Bug 1310040 - Make nsSupportsArray implement nsIArray. r=froydnj

This makes nsSupportsArray implement the |nsIArray| interface. This will allow
us to replace references to nsISupportsArray as a param in our gecko interfaces
with nsIArray instead.

The goal is to remove this adapter (and nsISupportsArray) after a full release
cycle.

MozReview-Commit-ID: If7RiO5muIk

xpcom/ds/nsICollection.idl

@@ -19,6 +19,12 @@ interface nsICollection : nsISerializable
   void AppendElement(in nsISupports item);
   void RemoveElement(in nsISupports item);
 
+  /**
+   * This clashes with |nsISimpleEnumerator nsIArray.enumerate()| (only on the
+   * binary side), so it is renamed with a 'Deprecated' prefix in favor of the
+   * non-deprecated |nsIArray.enumerate|.
+   */
+  [binaryname(DeprecatedEnumerate)]
   nsIEnumerator Enumerate();
 
   void Clear();

xpcom/ds/nsSupportsArray.cpp

@@ -7,6 +7,7 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "nsArrayEnumerator.h"
 #include "nsIObjectInputStream.h"
 #include "nsIObjectOutputStream.h"
 #include "nsSupportsArray.h"
@@ -47,7 +48,7 @@ nsSupportsArray::Create(nsISupports* aOuter, REFNSIID aIID, void** aResult)
   return it->QueryInterface(aIID, aResult);
 }
 
-NS_IMPL_ISUPPORTS(nsSupportsArray, nsISupportsArray, nsICollection,
+NS_IMPL_ISUPPORTS(nsSupportsArray, nsIArray, nsISupportsArray, nsICollection,
                   nsISerializable)
 
 NS_IMETHODIMP
@@ -172,7 +173,7 @@ nsSupportsArray::Clear(void)
 }
 
 NS_IMETHODIMP
-nsSupportsArray::Enumerate(nsIEnumerator** aResult)
+nsSupportsArray::DeprecatedEnumerate(nsIEnumerator** aResult)
 {
   RefPtr<nsSupportsArrayEnumerator> e = new nsSupportsArrayEnumerator(this);
   e.forget(aResult);
@@ -208,3 +209,39 @@ NS_NewISupportsArray(nsISupportsArray** aInstancePtrResult)
                                (void**)aInstancePtrResult);
   return rv;
 }
+
+/**
+ * nsIArray adapters.
+ */
+NS_IMETHODIMP
+nsSupportsArray::GetLength(uint32_t* aLength) {
+  return Count(aLength);
+}
+
+NS_IMETHODIMP
+nsSupportsArray::QueryElementAt(uint32_t aIndex, const nsIID& aIID, void** aResult)
+{
+  nsISupports* element = mArray.SafeElementAt(aIndex);
+  if (element) {
+    return element->QueryInterface(aIID, aResult);
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsSupportsArray::IndexOf(uint32_t aStartIndex, nsISupports* aElement, uint32_t* aResult)
+{
+  int32_t idx = mArray.IndexOf(aElement, aStartIndex);
+  if (idx < 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  *aResult = static_cast<uint32_t>(idx);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSupportsArray::Enumerate(nsISimpleEnumerator** aResult)
+{
+  return NS_NewArrayEnumerator(aResult, this);
+}

xpcom/ds/nsSupportsArray.h

@@ -11,7 +11,8 @@
 #include "nsCOMArray.h"
 #include "mozilla/Attributes.h"
 
-class nsSupportsArray final : public nsISupportsArray
+class nsSupportsArray final : public nsISupportsArray,
+                              public nsIArray
 {
   ~nsSupportsArray(void); // nonvirtual since we're not subclassed
 
@@ -33,15 +34,6 @@ public:
   }
   NS_IMETHOD GetElementAt(uint32_t aIndex, nsISupports** aResult) override;
   MOZ_MUST_USE NS_IMETHOD
-  QueryElementAt(uint32_t aIndex, const nsIID& aIID, void** aResult) override
-  {
-    nsISupports* element = mArray.SafeElementAt(aIndex);
-    if (element) {
-      return element->QueryInterface(aIID, aResult);
-    }
-    return NS_ERROR_FAILURE;
-  }
-  MOZ_MUST_USE NS_IMETHOD
   SetElementAt(uint32_t aIndex, nsISupports* aValue) override
   {
     return ReplaceElementAt(aValue, aIndex) ? NS_OK : NS_ERROR_FAILURE;
@@ -53,7 +45,7 @@ public:
   }
   // XXX this is badly named - should be RemoveFirstElement
   MOZ_MUST_USE NS_IMETHOD RemoveElement(nsISupports* aElement) override;
-  NS_IMETHOD Enumerate(nsIEnumerator** aResult) override;
+  NS_IMETHOD DeprecatedEnumerate(nsIEnumerator** aResult) override;
   NS_IMETHOD Clear(void) override;
 
   // nsISupportsArray methods:
@@ -81,6 +73,11 @@ public:
 
   MOZ_MUST_USE NS_IMETHOD Clone(nsISupportsArray** aResult) override;
 
+  /**
+   * nsIArray adapters.
+   */
+  NS_DECL_NSIARRAY
+
 private:
   // Copy constructors are not allowed
   explicit nsSupportsArray(const nsISupportsArray& aOther);

xpcom/tests/unit/test_nsIMutableArray.js

@@ -107,6 +107,46 @@ function test_enumerate()
   do_check_eq(arr.length, i);
 }
 
+function test_nssupportsarray_interop() {
+  // Tests to check that an nsSupportsArray instance can behave like an
+  // nsIArray.
+  let test = Components.classes["@mozilla.org/supports-array;1"]
+             .createInstance(Ci.nsISupportsArray);
+
+  let str = new SupportsString();
+  str.data = "element";
+  test.AppendElement(str);
+
+  // Now query to an nsIArray.
+  let iarray = test.QueryInterface(Ci.nsIArray);
+  do_check_neq(iarray, null);
+
+  // Make sure |nsIArray.length| works.
+  do_check_eq(iarray.length, 1);
+
+  // Make sure |nsIArray.queryElementAt| works.
+  let elm = iarray.queryElementAt(0, Ci.nsISupportsString);
+  do_check_eq(elm.data, "element");
+
+  // Make sure |nsIArray.indexOf| works.
+  let idx = iarray.indexOf(0, str);
+  do_check_eq(idx, 0);
+
+  // Make sure |nsIArray.enumerate| works.
+  let en = iarray.enumerate();
+  do_check_neq(en, null);
+  let i = 0;
+  while (en.hasMoreElements()) {
+    let str = en.getNext();
+    do_check_true(str instanceof Ci.nsISupportsString);
+    do_check_eq(str.data, "element");
+    i++;
+  }
+
+  do_check_eq(iarray.length, i);
+}
+
+
 var tests = [
   test_appending_null_actually_inserts,
   test_object_gets_appended,
@@ -114,6 +154,7 @@ var tests = [
   test_replace_element,
   test_clear,
   test_enumerate,
+  test_nssupportsarray_interop,
 ];
 
 function run_test() {