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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_CAST_API_BINDINGS_SCOPED_API_BINDING_H_
#define COMPONENTS_CAST_API_BINDINGS_SCOPED_API_BINDING_H_
#include <memory>
#include <string_view>
#include "base/check.h"
#include "base/memory/raw_ptr.h"
#include "components/cast/cast_component_export.h"
#include "components/cast/message_port/message_port.h"
namespace cast_api_bindings {
class Manager;
// Manages the registration of bindings Javascript and establishment of
// communication channels, as well as unregistration on object teardown, using
// RAII semantics.
class CAST_COMPONENT_EXPORT ScopedApiBinding final
: public cast_api_bindings::MessagePort::Receiver {
public:
// Methods for handling message I/O with bindings scripts.
class Delegate {
public:
virtual ~Delegate() = default;
// Expresses the name for which MessagePort connection requests should be
// routed to the Delegate implementation.
virtual std::string_view GetPortName() const = 0;
// Invoked when |message_port_| is connected. This allows the Delegate to do
// work when the client first connects, e.g. sending it a message conveying
// some initial state.
virtual void OnConnected() {}
// Invoked for messages received over |message_port_|.
virtual bool OnMessage(std::string_view message) = 0;
// Invoked when |message_port_| is disconnected.
// Allows the delegate to cleanup if the client unexpectedly disconnects.
virtual void OnDisconnected() {}
};
// |bindings_manager|: Specifies the Manager to which the binding will be
// published.
// |delegate|: If set, provides the necessary identifier and
// method implementations for connecting script message I/O with the
// bindings backend.
// Must outlive |this|.
// Can be nullptr if the bindings do not require communication.
// |js_bindings_id|: Id used for management of the |js_bindings| script.
// Must be unique.
// |js_bindings|: script to inject.
ScopedApiBinding(Manager* bindings_manager,
Delegate* delegate,
std::string_view js_bindings_id,
std::string_view js_bindings);
~ScopedApiBinding() override;
ScopedApiBinding(const ScopedApiBinding&) = delete;
ScopedApiBinding& operator=(const ScopedApiBinding&) = delete;
// Sends a |message| to |message_port_|.
// Returns true if the message was sent.
bool SendMessage(std::string_view message);
private:
// Called when a port is received from the page.
void OnPortConnected(std::unique_ptr<cast_api_bindings::MessagePort> port);
// cast_api_bindings::MessagePort::Receiver implementation:
bool OnMessage(std::string_view message,
std::vector<std::unique_ptr<cast_api_bindings::MessagePort>>
ports) override;
void OnPipeError() override;
const raw_ptr<Manager> bindings_manager_;
const raw_ptr<Delegate> delegate_;
const std::string js_bindings_id_;
// The MessagePort used to receive messages from the receiver JS.
std::unique_ptr<cast_api_bindings::MessagePort> message_port_;
};
} // namespace cast_api_bindings
#endif // COMPONENTS_CAST_API_BINDINGS_SCOPED_API_BINDING_H_
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