| /* |
| * Copyright (C) 2015, 2016 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| // https://whatwg.github.io/loader/#loader-object |
| // Module Loader has several hooks that can be customized by the platform. |
| // For example, the [[Fetch]] hook can be provided by the JavaScriptCore shell |
| // as fetching the payload from the local file system. |
| // Currently, there are 4 hooks. |
| // 1. Loader.resolve |
| // 2. Loader.fetch |
| |
| @globalPrivate |
| function setStateToMax(entry, newState) |
| { |
| // https://whatwg.github.io/loader/#set-state-to-max |
| |
| "use strict"; |
| |
| if (entry.state < newState) |
| entry.state = newState; |
| } |
| |
| @globalPrivate |
| function newRegistryEntry(key) |
| { |
| // https://whatwg.github.io/loader/#registry |
| // |
| // Each registry entry becomes one of the 5 states. |
| // 1. Fetch |
| // Ready to fetch (or now fetching) the resource of this module. |
| // Typically, we fetch the source code over the network or from the file system. |
| // a. If the status is Fetch and there is no entry.fetch promise, the entry is ready to fetch. |
| // b. If the status is Fetch and there is the entry.fetch promise, the entry is just fetching the resource. |
| // |
| // 2. Instantiate (AnalyzeModule) |
| // Ready to instantiate (or now instantiating) the module record from the fetched |
| // source code. |
| // Typically, we parse the module code, extract the dependencies and binding information. |
| // a. If the status is Instantiate and there is no entry.instantiate promise, the entry is ready to instantiate. |
| // b. If the status is Instantiate and there is the entry.fetch promise, the entry is just instantiating |
| // the module record. |
| // |
| // 3. Satisfy |
| // Ready to request the dependent modules (or now requesting & resolving). |
| // Without this state, the current draft causes infinite recursion when there is circular dependency. |
| // a. If the status is Satisfy and there is no entry.satisfy promise, the entry is ready to resolve the dependencies. |
| // b. If the status is Satisfy and there is the entry.satisfy promise, the entry is just resolving |
| // the dependencies. |
| // |
| // 4. Link |
| // Ready to link the module with the other modules. |
| // Linking means that the module imports and exports the bindings from/to the other modules. |
| // |
| // 5. Ready |
| // The module is linked, so the module is ready to be executed. |
| // |
| // Each registry entry has the 4 promises; "fetch", "instantiate" and "satisfy". |
| // They are assigned when starting the each phase. And they are fulfilled when the each phase is completed. |
| // |
| // In the current module draft, linking will be performed after the whole modules are instantiated and the dependencies are resolved. |
| // And execution is also done after the all modules are linked. |
| // |
| // TODO: We need to exploit the way to execute the module while fetching non-related modules. |
| // One solution; introducing the ready promise chain to execute the modules concurrently while keeping |
| // the execution order. |
| |
| "use strict"; |
| |
| return { |
| key: key, |
| state: @ModuleFetch, |
| fetch: @undefined, |
| instantiate: @undefined, |
| satisfy: @undefined, |
| dependencies: [], // To keep the module order, we store the module keys in the array. |
| dependenciesMap: @undefined, |
| module: @undefined, // JSModuleRecord |
| linkError: @undefined, |
| linkSucceeded: true, |
| evaluated: false, |
| }; |
| } |
| |
| function ensureRegistered(key) |
| { |
| // https://whatwg.github.io/loader/#ensure-registered |
| |
| "use strict"; |
| |
| var entry = this.registry.@get(key); |
| if (entry) |
| return entry; |
| |
| entry = @newRegistryEntry(key); |
| this.registry.@set(key, entry); |
| |
| return entry; |
| } |
| |
| function forceFulfillPromise(promise, value) |
| { |
| "use strict"; |
| |
| if (promise.@promiseState === @promiseStatePending) |
| @fulfillPromise(promise, value); |
| } |
| |
| function fulfillFetch(entry, source) |
| { |
| // https://whatwg.github.io/loader/#fulfill-fetch |
