1 files changed, 71 insertions, 0 deletions
diff --git a/comm/mailnews/imap/src/ImapFolderContentHandler.sys.mjs b/comm/mailnews/imap/src/ImapFolderContentHandler.sys.mjs
new file mode 100644
index 0000000000..da33c08829
--- /dev/null
+++ b/comm/mailnews/imap/src/ImapFolderContentHandler.sys.mjs
@@ -0,0 +1,71 @@
+/* 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/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const { MailServices } = ChromeUtils.import(
+  "resource:///modules/MailServices.jsm"
+);
+
+const lazy = {};
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  MailUtils: "resource:///modules/MailUtils.jsm",
+});
+
+/**
+ * A service for handling content type x-application-imapfolder;
+ * that is, opening IMAP folder URLs.
+ *
+ * Set mailnews.imap.jsmodule to true to use this module.
+ *
+ * @implements {nsIContentHandler}
+ */
+export class ImapFolderContentHandler {
+  QueryInterface = ChromeUtils.generateQI(["nsIContentHandler"]);
+
+  /**
+   * @param contentType - The content type of request.
+   * @param windowContest - Window context, used to get things like the current
+   *   nsIDOMWindow for this request.
+   * @param request - A request whose content type is already known.
+   * @see {nsIContentHandler}
+   */
+  handleContent(contentType, windowContext, request) {
+    if (contentType != "x-application-imapfolder") {
+      throw Components.Exception(
+        `Won't handle ${contentType}`,
+        Cr.NS_ERROR_WONT_HANDLE_CONTENT
+      );
+    }
+    request = request.QueryInterface(Ci.nsIChannel);
+
+    let imapFolderURL = Services.io.unescapeString(
+      request.URI.spec,
+      Ci.nsINetUtil.ESCAPE_URL_PATH
+    );
+
+    if (Services.wm.getMostRecentWindow("mail:3pane")) {
+      // Clicked IMAP folder URL in the window.
+      let folder = MailServices.folderLookup.getFolderForURL(imapFolderURL);
+      if (folder) {
+        lazy.MailUtils.displayFolderIn3Pane(folder.URI);
+      } else {
+        folder =
+          MailServices.folderLookup.getOrCreateFolderForURL(imapFolderURL);
+        // TODO: ask and maybe subscribe, like
+        // https://searchfox.org/comm-central/rev/1dd06be9d6c1178a34e6c28db03161e07e97d98c/mailnews/imap/src/nsImapService.cpp#2471-2534
+        dump(`Maybe subscribe to folder ${folder.URI}\n`);
+      }
+    } else {
+      // Got IMAP folder URL from command line (most likely).
+      Cc["@mozilla.org/messenger/windowservice;1"]
+        .getService(Ci.nsIMessengerWindowService)
+        .openMessengerWindowWithUri("mail:3pane", imapFolderURL, -1);
+    }
+  }
+}
+
+ImapFolderContentHandler.prototype.classID = Components.ID(
+  "{d927a82f-2d15-4972-ab88-6d84601aae68}"
+);