Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2012 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | "use strict"; |
| 6 | |
| 7 | // This file relies on the fact that the following declaration has been made |
| 8 | // in runtime.js: |
| 9 | // var $Object = global.Object |
| 10 | // var $WeakMap = global.WeakMap |
| 11 | |
| 12 | // For bootstrapper. |
| 13 | |
| 14 | var IsPromise; |
| 15 | var PromiseCreate; |
| 16 | var PromiseResolve; |
| 17 | var PromiseReject; |
| 18 | var PromiseChain; |
| 19 | var PromiseCatch; |
| 20 | var PromiseThen; |
| 21 | var PromiseHasRejectHandler; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 22 | var PromiseHasUserDefinedRejectHandler; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 23 | |
| 24 | // mirror-debugger.js currently uses builtins.promiseStatus. It would be nice |
| 25 | // if we could move these property names into the closure below. |
| 26 | // TODO(jkummerow/rossberg/yangguo): Find a better solution. |
| 27 | |
| 28 | // Status values: 0 = pending, +1 = resolved, -1 = rejected |
| 29 | var promiseStatus = GLOBAL_PRIVATE("Promise#status"); |
| 30 | var promiseValue = GLOBAL_PRIVATE("Promise#value"); |
| 31 | var promiseOnResolve = GLOBAL_PRIVATE("Promise#onResolve"); |
| 32 | var promiseOnReject = GLOBAL_PRIVATE("Promise#onReject"); |
| 33 | var promiseRaw = GLOBAL_PRIVATE("Promise#raw"); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 34 | var promiseHasHandler = %PromiseHasHandlerSymbol(); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 35 | var lastMicrotaskId = 0; |
| 36 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 37 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 38 | (function() { |
| 39 | |
| 40 | var $Promise = function Promise(resolver) { |
| 41 | if (resolver === promiseRaw) return; |
| 42 | if (!%_IsConstructCall()) throw MakeTypeError('not_a_promise', [this]); |
| 43 | if (!IS_SPEC_FUNCTION(resolver)) |
| 44 | throw MakeTypeError('resolver_not_a_function', [resolver]); |
| 45 | var promise = PromiseInit(this); |
| 46 | try { |
| 47 | %DebugPushPromise(promise); |
| 48 | resolver(function(x) { PromiseResolve(promise, x) }, |
| 49 | function(r) { PromiseReject(promise, r) }); |
| 50 | } catch (e) { |
| 51 | PromiseReject(promise, e); |
| 52 | } finally { |
| 53 | %DebugPopPromise(); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | // Core functionality. |
| 58 | |
| 59 | function PromiseSet(promise, status, value, onResolve, onReject) { |
| 60 | SET_PRIVATE(promise, promiseStatus, status); |
| 61 | SET_PRIVATE(promise, promiseValue, value); |
| 62 | SET_PRIVATE(promise, promiseOnResolve, onResolve); |
| 63 | SET_PRIVATE(promise, promiseOnReject, onReject); |
| 64 | if (DEBUG_IS_ACTIVE) { |
| 65 | %DebugPromiseEvent({ promise: promise, status: status, value: value }); |
| 66 | } |
| 67 | return promise; |
| 68 | } |
| 69 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 70 | function PromiseCreateAndSet(status, value) { |
| 71 | var promise = new $Promise(promiseRaw); |
| 72 | // If debug is active, notify about the newly created promise first. |
| 73 | if (DEBUG_IS_ACTIVE) PromiseSet(promise, 0, UNDEFINED); |
| 74 | return PromiseSet(promise, status, value); |
| 75 | } |
| 76 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 77 | function PromiseInit(promise) { |
| 78 | return PromiseSet( |
| 79 | promise, 0, UNDEFINED, new InternalArray, new InternalArray) |
| 80 | } |
| 81 | |
| 82 | function PromiseDone(promise, status, value, promiseQueue) { |
| 83 | if (GET_PRIVATE(promise, promiseStatus) === 0) { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 84 | var tasks = GET_PRIVATE(promise, promiseQueue); |
| 85 | if (tasks.length) PromiseEnqueue(value, tasks, status); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 86 | PromiseSet(promise, status, value); |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | function PromiseCoerce(constructor, x) { |
| 91 | if (!IsPromise(x) && IS_SPEC_OBJECT(x)) { |
| 92 | var then; |
| 93 | try { |
| 94 | then = x.then; |
| 95 | } catch(r) { |
| 96 | return %_CallFunction(constructor, r, PromiseRejected); |