| |
| "use strict"; |
| |
| if (!entry.fetch) |
| entry.fetch = @newPromiseCapability(@InternalPromise).@promise; |
| this.forceFulfillPromise(entry.fetch, source); |
| @setStateToMax(entry, @ModuleInstantiate); |
| } |
| |
| // Loader. |
| |
| function requestFetch(entry, parameters, fetcher) |
| { |
| // https://whatwg.github.io/loader/#request-fetch |
| |
| "use strict"; |
| |
| if (entry.fetch) { |
| var currentAttempt = entry.fetch; |
| if (entry.state !== @ModuleFetch) |
| return currentAttempt; |
| |
| return currentAttempt.catch((error) => { |
| // Even if the existing fetching request failed, this attempt may succeed. |
| // For example, previous attempt used invalid integrity="" value. But this |
| // request could have the correct integrity="" value. In that case, we should |
| // retry fetching for this request. |
| // https://html.spec.whatwg.org/#fetch-a-single-module-script |
| if (currentAttempt === entry.fetch) |
| entry.fetch = @undefined; |
| return this.requestFetch(entry, parameters, fetcher); |
| }); |
| } |
| |
| // Hook point. |
| // 2. Loader.fetch |
| // https://whatwg.github.io/loader/#browser-fetch |
| // Take the key and fetch the resource actually. |
| // For example, JavaScriptCore shell can provide the hook fetching the resource |
| // from the local file system. |
| var fetchPromise = this.fetch(entry.key, parameters, fetcher).then((source) => { |
| @setStateToMax(entry, @ModuleInstantiate); |
| return source; |
| }); |
| entry.fetch = fetchPromise; |
| return fetchPromise; |
| } |
| |
| function requestInstantiate(entry, parameters, fetcher) |
| { |
| // https://whatwg.github.io/loader/#request-instantiate |
| |
| "use strict"; |
| |
| // entry.instantiate is set if fetch succeeds. |
| if (entry.instantiate) |
| return entry.instantiate; |
| |
| var instantiatePromise = this.requestFetch(entry, parameters, fetcher).then((source) => { |
| // https://html.spec.whatwg.org/#fetch-a-single-module-script |
| // Now fetching request succeeds. Then even if instantiation fails, we should cache it. |
| // Instantiation won't be retried. |
| if (entry.instantiate) |
| return entry.instantiate; |
| entry.instantiate = instantiatePromise; |
| |
| var key = entry.key; |
| var moduleRecord = this.parseModule(key, source); |
| var dependenciesMap = moduleRecord.dependenciesMap; |
| var requestedModules = this.requestedModules(moduleRecord); |
| var dependencies = @newArrayWithSize(requestedModules.length); |
| for (var i = 0, length = requestedModules.length; i < length; ++i) { |
| var depName = requestedModules[i]; |
| var depKey = this.resolveSync(depName, key, fetcher); |
| var depEntry = this.ensureRegistered(depKey); |
| @putByValDirect(dependencies, i, depEntry); |
| dependenciesMap.@set(depName, depEntry); |
| } |
| entry.dependencies = dependencies; |
| entry.dependenciesMap = dependenciesMap; |
| entry.module = moduleRecord; |
| @setStateToMax(entry, @ModuleSatisfy); |
| return entry; |
| }); |
| return instantiatePromise; |
| } |
| |
| function requestSatisfy(entry, parameters, fetcher, visited) |
| { |
| // https://html.spec.whatwg.org/#internal-module-script-graph-fetching-procedure |
| |
| "use strict"; |
| |
| if (entry.satisfy) |
| return entry.satisfy; |
| |
| visited.@add(entry); |
| var satisfyPromise = this.requestInstantiate(entry, parameters, fetcher).then((entry) => { |
| if (entry.satisfy) |
| return entry.satisfy; |
| |
| var depLoads = @newArrayWithSize(entry.dependencies.length); |
| for (var i = 0, length = entry.dependencies.length; i < length; ++i) { |
| var depEntry = entry.dependencies[i]; |
| var promise; |
| |
| // Recursive resolving. The dependencies of this entry is being resolved or already resolved. |
| // Stop tracing the circular dependencies. |
| // But to retrieve the instantiated module record correctly, |
| // we need to wait for the instantiation for the dependent module. |
| // For example, reaching here, the module is starting resolving the dependencies. |
| // But the module may or may not reach the instantiation phase in the loader's pipeline. |
