Mojo: Replace RemotePtr with InterfacePtr and InterfaceImpl

mojo/public/cpp/bindings/interface_ptr.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_INTERFACE_PTR_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_
+
+#include <assert.h>
+#include <stdio.h>
+
+#include <algorithm>
+
+#include "mojo/public/cpp/bindings/error_handler.h"
+#include "mojo/public/cpp/bindings/lib/interface_ptr_internal.h"
+#include "mojo/public/cpp/system/macros.h"
+
+namespace mojo {
+
+template <typename T>
+class InterfacePtr {
+  MOJO_MOVE_ONLY_TYPE_FOR_CPP_03(InterfacePtr, RValue)
+ public:
+  typedef T Interface;
+
+  InterfacePtr() {}
+  explicit InterfacePtr(Interface* impl) { state_.impl = impl; }
+
+  InterfacePtr(RValue other) { other.object->state_.Swap(&state_); }
+  InterfacePtr& operator=(RValue other) {
+    other.object->state_.Swap(&state_);
+    return *this;
+  }
+
+  ~InterfacePtr() {}
+
+  Interface* get() const {
+    return state_.impl;
+  }
+  Interface* operator->() const { return get(); }
+  Interface* operator*() const { return get(); }
+
+  void reset() {
+    State doomed;
+    state_.Swap(&doomed);
+  }
+
+  void Bind(Interface* impl) {
+    reset();
+    state_.impl = impl;
+  }
+
+  bool encountered_error() const;
+
+  void set_error_handler(ErrorHandler* error_handler);
+
+  // XXX figure out how to hide these!
+
+  bool has_context() const { return !!state_.context; }
+
+  void ConfigureProxy(ScopedMessagePipeHandle handle,
+                      MojoAsyncWaiter* waiter = GetDefaultAsyncWaiter()) {
+    assert(!state_.impl);
+    assert(!state_.context);
+    
+    internal::InterfacePtrContext* context =
+        new internal::InterfacePtrContext(handle.Pass(), waiter);
+    ProxyWithStub* proxy = new ProxyWithStub(context->router());
+    context->router()->set_incoming_receiver(&proxy->stub);
+
+    state_.impl = proxy;
+    state_.context = context;
+  }
+
+  void ConfigureStub(ScopedMessagePipeHandle handle,
+                     MojoAsyncWaiter* waiter = GetDefaultAsyncWaiter()) {
+    assert(state_.impl);  // Should have already been set!
+    assert(!state_.context);
+
+    // Stub for binding to state_.impl
+    // Proxy for communicating to the client on the other end of the pipe.
+
+    internal::InterfacePtrContext* context =
+        new internal::InterfacePtrContext(handle.Pass(), waiter);
+    ClientProxyWithStub* proxy = new ClientProxyWithStub(context->router());
+    proxy->stub.set_sink(state_.impl);
+    context->router()->set_incoming_receiver(&proxy->stub);
+
+    state_.impl->SetClient(proxy);
+
+    state_.client = proxy;
+    state_.context = context;
+  }
+
+  void Detach() {
+    new DetachedState(&state_);
+  }
+
+ private:
+  struct ProxyWithStub : public Interface::Proxy_ {
+    explicit ProxyWithStub(MessageReceiver* receiver)
+        : Interface::Proxy_(receiver) {
+    }
+    virtual void SetClient(typename Interface::Client_* client) MOJO_OVERRIDE {
+      stub.set_sink(client);
+    }
+    typename Interface::Client_::Stub_ stub;
+  };
+
+  struct ClientProxyWithStub : public Interface::Client_::Proxy_ {
+    explicit ClientProxyWithStub(MessageReceiver* receiver)
+        : Interface::Client_::Proxy_(receiver) {
+    }
+    typename Interface::Stub_ stub;
+  };
+
+  struct State {
+    State() : impl(NULL), client(NULL), context(NULL) {}
+
+    ~State() {
+      delete context;  // context depends on impl
+      delete impl;     // impl depends on client
+      delete client;
+    }
+
+    void Swap(State* other) {
+      std::swap(other->impl, impl);
+      std::swap(other->client, client);
+      std::swap(other->context, context);
+    }
+
+    Interface* impl;
+    typename Interface::Client_* client;
+    internal::InterfacePtrContext* context;
+
+    MOJO_DISALLOW_COPY_AND_ASSIGN(State);
+  };
+
+  class DetachedState : public ErrorHandler {
+   public:
+    explicit DetachedState(State* state) {
+      internal::LogDetachedState(this, +1);
+
+      state_.Swap(state);
+
+      assert(state_.context);
+      assert(!state_.context->router()->encountered_error());
+
+      // Register to observe when the pipe is broken.
+      state_.context->router()->set_error_handler(this);
+    }
+
+    virtual void OnError() MOJO_OVERRIDE {
+      internal::LogDetachedState(this, -1);
+
+      delete this;
+    }
+
+    State state_;
+  };
+
+  State state_;
+};
+
+// Takes a handle to the proxy end-point of a pipe. On the other end is
+// presumed to be an interface implementation of type |Interface|. Returns a
+// generated proxy to that interface, which may be used on the current thread.
+// It is valid to call SetClient on the returned Interface to set an instance
+// of Interface::Client.
+//
+// XXX not sure if MakeProxy is the best name here.
+template <typename Interface>
+InterfacePtr<Interface> MakeProxy(
+    ScopedMessagePipeHandle handle,
+    MojoAsyncWaiter* waiter = GetDefaultAsyncWaiter()) {
+  InterfacePtr<Interface> ptr;
+  if (handle.is_valid())
+    ptr.ConfigureProxy(handle.Pass(), waiter);
+  return ptr.Pass();
+}
+
+// Takes a heap-allocated interface implementation and binds its lifetime to
+// that of a MessagePipe. A handle to the proxy end-point of the pipe is
+// returned. If that pipe is closed, then the interface implementation will be
+// deleted.
+//
+// The interface implementation is also bound to the current thread. Its
+// methods will only be called on the current thread, and if the current thread
+// exits, then it will also be deleted and its end point of the pipe will be
+// closed.
+//
+// Before returning the interface implementation will receive a SetClient call,
+// providing it with a proxy to the client on the other end of the pipe.
+//
+// XXX not sure if BindToPipe is the best name here.
+template <typename Interface>
+ScopedMessagePipeHandle BindToPipe(Interface* impl) {
+  InterfacePtr<Interface> ptr(impl);
+  MessagePipe pipe;
+  ptr.ConfigureStub(pipe.handle0.Pass());
+  ptr.Detach();
+  return pipe.handle1.Pass();
+}
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_