| 97 | } |
| 98 | if (IS_SPEC_FUNCTION(then)) { |
| 99 | var deferred = %_CallFunction(constructor, PromiseDeferred); |
| 100 | try { |
| 101 | %_CallFunction(x, deferred.resolve, deferred.reject, then); |
| 102 | } catch(r) { |
| 103 | deferred.reject(r); |
| 104 | } |
| 105 | return deferred.promise; |
| 106 | } |
| 107 | } |
| 108 | return x; |
| 109 | } |
| 110 | |
| 111 | function PromiseHandle(value, handler, deferred) { |
| 112 | try { |
| 113 | %DebugPushPromise(deferred.promise); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 114 | DEBUG_PREPARE_STEP_IN_IF_STEPPING(handler); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 115 | var result = handler(value); |
| 116 | if (result === deferred.promise) |
| 117 | throw MakeTypeError('promise_cyclic', [result]); |
| 118 | else if (IsPromise(result)) |
| 119 | %_CallFunction(result, deferred.resolve, deferred.reject, PromiseChain); |
| 120 | else |
| 121 | deferred.resolve(result); |
| 122 | } catch (exception) { |
| 123 | try { deferred.reject(exception); } catch (e) { } |
| 124 | } finally { |
| 125 | %DebugPopPromise(); |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | function PromiseEnqueue(value, tasks, status) { |
| 130 | var id, name, instrumenting = DEBUG_IS_ACTIVE; |
| 131 | %EnqueueMicrotask(function() { |
| 132 | if (instrumenting) { |
| 133 | %DebugAsyncTaskEvent({ type: "willHandle", id: id, name: name }); |
| 134 | } |
| 135 | for (var i = 0; i < tasks.length; i += 2) { |
| 136 | PromiseHandle(value, tasks[i], tasks[i + 1]) |
| 137 | } |
| 138 | if (instrumenting) { |
| 139 | %DebugAsyncTaskEvent({ type: "didHandle", id: id, name: name }); |
| 140 | } |
| 141 | }); |
| 142 | if (instrumenting) { |
| 143 | id = ++lastMicrotaskId; |
| 144 | name = status > 0 ? "Promise.resolve" : "Promise.reject"; |
| 145 | %DebugAsyncTaskEvent({ type: "enqueue", id: id, name: name }); |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | function PromiseIdResolveHandler(x) { return x } |
| 150 | function PromiseIdRejectHandler(r) { throw r } |
| 151 | |
| 152 | function PromiseNopResolver() {} |
| 153 | |
| 154 | // ------------------------------------------------------------------- |
| 155 | // Define exported functions. |
| 156 | |
| 157 | // For bootstrapper. |
| 158 | |
| 159 | IsPromise = function IsPromise(x) { |
| 160 | return IS_SPEC_OBJECT(x) && HAS_DEFINED_PRIVATE(x, promiseStatus); |
| 161 | } |
| 162 | |
| 163 | PromiseCreate = function PromiseCreate() { |
| 164 | return new $Promise(PromiseNopResolver) |
| 165 | } |
| 166 | |
| 167 | PromiseResolve = function PromiseResolve(promise, x) { |
| 168 | PromiseDone(promise, +1, x, promiseOnResolve) |
| 169 | } |
| 170 | |
| 171 | PromiseReject = function PromiseReject(promise, r) { |
| 172 | // Check promise status to confirm that this reject has an effect. |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 173 | // Call runtime for callbacks to the debugger or for unhandled reject. |
| 174 | if (GET_PRIVATE(promise, promiseStatus) == 0) { |
| 175 | var debug_is_active = DEBUG_IS_ACTIVE; |
| 176 | if (debug_is_active || !HAS_DEFINED_PRIVATE(promise, promiseHasHandler)) { |
| 177 | %PromiseRejectEvent(promise, r, debug_is_active); |
| 178 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 179 | } |
| 180 | PromiseDone(promise, -1, r, promiseOnReject) |
| 181 | } |
| 182 | |
| 183 | // Convenience. |
| 184 | |
| 185 | function PromiseDeferred() { |
| 186 | if (this === $Promise) { |
| 187 | // Optimized case, avoid extra closure. |
| 188 | var promise = PromiseInit(new $Promise(promiseRaw)); |
| 189 | return { |
| 190 | promise: promise, |
| 191 | resolve: function(x) { PromiseResolve(promise, x) }, |
| 192 | reject: function(r) { PromiseReject(promise, r) } |
| 193 | }; |
| 194 | } else { |
| 195 | var result = {}; |
| 196 | result.promise = new this(function(resolve, reject) { |
| 197 | result.resolve = resolve; |
| 198 | result.reject = reject; |
| 199 | }) |
| 200 | return result; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | function PromiseResolved(x) { |
| 205 | if (this === $Promise) { |
