[embedlite-components] Use promptForSaveToFileAsync. Contributes to J…

…B#49723

The promptForSaveToFile() method, used to determine the path to save
downloaded files to (usually the Downloads directory) has been removed
in favour of promptForSaveToFileAsync().

This change updates the code to use the async version.

The previous version had code for prompting the user with a file
dialogue box, but it didn't seem operational, so this has been removed.

jscomps/HelperAppDialog.js

@@ -12,6 +12,7 @@ const URI_GENERIC_ICON_DOWNLOAD = "drawable://alert_download";
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
 
 // -----------------------------------------------------------------------
 // HelperApp Launcher Dialog
@@ -40,105 +41,26 @@ HelperAppLauncherDialog.prototype = {
   promptForSaveToFileAsync: function hald_promptForSaveToFileAsync(aLauncher, aWindowContext, aDefaultFileName,
                                   aSuggestedFileExtension,
                                   aForcePrompt) {
-    dump("HelperAppLauncherDialog promptForSaveToFileAsync -- not supported\n");
-  },
+    dump("HelperAppLauncherDialog promptForSaveToFileAsync\n");
 
-  promptForSaveToFile: function hald_promptForSaveToFile(aLauncher, aContext, aDefaultFile, aSuggestedFileExt, aForcePrompt) {
-    let file = null;
-    let prefs = Services.prefs;
-    dump("HelperAppLauncherDialog promptForSaveToFile\n");
-
-    if (!aForcePrompt) {
-      // Check to see if the user wishes to auto save to the default download
-      // folder without prompting. Note that preference might not be set.
-      let autodownload = true;
+    // Even if aForcePrompt is set, we don't know what to do with it, so just ignore it
+    Task.spawn(function* () {
+      let file = null;
       try {
-        autodownload = prefs.getBoolPref(PREF_BD_USEDOWNLOADDIR);
-      } catch (e) { }
-
-      if (autodownload) {
-        // Retrieve the user's default download directory
         let dnldMgr = Cc["@mozilla.org/download-manager;1"].getService(Ci.nsIDownloadManager);
         let defaultFolder = dnldMgr.userDownloadsDirectory;
 
-        try {
-          file = this.validateLeafName(defaultFolder, aDefaultFile, aSuggestedFileExt);
-        }
-        catch (e) {
-        }
-
-        // Check to make sure we have a valid directory, otherwise, prompt
-        if (file) {
-          return file;
-        }
-      }
-    }
-
-    // Use file picker to show dialog.
-    let picker = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
-    let windowTitle = "";
-    let parent = aContext.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindow);
-    picker.init(parent, windowTitle, Ci.nsIFilePicker.modeSave);
-    picker.defaultString = aDefaultFile;
-
-    if (aSuggestedFileExt) {
-      // aSuggestedFileExtension includes the period, so strip it
-      picker.defaultExtension = aSuggestedFileExt.substring(1);
-    }
-    else {
-      try {
-        picker.defaultExtension = aLauncher.MIMEInfo.primaryExtension;
+        file = this.validateLeafName(defaultFolder, aDefaultFileName, aSuggestedFileExtension);
+      } finally {
+        // The file argument will be null in case any exception occurred.
+        aLauncher.saveDestinationAvailable(file);
       }
-      catch (e) { }
-    }
-
-    var wildCardExtension = "*";
-    if (aSuggestedFileExt) {
-      wildCardExtension += aSuggestedFileExt;
-      picker.appendFilter(aLauncher.MIMEInfo.description, wildCardExtension);
-    }
-
-    picker.appendFilters(Ci.nsIFilePicker.filterAll);
-
-    // Default to lastDir if it is valid, otherwise use the user's default
-    // downloads directory.  userDownloadsDirectory should always return a
-    // valid directory, so we can safely default to it.
-    var dnldMgr = Cc["@mozilla.org/download-manager;1"].getService(Ci.nsIDownloadManager);
-    picker.displayDirectory = dnldMgr.userDownloadsDirectory;
-
-    // The last directory preference may not exist, which will throw.
-    try {
-      let lastDir = prefs.getComplexValue("browser.download.lastDir", Ci.nsILocalFile);
-      if (isUsableDirectory(lastDir)) {
-        picker.displayDirectory = lastDir;
-      }
-    }
-    catch (e) { }
-
-    if (picker.show() == Ci.nsIFilePicker.returnCancel) {
-      // null result means user cancelled.
-      return null;
-    }
-
-    // Be sure to save the directory the user chose through the Save As...
-    // dialog  as the new browser.download.dir since the old one
-    // didn't exist.
-    file = picker.file;
+    }.bind(this)).catch(Cu.reportError);
+  },
 
-    if (file) {
-      try {
-        // Remove the file so that it's not there when we ensure non-existence later;
-        // this is safe because for the file to exist, the user would have had to
-        // confirm that he wanted the file overwritten.
-        if (file.exists())
-          file.remove(false);
-      }
-      catch (e) { }
-      var newDir = file.parent.QueryInterface(Ci.nsILocalFile);
-      prefs.setComplexValue("browser.download.lastDir", Ci.nsILocalFile, newDir);
-      file = this.validateLeafName(newDir, file.leafName, null);
-    }
-    return file;
+  promptForSaveToFile: function hald_promptForSaveToFile(aLauncher, aContext, aDefaultFile, aSuggestedFileExt, aForcePrompt) {
+    dump("HelperAppLauncherDialog promptForSaveToFile -- not supported\n");
+    throw Cr.NS_ERROR_NOT_AVAILABLE;
   },
 
   validateLeafName: function hald_validateLeafName(aLocalFile, aLeafName, aFileExt) {