1 files changed, 230 insertions, 0 deletions
diff --git a/dom/file/StreamBlobImpl.cpp b/dom/file/StreamBlobImpl.cpp
new file mode 100644
index 0000000000..ff21d3a536
--- /dev/null
+++ b/dom/file/StreamBlobImpl.cpp
@@ -0,0 +1,230 @@
+/* -*- 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 "EmptyBlobImpl.h"
+#include "mozilla/InputStreamLengthWrapper.h"
+#include "mozilla/SlicedInputStream.h"
+#include "StreamBlobImpl.h"
+#include "nsNetCID.h"
+#include "nsServiceManagerUtils.h"
+#include "nsStreamUtils.h"
+#include "nsStringStream.h"
+#include "nsIAsyncOutputStream.h"
+#include "nsICloneableInputStream.h"
+#include "nsIEventTarget.h"
+#include "nsIPipe.h"
+#include "js/GCAPI.h"
+
+namespace mozilla::dom {
+
+NS_IMPL_ISUPPORTS_INHERITED(StreamBlobImpl, BlobImpl, nsIMemoryReporter)
+
+static already_AddRefed<nsICloneableInputStream> EnsureCloneableStream(
+    nsIInputStream* aInputStream, uint64_t aLength) {
+  nsCOMPtr<nsICloneableInputStream> cloneable = do_QueryInterface(aInputStream);
+  if (cloneable && cloneable->GetCloneable()) {
+    return cloneable.forget();
+  }
+
+  // If the stream we're copying is known to be small, specify the size of the
+  // pipe's segments precisely to limit wasted space. An extra byte above length
+  // is included to avoid allocating an extra segment immediately before reading
+  // EOF from the source stream.  Otherwise, allocate 64k buffers rather than
+  // the default of 4k buffers to reduce segment counts for very large payloads.
+  static constexpr uint32_t kBaseSegmentSize = 64 * 1024;
+  uint32_t segmentSize = kBaseSegmentSize;
+  if (aLength + 1 <= kBaseSegmentSize * 4) {
+    segmentSize = aLength + 1;
+  }
+
+  // NOTE: We specify unlimited segments to eagerly build a complete copy of the
+  // source stream locally without waiting for the blob to be consumed.
+  nsCOMPtr<nsIAsyncInputStream> reader;
+  nsCOMPtr<nsIAsyncOutputStream> writer;
+  NS_NewPipe2(getter_AddRefs(reader), getter_AddRefs(writer), true, true,
+              segmentSize, UINT32_MAX);
+
+  nsresult rv;
+  nsCOMPtr<nsIEventTarget> target =
+      do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID, &rv);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  rv = NS_AsyncCopy(aInputStream, writer, target,
+                    NS_ASYNCCOPY_VIA_WRITESEGMENTS, segmentSize);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  cloneable = do_QueryInterface(reader);
+  MOZ_ASSERT(cloneable && cloneable->GetCloneable());
+  return cloneable.forget();
+}
+
+/* static */
+already_AddRefed<StreamBlobImpl> StreamBlobImpl::Create(
+    already_AddRefed<nsIInputStream> aInputStream,
+    const nsAString& aContentType, uint64_t aLength,
+    const nsAString& aBlobImplType) {
+  nsCOMPtr<nsIInputStream> inputStream = std::move(aInputStream);
+  nsCOMPtr<nsICloneableInputStream> cloneable =
+      EnsureCloneableStream(inputStream, aLength);
+
+  RefPtr<StreamBlobImpl> blobImplStream = new StreamBlobImpl(
+      cloneable.forget(), aContentType, aLength, aBlobImplType);
+  blobImplStream->MaybeRegisterMemoryReporter();
+  return blobImplStream.forget();
+}
+
+/* static */
+already_AddRefed<StreamBlobImpl> StreamBlobImpl::Create(
+    already_AddRefed<nsIInputStream> aInputStream, const nsAString& aName,
+    const nsAString& aContentType, int64_t aLastModifiedDate, uint64_t aLength,
+    const nsAString& aBlobImplType) {
+  nsCOMPtr<nsIInputStream> inputStream = std::move(aInputStream);
+  nsCOMPtr<nsICloneableInputStream> cloneable =
+      EnsureCloneableStream(inputStream, aLength);
+
+  RefPtr<StreamBlobImpl> blobImplStream =
+      new StreamBlobImpl(cloneable.forget(), aName, aContentType,
+                         aLastModifiedDate, aLength, aBlobImplType);
+  blobImplStream->MaybeRegisterMemoryReporter();
+  return blobImplStream.forget();
+}
+
+StreamBlobImpl::StreamBlobImpl(
+    already_AddRefed<nsICloneableInputStream> aInputStream,
+    const nsAString& aContentType, uint64_t aLength,
+    const nsAString& aBlobImplType)
+    : BaseBlobImpl(aContentType, aLength),
+      mInputStream(std::move(aInputStream)),
+      mBlobImplType(aBlobImplType),
+      mIsDirectory(false),
+      mFileId(-1) {}
+
+StreamBlobImpl::StreamBlobImpl(
+    already_AddRefed<nsICloneableInputStream> aInputStream,
+    const nsAString& aName, const nsAString& aContentType,
+    int64_t aLastModifiedDate, uint64_t aLength, const nsAString& aBlobImplType)
+    : BaseBlobImpl(aName, aContentType, aLength, aLastModifiedDate),
+      mInputStream(std::move(aInputStream)),
+      mBlobImplType(aBlobImplType),
+      mIsDirectory(false),
+      mFileId(-1) {}
+
+StreamBlobImpl::~StreamBlobImpl() {
+  if (mInputStream) {
+    nsCOMPtr<nsIInputStream> stream = do_QueryInterface(mInputStream);
+    stream->Close();
+  }
+  UnregisterWeakMemoryReporter(this);
+}
+
+void StreamBlobImpl::CreateInputStream(nsIInputStream** aStream,
+                                       ErrorResult& aRv) const {
+  if (!mInputStream) {
+    // We failed to clone the input stream in EnsureCloneableStream.
