drop.js

// This is cribbed from comm/mail/base/content/folderPane.js
gFolderTreeView.drop = function ftv_drop(aRow, aOrientation) {
  let targetFolder = gFolderTreeView._rowMap[aRow]._folder;

  let dt = this._currentTransfer;
  let count = dt.mozItemCount;
  let cs = MailServices.copy;

  // This is a potential rss feed.  A link image as well as link text url
  // should be handled; try to extract a url from non moz apps as well.
  let feedUri = targetFolder.server.type == "rss" && count == 1 ?
                  FeedUtils.getFeedUriFromDataTransfer(dt) : null;

  // we only support drag of a single flavor at a time.
  let types = Array.from(dt.mozTypesAt(0));
  if (types.includes("text/x-moz-folder")) {
    // BEGIN CHANGES
    // Moving folders is annoying if that's not actually what
    // somebody wanted to do.  So ASK FIRST.

    // get folder dragging pref
    let confirmFolderDrag = Services.prefs.getBoolPref("extensions.confirmfmv.drag.confirm");
    let promptService = Cc["@mozilla.org/embedcomp/prompt-service;1"]
                           .getService(Ci.nsIPromptService);
    let disableDrag = Services.prefs.getBoolPref("extensions.confirmfmv.drag.disableDialog");
    let confirmfmvBundle = document.getElementById("bundle_confirmfmv");
    let title = confirmfmvBundle.getString("confirmMoveFolderTitle");
    let text = confirmfmvBundle.getFormattedString("confirmMoveFolderText", [dt.mozGetDataAt("text/x-moz-folder", 0).QueryInterface(Ci.nsIMsgFolder).name]);
    if (confirmFolderDrag && disableDrag)
      return false;

    // if the user says no, then just fall out
    if (confirmFolderDrag) {
      if (!promptService.confirm(window, title, text))
        return false;
    }
    // END CHANGES

    for (let i = 0; i < count; i++) {
      let folders = new Array;
      folders.push(dt.mozGetDataAt("text/x-moz-folder", i)
                     .QueryInterface(Ci.nsIMsgFolder));
      let array = toXPCOMArray(folders, Ci.nsIMutableArray);
      cs.CopyFolders(array, targetFolder,
                    (folders[0].server == targetFolder.server), null,
                     msgWindow);
    }
  }
  else if (types.includes("text/x-moz-newsfolder")) {
    // Start by getting folders into order.
    let folders = new Array;
    for (let i = 0; i < count; i++) {
      let folder = dt.mozGetDataAt("text/x-moz-newsfolder", i)
                     .QueryInterface(Ci.nsIMsgFolder);
      folders[this.getIndexOfFolder(folder)] = folder;
    }
    let newsFolder = targetFolder.rootFolder
                                 .QueryInterface(Ci.nsIMsgNewsFolder);
    // When moving down, want to insert first one last.
    // When moving up, want to insert first one first.
    let i = (aOrientation == 1) ? folders.length - 1 : 0;
    while (i >= 0 && i < folders.length) {
      let folder = folders[i];
      if (folder) {
        newsFolder.moveFolder(folder, targetFolder, aOrientation);
        this.selection.toggleSelect(this.getIndexOfFolder(folder));
      }
      i -= aOrientation;
    }
  }
  else if (types.includes("text/x-moz-message")) {
    let array = Cc["@mozilla.org/array;1"]
                  .createInstance(Ci.nsIMutableArray);
    let sourceFolder;
    let messenger = Cc["@mozilla.org/messenger;1"].createInstance(Ci.nsIMessenger);
    for (let i = 0; i < count; i++) {
      let msgHdr = messenger.msgHdrFromURI(dt.mozGetDataAt("text/x-moz-message", i));
      if (!i)
        sourceFolder = msgHdr.folder;
      array.appendElement(msgHdr);
    }
    let prefBranch = Services.prefs.getBranch("mail.");
    let isMove = Cc["@mozilla.org/widget/dragservice;1"]
                    .getService(Ci.nsIDragService).getCurrentSession()
                    .dragAction == Ci.nsIDragService.DRAGDROP_ACTION_MOVE;
    if (!sourceFolder.canDeleteMessages)
      isMove = false;

    prefBranch.setCharPref("last_msg_movecopy_target_uri", targetFolder.URI);
    prefBranch.setBoolPref("last_msg_movecopy_was_move", isMove);
    // ### ugh, so this won't work with cross-folder views. We would
    // really need to partition the messages by folder.
    cs.CopyMessages(sourceFolder, array, targetFolder, isMove, null,
                      msgWindow, true);
  }
  else if (feedUri) {
    Cc["@mozilla.org/newsblog-feed-downloader;1"]
       .getService(Ci.nsINewsBlogFeedDownloader)
       .subscribeToFeed(feedUri.spec, targetFolder, msgWindow);
  }
  else if (types.includes("application/x-moz-file")) {
    for (let i = 0; i < count; i++) {
      let extFile = dt.mozGetDataAt("application/x-moz-file", i)
                      .QueryInterface(Ci.nsIFile);
      if (extFile.isFile()) {
        let len = extFile.leafName.length;
        if (len > 4 && extFile.leafName.toLowerCase().endsWith(".eml"))
          cs.CopyFileMessage(extFile, targetFolder, null, false, 1, "", null, msgWindow);
      }
    }
  }
}