Mojo C++ bindings: InterfacePtr<T> and Binding<T> use MultiplexRouter when T passes associated inte…

mojo/public/cpp/bindings/lib/interface_ptr_internal.h

-// Copyright 2014 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_PTR_INTERNAL_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_PTR_INTERNAL_H_
-
-#include <algorithm>  // For |std::swap()|.
-
-#include "mojo/public/cpp/bindings/callback.h"
-#include "mojo/public/cpp/bindings/interface_ptr_info.h"
-#include "mojo/public/cpp/bindings/lib/control_message_proxy.h"
-#include "mojo/public/cpp/bindings/lib/filter_chain.h"
-#include "mojo/public/cpp/bindings/lib/message_header_validator.h"
-#include "mojo/public/cpp/bindings/lib/router.h"
-#include "mojo/public/cpp/environment/logging.h"
-
-struct MojoAsyncWaiter;
-
-namespace mojo {
-namespace internal {
-
-template <typename Interface>
-class InterfacePtrState {
- public:
-  InterfacePtrState()
-      : proxy_(nullptr), router_(nullptr), waiter_(nullptr), version_(0u) {}
-
-  ~InterfacePtrState() {
-    // Destruction order matters here. We delete |proxy_| first, even though
-    // |router_| may have a reference to it, so that destructors for any request
-    // callbacks still pending can interact with the InterfacePtr.
-    delete proxy_;
-    delete router_;
-  }
-
-  Interface* instance() {
-    ConfigureProxyIfNecessary();
-
-    // This will be null if the object is not bound.
-    return proxy_;
-  }
-
-  uint32_t version() const { return version_; }
-
-  void QueryVersion(const Callback<void(uint32_t)>& callback) {
-    ConfigureProxyIfNecessary();
-
-    // It is safe to capture |this| because the callback won't be run after this
-    // object goes away.
-    auto callback_wrapper = [this, callback](uint32_t version) {
-      this->version_ = version;
-      callback.Run(version);
-    };
-
-    // Do a static cast in case the interface contains methods with the same
-    // name.
-    static_cast<ControlMessageProxy*>(proxy_)->QueryVersion(callback_wrapper);
-  }
-
-  void RequireVersion(uint32_t version) {
-    ConfigureProxyIfNecessary();
-
-    if (version <= version_)
-      return;
-
-    version_ = version;
-    // Do a static cast in case the interface contains methods with the same
-    // name.
-    static_cast<ControlMessageProxy*>(proxy_)->RequireVersion(version);
-  }
-
-  void Swap(InterfacePtrState* other) {
-    using std::swap;
-    swap(other->proxy_, proxy_);
-    swap(other->router_, router_);
-    handle_.swap(other->handle_);
-    swap(other->waiter_, waiter_);
-    swap(other->version_, version_);
-  }
-
-  void Bind(InterfacePtrInfo<Interface> info, const MojoAsyncWaiter* waiter) {
-    MOJO_DCHECK(!proxy_);
-    MOJO_DCHECK(!router_);
-    MOJO_DCHECK(!handle_.is_valid());
-    MOJO_DCHECK(!waiter_);
-    MOJO_DCHECK(version_ == 0u);
-    MOJO_DCHECK(info.is_valid());
-
-    handle_ = info.PassHandle();
-    waiter_ = waiter;
-    version_ = info.version();
-  }
-
-  bool WaitForIncomingResponse() {
-    ConfigureProxyIfNecessary();
-
-    MOJO_DCHECK(router_);
-    return router_->WaitForIncomingMessage(MOJO_DEADLINE_INDEFINITE);
-  }
-
-  // After this method is called, the object is in an invalid state and
-  // shouldn't be reused.
-  InterfacePtrInfo<Interface> PassInterface() {
-    return InterfacePtrInfo<Interface>(
-        router_ ? router_->PassMessagePipe() : handle_.Pass(), version_);
-  }
-
-  bool is_bound() const { return handle_.is_valid() || router_; }
-
-  bool encountered_error() const {
-    return router_ ? router_->encountered_error() : false;
-  }
-
-  void set_connection_error_handler(const Closure& error_handler) {
-    ConfigureProxyIfNecessary();
-
-    MOJO_DCHECK(router_);
-    router_->set_connection_error_handler(error_handler);
-  }
-
-  // Returns true if bound and awaiting a response to a message.
-  bool has_pending_callbacks() const {
-    return router_ && router_->has_pending_responders();
-  }
-
-  Router* router_for_testing() {
-    ConfigureProxyIfNecessary();
-    return router_;
-  }
-
- private:
-  using Proxy = typename Interface::Proxy_;
-
-  void ConfigureProxyIfNecessary() {
-    // The proxy has been configured.
-    if (proxy_) {
-      MOJO_DCHECK(router_);
-      return;
-    }
-    // The object hasn't been bound.
-    if (!waiter_) {
-      MOJO_DCHECK(!handle_.is_valid());
-      return;
-    }
-
-    FilterChain filters;
-    filters.Append<MessageHeaderValidator>();
-    filters.Append<typename Interface::ResponseValidator_>();
-
-    router_ = new Router(handle_.Pass(), filters.Pass(), waiter_);
-    waiter_ = nullptr;
-
-    proxy_ = new Proxy(router_);
-  }
-
-  Proxy* proxy_;
-  Router* router_;
-
-  // |proxy_| and |router_| are not initialized until read/write with the
-  // message pipe handle is needed. |handle_| and |waiter_| are valid between
-  // the Bind() call and the initialization of |proxy_| and |router_|.
-  ScopedMessagePipeHandle handle_;
-  const MojoAsyncWaiter* waiter_;
-
-  uint32_t version_;
-
-  MOJO_DISALLOW_COPY_AND_ASSIGN(InterfacePtrState);
-};
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_INTERFACE_PTR_INTERNAL_H_