+    *aStream = nullptr;
+    aRv.ThrowUnknownError("failed to read blob data");
+    return;
+  }
+
+  nsCOMPtr<nsIInputStream> clonedStream;
+  aRv = mInputStream->Clone(getter_AddRefs(clonedStream));
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
+  }
+
+  nsCOMPtr<nsIInputStream> wrappedStream =
+      InputStreamLengthWrapper::MaybeWrap(clonedStream.forget(), mLength);
+
+  wrappedStream.forget(aStream);
+}
+
+already_AddRefed<BlobImpl> StreamBlobImpl::CreateSlice(
+    uint64_t aStart, uint64_t aLength, const nsAString& aContentType,
+    ErrorResult& aRv) const {
+  if (!aLength) {
+    RefPtr<BlobImpl> impl = new EmptyBlobImpl(aContentType);
+    return impl.forget();
+  }
+
+  nsCOMPtr<nsIInputStream> clonedStream;
+
+  nsCOMPtr<nsICloneableInputStreamWithRange> stream =
+      do_QueryInterface(mInputStream);
+  if (stream) {
+    aRv = stream->CloneWithRange(aStart, aLength, getter_AddRefs(clonedStream));
+    if (NS_WARN_IF(aRv.Failed())) {
+      return nullptr;
+    }
+  } else {
+    CreateInputStream(getter_AddRefs(clonedStream), aRv);
+    if (NS_WARN_IF(aRv.Failed())) {
+      return nullptr;
+    }
+
+    clonedStream =
+        new SlicedInputStream(clonedStream.forget(), aStart, aLength);
+  }
+
+  MOZ_ASSERT(clonedStream);
+
+  return StreamBlobImpl::Create(clonedStream.forget(), aContentType, aLength,
+                                mBlobImplType);
+}
+
+void StreamBlobImpl::MaybeRegisterMemoryReporter() {
+  // We report only stringInputStream.
+  nsCOMPtr<nsIStringInputStream> stringInputStream =
+      do_QueryInterface(mInputStream);
+  if (!stringInputStream) {
+    return;
+  }
+
+  RegisterWeakMemoryReporter(this);
+}
+
+NS_IMETHODIMP
+StreamBlobImpl::CollectReports(nsIHandleReportCallback* aHandleReport,
+                               nsISupports* aData, bool aAnonymize) {
+  nsCOMPtr<nsIStringInputStream> stringInputStream =
+      do_QueryInterface(mInputStream);
+  if (!stringInputStream) {
+    return NS_OK;
+  }
+
+  MOZ_COLLECT_REPORT(
+      "explicit/dom/memory-file-data/stream", KIND_HEAP, UNITS_BYTES,
+      stringInputStream->SizeOfIncludingThisIfUnshared(MallocSizeOf),
+      "Memory used to back a File/Blob based on an input stream.");
+
+  return NS_OK;
+}
+
+size_t StreamBlobImpl::GetAllocationSize() const {
+  // do_QueryInterface may run GC if the object is implemented in JS, but
+  // mInputStream is nsICloneableInputStream which doesn't have a JS
+  // implementation.
+  JS::AutoSuppressGCAnalysis nogc;
+
+  nsCOMPtr<nsIStringInputStream> stringInputStream =
+      do_QueryInterface(mInputStream);
+  if (!stringInputStream) {
+    return 0;
+  }
+
+  return stringInputStream->SizeOfIncludingThisEvenIfShared(MallocSizeOf);
+}
+
+void StreamBlobImpl::GetBlobImplType(nsAString& aBlobImplType) const {
+  aBlobImplType.AssignLiteral("StreamBlobImpl[");
+  aBlobImplType.Append(mBlobImplType);
+  aBlobImplType.AppendLiteral("]");
+}
+
+}  // namespace mozilla::dom