Backed out changeset bb30697071b2 (bug 1308317)

xpcom/ds/nsISupportsArray.idl

@@ -33,6 +33,8 @@ class nsISupportsArray;
 [scriptable, uuid(241addc8-3608-4e73-8083-2fd6fa09eba2)]
 interface nsISupportsArray : nsICollection {
 
+  [notxpcom] boolean Equals([const] in nsISupportsArray other);
+  
   [notxpcom] long IndexOf([const] in nsISupports aPossibleElement);
   [notxpcom] long IndexOfStartingAt([const] in nsISupports aPossibleElement,
                                     in unsigned long aStartIndex);

xpcom/ds/nsSupportsArray.cpp

@@ -196,6 +196,35 @@ nsSupportsArray::DeleteArray(void)
   }
 }
 
+
+NS_IMETHODIMP_(bool)
+nsSupportsArray::Equals(const nsISupportsArray* aOther)
+{
+  if (aOther) {
+    uint32_t countOther;
+    nsISupportsArray* other = const_cast<nsISupportsArray*>(aOther);
+    nsresult rv = other->Count(&countOther);
+    if (NS_FAILED(rv)) {
+      return false;
+    }
+
+    if (mCount == countOther) {
+      uint32_t index = mCount;
+      nsCOMPtr<nsISupports> otherElem;
+      while (index--) {
+        if (NS_FAILED(other->GetElementAt(index, getter_AddRefs(otherElem)))) {
+          return false;
+        }
+        if (mArray[index] != otherElem) {
+          return false;
+        }
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
 NS_IMETHODIMP
 nsSupportsArray::GetElementAt(uint32_t aIndex, nsISupports** aOutPtr)
 {

xpcom/ds/nsSupportsArray.h

@@ -60,6 +60,8 @@ public:
   NS_IMETHOD Clear(void) override;
 
   // nsISupportsArray methods:
+  NS_IMETHOD_(bool) Equals(const nsISupportsArray* aOther) override;
+
   NS_IMETHOD_(int32_t) IndexOf(const nsISupports* aPossibleElement) override;
   NS_IMETHOD_(int32_t) IndexOfStartingAt(const nsISupports* aPossibleElement,
                                          uint32_t aStartIndex = 0) override;