window.prompt() returns jsval instead of string, allowing it to return null when required. wants to be changed back to a string once the DOM APIs support this same thing. bug 12021. r=jst@netscape.com

dom/public/base/nsIDOMWindow.h

@@ -141,7 +141,7 @@ public:
 
   NS_IMETHOD    Confirm(JSContext* cx, jsval* argv, PRUint32 argc, PRBool* aReturn)=0;
 
-  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, nsString& aReturn)=0;
+  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, jsval* aReturn)=0;
 
   NS_IMETHOD    Focus()=0;
 
@@ -265,7 +265,7 @@ public:
   NS_IMETHOD    Dump(const nsString& aStr);  \
   NS_IMETHOD    Alert(JSContext* cx, jsval* argv, PRUint32 argc);  \
   NS_IMETHOD    Confirm(JSContext* cx, jsval* argv, PRUint32 argc, PRBool* aReturn);  \
-  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, nsString& aReturn);  \
+  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, jsval* aReturn);  \
   NS_IMETHOD    Focus();  \
   NS_IMETHOD    Blur();  \
   NS_IMETHOD    Back();  \
@@ -355,7 +355,7 @@ public:
   NS_IMETHOD    Dump(const nsString& aStr) { return _to Dump(aStr); }  \
   NS_IMETHOD    Alert(JSContext* cx, jsval* argv, PRUint32 argc) { return _to Alert(cx, argv, argc); }  \
   NS_IMETHOD    Confirm(JSContext* cx, jsval* argv, PRUint32 argc, PRBool* aReturn) { return _to Confirm(cx, argv, argc, aReturn); }  \
-  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, nsString& aReturn) { return _to Prompt(cx, argv, argc, aReturn); }  \
+  NS_IMETHOD    Prompt(JSContext* cx, jsval* argv, PRUint32 argc, jsval* aReturn) { return _to Prompt(cx, argv, argc, aReturn); }  \
   NS_IMETHOD    Focus() { return _to Focus(); }  \
   NS_IMETHOD    Blur() { return _to Blur(); }  \
   NS_IMETHOD    Back() { return _to Back(); }  \

dom/public/idl/base/Window.idl

@@ -42,7 +42,10 @@ interface Window {
         void  dump(in wstring str);
         void  alert(/* ... */);
 	      boolean  confirm(/* ... */);
-        DOMString  prompt(/* ... */);
+        // XXX prompt() should be changed back to return a string once
+        // the DOM APIs allow us to return null js values for a string.
+        // in the meantime, this is the only way to do that:
+        jsval  prompt(/* ... */);
         void  focus();
         void  blur();
         void  back();

dom/src/base/nsGlobalWindow.cpp

@@ -1205,23 +1205,21 @@ NS_IMETHODIMP GlobalWindowImpl::Confirm(JSContext* cx, jsval* argv,
 }
 
 NS_IMETHODIMP GlobalWindowImpl::Prompt(JSContext* cx, jsval* argv, 
-   PRUint32 argc, nsString& aReturn)
+   PRUint32 argc, jsval* aReturn)
 {
    NS_ENSURE_STATE(mDocShell);
 
    nsresult ret = NS_OK;
-   nsAutoString str, initial;
+   nsAutoString message, initial;
 
-   aReturn.Truncate();
-   if(argc > 0)
-      {
-      nsJSUtils::nsConvertJSValToString(str, cx, argv[0]);
+   if(argc > 0) {
+      nsJSUtils::nsConvertJSValToString(message, cx, argv[0]);
    
       if(argc > 1)
          nsJSUtils::nsConvertJSValToString(initial, cx, argv[1]);
       else 
          initial.AssignWithConversion("undefined");
-      }
+   }
 
    nsCOMPtr<nsIPrompt> prompter(do_GetInterface(mDocShell));
 
@@ -1229,18 +1227,18 @@ NS_IMETHODIMP GlobalWindowImpl::Prompt(JSContext* cx, jsval* argv,
 
    PRBool b;
    PRUnichar* uniResult = nsnull;
-   ret = prompter->Prompt(nsnull, str.GetUnicode(), nsnull,
+   ret = prompter->Prompt(nsnull, message.GetUnicode(), nsnull,
                           initial.GetUnicode(), &uniResult, &b);
-   aReturn = uniResult;
-   if(uniResult)
+
+   if (NS_SUCCEEDED(ret) && uniResult && b) {
+      JSString *jsret = JS_NewUCStringCopyZ(cx, uniResult);
+      *aReturn = STRING_TO_JSVAL(jsret);
+   }
+   else
+      *aReturn = JSVAL_NULL;
+
+   if (uniResult)
       nsMemory::Free(uniResult);
-   if(NS_FAILED(ret) || !b)
-      {
-      // XXX Need to check return value and return null if the
-      // user hits cancel. Currently, we can only return a 
-      // string reference.
-      aReturn.SetLength(0);
-      }
 
   return ret;
 }

dom/src/base/nsJSWindow.cpp

@@ -1163,7 +1163,7 @@ WindowPrompt(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
 {
   nsIDOMWindow *nativeThis = (nsIDOMWindow*)nsJSUtils::nsGetNativeThis(cx, obj);
   nsresult result = NS_OK;
-  nsAutoString nativeRet;
+  jsval nativeRet;
   // If there's no private data, this must be the prototype, so ignore
   if (nsnull == nativeThis) {
     return JS_TRUE;
@@ -1179,12 +1179,12 @@ WindowPrompt(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
       return nsJSUtils::nsReportError(cx, obj, result);
     }
 
-    result = nativeThis->Prompt(cx, argv+0, argc-0, nativeRet);
+    result = nativeThis->Prompt(cx, argv+0, argc-0, &nativeRet);
     if (NS_FAILED(result)) {
       return nsJSUtils::nsReportError(cx, obj, result);
     }
 
-    nsJSUtils::nsConvertStringToJSVal(nativeRet, cx, rval);
+    *rval = nativeRet;
   }
 
   return JS_TRUE;