| // If we wait for the Satisfy for this module, it construct the circular promise chain and |
| // rejected by the Promises runtime. Since only we need is the instantiated module, instead of waiting |
| // the Satisfy for this module, we just wait Instantiate for this. |
| if (visited.@has(depEntry)) |
| promise = this.requestInstantiate(depEntry, @undefined, fetcher); |
| else { |
| // Currently, module loader do not pass any information for non-top-level module fetching. |
| promise = this.requestSatisfy(depEntry, @undefined, fetcher, visited); |
| } |
| @putByValDirect(depLoads, i, promise); |
| } |
| |
| return @InternalPromise.internalAll(depLoads).then((entries) => { |
| if (entry.satisfy) |
| return entry; |
| @setStateToMax(entry, @ModuleLink); |
| entry.satisfy = satisfyPromise; |
| return entry; |
| }); |
| }); |
| |
| return satisfyPromise; |
| } |
| |
| // Linking semantics. |
| |
| function link(entry, fetcher) |
| { |
| // https://html.spec.whatwg.org/#fetch-the-descendants-of-and-instantiate-a-module-script |
| |
| "use strict"; |
| |
| if (!entry.linkSucceeded) |
| throw entry.linkError; |
| if (entry.state === @ModuleReady) |
| return; |
| @setStateToMax(entry, @ModuleReady); |
| |
| try { |
| // Since we already have the "dependencies" field, |
| // we can call moduleDeclarationInstantiation with the correct order |
| // without constructing the dependency graph by calling dependencyGraph. |
| var dependencies = entry.dependencies; |
| for (var i = 0, length = dependencies.length; i < length; ++i) |
| this.link(dependencies[i], fetcher); |
| |
| this.moduleDeclarationInstantiation(entry.module, entry.key, fetcher); |
| } catch (error) { |
| entry.linkSucceeded = false; |
| entry.linkError = error; |
| throw error; |
| } |
| } |
| |
| // Module semantics. |
| |
| function moduleEvaluation(entry, fetcher) |
| { |
| // http://www.ecma-international.org/ecma-262/6.0/#sec-moduleevaluation |
| |
| "use strict"; |
| |
| if (entry.evaluated) |
| return; |
| entry.evaluated = true; |
| |
| // The contents of the [[RequestedModules]] is cloned into entry.dependencies. |
| var dependencies = entry.dependencies; |
| for (var i = 0, length = dependencies.length; i < length; ++i) |
| this.moduleEvaluation(dependencies[i], fetcher); |
| |
| this.evaluate(entry.key, entry.module, fetcher); |
| } |
| |
| // APIs to control the module loader. |
| |
| function provideFetch(key, value) |
| { |
| "use strict"; |
| |
| var entry = this.ensureRegistered(key); |
| |
| if (entry.state > @ModuleFetch) |
| @throwTypeError("Requested module is already fetched."); |
| this.fulfillFetch(entry, value); |
| } |
| |
| function loadModule(moduleName, parameters, fetcher) |
| { |
| "use strict"; |
| |
| // Loader.resolve hook point. |
| // resolve: moduleName => Promise(moduleKey) |
| // Take the name and resolve it to the unique identifier for the resource location. |
| // For example, take the "jquery" and return the URL for the resource. |
| return this.resolve(moduleName, @undefined, fetcher).then((key) => { |
| return this.requestSatisfy(this.ensureRegistered(key), parameters, fetcher, new @Set); |
| }).then((entry) => { |
| return entry.key; |
| }); |
| } |
| |
| function linkAndEvaluateModule(key, fetcher) |
| { |
| "use strict"; |
| |
| var entry = this.ensureRegistered(key); |
| if (entry.state < @ModuleLink) |
| @throwTypeError("Requested module is not instantiated yet."); |
| |
| this.link(entry, fetcher); |
| return this.moduleEvaluation(entry, fetcher); |
| } |
| |
| function loadAndEvaluateModule(moduleName, parameters, fetcher) |
| { |
| "use strict"; |
| |
| return this.loadModule(moduleName, parameters, fetcher).then((key) => { |
| return this.linkAndEvaluateModule(key, fetcher); |
| }); |
| } |
| |
| function requestImportModule(key, parameters, fetcher) |
| { |
| "use strict"; |
| |
| return this.requestSatisfy(this.ensureRegistered(key), parameters, fetcher, new @Set).then((entry) => { |
| this.linkAndEvaluateModule(entry.key, fetcher); |
| return this.getModuleNamespaceObject(entry.module); |
| }); |
| } |