1 files changed, 155 insertions, 0 deletions
diff --git a/xpcom/io/FixedBufferOutputStream.cpp b/xpcom/io/FixedBufferOutputStream.cpp
new file mode 100644
index 0000000000..d2bd235a15
--- /dev/null
+++ b/xpcom/io/FixedBufferOutputStream.cpp
@@ -0,0 +1,155 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "FixedBufferOutputStream.h"
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/StreamBufferSinkImpl.h"
+#include "nsStreamUtils.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+FixedBufferOutputStream::FixedBufferOutputStream(
+    UniquePtr<StreamBufferSink>&& aSink)
+    : mSink(std::move(aSink)),
+      mMutex("FixedBufferOutputStream::mMutex"),
+      mOffset(0),
+      mWriting(false),
+      mClosed(false) {}
+
+// static
+RefPtr<FixedBufferOutputStream> FixedBufferOutputStream::Create(
+    size_t aLength) {
+  MOZ_ASSERT(aLength);
+
+  return MakeRefPtr<FixedBufferOutputStream>(MakeUnique<BufferSink>(aLength));
+}
+
+// static
+RefPtr<FixedBufferOutputStream> FixedBufferOutputStream::Create(
+    size_t aLength, const mozilla::fallible_t&) {
+  MOZ_ASSERT(aLength);
+
+  auto sink = BufferSink::Alloc(aLength);
+
+  if (NS_WARN_IF(!sink)) {
+    return nullptr;
+  }
+
+  return MakeRefPtr<FixedBufferOutputStream>(std::move(sink));
+}
+
+// static
+RefPtr<FixedBufferOutputStream> FixedBufferOutputStream::Create(
+    mozilla::Span<char> aBuffer) {
+  return MakeRefPtr<FixedBufferOutputStream>(
+      MakeUnique<nsBorrowedSink>(aBuffer));
+}
+
+// static
+RefPtr<FixedBufferOutputStream> FixedBufferOutputStream::Create(
+    UniquePtr<StreamBufferSink>&& aSink) {
+  return MakeRefPtr<FixedBufferOutputStream>(std::move(aSink));
+}
+
+nsDependentCSubstring FixedBufferOutputStream::WrittenData() {
+  MutexAutoLock autoLock(mMutex);
+
+  return mSink->Slice(mOffset);
+}
+
+NS_IMPL_ISUPPORTS(FixedBufferOutputStream, nsIOutputStream)
+
+NS_IMETHODIMP
+FixedBufferOutputStream::Close() {
+  MutexAutoLock autoLock(mMutex);
+
+  if (mWriting) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mClosed = true;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FixedBufferOutputStream::Flush() { return NS_OK; }
+
+NS_IMETHODIMP
+FixedBufferOutputStream::Write(const char* aBuf, uint32_t aCount,
+                               uint32_t* _retval) {
+  return WriteSegments(NS_CopyBufferToSegment, const_cast<char*>(aBuf), aCount,
+                       _retval);
+}
+
+NS_IMETHODIMP
+FixedBufferOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
+                                   uint32_t* _retval) {
+  return WriteSegments(NS_CopyStreamToSegment, aFromStream, aCount, _retval);
+}
+
+NS_IMETHODIMP
+FixedBufferOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
+                                       uint32_t aCount, uint32_t* _retval) {
+  MOZ_ASSERT(_retval);
+
+  MutexAutoLock autoLock(mMutex);
+
+  if (mWriting) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (mClosed) {
+    return NS_BASE_STREAM_CLOSED;
+  }
+
+  size_t length = mSink->Data().Length();
+  size_t offset = mOffset;
+
+  MOZ_ASSERT(length >= offset, "Bad stream state!");
+
+  size_t maxCount = length - offset;
+  if (maxCount == 0) {
+    *_retval = 0;
+    return NS_OK;
+  }
+
+  if (aCount > maxCount) {
+    aCount = maxCount;
+  }
+
+  mWriting = true;
+
+  nsresult rv;
+
+  {
+    MutexAutoUnlock autoUnlock(mMutex);
+
+    rv = aReader(this, aClosure, mSink->Data().Elements() + offset, 0, aCount,
+                 _retval);
+  }
+
+  mWriting = false;
+
+  if (NS_SUCCEEDED(rv)) {
+    MOZ_ASSERT(*_retval <= aCount,
+               "Reader should not read more than we asked it to read!");
+    mOffset += *_retval;
+  }
+
+  // As defined in nsIOutputStream.idl, do not pass reader func errors.
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FixedBufferOutputStream::IsNonBlocking(bool* _retval) {
+  *_retval = true;
+  return NS_OK;
+}
+
+}  // namespace mozilla