Bug 60708; prevent user from creating helper app entries with blank mime type fields; r=pchen, sr=ben

suite/common/pref/overrideHandler.js

@@ -403,3 +403,22 @@ function removeOverride(aMIMEType)
     }
   }
 }
+
+function checkInput() {
+  var result = true;
+  // Check for empty MIME type field.
+  if ( gMIMEField.value == "" ) {
+    // Input is not OK.
+    result = false;
+
+    // Focus the mime type field.
+    gMIMEField.focus();
+
+    // Put up alert.  Title is same as parent dialog's.
+    var title    = window.document.documentElement.getAttribute( "title" );
+    var text     = gPrefApplicationsBundle.getString("emptyMIMEType");
+    var prompter = Components.classes["@mozilla.org/embedcomp/prompt-service;1"].getService(Components.interfaces.nsIPromptService);
+    prompter.alert(window, title, text);
+  }
+  return result;
+}

suite/common/pref/pref-applications-edit.xul

@@ -178,6 +178,10 @@
 
     function onAccept()
     {
+      // Validate input.
+      if ( !checkInput() ) {
+        return false;
+      }
       getDS();
       // figure out if this mime type already exists. 
       if (gMIMEField.value != gOldMIME) {

suite/locales/en-US/chrome/common/pref/pref-applications.properties

@@ -9,5 +9,7 @@ programsFilter=Programs
 handlerExists=A helper already exists for the MIME type '%mime%'. Do you want to replace it? 
 handlerExistsTitle=Helper Application Exists
 
+emptyMIMEType=You must specify a MIME type.
+
 removeHandlerTitle=Remove File Type
-removeHandler=If you remove a registered type, the helper will no longer be able to automatically handle files of this type. %n%nAre you sure you want to remove this file type? 
+removeHandler=If you remove a registered type, the helper will no longer be able to automatically handle files of this type. %n%nAre you sure you want to remove this file type?