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
import type {JSONValue} from './json';import type {ReadTransaction} from './transactions';import * as db from './db/mod';import type * as sync from './sync/mod';
export type ScanSubscriptionInfo = {  options: db.ScanOptions;  inclusiveLimitKey?: string;};
export type Subscription<R extends JSONValue | undefined, E> = {  body: (tx: ReadTransaction) => Promise<R>;  onData: (r: R) => void;  onError?: (e: E) => void;  onDone?: () => void;  lastValue?: R;  keys: ReadonlySet<string>;  scans: ReadonlyArray<Readonly<ScanSubscriptionInfo>>;};
function keyMatchesSubscription<V, E>(  subscription: Subscription<V, E>,  indexName: string,  changedKey: string,) {  // subscription.keys contains the primary index keys. If we are passing in an  // indexName there was a change to the index map, in which case the changedKey  // is an encoded index key. We could skip checking the indexName here since  // the set would never contain encoded index keys but we do the check for  // clarity.  if (indexName === '' && subscription.keys.has(changedKey)) {    return true;  }
  for (const scanInfo of subscription.scans) {    if (scanInfoMatchesKey(scanInfo, indexName, changedKey)) {      return true;    }  }
  return false;}
export function scanInfoMatchesKey(  scanInfo: ScanSubscriptionInfo,  changeIndexName: string,  changedKey: string,): boolean {  const {indexName, prefix, startKey, startExclusive, startSecondaryKey} =    scanInfo.options;
  if (!indexName) {    if (changeIndexName) {      return false;    }
    // A scan with limit <= 0 can have no matches    if (scanInfo.options.limit !== undefined && scanInfo.options.limit <= 0) {      return false;    }
    // No prefix and no start. Must recompute the subscription because all keys    // will have an effect on the subscription.    if (!prefix && !startKey) {      return true;    }
    if (      prefix &&      (!changedKey.startsWith(prefix) ||        isKeyPastInclusiveLimit(scanInfo, changedKey))    ) {      return false;    }
    if (      startKey &&      ((startExclusive && changedKey <= startKey) ||        changedKey < startKey ||        isKeyPastInclusiveLimit(scanInfo, changedKey))    ) {      return false;    }
    return true;  }
  if (changeIndexName !== indexName) {    return false;  }
  // No prefix and no start. Must recompute the subscription because all keys  // will have an effect on the subscription.  if (!prefix && !startKey && !startSecondaryKey) {    return true;  }
  const [changedKeySecondary, changedKeyPrimary] =    db.decodeIndexKey(changedKey);
  if (prefix) {    if (!changedKeySecondary.startsWith(prefix)) {      return false;    }  }
  if (    startSecondaryKey &&    ((startExclusive && changedKeySecondary <= startSecondaryKey) ||      changedKeySecondary < startSecondaryKey)  ) {    return false;  }
  if (    startKey &&    ((startExclusive && changedKeyPrimary <= startKey) ||      changedKeyPrimary < startKey)  ) {    return false;  }
  return true;}
function isKeyPastInclusiveLimit(  scanInfo: ScanSubscriptionInfo,  changedKey: string,): boolean {  const {inclusiveLimitKey} = scanInfo;  return (    scanInfo.options.limit !== undefined &&    inclusiveLimitKey !== undefined &&    changedKey > inclusiveLimitKey  );}
export function* subscriptionsForChangedKeys<V, E>(  subscriptions: Set<Subscription<V, E>>,  changedKeysMap: sync.ChangedKeysMap,): Generator<Subscription<V, E>> {  outer: for (const subscription of subscriptions) {    for (const [indexName, changedKeys] of changedKeysMap) {      for (const key of changedKeys) {        if (keyMatchesSubscription(subscription, indexName, key)) {          yield subscription;          continue outer;        }      }    }  }}
export function* subscriptionsForIndexDefinitionChanged<V, E>(  subscriptions: Set<Subscription<V, E>>,  name: string,): Generator<Subscription<V, E>> {  for (const subscription of subscriptions) {    if (      subscription.scans.some(scanInfo => scanInfo.options.indexName === name)    ) {      yield subscription;    }  }}