Files
react-native/local-cli/server/util/debugger-ui/DeltaPatcher.js
Alexandre Kirszenberg 1eedf05651 Update the Delta/HMR format
Summary:
Makes the delta bundle data structures more consistent.

The changes are as follows:
* There are now two types of JSON bundles that can be downloaded from the delta endpoint. Base bundles (`Bundle` type), and Delta bundles (`DeltaBundle` type).
* The `reset` boolean is renamed to `base`.
* `pre` and `post` properties are now strings.
* Only `Bundle` can define `pre` and `post` properties.
* The `delta` property is renamed to `modules`.
* Deleted modules are now listed inside of the `deleted` property, which is only defined by `DeltaBundle`.

Reviewed By: mjesun

Differential Revision: D10446831

fbshipit-source-id: 40e229a2811d48950f0bad8dd341ece189089e9b
2018-10-29 08:58:30 -07:00

128 lines
3.2 KiB
JavaScript

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