            tx.abort();
            return;
          }
          throw e;
        }

        tx.objectStore(store.name).put(m);
      }
    };
    this.scheduleFinish();
    this.addWork(doPut, store.name, 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<T>(store: Store<T>, iterable: T[]): QueryRoot {
    const doPutAll = (tx: IDBTransaction) => {
      for (let obj of iterable) {
        tx.objectStore(store.name).put(obj);
      }
    };
    this.scheduleFinish();
    this.addWork(doPutAll, store.name, 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<T>(store: Store<T>, val: T): QueryRoot {
    const doAdd = (tx: IDBTransaction) => {
      tx.objectStore(store.name).add(val);
    };
    this.scheduleFinish();
    this.addWork(doAdd, store.name, true);
    return this;
  }

  /**
   * Get one object from a store by its key.
   */
  get<T>(store: Store<T>, key: any): Promise<T|undefined> {
    if (key === void 0) {
      throw Error("key must not be undefined");
    }

    const {resolve, promise} = openPromise();

    const doGet = (tx: IDBTransaction) => {
      const req = tx.objectStore(store.name).get(key);
      req.onsuccess = () => {
        resolve(req.result);
      };
    };

    this.addWork(doGet, store.name, false);
    return Promise.resolve()
                  .then(() => this.finish())
                  .then(() => promise);
  }

  /**
   * Get one object from a store by its key.
   */
  getIndexed<I extends IDBValidKey,T>(index: Index<I,T>,
                                      key: I): Promise<T|undefined> {
    if (key === void 0) {
      throw Error("key must not be undefined");
    }

    const {resolve, promise} = openPromise();

    const doGetIndexed = (tx: IDBTransaction) => {
      const req = tx.objectStore(index.storeName)
                    .index(index.indexName)
                    .get(key);
      req.onsuccess = () => {
        resolve(req.result);
      };
    };

    this.addWork(doGetIndexed, index.storeName, false);
    return Promise.resolve()
                  .then(() => this.finish())
                  .then(() => promise);
  }

  private scheduleFinish() {
    if (!this.finishScheduled) {
      Promise.resolve().then(() => this.finish());
      this.finishScheduled = true;
    }
  }

  /**
   * 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<void>((resolve, reject) => {
      if (this.work.length == 0) {
        resolve();
        return;
      }
      const mode = this.hasWrite ? "readwrite" : "readonly";
      const tx = this.db.transaction(Array.from(this.stores), mode);
      tx.oncomplete = () => {
        resolve();
      };
      tx.onabort = () => {
        reject(Error("transaction aborted"));
      };
      for (let w of this.work) {
        w(tx);
      }
    });
    return this.kickoffPromise;
  }

  /**
   * Delete an object by from the given object store.
   */
  delete(storeName: string, key: any): QueryRoot {
    const doDelete = (tx: IDBTransaction) => {
      tx.objectStore(storeName).delete(key);
    };
    this.scheduleFinish();
    this.addWork(doDelete, storeName, true);
    return this;
  }

  /**
   * Low-level function to add a task to the internal work queue.
   */
  addWork(workFn: (t: IDBTransaction) => void,
          storeName?: string,
          isWrite?: boolean) {
    this.work.push(workFn);
    if (storeName) {
      this.addStoreAccess(storeName, isWrite);
    }
  }

  addStoreAccess(storeName: string, isWrite?: boolean) {
    if (storeName) {
      this.stores.add(storeName);
    }
    if (isWrite) {
      this.hasWrite = true;
    }
  }
}