Make ReplaceObjectAt a little safer. Bug 227780, r=timeless, sr=alecf

bzbarsky%mit.edu · bzbarsky%mit.edu · commit 7d1f0c7ed2ac · 2004-01-05T23:43:28.000Z
diff --git a/xpcom/ds/nsCOMArray.cpp b/xpcom/ds/nsCOMArray.cpp
@@ -115,8 +115,9 @@ nsCOMArray_base::ReplaceObjectAt(nsISupports* aObject, PRInt32 aIndex)
     // ReplaceElementAt could fail, such as if the array grows
     // so only release the existing object if the replacement succeeded
     if (result) {
-        NS_IF_RELEASE(oldObject);
+        // Make sure to addref first, in case aObject == oldObject
         NS_IF_ADDREF(aObject);
+        NS_IF_RELEASE(oldObject);
     }
     return result;
 }

Original file line number	Diff line number	Diff line change
`@@ -115,8 +115,9 @@ nsCOMArray_base::ReplaceObjectAt(nsISupports* aObject, PRInt32 aIndex)`
`115`	`115`	`// ReplaceElementAt could fail, such as if the array grows`
`116`	`116`	`// so only release the existing object if the replacement succeeded`
`117`	`117`	`if (result) {`
`118`		`- NS_IF_RELEASE(oldObject);`
	`118`	`+ // Make sure to addref first, in case aObject == oldObject`
`119`	`119`	`NS_IF_ADDREF(aObject);`
	`120`	`+ NS_IF_RELEASE(oldObject);`
`120`	`121`	`}`
`121`	`122`	`return result;`
`122`	`123`	`}`