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| /**
* Copyright 2017 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { Query } from '../core/query';
import { SnapshotVersion } from '../core/snapshot_version';
import { Timestamp } from '../core/timestamp';
import { TargetId } from '../core/types';
import { DocumentKeySet, documentKeySet } from '../model/collections';
import { DocumentKey } from '../model/document_key';
import { assert, fail } from '../util/assert';
import { immediateSuccessor } from '../util/misc';
import * as EncodedResourcePath from './encoded_resource_path';
import { GarbageCollector } from './garbage_collector';
import {
DbTarget,
DbTargetDocument,
DbTargetDocumentKey,
DbTargetGlobal,
DbTargetGlobalKey,
DbTargetKey
} from './indexeddb_schema';
import { LocalSerializer } from './local_serializer';
import { PersistenceTransaction } from './persistence';
import { PersistencePromise } from './persistence_promise';
import { QueryCache } from './query_cache';
import { QueryData } from './query_data';
import { SimpleDbStore, SimpleDbTransaction } from './simple_db';
export class IndexedDbQueryCache implements QueryCache {
constructor(private serializer: LocalSerializer) {}
/**
* The last received snapshot version. We store this seperately from the
* metadata to avoid the extra conversion to/from DbTimestamp.
*/
private lastRemoteSnapshotVersion = SnapshotVersion.MIN;
/**
* A cached copy of the metadata for the query cache.
*/
private metadata = null;
/** The garbage collector to notify about potential garbage keys. */
private garbageCollector: GarbageCollector | null = null;
start(transaction: PersistenceTransaction): PersistencePromise<void> {
return globalTargetStore(transaction)
.get(DbTargetGlobal.key)
.next(metadata => {
assert(
metadata !== null,
'Missing metadata row that should be added by schema migration.'
);
this.metadata = metadata;
const lastSavedVersion = metadata.lastRemoteSnapshotVersion;
this.lastRemoteSnapshotVersion = SnapshotVersion.fromTimestamp(
new Timestamp(lastSavedVersion.seconds, lastSavedVersion.nanos)
);
return PersistencePromise.resolve();
});
}
getHighestTargetId(): TargetId {
return this.metadata.highestTargetId;
}
getLastRemoteSnapshotVersion(): SnapshotVersion {
return this.lastRemoteSnapshotVersion;
}
setLastRemoteSnapshotVersion(
transaction: PersistenceTransaction,
snapshotVersion: SnapshotVersion
): PersistencePromise<void> {
this.lastRemoteSnapshotVersion = snapshotVersion;
this.metadata.lastRemoteSnapshotVersion = snapshotVersion.toTimestamp();
return globalTargetStore(transaction).put(
DbTargetGlobal.key,
this.metadata
);
}
addQueryData(
transaction: PersistenceTransaction,
queryData: QueryData
): PersistencePromise<void> {
return this.saveQueryData(transaction, queryData).next(() => {
this.metadata.targetCount += 1;
this.updateMetadataFromQueryData(queryData);
return this.saveMetadata(transaction);
});
}
updateQueryData(
transaction: PersistenceTransaction,
queryData: QueryData
): PersistencePromise<void> {
return this.saveQueryData(transaction, queryData).next(() => {
Iif (this.updateMetadataFromQueryData(queryData)) {
return this.saveMetadata(transaction);
} else {
return PersistencePromise.resolve();
}
});
}
removeQueryData(
transaction: PersistenceTransaction,
queryData: QueryData
): PersistencePromise<void> {
assert(this.metadata.targetCount > 0, 'Removing from an empty query cache');
return this.removeMatchingKeysForTargetId(transaction, queryData.targetId)
.next(() => targetsStore(transaction).delete(queryData.targetId))
.next(() => {
this.metadata.targetCount -= 1;
return this.saveMetadata(transaction);
});
}
private saveMetadata(
transaction: PersistenceTransaction
): PersistencePromise<void> {
return globalTargetStore(transaction).put(
DbTargetGlobal.key,
this.metadata
);
}
private saveQueryData(
transaction: PersistenceTransaction,
queryData: QueryData
): PersistencePromise<void> {
return targetsStore(transaction).put(this.serializer.toDbTarget(queryData));
}
/**
* Updates the in-memory version of the metadata to account for values in the
* given QueryData. Saving is done separately. Returns true if there were any
* changes to the metadata.
*/
private updateMetadataFromQueryData(queryData: QueryData): boolean {
let needsUpdate = false;
if (queryData.targetId > this.metadata.highestTargetId) {
this.metadata.highestTargetId = queryData.targetId;
needsUpdate = true;
}
// TODO(GC): add sequence number check
return needsUpdate;
}
get count(): number {
return this.metadata.targetCount;
}
getQueryData(
transaction: PersistenceTransaction,
query: Query
): PersistencePromise<QueryData | null> {
// Iterating by the canonicalId may yield more than one result because
// canonicalId values are not required to be unique per target. This query
// depends on the queryTargets index to be efficent.
const canonicalId = query.canonicalId();
const range = IDBKeyRange.bound(
[canonicalId, Number.NEGATIVE_INFINITY],
[canonicalId, Number.POSITIVE_INFINITY]
);
let result: QueryData | null = null;
return targetsStore(transaction)
.iterate(
{ range, index: DbTarget.queryTargetsIndexName },
(key, value, control) => {
const found = this.serializer.fromDbTarget(value);
// After finding a potential match, check that the query is
// actually equal to the requested query.
