Add (considerably evil) dactylIUtils.getScrollable. Deal with some quirky sites without scrollable elements. Closes issue #525.

binary/src/dactylIUtils.idl

@@ -8,9 +8,12 @@
 %}
 
 
-[scriptable, uuid(29d1c61f-5959-42b3-8a13-4b473b2b47bf)]
+[scriptable, uuid(d8ef4492-8f4a-4f5d-8f19-1d71f7f895ed)]
 interface dactylIUtils : nsISupports
 {
+    const PRUint32 DIRECTION_HORIZONTAL = 1 << 0;
+    const PRUint32 DIRECTION_VERTICAL   = 1 << 1;
+
     [implicit_jscontext]
     jsval createGlobal();
 
@@ -25,6 +28,8 @@ interface dactylIUtils : nsISupports
     [implicit_jscontext]
     jsval getGlobalForObject(in jsval object);
 
+    PRUint32 getScrollable(in nsIDOMElement element);
+
     void loadSubScript (in wstring url
                         /* [optional] in jsval context, */
                         /* [optional] in wstring charset */);

binary/src/dactylUtils.cpp

@@ -40,6 +40,23 @@
 #include "jsdbgapi.h"
 #include "jsobj.h"
 
+#include "nsStringAPI.h"
+
+/*
+ * Evil. Evil, evil, evil.
+ */
+#define MOZILLA_INTERNAL_API
+#  define nsAString_h___
+#  define nsString_h___
+#  define nsStringFwd_h___
+#  define nsStringGlue_h__
+class nsAFlatCString;
+typedef nsString nsSubstring;
+#  include "nsIScrollableFrame.h"
+#undef MOZILLA_INTERNAL_API
+#include "nsPresContext.h"
+#include "nsQueryFrame.h"
+
 #include "nsIContent.h"
 #include "nsIDOMXULElement.h"
 #include "nsIXULTemplateBuilder.h"
@@ -49,7 +66,6 @@
 
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
-#include "nsStringAPI.h"
 
 
 class autoDropPrincipals {
@@ -322,4 +338,32 @@ dactylUtils::GetGlobalForObject(const jsval &aObject,
     return NS_OK;
 }
 
+NS_IMETHODIMP
+dactylUtils::GetScrollable(nsIDOMElement *aElement, PRUint32 *rval)
+{
+    nsCOMPtr<nsIContent> content = do_QueryInterface(aElement);
+
+    nsIFrame *frame = content->GetPrimaryFrame();
+    nsIScrollableFrame *scrollFrame = do_QueryFrame(frame);
+
+    *rval = 0;
+    if (scrollFrame) {
+        nsPresContext::ScrollbarStyles ss = scrollFrame->GetScrollbarStyles();
+        PRUint32 scrollbarVisibility = scrollFrame->GetScrollbarVisibility();
+        nsRect scrollRange = scrollFrame->GetScrollRange();
+
+        if (ss.mHorizontal != NS_STYLE_OVERFLOW_HIDDEN &&
+             ((scrollbarVisibility & nsIScrollableFrame::HORIZONTAL) ||
+              scrollRange.width > 0))
+            *rval |= dactylIUtils::DIRECTION_HORIZONTAL;
+
+        if (ss.mVertical != NS_STYLE_OVERFLOW_HIDDEN &&
+             ((scrollbarVisibility & nsIScrollableFrame::VERTICAL) ||
+              scrollRange.height > 0))
+            *rval |= dactylIUtils::DIRECTION_VERTICAL;
+    }
+
+    return NS_OK;
+}
+
 /* vim:se sts=4 sw=4 et ft=cpp: */

common/content/buffer.js

@@ -784,9 +784,29 @@ var Buffer = Module("buffer", {
         function find(elem) {
             while (elem && !(elem instanceof Element) && elem.parentNode)
                 elem = elem.parentNode;
-            for (; elem && elem.parentNode instanceof Element; elem = elem.parentNode)
+            for (; elem instanceof Element; elem = elem.parentNode)
                 if (Buffer.isScrollable(elem, dir, horizontal))
                     break;
+
+            if (!(elem instanceof Element))
+                return {
+                    __proto__: elem.documentElement || elem.ownerDocument.documentElement,
+
+                    win: elem.defaultView || elem.ownerDocument.defaultView,
+
+                    get clientWidth() this.win.innerWidth,
+                    get clientHeight() this.win.innerHeight,
+
+                    get scrollWidth() this.win.scrollMaxX + this.win.innerWidth,
+                    get scrollHeight() this.win.scrollMaxY + this.win.innerHeight,
+
+                    get scrollLeft() this.win.scrollX,
+                    set scrollLeft(val) { this.win.scrollTo(val, this.win.scrollY) },
+
+                    get scrollTop() this.win.scrollY,
+                    set scrollTop(val) { this.win.scrollTo(this.win.scrollX, val) }
+                };
+
             return elem;
         }
 
@@ -1263,6 +1283,9 @@ var Buffer = Module("buffer", {
     findScrollable: deprecated("buffer.findScrollable", function findScrollable() buffer.findScrollable.apply(buffer, arguments)),
 
     isScrollable: function isScrollable(elem, dir, horizontal) {
+        if (!DOM(elem).isScrollable(horizontal ? "horizontal" : "vertical"))
+            return false;
+
         let pos = "scrollTop", size = "clientHeight", max = "scrollHeight", layoutSize = "offsetHeight",
             overflow = "overflowX", border1 = "borderTopWidth", border2 = "borderBottomWidth";
         if (horizontal)
@@ -1272,9 +1295,11 @@ var Buffer = Module("buffer", {
         let style = DOM(elem).style;
         let borderSize = Math.round(parseFloat(style[border1]) + parseFloat(style[border2]));
         let realSize = elem[size];
+
         // Stupid Gecko eccentricities. May fail for quirks mode documents.
         if (elem[size] + borderSize == elem[max] || elem[size] == 0) // Stupid, fallible heuristic.
             return false;
+
         if (style[overflow] == "hidden")
             realSize += borderSize;
         return dir < 0 && elem[pos] > 0 || dir > 0 && elem[pos] + realSize < elem[max] || !dir && realSize < elem[max];

common/modules/dom.jsm

@@ -691,6 +691,9 @@ var DOM = Class("DOM", {
     createContents: function createContents()
         this.each(DOM.createContents, this),
 
+    isScrollable: function isScrollable(direction)
+        this.length && DOM.isScrollable(this[0], direction),
+
     getSet: function getSet(args, get, set) {
         if (!args.length)
             return this[0] && get.call(this, this[0]);
@@ -1246,6 +1249,10 @@ var DOM = Class("DOM", {
     createContents: Class.Memoize(function () services.has("dactyl") && services.dactyl.createContents
         || function (elem) {}),
 
+    isScrollable: Class.Memoize(function () services.has("dactyl") && services.dactyl.getScrollable
+        ? function (elem, dir) services.dactyl.getScrollable(elem) & (dir ? services.dactyl["DIRECTION_" + dir.toUpperCase()] : ~0)
+        : function (elem, dir) true),
+
     /**
      * The set of input element type attribute values that mark the element as
      * an editable field.