mirror of
https://github.com/overleaf/overleaf.git
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104 lines
2.6 KiB
JavaScript
104 lines
2.6 KiB
JavaScript
'use strict'
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const assert = require('check-types').assert
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const OError = require('@overleaf/o-error')
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const TextOperation = require('./operation/text_operation')
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class NotFoundError extends OError {
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constructor(hash) {
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super(`blob ${hash} not found`, { hash })
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this.hash = hash
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}
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}
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/**
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* Metadata record for the content of a file.
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*/
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class Blob {
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static HEX_HASH_RX_STRING = '^[0-9a-f]{40,40}$'
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static HEX_HASH_RX = new RegExp(Blob.HEX_HASH_RX_STRING)
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/**
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* Size of the largest file that we'll read to determine whether we can edit it
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* or not, in bytes. The final decision on whether a file is editable or not is
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* based on the number of characters it contains, but we need to read the file
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* in to determine that; so it is useful to have an upper bound on the byte
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* length of a file that might be editable.
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*
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* The reason for the factor of 3 is as follows. We cannot currently edit files
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* that contain characters outside of the basic multilingual plane, so we're
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* limited to characters that can be represented in a single, two-byte UCS-2
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* code unit. Encoding the largest such value, 0xFFFF (which is not actually
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* a valid character), takes three bytes in UTF-8: 0xEF 0xBF 0xBF. A file
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* composed entirely of three-byte UTF-8 codepoints is the worst case; in
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* practice, this is a very conservative upper bound.
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*
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* @type {number}
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*/
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static MAX_EDITABLE_BYTE_LENGTH_BOUND = 3 * TextOperation.MAX_STRING_LENGTH
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static NotFoundError = NotFoundError
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constructor(hash, byteLength, stringLength) {
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this.setHash(hash)
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this.setByteLength(byteLength)
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this.setStringLength(stringLength)
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}
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static fromRaw(raw) {
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if (raw) {
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return new Blob(raw.hash, raw.byteLength, raw.stringLength)
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}
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return null
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}
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toRaw() {
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return {
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hash: this.hash,
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byteLength: this.byteLength,
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stringLength: this.stringLength,
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}
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}
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/**
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* Hex hash.
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* @return {?String}
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*/
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getHash() {
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return this.hash
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}
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setHash(hash) {
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assert.maybe.match(hash, Blob.HEX_HASH_RX, 'bad hash')
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this.hash = hash
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}
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/**
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* Length of the blob in bytes.
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* @return {number}
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*/
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getByteLength() {
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return this.byteLength
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}
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setByteLength(byteLength) {
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assert.maybe.integer(byteLength, 'bad byteLength')
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this.byteLength = byteLength
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}
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/**
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* Utf-8 length of the blob content, if it appears to be valid UTF-8.
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* @return {?number}
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*/
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getStringLength() {
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return this.stringLength
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}
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setStringLength(stringLength) {
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assert.maybe.integer(stringLength, 'bad stringLength')
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this.stringLength = stringLength
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}
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}
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module.exports = Blob
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