if (query.isEqual(found.query)) {
result = found;
control.done();
}
}
)
.next(() => result);
}
addMatchingKeys(
txn: PersistenceTransaction,
keys: DocumentKeySet,
targetId: TargetId
): PersistencePromise<void> {
// PORTING NOTE: The reverse index (documentsTargets) is maintained by
// Indexeddb.
const promises: Array<PersistencePromise<void>> = [];
const store = documentTargetStore(txn);
keys.forEach(key => {
const path = EncodedResourcePath.encode(key.path);
promises.push(store.put(new DbTargetDocument(targetId, path)));
});
return PersistencePromise.waitFor(promises);
}
removeMatchingKeys(
txn: PersistenceTransaction,
keys: DocumentKeySet,
targetId: TargetId
): PersistencePromise<void> {
// PORTING NOTE: The reverse index (documentsTargets) is maintained by
// IndexedDb.
const promises: Array<PersistencePromise<void>> = [];
const store = documentTargetStore(txn);
keys.forEach(key => {
const path = EncodedResourcePath.encode(key.path);
promises.push(store.delete([targetId, path]));
if (this.garbageCollector !== null) {
this.garbageCollector.addPotentialGarbageKey(key);
}
});
return PersistencePromise.waitFor(promises);
}
removeMatchingKeysForTargetId(
txn: PersistenceTransaction,
targetId: TargetId
): PersistencePromise<void> {
const store = documentTargetStore(txn);
const range = IDBKeyRange.bound(
[targetId],
[targetId + 1],
/*lowerOpen=*/ false,
/*upperOpen=*/ true
);
return this.notifyGCForRemovedKeys(txn, range).next(() =>
store.delete(range)
);
}
private notifyGCForRemovedKeys(
txn: PersistenceTransaction,
range: IDBKeyRange
): PersistencePromise<void> {
const store = documentTargetStore(txn);
if (this.garbageCollector !== null && this.garbageCollector.isEager) {
// In order to generate garbage events properly, we need to read these
// keys before deleting.
return store.iterate({ range, keysOnly: true }, (key, _, control) => {
const path = EncodedResourcePath.decode(key[1]);
const docKey = new DocumentKey(path);
// Paranoid assertion in case the the collector is set to null
// during the iteration.
assert(
this.garbageCollector !== null,
'GarbageCollector for query cache set to null during key removal.'
);
this.garbageCollector!.addPotentialGarbageKey(docKey);
});
} else {
return PersistencePromise.resolve();
}
}
getMatchingKeysForTargetId(
txn: PersistenceTransaction,
targetId: TargetId
): PersistencePromise<DocumentKeySet> {
const range = IDBKeyRange.bound(
[targetId],
[targetId + 1],
/*lowerOpen=*/ false,
/*upperOpen=*/ true
);
const store = documentTargetStore(txn);
let result = documentKeySet();
return store
.iterate({ range, keysOnly: true }, (key, _, control) => {
const path = EncodedResourcePath.decode(key[1]);
const docKey = new DocumentKey(path);
result = result.add(docKey);
})
.next(() => result);
}
setGarbageCollector(gc: GarbageCollector | null): void {
this.garbageCollector = gc;
}
containsKey(
txn: PersistenceTransaction | null,
key: DocumentKey
): PersistencePromise<boolean> {
assert(
txn !== null,
'Persistence Transaction cannot be null for query cache containsKey'
);
const path = EncodedResourcePath.encode(key.path);
const range = IDBKeyRange.bound(
[path],
[immediateSuccessor(path)],
/*lowerOpen=*/ false,
/*upperOpen=*/ true
);
let count = 0;
return documentTargetStore(txn!)
.iterate(
{
index: DbTargetDocument.documentTargetsIndex,
keysOnly: true,
range
},
(key, _, control) => {
count++;
control.done();
}
)
.next(() => count > 0);
}
}
/**
* Helper to get a typed SimpleDbStore for the queries object store.
*/
function targetsStore(
txn: PersistenceTransaction
): SimpleDbStore<DbTargetKey, DbTarget> {
return getStore<DbTargetKey, DbTarget>(txn, DbTarget.store);
}
/**
* Helper to get a typed SimpleDbStore for the target globals object store.
*/
function globalTargetStore(
txn: PersistenceTransaction
): SimpleDbStore<DbTargetGlobalKey, DbTargetGlobal> {
return getStore<DbTargetGlobalKey, DbTargetGlobal>(txn, DbTargetGlobal.store);
}
/**
* Helper to get a typed SimpleDbStore for the document target object store.
*/
function documentTargetStore(
txn: PersistenceTransaction
): SimpleDbStore<DbTargetDocumentKey, DbTargetDocument> {
return getStore<DbTargetDocumentKey, DbTargetDocument>(
txn,
DbTargetDocument.store
);
}
/**
* Helper to get a typed SimpleDbStore from a transaction.
*/
function getStore<KeyType extends IDBValidKey, ValueType>(
txn: PersistenceTransaction,
store: string
): SimpleDbStore<KeyType, ValueType> {
Eif (txn instanceof SimpleDbTransaction) {
return txn.store<KeyType, ValueType>(store);
} else {
return fail('Invalid transaction object provided!');
}
}
|