bug 331259: make the helper apps dialog create the urn:mimetypes:root resource if it doesn't already exist so checking the 'do this automatically for files like this from now on' checkbox saves that pref to the helper apps datasource and thus has an effect on future downloads of same file type; r=sdwilsh,myk

toolkit/mozapps/downloads/content/helperApps.js

@@ -36,8 +36,22 @@
 #
 # ***** END LICENSE BLOCK *****
 
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+
 var gRDF;    
 
+const CLASS_MIMEINFO        = "mimetype";
+const CLASS_PROTOCOLINFO    = "scheme";
+
+// namespace prefix
+const NC_NS                 = "http://home.netscape.com/NC-rdf#";
+
+// type list properties
+
+const NC_MIME_TYPES         = NC_NS + "MIME-types";
+const NC_PROTOCOL_SCHEMES   = NC_NS + "Protocol-Schemes";
+
 ///////////////////////////////////////////////////////////////////////////////
 // MIME Types DataSource Wrapper
 
@@ -616,17 +630,10 @@ HandlerOverride.prototype = {
     var helperAppResource = gRDF.GetUnicodeResource(APP_URI(this.mimeType));
     this._DS.Assert(handlerResource, helperAppProperty, helperAppResource, true);
     // add the mime type to the MIME types seq
-    var container = Components.classes["@mozilla.org/rdf/container;1"].createInstance();
-    if (container) {
-      container = container.QueryInterface(Components.interfaces.nsIRDFContainer);
-      if (container) {
-        var containerRes = gRDF.GetUnicodeResource("urn:mimetypes:root");
-        container.Init(this._DS, containerRes);
-        var element = gRDF.GetUnicodeResource(MIME_URI(this.mimeType));
-        if (container.IndexOf(element) == -1)
-          container.AppendElement(element);
-      }
-    }
+    var container = this.ensureAndGetTypeList("mimetype");
+    var element = gRDF.GetUnicodeResource(MIME_URI(this.mimeType));
+    if (container.IndexOf(element) == -1)
+      container.AppendElement(element);
   }, 
   
   // Implementation helper methods
@@ -698,6 +705,43 @@ HandlerOverride.prototype = {
     var valueProperty = gRDF.GetUnicodeResource(NC_URI(aPropertyString));
     var mimeLiteral = gRDF.GetLiteral(aValueString);
     this._DS.Unassert(mimeSource, valueProperty, mimeLiteral, true);
+  },
+
+  /**
+   * Get the list of types for the given class, creating the list if it doesn't
+   * already exist. The class can be either CLASS_MIMEINFO or CLASS_PROTOCOLINFO
+   * (i.e. the result of a call to _getClass).
+   * 
+   * |urn:<class>s|
+   * |urn:<class>s:root|
+   * 
+   * @param aClass {string} the class for which to retrieve a list of types
+   *
+   * @returns {nsIRDFContainer} the list of types
+   */
+  ensureAndGetTypeList: function (aClass) {
+    var source = gRDF.GetResource("urn:" + aClass + "s");
+    var property =
+      gRDF.GetResource(aClass == CLASS_MIMEINFO ? NC_MIME_TYPES
+                                                : NC_PROTOCOL_SCHEMES);
+    var target = gRDF.GetResource("urn:" + aClass + "s:root");
+
+    // Make sure we have an arc from the source to the target.
+    if (!this._DS.HasAssertion(source, property, target, true))
+      this._DS.Assert(source, property, target, true);
+
+    // Make sure the target is a container.
+    var containerUtils = Cc["@mozilla.org/rdf/container-utils;1"]
+                            .getService(Ci.nsIRDFContainerUtils);
+    if (!containerUtils.IsContainer(this._DS, target))
+      containerUtils.MakeSeq(this._DS, target);
+
+    // Get the type list as an RDF container.
+    var typeList =
+          Cc["@mozilla.org/rdf/container;1"].createInstance(Ci.nsIRDFContainer);
+    typeList.Init(this._DS, target);
+
+    return typeList;
   }
 };