Add binary format support to CefMessageRouter (fixes #3502)

libcef_dll/wrapper/cef_message_router_utils.h

@@ -0,0 +1,92 @@
+// Copyright (c) 2023 The Chromium Embedded Framework 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 CEF_LIBCEF_DLL_WRAPPER_CEF_MESSAGE_ROUTER_UTILS_H_
+#define CEF_LIBCEF_DLL_WRAPPER_CEF_MESSAGE_ROUTER_UTILS_H_
+#pragma once
+
+#include <variant>
+
+#include "include/wrapper/cef_message_router.h"
+
+namespace cef_message_router_utils {
+
+///
+/// This class handles the task of copying user data, such as CefString or
+/// binary values like (void*, size_t), directly to an appropriate buffer based
+/// on the user data type and size.
+///
+/// There are four specializations of this abstract class. The appropriate
+/// specialization is chosen by the `CreateBrowserResponseBuilder` function,
+/// based on the provided data type and size. For instance, for a "short"
+/// CefString, a StringResponseBuilder specialization is used, and for an empty
+/// binary value - EmptyResponseBuilder.
+///
+class BrowserResponseBuilder : public CefBaseRefCounted {
+ public:
+  ///
+  /// Creates a new CefProcessMessage from the data provided to the builder.
+  /// Returns nullptr for invalid instances. Invalidates this builder instance.
+  ///
+  virtual CefRefPtr<CefProcessMessage> Build(int context_id,
+                                             int request_id) = 0;
+};
+
+struct BrowserMessage {
+  int context_id;
+  int request_id;
+  bool is_success;
+  int error_code;
+  std::variant<CefString, CefRefPtr<CefBinaryBuffer>> payload;
+};
+
+struct RendererMessage {
+  int context_id;
+  int request_id;
+  bool is_persistent;
+  std::variant<CefString, CefRefPtr<const CefBinaryBuffer>> payload;
+};
+
+class BinaryValueABRCallback final : public CefV8ArrayBufferReleaseCallback {
+ public:
+  explicit BinaryValueABRCallback(CefRefPtr<CefBinaryBuffer> value)
+      : value_(std::move(value)) {}
+  BinaryValueABRCallback(const BinaryValueABRCallback&) = delete;
+  BinaryValueABRCallback& operator=(const BinaryValueABRCallback&) = delete;
+
+  void ReleaseBuffer(void* buffer) override {}
+
+ private:
+  const CefRefPtr<CefBinaryBuffer> value_;
+
+  IMPLEMENT_REFCOUNTING(BinaryValueABRCallback);
+};
+
+CefRefPtr<BrowserResponseBuilder> CreateBrowserResponseBuilder(
+    size_t threshold,
+    const std::string& name,
+    const CefString& response);
+
+CefRefPtr<BrowserResponseBuilder> CreateBrowserResponseBuilder(
+    size_t threshold,
+    const std::string& name,
+    const void* data,
+    size_t size);
+
+CefRefPtr<CefProcessMessage> BuildRendererMsg(
+    size_t threshold,
+    const std::string& name,
+    int context_id,
+    int request_id,
+    const CefRefPtr<CefV8Value>& request,
+    bool persistent);
+
+BrowserMessage ParseBrowserMessage(const CefRefPtr<CefProcessMessage>& message);
+
+RendererMessage ParseRendererMessage(
+    const CefRefPtr<CefProcessMessage>& message);
+
+}  // namespace cef_message_router_utils
+
+#endif  // CEF_LIBCEF_DLL_WRAPPER_CEF_MESSAGE_ROUTER_UTILS_H_