From 6ec2ba049c4a1fffa9a24809fef51aff6a5f1e88 Mon Sep 17 00:00:00 2001
From: Mats Palmgren <mats@mozilla.com>
Date: Sun, 14 Oct 2018 18:12:23 +0200
Subject: [PATCH] Bug 1494745 part 6 - Make ns[Auto]TObserverArray methods that
 insert/append an Item return void since they're infallible.  r=bz

---
 xpcom/ds/nsTObserverArray.h | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/xpcom/ds/nsTObserverArray.h b/xpcom/ds/nsTObserverArray.h
index 91725c244389..18289eb1c41c 100644
--- a/xpcom/ds/nsTObserverArray.h
+++ b/xpcom/ds/nsTObserverArray.h
@@ -175,13 +175,11 @@ public:
   // Insert a given element at the given index.
   // @param aIndex The index at which to insert item.
   // @param aItem  The item to insert,
-  // @return A pointer to the newly inserted element, or a null on DOM
   template<class Item>
-  elem_type* InsertElementAt(index_type aIndex, const Item& aItem)
+  void InsertElementAt(index_type aIndex, const Item& aItem)
   {
-    elem_type* item = mArray.InsertElementAt(aIndex, aItem);
+    mArray.InsertElementAt(aIndex, aItem);
     AdjustIterators(aIndex, 1);
-    return item;
   }
 
   // Same as above but without copy constructing.
@@ -196,26 +194,21 @@ public:
   // Prepend an element to the array unless it already exists in the array.
   // 'operator==' must be defined for elem_type.
   // @param aItem The item to prepend.
-  // @return true if the element was found, or inserted successfully.
   template<class Item>
-  bool PrependElementUnlessExists(const Item& aItem)
+  void PrependElementUnlessExists(const Item& aItem)
   {
-    if (Contains(aItem)) {
-      return true;
+    if (!Contains(aItem)) {
+      mArray.InsertElementAt(0, aItem);
+      AdjustIterators(0, 1);
     }
-
-    bool inserted = mArray.InsertElementAt(0, aItem) != nullptr;
-    AdjustIterators(0, 1);
-    return inserted;
   }
 
   // Append an element to the array.
   // @param aItem The item to append.
-  // @return A pointer to the newly appended element, or null on OOM.
   template<class Item>
-  elem_type* AppendElement(const Item& aItem)
+  void AppendElement(const Item& aItem)
   {
-    return mArray.AppendElement(aItem);
+    mArray.AppendElement(aItem);
   }
 
   // Same as above, but without copy-constructing. This is useful to avoid
@@ -228,11 +221,12 @@ public:
   // Append an element to the array unless it already exists in the array.
   // 'operator==' must be defined for elem_type.
   // @param aItem The item to append.
-  // @return true if the element was found, or inserted successfully.
   template<class Item>
-  bool AppendElementUnlessExists(const Item& aItem)
+  void AppendElementUnlessExists(const Item& aItem)
   {
-    return Contains(aItem) || AppendElement(aItem) != nullptr;
+    if (!Contains(aItem)) {
+      mArray.AppendElement(aItem);
+    }
   }
 
   // Remove an element from the array.