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1// Copyright (C) 2019 The Android Open Source Project
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15import {
16  decode as b64Decode,
17  encode as b64Encode,
18  length as b64Len,
19} from '@protobufjs/base64';
20import {
21  length as utf8Len,
22  read as utf8Read,
23  write as utf8Write,
24} from '@protobufjs/utf8';
25
26import {assertTrue} from './logging';
27
28// TextDecoder/Decoder requires the full DOM and isn't available in all types
29// of tests. Use fallback implementation from protbufjs.
30let Utf8Decoder: {decode: (buf: Uint8Array) => string;};
31let Utf8Encoder: {encode: (str: string) => Uint8Array;};
32try {
33  Utf8Decoder = new TextDecoder('utf-8');
34  Utf8Encoder = new TextEncoder();
35} catch (_) {
36  if (typeof process === 'undefined') {
37    // Silence the warning when we know we are running under NodeJS.
38    console.warn(
39        'Using fallback UTF8 Encoder/Decoder, This should happen only in ' +
40        'tests and NodeJS-based environments, not in browsers.');
41  }
42  Utf8Decoder = {decode: (buf: Uint8Array) => utf8Read(buf, 0, buf.length)};
43  Utf8Encoder = {
44    encode: (str: string) => {
45      const arr = new Uint8Array(utf8Len(str));
46      const written = utf8Write(str, arr, 0);
47      assertTrue(written === arr.length);
48      return arr;
49    },
50  };
51}
52
53export function base64Encode(buffer: Uint8Array): string {
54  return b64Encode(buffer, 0, buffer.length);
55}
56
57export function base64Decode(str: string): Uint8Array {
58  // if the string is in base64url format, convert to base64
59  const b64 = str.replace(/-/g, '+').replace(/_/g, '/');
60  const arr = new Uint8Array(b64Len(b64));
61  const written = b64Decode(b64, arr, 0);
62  assertTrue(written === arr.length);
63  return arr;
64}
65
66// encode binary array to hex string
67export function hexEncode(bytes: Uint8Array): string {
68  return bytes.reduce(
69      (prev, cur) => prev + ('0' + cur.toString(16)).slice(-2), '');
70}
71
72export function utf8Encode(str: string): Uint8Array {
73  return Utf8Encoder.encode(str);
74}
75
76// Note: not all byte sequences can be converted to<>from UTF8. This can be
77// used only with valid unicode strings, not arbitrary byte buffers.
78export function utf8Decode(buffer: Uint8Array): string {
79  return Utf8Decoder.decode(buffer);
80}
81
82// The binaryEncode/Decode functions below allow to encode an arbitrary binary
83// buffer into a string that can be JSON-encoded. binaryEncode() applies
84// UTF-16 encoding to each byte individually.
85// Unlike utf8Encode/Decode, any arbitrary byte sequence can be converted into a
86// valid string, and viceversa.
87// This should be only used when a byte array needs to be transmitted over an
88// interface that supports only JSON serialization (e.g., postmessage to a
89// chrome extension).
90
91export function binaryEncode(buf: Uint8Array): string {
92  let str = '';
93  for (let i = 0; i < buf.length; i++) {
94    str += String.fromCharCode(buf[i]);
95  }
96  return str;
97}
98
99export function binaryDecode(str: string): Uint8Array {
100  const buf = new Uint8Array(str.length);
101  const strLen = str.length;
102  for (let i = 0; i < strLen; i++) {
103    buf[i] = str.charCodeAt(i);
104  }
105  return buf;
106}
107
108// A function used to interpolate strings into SQL query. The only replacement
109// is done is that single quote replaced with two single quotes, according to
110// SQLite documentation:
111// https://www.sqlite.org/lang_expr.html#literal_values_constants_
112//
113// The purpose of this function is to use in simple comparisons, to escape
114// strings used in GLOB clauses see escapeQuery function.
115export function sqliteString(str: string): string {
116  return `'${str.replace(/'/g, '\'\'')}'`;
117}
118