Adding checks to prevent null pointer dereferences

(bzr r11325)

7 files changed, 124 insertions, 70 deletions

diff --git a/src/gradient-chemistry.cpp b/src/gradient-chemistry.cpp
index a0da1e430..6983849fa 100644
--- a/src/gradient-chemistry.cpp
+++ b/src/gradient-chemistry.cpp
@@ -77,10 +77,12 @@ SPGradient *sp_gradient_ensure_vector_normalized(SPGradient *gr)
     }
 
     /* If gr hrefs some other gradient, remove the href */
-    if (gr->ref->getObject()) {
-        // We are hrefing someone, so require flattening
-        gr->updateRepr(SP_OBJECT_WRITE_EXT | SP_OBJECT_WRITE_ALL);
-        sp_gradient_repr_set_link(gr->getRepr(), NULL);
+    if (gr->ref){
+        if (gr->ref->getObject()) {
+            // We are hrefing someone, so require flattening
+            gr->updateRepr(SP_OBJECT_WRITE_EXT | SP_OBJECT_WRITE_ALL);
+            sp_gradient_repr_set_link(gr->getRepr(), NULL);
+        }
     }
 
     /* Everything is OK, set state flag */
diff --git a/src/object-snapper.cpp b/src/object-snapper.cpp
index bda856914..e6f6d87db 100644
--- a/src/object-snapper.cpp
+++ b/src/object-snapper.cpp
@@ -111,11 +111,11 @@ void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
                         // The current item is not a clipping path or a mask, but might
                         // still be the subject of clipping or masking itself ; if so, then
                         // we should also consider that path or mask for snapping to
-                        obj = SP_OBJECT(item->clip_ref->getObject());
+                        obj = SP_OBJECT(item->clip_ref ? item->clip_ref->getObject() : NULL);
                         if (obj && _snapmanager->snapprefs.isTargetSnappable(SNAPTARGET_PATH_CLIP)) {
                             _findCandidates(obj, it, false, bbox_to_snap, true, item->i2doc_affine());
                         }
-                        obj = SP_OBJECT(item->mask_ref->getObject());
+                        obj = SP_OBJECT(item->mask_ref ? item->mask_ref->getObject() : NULL);
                         if (obj && _snapmanager->snapprefs.isTargetSnappable(SNAPTARGET_PATH_MASK)) {
                             _findCandidates(obj, it, false, bbox_to_snap, true, item->i2doc_affine());
                         }
diff --git a/src/sp-item.cpp b/src/sp-item.cpp
index d6395cfee..e0a9b97f2 100644
--- a/src/sp-item.cpp
+++ b/src/sp-item.cpp
@@ -660,15 +660,19 @@ Inkscape::XML::Node *SPItem::sp_item_write(SPObject *const object, Inkscape::XML
             repr->setAttribute ("inkscape:transform-center-y", NULL);
     }
 
-    if (item->clip_ref->getObject()) {
-        const gchar *value = g_strdup_printf ("url(%s)", item->clip_ref->getURI()->toString());
-        repr->setAttribute ("clip-path", value);
-        g_free ((void *) value);
-    }
-    if (item->mask_ref->getObject()) {
-        const gchar *value = g_strdup_printf ("url(%s)", item->mask_ref->getURI()->toString());
-        repr->setAttribute ("mask", value);
-        g_free ((void *) value);
+    if (item->clip_ref){
+        if (item->clip_ref->getObject()) {
+            const gchar *value = g_strdup_printf ("url(%s)", item->clip_ref->getURI()->toString());
+            repr->setAttribute ("clip-path", value);
+            g_free ((void *) value);
+        }
+    }
+    if (item->mask_ref){
+        if (item->mask_ref->getObject()) {
+            const gchar *value = g_strdup_printf ("url(%s)", item->mask_ref->getURI()->toString());
+            repr->setAttribute ("mask", value);
+            g_free ((void *) value);
+        }
     }
 
     if (((SPObjectClass *) (SPItemClass::static_parent_class))->write) {
diff --git a/src/sp-use.cpp b/src/sp-use.cpp
index 5bbb1c1a8..e39f560c3 100644
--- a/src/sp-use.cpp
+++ b/src/sp-use.cpp
@@ -741,10 +741,14 @@ SPItem *sp_use_unlink(SPUse *use)
     return item;
 }
 
