Bug 1100398 P2 Make nsStringInputStream cloneable. r=froydnj

xpcom/io/nsStringStream.cpp

@@ -13,6 +13,7 @@
 #include "nsStringStream.h"
 #include "nsStreamUtils.h"
 #include "nsReadableUtils.h"
+#include "nsICloneableInputStream.h"
 #include "nsISeekableStream.h"
 #include "nsISupportsPrimitives.h"
 #include "nsCRT.h"
@@ -34,6 +35,7 @@ class nsStringInputStream MOZ_FINAL
   , public nsISeekableStream
   , public nsISupportsCString
   , public nsIIPCSerializableInputStream
+  , public nsICloneableInputStream
 {
 public:
   NS_DECL_THREADSAFE_ISUPPORTS
@@ -43,12 +45,21 @@ public:
   NS_DECL_NSISUPPORTSPRIMITIVE
   NS_DECL_NSISUPPORTSCSTRING
   NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
+  NS_DECL_NSICLONEABLEINPUTSTREAM
 
   nsStringInputStream()
   {
     Clear();
   }
 
+  explicit nsStringInputStream(const nsStringInputStream& aOther)
+    : mOffset(aOther.mOffset)
+  {
+    // Use Assign() here because we don't want the life of the clone to be
+    // dependent on the life of the original stream.
+    mData.Assign(aOther.mData);
+  }
+
 private:
   ~nsStringInputStream()
   {
@@ -90,12 +101,14 @@ NS_IMPL_QUERY_INTERFACE_CI(nsStringInputStream,
                            nsIInputStream,
                            nsISupportsCString,
                            nsISeekableStream,
-                           nsIIPCSerializableInputStream)
+                           nsIIPCSerializableInputStream,
+                           nsICloneableInputStream)
 NS_IMPL_CI_INTERFACE_GETTER(nsStringInputStream,
                             nsIStringInputStream,
                             nsIInputStream,
                             nsISupportsCString,
-                            nsISeekableStream)
+                            nsISeekableStream,
+                            nsICloneableInputStream)
 
 /////////
 // nsISupportsCString implementation
@@ -308,6 +321,10 @@ nsStringInputStream::SetEOF()
   return NS_OK;
 }
 
+/////////
+// nsIIPCSerializableInputStream implementation
+/////////
+
 void
 nsStringInputStream::Serialize(InputStreamParams& aParams,
                                FileDescriptorArray& /* aFDs */)
@@ -337,6 +354,25 @@ nsStringInputStream::Deserialize(const InputStreamParams& aParams,
   return true;
 }
 
+/////////
+// nsICloneableInputStream implementation
+/////////
+
+NS_IMETHODIMP
+nsStringInputStream::GetCloneable(bool* aCloneableOut)
+{
+  *aCloneableOut = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsStringInputStream::Clone(nsIInputStream** aCloneOut)
+{
+  nsRefPtr<nsIInputStream> ref = new nsStringInputStream(*this);
+  ref.forget(aCloneOut);
+  return NS_OK;
+}
+
 nsresult
 NS_NewByteInputStream(nsIInputStream** aStreamResult,
                       const char* aStringToRead, int32_t aLength,

xpcom/tests/gtest/TestStringStream.cpp

@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "Helpers.h"
+#include "nsICloneableInputStream.h"
+#include "nsStringStream.h"
+
+namespace {
+
+static void TestStringStream(uint32_t aNumBytes)
+{
+  nsTArray<char> inputData;
+  testing::CreateData(aNumBytes, inputData);
+  nsDependentCSubstring inputString(inputData.Elements(), inputData.Length());
+
+  nsCOMPtr<nsIInputStream> stream;
+  nsresult rv = NS_NewCStringInputStream(getter_AddRefs(stream), inputString);
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+
+  testing::ConsumeAndValidateStream(stream, inputString);
+}
+
+static void TestStringStreamClone(uint32_t aNumBytes)
+{
+  nsTArray<char> inputData;
+  testing::CreateData(aNumBytes, inputData);
+  nsDependentCSubstring inputString(inputData.Elements(), inputData.Length());
+
+  nsCOMPtr<nsIInputStream> stream;
+  nsresult rv = NS_NewCStringInputStream(getter_AddRefs(stream), inputString);
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+
+  nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(stream);
+  ASSERT_TRUE(cloneable != nullptr);
+  ASSERT_TRUE(cloneable->GetCloneable());
+
+  nsCOMPtr<nsIInputStream> clone;
+  rv = cloneable->Clone(getter_AddRefs(clone));
+
+  testing::ConsumeAndValidateStream(stream, inputString);
+
+  // Release the stream to verify that the clone's string survives correctly.
+  stream = nullptr;
+
+  testing::ConsumeAndValidateStream(clone, inputString);
+}
+
+} // anonymous namespace
+
+TEST(StringStream, Simple_4k)
+{
+  TestStringStream(1024 * 4);
+}
+
+TEST(StringStream, Clone_4k)
+{
+  TestStringStreamClone(1024 * 4);
+}

xpcom/tests/gtest/moz.build

@@ -14,6 +14,7 @@ UNIFIED_SOURCES += [
     'TestSnappyStreams.cpp',
     'TestStorageStream.cpp',
     'TestStrings.cpp',
+    'TestStringStream.cpp',
     'TestSynchronization.cpp',
     'TestThreadPool.cpp',
     'TestTimeStamp.cpp',