1 files changed, 168 insertions, 0 deletions
diff --git a/dom/manifest/ManifestObtainer.jsm b/dom/manifest/ManifestObtainer.jsm
new file mode 100644
index 0000000000..e477e495c3
--- /dev/null
+++ b/dom/manifest/ManifestObtainer.jsm
@@ -0,0 +1,168 @@
+/* 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/.
+ */
+/*
+ * ManifestObtainer is an implementation of:
+ * http://w3c.github.io/manifest/#obtaining
+ *
+ * Exposes 2 public method:
+ *
+ *  .contentObtainManifest(aContent) - used in content process
+ *  .browserObtainManifest(aBrowser) - used in browser/parent process
+ *
+ * both return a promise. If successful, you get back a manifest object.
+ *
+ * Import it with URL:
+ *   'chrome://global/content/manifestMessages.js'
+ *
+ * e10s IPC message from this components are handled by:
+ *   dom/ipc/manifestMessages.js
+ *
+ * Which is injected into every browser instance via browser.js.
+ */
+"use strict";
+
+const { ManifestProcessor } = ChromeUtils.import(
+  "resource://gre/modules/ManifestProcessor.jsm"
+);
+
+var ManifestObtainer = {
+  /**
+   * Public interface for obtaining a web manifest from a XUL browser, to use
+   * on the parent process.
+   * @param  {XULBrowser} The browser to check for the manifest.
+   * @param {Object} aOptions
+   * @param {Boolean} aOptions.checkConformance If spec conformance messages should be collected.
+   *                                            Adds proprietary moz_* members to manifest.
+   * @return {Promise<Object>} The processed manifest.
+   */
+  async browserObtainManifest(
+    aBrowser,
+    aOptions = { checkConformance: false }
+  ) {
+    if (!isXULBrowser(aBrowser)) {
+      throw new TypeError("Invalid input. Expected XUL browser.");
+    }
+
+    const actor = aBrowser.browsingContext.currentWindowGlobal.getActor(
+      "ManifestMessages"
+    );
+
+    const reply = await actor.sendQuery(
+      "DOM:ManifestObtainer:Obtain",
+      aOptions
+    );
+    if (!reply.success) {
+      const error = toError(reply.result);
+      throw error;
+    }
+    return reply.result;
+  },
+  /**
+   * Public interface for obtaining a web manifest from a XUL browser.
+   * @param {Window} aContent A content Window from which to extract the manifest.
+   * @param {Object} aOptions
+   * @param {Boolean} aOptions.checkConformance If spec conformance messages should be collected.
+   *                                            Adds proprietary moz_* members to manifest.
+   * @return {Promise<Object>} The processed manifest.
+   */
+  async contentObtainManifest(
+    aContent,
+    aOptions = { checkConformance: false }
+  ) {
+    if (!Services.prefs.getBoolPref("dom.manifest.enabled")) {
+      throw new Error(
+        "Obtaining manifest is disabled by pref: dom.manifest.enabled"
+      );
+    }
+    if (!aContent || isXULBrowser(aContent)) {
+      const err = new TypeError("Invalid input. Expected a DOM Window.");
+      return Promise.reject(err);
+    }
+    const response = await fetchManifest(aContent);
+    const result = await processResponse(response, aContent, aOptions);
+    const clone = Cu.cloneInto(result, aContent);
+    return clone;
+  },
+};
+
+function toError(aErrorClone) {
+  let error;
+  switch (aErrorClone.name) {
+    case "TypeError":
+      error = new TypeError();
+      break;
+    default:
+      error = new Error();
+  }
+  Object.getOwnPropertyNames(aErrorClone).forEach(
+    name => (error[name] = aErrorClone[name])
+  );
+  return error;
+}
+
+function isXULBrowser(aBrowser) {
+  if (!aBrowser || !aBrowser.namespaceURI || !aBrowser.localName) {
+    return false;
+  }
+  const XUL_NS =
+    "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+  return aBrowser.namespaceURI === XUL_NS && aBrowser.localName === "browser";
+}
+
+/**
+ * Asynchronously processes the result of response after having fetched
+ * a manifest.
+ * @param {Response} aResp Response from fetch().
+ * @param {Window} aContentWindow The content window.
+ * @return {Promise<Object>} The processed manifest.
+ */
+async function processResponse(aResp, aContentWindow, aOptions) {
+  const badStatus = aResp.status < 200 || aResp.status >= 300;
+  if (aResp.type === "error" || badStatus) {
+    const msg = `Fetch error: ${aResp.status} - ${aResp.statusText} at ${aResp.url}`;
+    throw new Error(msg);
+  }
+  const text = await aResp.text();
+  const args = {
+    jsonText: text,
+    manifestURL: aResp.url,
+    docURL: aContentWindow.location.href,
+  };
+  const processingOptions = Object.assign({}, args, aOptions);
+  const manifest = ManifestProcessor.process(processingOptions);
+  return manifest;
+}
+
+/**
+ * Asynchronously fetches a web manifest.
+ * @param {Window} a The content Window from where to extract the manifest.
+ * @return {Promise<Object>}
+ */
+async function fetchManifest(aWindow) {
+  if (!aWindow || aWindow.top !== aWindow) {
+    const msg = "Window must be a top-level browsing context.";
+    throw new Error(msg);
+  }
+  const elem = aWindow.document.querySelector("link[rel~='manifest']");
+  if (!elem || !elem.getAttribute("href")) {
+    // There is no actual manifest to fetch, we just return null.
+    return new aWindow.Response("null");
+  }
+  // Throws on malformed URLs
+  const manifestURL = new aWindow.URL(elem.href, elem.baseURI);
+  const reqInit = {
+    credentials: "omit",
+    mode: "cors",
+  };
+  if (elem.crossOrigin === "use-credentials") {
+    reqInit.credentials = "include";
+  }
+  const request = new aWindow.Request(manifestURL, reqInit);
+  request.overrideContentPolicyType(Ci.nsIContentPolicy.TYPE_WEB_MANIFEST);
+  // Can reject...
+  return aWindow.fetch(request);
+}
+
+var EXPORTED_SYMBOLS = ["ManifestObtainer"];