-SPItem *
-sp_use_get_original(SPUse *use)
+SPItem *sp_use_get_original(SPUse *use)
 {
-    SPItem *ref = use->ref->getObject();
+    SPItem *ref = NULL;
+    if (use){
+        if (use->ref){
+            ref = use->ref->getObject();
+        }
+    }
     return ref;
 }
 
diff --git a/src/style.cpp b/src/style.cpp
index 93bd5ac76..40cd1663e 100644
--- a/src/style.cpp
+++ b/src/style.cpp
@@ -8,10 +8,12 @@
  *   bulia byak <buliabyak@users.sf.net>
  *   Abhishek Sharma
  *   Tavmjong Bah <tavmjong@free.fr>
+ *   Kris De Gussem <Kris.DeGussem@gmail.com>
  *
  * Copyright (C) 2001-2002 Lauris Kaplinski
  * Copyright (C) 2001 Ximian, Inc.
  * Copyright (C) 2005 Monash University
+ * Copyright (C) 2012 Kris De Gussem
  *
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
@@ -1169,7 +1171,7 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
              */
             g_warning("attribute 'clip-path' given as CSS");
 
-			//XML Tree being directly used here.
+            //XML Tree being directly used here.
             style->object->getRepr()->setAttribute("clip-path", val);
             break;
         case SP_PROP_CLIP_RULE:
@@ -1182,8 +1184,8 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
              * See comment for SP_PROP_CLIP_PATH
              */
             g_warning("attribute 'mask' given as CSS");
-			
-			//XML Tree being directly used here.
+            
+            //XML Tree being directly used here.
             style->object->getRepr()->setAttribute("mask", val);
             break;
         case SP_PROP_OPACITY:
@@ -2407,8 +2409,11 @@ sp_style_set_ipaint_to_uri(SPStyle *style, SPIPaint *paint, const Inkscape::URI
         paint->value.href->changedSignal().connect(sigc::bind(sigc::ptr_fun((paint == &style->fill)? sp_style_fill_paint_server_ref_changed : sp_style_stroke_paint_server_ref_changed), style));
     }
 
-    if (paint->value.href && paint->value.href->getObject())
-        paint->value.href->detach();
+    if (paint->value.href){
+        if (paint->value.href->getObject()){
+            paint->value.href->detach();
+        }
+    }
 
     if (paint->value.href) {
         try {
@@ -2486,21 +2491,29 @@ sp_style_merge_ifilter(SPStyle *style, SPIFilter const *parent)
     style->filter.set = parent->set;
     style->filter.inherit = parent->inherit;
 
-    if (style->filter.href && style->filter.href->getObject())
-       style->filter.href->detach();
-
-    // it may be that this style has not yet created its SPFilterReference
-    if (!style->filter.href && style->object && style->object->document) {
-            style->filter.href = new SPFilterReference(style->object->document);
-            style->filter.href->changedSignal().connect(sigc::bind(sigc::ptr_fun(sp_style_filter_ref_changed), style));
+    if (style->filter.href){
+        if (style->filter.href->getObject()){
+            style->filter.href->detach();
+        }
+    }
+    else{
+        // it may be that this style has not yet created its SPFilterReference
+        if (style->object){
+            if (style->object->document) {
+                style->filter.href = new SPFilterReference(style->object->document);
+                style->filter.href->changedSignal().connect(sigc::bind(sigc::ptr_fun(sp_style_filter_ref_changed), style));
+            }
+        }
     }
 
