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| 1 | +/* eslint-disable @typescript-eslint/no-use-before-define */ |
| 2 | +import * as fs from "fs"; |
| 3 | +import * as os from "os"; |
| 4 | +import path from "path"; |
| 5 | +import { performance } from "perf_hooks"; |
| 6 | +import { |
| 7 | + AbstractCancellationTokenSource, |
| 8 | + CancellationId, |
| 9 | + CancellationReceiverStrategy, |
| 10 | + CancellationSenderStrategy, |
| 11 | + CancellationStrategy, |
| 12 | + CancellationToken, |
| 13 | + Emitter, |
| 14 | + Event, |
| 15 | +} from "vscode-languageserver"; |
| 16 | + |
| 17 | +class FileBasedToken implements CancellationToken { |
| 18 | + private _isCancelled = false; |
| 19 | + private _emitter: Emitter<any> | undefined; |
| 20 | + |
| 21 | + constructor(private _cancellationFilePath: string) {} |
| 22 | + |
| 23 | + public cancel(): void { |
| 24 | + if (!this._isCancelled) { |
| 25 | + this._isCancelled = true; |
| 26 | + if (this._emitter) { |
| 27 | + this._emitter.fire(undefined); |
| 28 | + this.dispose(); |
| 29 | + } |
| 30 | + } |
| 31 | + } |
| 32 | + |
| 33 | + get isCancellationRequested(): boolean { |
| 34 | + if (this._isCancelled) { |
| 35 | + return true; |
| 36 | + } |
| 37 | + |
| 38 | + if (this._pipeExists()) { |
| 39 | + // the first time it encounters cancellation file, it will |
| 40 | + // cancel itself and raise cancellation event. |
| 41 | + // in this mode, cancel() might not be called explicitly by jsonrpc layer |
| 42 | + this.cancel(); |
| 43 | + } |
| 44 | + |
| 45 | + return this._isCancelled; |
| 46 | + } |
| 47 | + |
| 48 | + get onCancellationRequested(): Event<any> { |
| 49 | + if (!this._emitter) { |
| 50 | + this._emitter = new Emitter<any>(); |
| 51 | + } |
| 52 | + return this._emitter.event; |
| 53 | + } |
| 54 | + |
| 55 | + public dispose(): void { |
| 56 | + if (this._emitter) { |
| 57 | + this._emitter.dispose(); |
| 58 | + this._emitter = undefined; |
| 59 | + } |
| 60 | + } |
| 61 | + |
| 62 | + private _pipeExists(): boolean { |
| 63 | + try { |
| 64 | + fs.statSync(this._cancellationFilePath); |
| 65 | + return true; |
| 66 | + } catch (e) { |
| 67 | + return false; |
| 68 | + } |
| 69 | + } |
| 70 | +} |
| 71 | + |
| 72 | +export class FileBasedCancellationTokenSource |
| 73 | + implements AbstractCancellationTokenSource { |
| 74 | + private _token: CancellationToken | undefined; |
| 75 | + constructor(private _cancellationFilePath: string) {} |
| 76 | + |
| 77 | + get token(): CancellationToken { |
| 78 | + if (!this._token) { |
| 79 | + // be lazy and create the token only when |
| 80 | + // actually needed |
| 81 | + this._token = new FileBasedToken(this._cancellationFilePath); |
| 82 | + } |
| 83 | + return this._token; |
| 84 | + } |
| 85 | + |
| 86 | + cancel(): void { |
| 87 | + if (!this._token) { |
| 88 | + // save an object by returning the default |
| 89 | + // cancelled token when cancellation happens |
| 90 | + // before someone asks for the token |
| 91 | + this._token = CancellationToken.Cancelled; |
| 92 | + } else { |
| 93 | + (this._token as FileBasedToken).cancel(); |
| 94 | + } |
| 95 | + } |
| 96 | + |
| 97 | + dispose(): void { |
| 98 | + if (!this._token) { |
| 99 | + // ensure to initialize with an empty token if we had none |
| 100 | + this._token = CancellationToken.None; |
| 101 | + } else if (this._token instanceof FileBasedToken) { |
| 102 | + // actually dispose |
| 103 | + this._token.dispose(); |
| 104 | + } |
| 105 | + } |
| 106 | +} |
| 107 | + |
| 108 | +export function getCancellationFolderPath(folderName: string): string { |
| 109 | + return path.join(os.tmpdir(), "elm-language-server-cancellation", folderName); |
| 110 | +} |
| 111 | + |
| 112 | +export function getCancellationFilePath( |
| 113 | + folderName: string, |
| 114 | + id: CancellationId, |
| 115 | +): string { |
| 116 | + return path.join( |