| 206 | // Optimized case, avoid extra closure. |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 207 | return PromiseCreateAndSet(+1, x); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 208 | } else { |
| 209 | return new this(function(resolve, reject) { resolve(x) }); |
| 210 | } |
| 211 | } |
| 212 | |
| 213 | function PromiseRejected(r) { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 214 | var promise; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 215 | if (this === $Promise) { |
| 216 | // Optimized case, avoid extra closure. |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 217 | promise = PromiseCreateAndSet(-1, r); |
| 218 | // The debug event for this would always be an uncaught promise reject, |
| 219 | // which is usually simply noise. Do not trigger that debug event. |
| 220 | %PromiseRejectEvent(promise, r, false); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 221 | } else { |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 222 | promise = new this(function(resolve, reject) { reject(r) }); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 223 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 224 | return promise; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 225 | } |
| 226 | |
| 227 | // Simple chaining. |
| 228 | |
| 229 | PromiseChain = function PromiseChain(onResolve, onReject) { // a.k.a. |
| 230 | // flatMap |
| 231 | onResolve = IS_UNDEFINED(onResolve) ? PromiseIdResolveHandler : onResolve; |
| 232 | onReject = IS_UNDEFINED(onReject) ? PromiseIdRejectHandler : onReject; |
| 233 | var deferred = %_CallFunction(this.constructor, PromiseDeferred); |
| 234 | switch (GET_PRIVATE(this, promiseStatus)) { |
| 235 | case UNDEFINED: |
| 236 | throw MakeTypeError('not_a_promise', [this]); |
| 237 | case 0: // Pending |
| 238 | GET_PRIVATE(this, promiseOnResolve).push(onResolve, deferred); |
| 239 | GET_PRIVATE(this, promiseOnReject).push(onReject, deferred); |
| 240 | break; |
| 241 | case +1: // Resolved |
| 242 | PromiseEnqueue(GET_PRIVATE(this, promiseValue), |
| 243 | [onResolve, deferred], |
| 244 | +1); |
| 245 | break; |
| 246 | case -1: // Rejected |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 247 | if (!HAS_DEFINED_PRIVATE(this, promiseHasHandler)) { |
| 248 | // Promise has already been rejected, but had no handler. |
| 249 | // Revoke previously triggered reject event. |
| 250 | %PromiseRevokeReject(this); |
| 251 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 252 | PromiseEnqueue(GET_PRIVATE(this, promiseValue), |
| 253 | [onReject, deferred], |
| 254 | -1); |
| 255 | break; |
| 256 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 257 | // Mark this promise as having handler. |
| 258 | SET_PRIVATE(this, promiseHasHandler, true); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 259 | if (DEBUG_IS_ACTIVE) { |
| 260 | %DebugPromiseEvent({ promise: deferred.promise, parentPromise: this }); |
| 261 | } |
| 262 | return deferred.promise; |
| 263 | } |
| 264 | |
| 265 | PromiseCatch = function PromiseCatch(onReject) { |
| 266 | return this.then(UNDEFINED, onReject); |
| 267 | } |
| 268 | |
| 269 | // Multi-unwrapped chaining with thenable coercion. |
| 270 | |
| 271 | PromiseThen = function PromiseThen(onResolve, onReject) { |
| 272 | onResolve = IS_SPEC_FUNCTION(onResolve) ? onResolve |
| 273 | : PromiseIdResolveHandler; |
| 274 | onReject = IS_SPEC_FUNCTION(onReject) ? onReject |
| 275 | : PromiseIdRejectHandler; |
| 276 | var that = this; |
| 277 | var constructor = this.constructor; |
| 278 | return %_CallFunction( |
| 279 | this, |
| 280 | function(x) { |
| 281 | x = PromiseCoerce(constructor, x); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 282 | if (x === that) { |
| 283 | DEBUG_PREPARE_STEP_IN_IF_STEPPING(onReject); |
| 284 | return onReject(MakeTypeError('promise_cyclic', [x])); |
| 285 | } else if (IsPromise(x)) { |
| 286 | return x.then(onResolve, onReject); |
| 287 | } else { |
| 288 | DEBUG_PREPARE_STEP_IN_IF_STEPPING(onResolve); |
| 289 | return onResolve(x); |
| 290 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 291 | }, |
| 292 | onReject, |
| 293 | PromiseChain |
| 294 | ); |
| 295 | } |