-    if (style->filter.href && parent->href && parent->href->getObject()) {
-        try {
-            style->filter.href->attach(*parent->href->getURI());
-        } catch (Inkscape::BadURIException &e) {
-            g_warning("%s", e.what());
-            style->filter.href->detach();
+    if (style->filter.href && parent->href){
+        if (parent->href->getObject()) {
+            try {
+                style->filter.href->attach(*parent->href->getURI());
+            } catch (Inkscape::BadURIException &e) {
+                g_warning("%s", e.what());
+                style->filter.href->detach();
+            }
         }
     }
 }
@@ -3595,13 +3608,19 @@ sp_style_read_ifilter(gchar const *str, SPStyle * style, SPDocument *document)
     if (streq(str, "inherit")) {
         f->set = TRUE;
         f->inherit = TRUE;
-        if (f->href && f->href->getObject())
-            f->href->detach();
+        if (f->href){
+            if (f->href->getObject()){
+                f->href->detach();
+            }
+        }
     } else if(streq(str, "none")) {
         f->set = TRUE;
         f->inherit = FALSE;
-        if (f->href && f->href->getObject())
-           f->href->detach();
+        if (f->href){
+            if (f->href->getObject()){
+                f->href->detach();
+            }
+        }
     } else if (strneq(str, "url", 3)) {
         char *uri = extract_uri(str);
         if(uri == NULL || uri[0] == '\0') {
@@ -3612,8 +3631,11 @@ sp_style_read_ifilter(gchar const *str, SPStyle * style, SPDocument *document)
         }
         f->set = TRUE;
         f->inherit = FALSE;
-        if (f->href && f->href->getObject())
-            f->href->detach();
+        if (f->href){
+            if (f->href->getObject()){
+                f->href->detach();
+            }
+        }
 
         // it may be that this style has not yet created its SPFilterReference;
         // now that we have a document, we can create it here
@@ -3634,8 +3656,11 @@ sp_style_read_ifilter(gchar const *str, SPStyle * style, SPDocument *document)
         /* We shouldn't reach this if SVG input is well-formed */
         f->set = FALSE;
         f->inherit = FALSE;
-        if (f->href && f->href->getObject())
-            f->href->detach();
+        if (f->href){
+            if (f->href->getObject()){
+                f->href->detach();
+            }
+        }
     }
 }
 
@@ -4258,9 +4283,10 @@ void SPIPaint::clear()
     colorSet = false;
     noneSet = false;
     value.color.set( 0 );
-    if ( value.href && value.href->getObject() )
-    {
-        value.href->detach();
+    if (value.href){
+        if (value.href->getObject()){
+            value.href->detach();
+        }
     }
 }
 
@@ -4271,8 +4297,11 @@ void SPIPaint::clear()
 static void
 sp_style_filter_clear(SPStyle *style)
 {
-    if (style->filter.href && style->filter.href->getObject())
-        style->filter.href->detach();
+    if (style->filter.href){
+        if (style->filter.href->getObject()){
+            style->filter.href->detach();
+        }
+    }
 }
 
 
diff --git a/src/style.h b/src/style.h
index 9a3d7309e..bdea441a6 100644
--- a/src/style.h
+++ b/src/style.h
@@ -168,7 +168,7 @@ struct SPIPaint {
 
     bool isNone() const {return !currentcolor && !colorSet && !isPaintserver();} // TODO refine
     bool isColor() const {return colorSet && !isPaintserver();}
-    bool isPaintserver() const {return value.href && value.href->getObject();}
+    bool isPaintserver() const {return (value.href) ? value.href->getObject():0;}
 
     void clear();
 
@@ -404,17 +404,17 @@ struct SPStyle {
     sigc::connection fill_ps_modified_connection;
     sigc::connection stroke_ps_modified_connection;
 
-    SPObject *getFilter() { return (filter.href) ? filter.href->getObject() : 0; }
-    SPObject const *getFilter() const { return (filter.href) ? filter.href->getObject() : 0; }
-    gchar const *getFilterURI() const { return (filter.href) ? filter.href->getURI()->toString() : 0; }
+    SPObject *getFilter() { return (filter.href) ? filter.href->getObject() : NULL; }
+    SPObject const *getFilter() const { return (filter.href) ? filter.href->getObject() : NULL; }
+    gchar const *getFilterURI() const { return (filter.href) ? filter.href->getURI()->toString() : NULL; }
 
