fixed crash bug for patching, happened at cleanup() stage. removed the

enumerate call to delete the pointers in hash table, since it has
already been deleted.  also added some error checking and reset pointers
to null bug 24455, r=dbragg

xpinstall/src/nsInstall.cpp

@@ -1260,11 +1260,14 @@ nsInstall::Patch(const nsString& aRegName, const nsString& aVersion, const nsStr
         return NS_OK;
     }
 
-    mPatchList = new nsHashtable();
-    if (mPatchList == nsnull)
+    if (!mPatchList)
     {
-        *aReturn = SaveError(nsInstall::OUT_OF_MEMORY);
-        return NS_OK;
+        mPatchList = new nsHashtable();
+        if (mPatchList == nsnull)
+        {
+            *aReturn = SaveError(nsInstall::OUT_OF_MEMORY);
+            return NS_OK;
+        }
     }
  
     nsInstallPatch* ip = new nsInstallPatch( this,
@@ -1446,6 +1449,11 @@ nsInstall::AddPatch(nsHashKey *aKey, nsFileSpec* fileName)
 void       
 nsInstall::GetPatch(nsHashKey *aKey, nsFileSpec** fileName)
 {
+    if (!fileName) 
+        return;
+    else
+        *fileName = nsnull;
+
     if (mPatchList != nsnull)
     {
         *fileName = (nsFileSpec*) mPatchList->Get(aKey);
@@ -2063,16 +2071,6 @@ nsInstall::SaveError(PRInt32 errcode)
   return errcode;
 }
 
-PRBool DeleteEntry(nsHashKey *aKey, void *aData, void *closure)
-{
-    nsFileSpec* data = (nsFileSpec *)aData;
-    if (data) {
-	    delete data;
-	    data = nsnull;
-    }
-    return PR_TRUE;
-}
-
 
 /*
  * CleanUp
@@ -2100,13 +2098,16 @@ nsInstall::CleanUp(void)
 
     if (mPatchList != nsnull)
     {
-        mPatchList->Enumerate(DeleteEntry, nsnull);
         mPatchList->Reset();
         delete mPatchList;
+        mPatchList = nsnull;
     }
     
-    if (mPackageFolder != nsnull)
+    if (mPackageFolder != nsnull) 
+    {
       delete (mPackageFolder);
+      mPackageFolder = nsnull;
+    }
 
     mRegistryPackageName = ""; // used to see if StartInstall() has been called
     mStartInstallCompleted = PR_FALSE;