1 files changed, 99 insertions, 0 deletions
diff --git a/dom/file/BlobImpl.cpp b/dom/file/BlobImpl.cpp
new file mode 100644
index 0000000000..fa31737c9d
--- /dev/null
+++ b/dom/file/BlobImpl.cpp
@@ -0,0 +1,99 @@
+/* -*- 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 "BlobImpl.h"
+#include "File.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ErrorResult.h"
+#include "nsIInputStream.h"
+
+namespace mozilla::dom {
+
+// Makes sure that aStart and aEnd is less then or equal to aSize and greater
+// than 0
+static void ParseSize(int64_t aSize, int64_t& aStart, int64_t& aEnd) {
+  CheckedInt64 newStartOffset = aStart;
+  if (aStart < -aSize) {
+    newStartOffset = 0;
+  } else if (aStart < 0) {
+    newStartOffset += aSize;
+  } else if (aStart > aSize) {
+    newStartOffset = aSize;
+  }
+
+  CheckedInt64 newEndOffset = aEnd;
+  if (aEnd < -aSize) {
+    newEndOffset = 0;
+  } else if (aEnd < 0) {
+    newEndOffset += aSize;
+  } else if (aEnd > aSize) {
+    newEndOffset = aSize;
+  }
+
+  if (!newStartOffset.isValid() || !newEndOffset.isValid() ||
+      newStartOffset.value() >= newEndOffset.value()) {
+    aStart = aEnd = 0;
+  } else {
+    aStart = newStartOffset.value();
+    aEnd = newEndOffset.value();
+  }
+}
+
+already_AddRefed<BlobImpl> BlobImpl::Slice(const Optional<int64_t>& aStart,
+                                           const Optional<int64_t>& aEnd,
+                                           const nsAString& aContentType,
+                                           ErrorResult& aRv) {
+  // Truncate aStart and aEnd so that we stay within this file.
+  uint64_t thisLength = GetSize(aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return nullptr;
+  }
+
+  int64_t start = aStart.WasPassed() ? aStart.Value() : 0;
+  int64_t end = aEnd.WasPassed() ? aEnd.Value() : (int64_t)thisLength;
+
+  ParseSize((int64_t)thisLength, start, end);
+
+  nsAutoString type(aContentType);
+  Blob::MakeValidBlobType(type);
+  return CreateSlice((uint64_t)start, (uint64_t)(end - start), type, aRv);
+}
+
+nsresult BlobImpl::GetSendInfo(nsIInputStream** aBody, uint64_t* aContentLength,
+                               nsACString& aContentType, nsACString& aCharset) {
+  MOZ_ASSERT(aContentLength);
+
+  ErrorResult rv;
+
+  nsCOMPtr<nsIInputStream> stream;
+  CreateInputStream(getter_AddRefs(stream), rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  *aContentLength = GetSize(rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  nsAutoString contentType;
+  GetType(contentType);
+
+  if (contentType.IsEmpty()) {
+    aContentType.SetIsVoid(true);
+  } else {
+    CopyUTF16toUTF8(contentType, aContentType);
+  }
+
+  aCharset.Truncate();
+
+  stream.forget(aBody);
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(BlobImpl, BlobImpl)
+
+}  // namespace mozilla::dom