125 lines
3.4 KiB
JavaScript
125 lines
3.4 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @format
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*/
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/**
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* This file is a copy of the reference `DeltaPatcher`, located in
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* metro. The reason to not reuse that file is that in this context
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* we cannot have flow annotations or CJS syntax (since this file is directly)
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* injected into a static HTML page.
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*
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* TODO: Find a simple and lightweight way to compile `DeltaPatcher` to avoid
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* having this duplicated file.
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*/
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(function(global) {
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'use strict';
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/**
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* This is a reference client for the Delta Bundler: it maintains cached the
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* last patched bundle delta and it's capable of applying new Deltas received
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* from the Bundler.
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*/
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class DeltaPatcher {
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constructor() {
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this._lastBundle = {
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pre: new Map(),
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post: new Map(),
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modules: new Map(),
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};
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this._initialized = false;
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this._lastNumModifiedFiles = 0;
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this._lastModifiedDate = new Date();
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}
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static get(id) {
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let deltaPatcher = this._deltaPatchers.get(id);
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if (!deltaPatcher) {
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deltaPatcher = new DeltaPatcher();
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this._deltaPatchers.set(id, deltaPatcher);
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}
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return deltaPatcher;
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}
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/**
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* Applies a Delta Bundle to the current bundle.
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*/
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applyDelta(deltaBundle) {
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// Make sure that the first received delta is a fresh one.
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if (!this._initialized && !deltaBundle.reset) {
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throw new Error(
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'DeltaPatcher should receive a fresh Delta when being initialized',
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);
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}
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this._initialized = true;
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// Reset the current delta when we receive a fresh delta.
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if (deltaBundle.reset) {
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this._lastBundle = {
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pre: new Map(),
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post: new Map(),
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modules: new Map(),
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};
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}
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this._lastNumModifiedFiles =
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deltaBundle.pre.size + deltaBundle.post.size + deltaBundle.delta.size;
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if (this._lastNumModifiedFiles > 0) {
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this._lastModifiedDate = new Date();
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}
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this._patchMap(this._lastBundle.pre, deltaBundle.pre);
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this._patchMap(this._lastBundle.post, deltaBundle.post);
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this._patchMap(this._lastBundle.modules, deltaBundle.delta);
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return this;
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}
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/**
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* Returns the number of modified files in the last received Delta. This is
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* currently used to populate the `X-Metro-Files-Changed-Count` HTTP header
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* when metro serves the whole JS bundle, and can potentially be removed once
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* we only send the actual deltas to clients.
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*/
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getLastNumModifiedFiles() {
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return this._lastNumModifiedFiles;
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}
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getLastModifiedDate() {
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return this._lastModifiedDate;
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}
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getAllModules() {
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return [].concat(
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Array.from(this._lastBundle.pre.values()),
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Array.from(this._lastBundle.modules.values()),
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Array.from(this._lastBundle.post.values()),
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);
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}
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_patchMap(original, patch) {
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for (const [key, value] of patch.entries()) {
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if (value == null) {
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original.delete(key);
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} else {
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original.set(key, value);
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}
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}
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}
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}
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DeltaPatcher._deltaPatchers = new Map();
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global.DeltaPatcher = DeltaPatcher;
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})(window);
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