1 files changed, 104 insertions, 0 deletions
diff --git a/chromium/third_party/blink/renderer/modules/native_io/native_io_file_sync.cc b/chromium/third_party/blink/renderer/modules/native_io/native_io_file_sync.cc
new file mode 100644
index 00000000000..466c4d75b43
--- /dev/null
+++ b/chromium/third_party/blink/renderer/modules/native_io/native_io_file_sync.cc
@@ -0,0 +1,104 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/blink/renderer/modules/native_io/native_io_file_sync.h"
+
+#include <limits>
+
+#include "base/numerics/safe_conversions.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context_lifecycle_observer.h"
+#include "third_party/blink/renderer/core/typed_arrays/array_buffer_view_helpers.h"
+#include "third_party/blink/renderer/core/typed_arrays/dom_array_buffer_view.h"
+#include "third_party/blink/renderer/modules/native_io/native_io_file.h"
+#include "third_party/blink/renderer/platform/bindings/exception_code.h"
+#include "third_party/blink/renderer/platform/bindings/exception_state.h"
+#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
+#include "third_party/blink/renderer/platform/heap/heap.h"
+#include "third_party/blink/renderer/platform/wtf/functional.h"
+
+namespace blink {
+
+// Extracts the read/write operation size from the buffer size.
+int OperationSize(const DOMArrayBufferView& buffer) {
+  // On 32-bit platforms, clamp operation sizes to 2^31-1.
+  return base::saturated_cast<int>(buffer.byteLengthAsSizeT());
+}
+
+NativeIOFileSync::NativeIOFileSync(
+    base::File backing_file,
+    mojo::Remote<mojom::blink::NativeIOFileHost> backend_file,
+    ExecutionContext* execution_context)
+    : ExecutionContextLifecycleObserver(execution_context),
+      backing_file_(std::move(backing_file)),
+      backend_file_(std::move(backend_file)) {
+  backend_file_.set_disconnect_handler(WTF::Bind(
+      &NativeIOFileSync::OnBackendDisconnect, WrapWeakPersistent(this)));
+}
+
+NativeIOFileSync::~NativeIOFileSync() = default;
+
+void NativeIOFileSync::close() {
+  backing_file_.Close();
+
+  if (!backend_file_) {
+    // If the backend went away, it already considers the file closed. Nothing
+    // to report here.
+    return;
+  }
+  backend_file_->Close();
+}
+
+int NativeIOFileSync::read(MaybeShared<DOMArrayBufferView> buffer,
+                           uint64_t file_offset,
+                           ExceptionState& exception_state) {
+  int read_size = OperationSize(*buffer.View());
+  char* read_data = static_cast<char*>(buffer.View()->BaseAddressMaybeShared());
+  if (!backing_file_.IsValid()) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
+                                      "File already closed");
+    return 0;
+  }
+  int read_bytes = backing_file_.Read(file_offset, read_data, read_size);
+  if (read_bytes < 0) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kDataError,
+                                      "read() failed");
+  }
+  return read_bytes;
+}
+
+int NativeIOFileSync::write(MaybeShared<DOMArrayBufferView> buffer,
+                            uint64_t file_offset,
+                            ExceptionState& exception_state) {
+  int write_size = OperationSize(*buffer.View());
+  char* write_data =
+      static_cast<char*>(buffer.View()->BaseAddressMaybeShared());
+  if (!backing_file_.IsValid()) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
+                                      "File already closed");
+    return 0;
+  }
+  int written_bytes = backing_file_.Write(file_offset, write_data, write_size);
+  if (written_bytes < 0) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kDataError,
+                                      "write() failed");
+  }
+  return written_bytes;
+}
+
+void NativeIOFileSync::Trace(Visitor* visitor) {
+  ScriptWrappable::Trace(visitor);
+  ExecutionContextLifecycleObserver::Trace(visitor);
+}
+
+void NativeIOFileSync::ContextDestroyed() {
+  backend_file_.reset();
+}
+
+void NativeIOFileSync::OnBackendDisconnect() {
+  backend_file_.reset();
+  backing_file_.Close();
+}
+
+}  // namespace blink