chromium/src/third_party/blink/renderer/platform/mojo/big_string_mojom_traits.h

// Copyright 2018 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.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_MOJO_BIG_STRING_MOJOM_TRAITS_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_MOJO_BIG_STRING_MOJOM_TRAITS_H_

#include "mojo/public/cpp/base/big_buffer.h"
#include "mojo/public/cpp/bindings/struct_traits.h"
#include "mojo/public/mojom/base/big_string.mojom-blink-forward.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/text/string_utf8_adaptor.h"

namespace mojo {

template <>
struct PLATFORM_EXPORT
    StructTraits<mojo_base::mojom::BigStringDataView, WTF::String> {
  static bool IsNull(const WTF::String& input) { return input.IsNull(); }
  static void SetToNull(WTF::String* output) { *output = WTF::String(); }

  static mojo_base::BigBuffer data(const WTF::String& input) {
    WTF::StringUTF8Adaptor adaptor(input);
    return mojo_base::BigBuffer(base::as_bytes(base::make_span(adaptor)));
  }

  static bool Read(mojo_base::mojom::BigStringDataView data, WTF::String* out) {
    mojo_base::BigBuffer buffer;
    if (!data.ReadData(&buffer))
      return false;
    size_t size = buffer.size();
    if (size % sizeof(char))
      return false;
    // An empty |mojo_base::BigBuffer| may have a null |data()| if empty.
    if (!size) {
      *out = g_empty_string;
    } else {
      *out = WTF::String::FromUTF8(reinterpret_cast<const char*>(buffer.data()),
                                   size / sizeof(char));
    }
    return true;
  }
};

}  // namespace mojo

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_MOJO_BIG_STRING_MOJOM_TRAITS_H_