gecko-dev/toolkit/components/utils/SimpleServices.jsm

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * Dumping ground for simple services for which the isolation of a full global
 * is overkill. Be careful about namespace pollution, and be mindful about
 * importing lots of JSMs in global scope, since this file will almost certainly
 * be loaded from enough callsites that any such imports will always end up getting
 * eagerly loaded at startup.
 */

"use strict";

/* globals WebExtensionPolicy */

const {XPCOMUtils} = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");

ChromeUtils.defineModuleGetter(this, "NetUtil",
                               "resource://gre/modules/NetUtil.jsm");
ChromeUtils.defineModuleGetter(this, "Services",
                               "resource://gre/modules/Services.jsm");

XPCOMUtils.defineLazyServiceGetter(this, "streamConv", "@mozilla.org/streamConverters;1",
                                   "nsIStreamConverterService");
const ArrayBufferInputStream = Components.Constructor(
  "@mozilla.org/io/arraybuffer-input-stream;1",
  "nsIArrayBufferInputStream", "setData");

/*
 * This class provides a stream filter for locale messages in CSS files served
 * by the moz-extension: protocol handler.
 *
 * See SubstituteChannel in netwerk/protocol/res/ExtensionProtocolHandler.cpp
 * for usage.
 */
function AddonLocalizationConverter() {
}

AddonLocalizationConverter.prototype = {
  QueryInterface: ChromeUtils.generateQI([Ci.nsIStreamConverter]),

  FROM_TYPE: "application/vnd.mozilla.webext.unlocalized",
  TO_TYPE: "text/css",

  checkTypes(aFromType, aToType) {
    if (aFromType != this.FROM_TYPE) {
      throw Components.Exception("Invalid aFromType value", Cr.NS_ERROR_INVALID_ARG,
                                 Components.stack.caller.caller);
    }
    if (aToType != this.TO_TYPE) {
      throw Components.Exception("Invalid aToType value", Cr.NS_ERROR_INVALID_ARG,
                                 Components.stack.caller.caller);
    }
  },

  // aContext must be a nsIURI object for a valid moz-extension: URL.
  getAddon(aContext) {
    // In this case, we want the add-on ID even if the URL is web accessible,
    // so check the root rather than the exact path.
    let uri = Services.io.newURI("/", null, aContext);

    let addon = WebExtensionPolicy.getByURI(uri);
    if (!addon) {
      throw new Components.Exception("Invalid context", Cr.NS_ERROR_INVALID_ARG);
    }
    return addon;
  },

  convertToStream(aAddon, aString) {
    aString = aAddon.localize(aString);
    let bytes = new TextEncoder().encode(aString).buffer;
    return new ArrayBufferInputStream(bytes, 0, bytes.byteLength);
  },

  convert(aStream, aFromType, aToType, aContext) {
    this.checkTypes(aFromType, aToType);
    let addon = this.getAddon(aContext);

    let count = aStream.available();
    let string = count ?
      new TextDecoder().decode(NetUtil.readInputStream(aStream, count)) : "";
    return this.convertToStream(addon, string);
  },

  asyncConvertData(aFromType, aToType, aListener, aContext) {
    this.checkTypes(aFromType, aToType);
    this.addon = this.getAddon(aContext);
    this.listener = aListener;
  },

  onStartRequest(aRequest) {
    this.parts = [];
    this.decoder = new TextDecoder();
  },

  onDataAvailable(aRequest, aInputStream, aOffset, aCount) {
    let bytes = NetUtil.readInputStream(aInputStream, aCount);
    this.parts.push(this.decoder.decode(bytes, {stream: true}));
  },

  onStopRequest(aRequest, aStatusCode) {
    try {
      this.listener.onStartRequest(aRequest, null);
      if (Components.isSuccessCode(aStatusCode)) {
        this.parts.push(this.decoder.decode());
        let string = this.parts.join("");
        let stream = this.convertToStream(this.addon, string);

        this.listener.onDataAvailable(aRequest, stream, 0, stream.available());
      }
    } catch (e) {
      aStatusCode = e.result || Cr.NS_ERROR_FAILURE;
    }
    this.listener.onStopRequest(aRequest, aStatusCode);
  },
};

function HttpIndexViewer() {
}

HttpIndexViewer.prototype = {
  QueryInterface: ChromeUtils.generateQI([Ci.nsIDocumentLoaderFactory]),

  createInstance(aCommand, aChannel, aLoadGroup, aContentType, aContainer,
                 aExtraInfo, aDocListenerResult) {
    aChannel.contentType = "text/html";

    let contract = Services.catMan.getCategoryEntry("Gecko-Content-Viewers", "text/html");
    let factory = Cc[contract].getService(Ci.nsIDocumentLoaderFactory);

    let listener = {};
    let res = factory.createInstance("view", aChannel, aLoadGroup,
                                     "text/html", aContainer, aExtraInfo,
                                     listener);

    aDocListenerResult.value =
      streamConv.asyncConvertData("application/http-index-format",
                                  "text/html", listener.value, null);

    return res;
  },
};

var EXPORTED_SYMBOLS = ["AddonLocalizationConverter", "HttpIndexViewer"];