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Signal-Desktop/ts/types/IndexedDB.ts

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Add license headers across the project
2020-10-30 20:34:04 +00:00
// Copyright 2018-2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
Index messages with attachments using a boolean When indexing message attachment metadata using numeric indexes such as: ```javascript { conversationId: '+12223334455', received_at: 123, attachments: […], numAttachments: 2, }, { conversationId: '+12223334455', received_at: 456, attachments: [], numAttachments: 0, } { conversationId: '+12223334455', received_at: 789, attachments: [], numAttachments: 1, } ``` It creates an index as follows: ``` [conversationId, received_at, numAttachments] ['+12223334455', 123, 2] ['+12223334455', 456, 0] ['+12223334455', 789, 1] ``` This means a query such as… ``` lowerBound: ['+12223334455', 0, 1 ] upperBound: ['+12223334455', Number.MAX_VALUE, Number.MAX_VALUE] ``` …will return all three original entries because they span the `received_at` from `0` through `Number.MAX_VALUE`. One workaround is to index booleans using `1 | undefined` where `1` is included in the index and `undefined` is not, but that way we lose the ability to query for the `false` value. Instead, we flip adjust the index to `[conversationId, hasAttachments, received_at]` and can then query messages with attachments using ``` [conversationId, 1 /* hasAttachments */, 0 /* received_at */] [conversationId, 1 /* hasAttachments */, Number.MAX_VALUE /* received_at */] ```
2018-04-14 01:47:06 +00:00
// IndexedDB doesn’t support boolean indexes so we map `true` to 1 and `false`
Use `IndexablePresence` for `hasFileAttachments` and `hasVisualMediaAttachments` Reduces index size, makes it easier to debug using IndexedDB inspector, and hopefully improves lookup performance.
2018-04-25 18:15:06 +00:00
// to `0`, i.e. `IndexableBoolean`.
Index messages with attachments using a boolean When indexing message attachment metadata using numeric indexes such as: ```javascript { conversationId: '+12223334455', received_at: 123, attachments: […], numAttachments: 2, }, { conversationId: '+12223334455', received_at: 456, attachments: [], numAttachments: 0, } { conversationId: '+12223334455', received_at: 789, attachments: [], numAttachments: 1, } ``` It creates an index as follows: ``` [conversationId, received_at, numAttachments] ['+12223334455', 123, 2] ['+12223334455', 456, 0] ['+12223334455', 789, 1] ``` This means a query such as… ``` lowerBound: ['+12223334455', 0, 1 ] upperBound: ['+12223334455', Number.MAX_VALUE, Number.MAX_VALUE] ``` …will return all three original entries because they span the `received_at` from `0` through `Number.MAX_VALUE`. One workaround is to index booleans using `1 | undefined` where `1` is included in the index and `undefined` is not, but that way we lose the ability to query for the `false` value. Instead, we flip adjust the index to `[conversationId, hasAttachments, received_at]` and can then query messages with attachments using ``` [conversationId, 1 /* hasAttachments */, 0 /* received_at */] [conversationId, 1 /* hasAttachments */, Number.MAX_VALUE /* received_at */] ```
2018-04-14 01:47:06 +00:00
// N.B. Using `undefined` allows excluding an entry from an index. Useful
Use `IndexablePresence` for `hasFileAttachments` and `hasVisualMediaAttachments` Reduces index size, makes it easier to debug using IndexedDB inspector, and hopefully improves lookup performance.
2018-04-25 18:15:06 +00:00
// when index size is a consideration or one only needs to query for `true`,
// i.e. `IndexablePresence`.
Improve `IndexableBoolean` type
2018-04-15 01:08:36 +00:00
export type IndexableBoolean = IndexableFalse | IndexableTrue;
Use `IndexablePresence` for `hasFileAttachments` and `hasVisualMediaAttachments` Reduces index size, makes it easier to debug using IndexedDB inspector, and hopefully improves lookup performance.
2018-04-25 18:15:06 +00:00
export type IndexablePresence = undefined | IndexableTrue;
Improve `IndexableBoolean` type
2018-04-15 01:08:36 +00:00
type IndexableFalse = 0;
Use `IndexablePresence` for `hasFileAttachments` and `hasVisualMediaAttachments` Reduces index size, makes it easier to debug using IndexedDB inspector, and hopefully improves lookup performance.
2018-04-25 18:15:06 +00:00
type IndexableTrue = 1;
Improve `IndexableBoolean` type
2018-04-15 01:08:36 +00:00
export const INDEXABLE_FALSE: IndexableFalse = 0;
export const INDEXABLE_TRUE: IndexableTrue = 1;
Index messages with attachments using a boolean When indexing message attachment metadata using numeric indexes such as: ```javascript { conversationId: '+12223334455', received_at: 123, attachments: […], numAttachments: 2, }, { conversationId: '+12223334455', received_at: 456, attachments: [], numAttachments: 0, } { conversationId: '+12223334455', received_at: 789, attachments: [], numAttachments: 1, } ``` It creates an index as follows: ``` [conversationId, received_at, numAttachments] ['+12223334455', 123, 2] ['+12223334455', 456, 0] ['+12223334455', 789, 1] ``` This means a query such as… ``` lowerBound: ['+12223334455', 0, 1 ] upperBound: ['+12223334455', Number.MAX_VALUE, Number.MAX_VALUE] ``` …will return all three original entries because they span the `received_at` from `0` through `Number.MAX_VALUE`. One workaround is to index booleans using `1 | undefined` where `1` is included in the index and `undefined` is not, but that way we lose the ability to query for the `false` value. Instead, we flip adjust the index to `[conversationId, hasAttachments, received_at]` and can then query messages with attachments using ``` [conversationId, 1 /* hasAttachments */, 0 /* received_at */] [conversationId, 1 /* hasAttachments */, Number.MAX_VALUE /* received_at */] ```
2018-04-14 01:47:06 +00:00
export const toIndexableBoolean = (value: boolean): IndexableBoolean =>
Improve `IndexableBoolean` type
2018-04-15 01:08:36 +00:00
value ? INDEXABLE_TRUE : INDEXABLE_FALSE;
Use `IndexablePresence` for `hasFileAttachments` and `hasVisualMediaAttachments` Reduces index size, makes it easier to debug using IndexedDB inspector, and hopefully improves lookup performance.
2018-04-25 18:15:06 +00:00
export const toIndexablePresence = (value: boolean): IndexablePresence =>
value ? INDEXABLE_TRUE : undefined;