| 296 | |
| 297 | // Combinators. |
| 298 | |
| 299 | function PromiseCast(x) { |
| 300 | // TODO(rossberg): cannot do better until we support @@create. |
| 301 | return IsPromise(x) ? x : new this(function(resolve) { resolve(x) }); |
| 302 | } |
| 303 | |
| 304 | function PromiseAll(values) { |
| 305 | var deferred = %_CallFunction(this, PromiseDeferred); |
| 306 | var resolutions = []; |
| 307 | if (!%_IsArray(values)) { |
| 308 | deferred.reject(MakeTypeError('invalid_argument')); |
| 309 | return deferred.promise; |
| 310 | } |
| 311 | try { |
| 312 | var count = values.length; |
| 313 | if (count === 0) { |
| 314 | deferred.resolve(resolutions); |
| 315 | } else { |
| 316 | for (var i = 0; i < values.length; ++i) { |
| 317 | this.resolve(values[i]).then( |
| 318 | (function() { |
| 319 | // Nested scope to get closure over current i (and avoid .bind). |
| 320 | // TODO(rossberg): Use for-let instead once available. |
| 321 | var i_captured = i; |
| 322 | return function(x) { |
| 323 | resolutions[i_captured] = x; |
| 324 | if (--count === 0) deferred.resolve(resolutions); |
| 325 | }; |
| 326 | })(), |
| 327 | function(r) { deferred.reject(r) } |
| 328 | ); |
| 329 | } |
| 330 | } |
| 331 | } catch (e) { |
| 332 | deferred.reject(e) |
| 333 | } |
| 334 | return deferred.promise; |
| 335 | } |
| 336 | |
| 337 | function PromiseOne(values) { |
| 338 | var deferred = %_CallFunction(this, PromiseDeferred); |
| 339 | if (!%_IsArray(values)) { |
| 340 | deferred.reject(MakeTypeError('invalid_argument')); |
| 341 | return deferred.promise; |
| 342 | } |
| 343 | try { |
| 344 | for (var i = 0; i < values.length; ++i) { |
| 345 | this.resolve(values[i]).then( |
| 346 | function(x) { deferred.resolve(x) }, |
| 347 | function(r) { deferred.reject(r) } |
| 348 | ); |
| 349 | } |
| 350 | } catch (e) { |
| 351 | deferred.reject(e) |
| 352 | } |
| 353 | return deferred.promise; |
| 354 | } |
| 355 | |
| 356 | |
| 357 | // Utility for debugger |
| 358 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 359 | function PromiseHasUserDefinedRejectHandlerRecursive(promise) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 360 | var queue = GET_PRIVATE(promise, promiseOnReject); |
| 361 | if (IS_UNDEFINED(queue)) return false; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 362 | for (var i = 0; i < queue.length; i += 2) { |
| 363 | if (queue[i] != PromiseIdRejectHandler) return true; |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 364 | if (PromiseHasUserDefinedRejectHandlerRecursive(queue[i + 1].promise)) { |
| 365 | return true; |
| 366 | } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 367 | } |
| 368 | return false; |
| 369 | } |
| 370 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 371 | // Return whether the promise will be handled by a user-defined reject |
| 372 | // handler somewhere down the promise chain. For this, we do a depth-first |
| 373 | // search for a reject handler that's not the default PromiseIdRejectHandler. |
| 374 | PromiseHasUserDefinedRejectHandler = |
| 375 | function PromiseHasUserDefinedRejectHandler() { |
| 376 | return PromiseHasUserDefinedRejectHandlerRecursive(this); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 377 | }; |
| 378 | |
| 379 | // ------------------------------------------------------------------- |
| 380 | // Install exported functions. |
| 381 | |
| 382 | %CheckIsBootstrapping(); |
| 383 | %AddNamedProperty(global, 'Promise', $Promise, DONT_ENUM); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 384 | %AddNamedProperty( |
| 385 | $Promise.prototype, symbolToStringTag, "Promise", DONT_ENUM | READ_ONLY); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 386 | InstallFunctions($Promise, DONT_ENUM, [ |
| 387 | "defer", PromiseDeferred, |
| 388 | "accept", PromiseResolved, |
| 389 | "reject", PromiseRejected, |
| 390 | "all", PromiseAll, |
| 391 | "race", PromiseOne, |
| 392 | "resolve", PromiseCast |
| 393 | ]); |
| 394 | InstallFunctions($Promise.prototype, DONT_ENUM, [ |
| 395 | "chain", PromiseChain, |
| 396 | "then", PromiseThen, |
| 397 | "catch", PromiseCatch |
| 398 | ]); |
| 399 | |
| 400 | })(); |