Partial fix for frame based and general memory leaks of webshells and prescontexts

docshell/base/nsWebShell.cpp

@@ -104,6 +104,7 @@ public:
   NS_IMETHOD MoveTo(PRInt32 aX, PRInt32 aY);
   NS_IMETHOD Show();
   NS_IMETHOD Hide();
+  NS_IMETHOD SetContentViewer(nsIContentViewer* aViewer);
   NS_IMETHOD GetContentViewer(nsIContentViewer*& aResult);
   NS_IMETHOD SetContainer(nsIWebShellContainer* aContainer);
   NS_IMETHOD GetContainer(nsIWebShellContainer*& aResult);
@@ -303,6 +304,9 @@ nsWebShell::ReleaseChildren()
   for (i = 0; i < n; i++) {
     nsIWebShell* shell = (nsIWebShell*) mChildren.ElementAt(i);
     shell->SetParent(nsnull);
+
+    //Break circular reference of webshell to contentviewer
+    shell->SetContentViewer(nsnull);
     NS_RELEASE(shell);
   }
   mChildren.Clear();
@@ -575,6 +579,15 @@ nsWebShell::Hide()
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsWebShell::SetContentViewer(nsIContentViewer* aViewer)
+{
+  NS_IF_RELEASE(mContentViewer);
+  mContentViewer = aViewer;
+  NS_IF_ADDREF(aViewer);
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsWebShell::GetContentViewer(nsIContentViewer*& aResult)
 {
@@ -654,16 +667,17 @@ nsresult
 nsWebShell::GetRootWebShell(nsIWebShell*& aResult)
 {
   nsIWebShell* top = this;
+  NS_ADDREF(this);
   for (;;) {
     nsIWebShell* parent;
     top->GetParent(parent);
     if (nsnull == parent) {
       break;
     }
+    NS_RELEASE(top);
     top = parent;
   }
   aResult = top;
-  NS_ADDREF(top);
   return NS_OK;
 }
 

layout/base/src/nsPresShell.cpp

@@ -313,8 +313,9 @@ PresShell::~PresShell()
   if (nsnull != mRootFrame) {
     mRootFrame->DeleteFrame();
   }
-  NS_IF_RELEASE(mPresContext);
   NS_IF_RELEASE(mViewManager);
+  //Release mPresContext after mViewManager
+  NS_IF_RELEASE(mPresContext);
   NS_IF_RELEASE(mStyleSet);
   mRefCnt = 0;
 }

layout/html/base/src/nsHTMLTagContent.cpp

@@ -1068,6 +1068,7 @@ void nsHTMLTagContent::TriggerLink(nsIPresContext& aPresContext,
     else {
       handler->OnOverLink(nsnull, absURLSpec, aTargetSpec);
     }
+    NS_RELEASE(handler);
   }
 }
 

webshell/public/nsIWebShell.h

@@ -100,8 +100,8 @@ public:
 
   NS_IMETHOD Hide() = 0;
 
+  NS_IMETHOD SetContentViewer(nsIContentViewer* aViewer) = 0;
   NS_IMETHOD GetContentViewer(nsIContentViewer*& aResult) = 0;
-  // XXX SetContentViewer?
 
   NS_IMETHOD SetContainer(nsIWebShellContainer* aContainer) = 0;
   NS_IMETHOD GetContainer(nsIWebShellContainer*& aResult) = 0;

webshell/src/nsWebShell.cpp

@@ -104,6 +104,7 @@ public:
   NS_IMETHOD MoveTo(PRInt32 aX, PRInt32 aY);
   NS_IMETHOD Show();
   NS_IMETHOD Hide();
+  NS_IMETHOD SetContentViewer(nsIContentViewer* aViewer);
   NS_IMETHOD GetContentViewer(nsIContentViewer*& aResult);
   NS_IMETHOD SetContainer(nsIWebShellContainer* aContainer);
   NS_IMETHOD GetContainer(nsIWebShellContainer*& aResult);
@@ -303,6 +304,9 @@ nsWebShell::ReleaseChildren()
   for (i = 0; i < n; i++) {
     nsIWebShell* shell = (nsIWebShell*) mChildren.ElementAt(i);
     shell->SetParent(nsnull);
+
+    //Break circular reference of webshell to contentviewer
+    shell->SetContentViewer(nsnull);
     NS_RELEASE(shell);
   }
   mChildren.Clear();
@@ -575,6 +579,15 @@ nsWebShell::Hide()
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsWebShell::SetContentViewer(nsIContentViewer* aViewer)
+{
+  NS_IF_RELEASE(mContentViewer);
+  mContentViewer = aViewer;
+  NS_IF_ADDREF(aViewer);
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsWebShell::GetContentViewer(nsIContentViewer*& aResult)
 {
@@ -654,16 +667,17 @@ nsresult
 nsWebShell::GetRootWebShell(nsIWebShell*& aResult)
 {
   nsIWebShell* top = this;
+  NS_ADDREF(this);
   for (;;) {
     nsIWebShell* parent;
     top->GetParent(parent);
     if (nsnull == parent) {
       break;
     }
+    NS_RELEASE(top);
     top = parent;
   }
   aResult = top;
-  NS_ADDREF(top);
   return NS_OK;
 }