| 117 | + getCancellationFolderPath(folderName), |
| 118 | + `cancellation-${String(id)}.tmp`, |
| 119 | + ); |
| 120 | +} |
| 121 | + |
| 122 | +class FileCancellationReceiverStrategy implements CancellationReceiverStrategy { |
| 123 | + constructor(readonly folderName: string) {} |
| 124 | + |
| 125 | + createCancellationTokenSource( |
| 126 | + id: CancellationId, |
| 127 | + ): AbstractCancellationTokenSource { |
| 128 | + return new FileBasedCancellationTokenSource( |
| 129 | + getCancellationFilePath(this.folderName, id), |
| 130 | + ); |
| 131 | + } |
| 132 | +} |
| 133 | + |
| 134 | +let cancellationFolderName: string; |
| 135 | + |
| 136 | +export function getCancellationStrategyFromArgv( |
| 137 | + argv: string[], |
| 138 | +): CancellationStrategy { |
| 139 | + let receiver: CancellationReceiverStrategy | undefined; |
| 140 | + |
| 141 | + for (let i = 0; i < argv.length; i++) { |
| 142 | + const arg = argv[i]; |
| 143 | + if (arg === "--cancellationReceive") { |
| 144 | + receiver = createReceiverStrategyFromArgv(argv[i + 1]); |
| 145 | + } else { |
| 146 | + const args = arg.split("="); |
| 147 | + if (args[0] === "--cancellationReceive") { |
| 148 | + receiver = createReceiverStrategyFromArgv(args[1]); |
| 149 | + } |
| 150 | + } |
| 151 | + } |
| 152 | + |
| 153 | + if (receiver && !cancellationFolderName) { |
| 154 | + cancellationFolderName = (receiver as FileCancellationReceiverStrategy) |
| 155 | + .folderName; |
| 156 | + } |
| 157 | + |
| 158 | + receiver = receiver ? receiver : CancellationReceiverStrategy.Message; |
| 159 | + return { receiver, sender: CancellationSenderStrategy.Message }; |
| 160 | + |
| 161 | + function createReceiverStrategyFromArgv( |
| 162 | + arg: string, |
| 163 | + ): CancellationReceiverStrategy | undefined { |
| 164 | + const folderName = extractCancellationFolderName(arg); |
| 165 | + return folderName |
| 166 | + ? new FileCancellationReceiverStrategy(folderName) |
| 167 | + : undefined; |
| 168 | + } |
| 169 | + |
| 170 | + function extractCancellationFolderName(arg: string): string | undefined { |
| 171 | + const fileRegex = /^file:(.+)$/; |
| 172 | + const folderName = fileRegex.exec(arg); |
| 173 | + return folderName ? folderName[1] : undefined; |
| 174 | + } |
| 175 | +} |
| 176 | + |
| 177 | +export class OperationCanceledException {} |
| 178 | + |
| 179 | +export interface ICancellationToken { |
| 180 | + isCancellationRequested(): boolean; |
| 181 | + |
| 182 | + /** @throws OperationCanceledException if isCancellationRequested is true */ |
| 183 | + throwIfCancellationRequested(): void; |
| 184 | +} |
| 185 | + |
| 186 | +export class ThrottledCancellationToken implements ICancellationToken { |
| 187 | + // Store when we last tried to cancel. Checking cancellation can be expensive (as we have |
| 188 | + // to marshall over to the host layer). So we only bother actually checking once enough |
| 189 | + // time has passed. |
| 190 | + private lastCancellationCheckTime = 0; |
| 191 | + |
| 192 | + constructor( |
| 193 | + private cancellationToken: CancellationToken, |
| 194 | + private readonly throttleWaitMilliseconds = 20, |
| 195 | + ) {} |
| 196 | + |
| 197 | + public isCancellationRequested(): boolean { |
| 198 | + const time = performance.now(); |
| 199 | + const duration = Math.abs(time - this.lastCancellationCheckTime); |
| 200 | + if (duration >= this.throttleWaitMilliseconds) { |
| 201 | + // Check no more than once every throttle wait milliseconds |
| 202 | + this.lastCancellationCheckTime = time; |
| 203 | + return this.cancellationToken.isCancellationRequested; |
| 204 | + } |
| 205 | + |
| 206 | + return false; |
| 207 | + } |
| 208 | + |
| 209 | + public throwIfCancellationRequested(): void { |
| 210 | + if (this.isCancellationRequested()) { |
| 211 | + throw new OperationCanceledException(); |
| 212 | + } |
| 213 | + } |
| 214 | +} |
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