-    SPPaintServer *getFillPaintServer() { return (fill.value.href) ? fill.value.href->getObject() : 0; }
-    SPPaintServer const *getFillPaintServer() const { return (fill.value.href) ? fill.value.href->getObject() : 0; }
-    gchar const *getFillURI() const { return (fill.value.href) ? fill.value.href->getURI()->toString() : 0; }
+    SPPaintServer *getFillPaintServer() { return (fill.value.href) ? fill.value.href->getObject() : NULL; }
+    SPPaintServer const *getFillPaintServer() const { return (fill.value.href) ? fill.value.href->getObject() : NULL; }
+    gchar const *getFillURI() const { return (fill.value.href) ? fill.value.href->getURI()->toString() : NULL; }
 
-    SPPaintServer *getStrokePaintServer() { return (stroke.value.href) ? stroke.value.href->getObject() : 0; }
-    SPPaintServer const *getStrokePaintServer() const { return (stroke.value.href) ? stroke.value.href->getObject() : 0; }
-    gchar const  *getStrokeURI() const { return (stroke.value.href) ? stroke.value.href->getURI()->toString() : 0; }
+    SPPaintServer *getStrokePaintServer() { return (stroke.value.href) ? stroke.value.href->getObject() : NULL; }
+    SPPaintServer const *getStrokePaintServer() const { return (stroke.value.href) ? stroke.value.href->getObject() : NULL; }
+    gchar const  *getStrokeURI() const { return (stroke.value.href) ? stroke.value.href->getURI()->toString() : NULL; }
 };
 
 SPStyle *sp_style_new(SPDocument *document);
diff --git a/src/ui/clipboard.cpp b/src/ui/clipboard.cpp
index b972997e2..8f0652a78 100644
--- a/src/ui/clipboard.cpp
+++ b/src/ui/clipboard.cpp
@@ -698,20 +698,25 @@ void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
         _copyTextPath(SP_TEXTPATH(item->firstChild()));
     }
     // Copy clipping objects
-    if (item->clip_ref->getObject()) {
-        _copyNode(item->clip_ref->getObject()->getRepr(), _doc, _defs);
+    if (item->clip_ref){
+        if (item->clip_ref->getObject()) {
+            _copyNode(item->clip_ref->getObject()->getRepr(), _doc, _defs);
+        }
     }
     // Copy mask objects
-    if (item->mask_ref->getObject()) {
-        SPObject *mask = item->mask_ref->getObject();
-        _copyNode(mask->getRepr(), _doc, _defs);
-        // recurse into the mask for its gradients etc.
-        for (SPObject *o = mask->children ; o != NULL ; o = o->next) {
-            if (SP_IS_ITEM(o)) {
-                _copyUsedDefs(SP_ITEM(o));
+    if (item->mask_ref){
+        if (item->mask_ref->getObject()) {
+            SPObject *mask = item->mask_ref->getObject();
+            _copyNode(mask->getRepr(), _doc, _defs);
+            // recurse into the mask for its gradients etc.
+            for (SPObject *o = mask->children ; o != NULL ; o = o->next) {
+                if (SP_IS_ITEM(o)) {
+                    _copyUsedDefs(SP_ITEM(o));
+                }
             }
         }
     }
+    
     // Copy filters
     if (style->getFilter()) {
         SPObject *filter = style->getFilter();
@@ -737,7 +742,12 @@ void ClipboardManagerImpl::_copyGradient(SPGradient *gradient)
     while (gradient) {
         // climb up the refs, copying each one in the chain
         _copyNode(gradient->getRepr(), _doc, _defs);
-        gradient = gradient->ref->getObject();
+        if (gradient->ref){
+            gradient = gradient->ref->getObject();
+        }
+        else {
+            gradient = NULL;
+        }
     }
 }
 
@@ -758,7 +768,12 @@ void ClipboardManagerImpl::_copyPattern(SPPattern *pattern)
             }
             _copyUsedDefs(SP_ITEM(child));
         }
-        pattern = pattern->ref->getObject();
+        if (pattern->ref){
+            pattern = pattern->ref->getObject();
+        }
+        else{
+            pattern = NULL;
+        }
     }
 }