Mojo C++ bindings: introduce public associated-interface-related types.

mojo/public/cpp/bindings/associated_binding.h

+// Copyright 2015 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_ASSOCIATED_BINDING_H_
+#define MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "mojo/public/cpp/bindings/associated_group.h"
+#include "mojo/public/cpp/bindings/associated_interface_request.h"
+#include "mojo/public/cpp/bindings/callback.h"
+#include "mojo/public/cpp/bindings/lib/interface_endpoint_client.h"
+#include "mojo/public/cpp/bindings/lib/multiplex_router.h"
+#include "mojo/public/cpp/bindings/lib/scoped_interface_endpoint_handle.h"
+
+namespace mojo {
+
+// Represents the implementation side of an associated interface. It is similar
+// to Binding, except that it doesn't own a message pipe handle.
+template <typename Interface>
+class AssociatedBinding {
+ public:
+  // Constructs an incomplete associated binding that will use the
+  // implementation |impl|. It may be completed with a subsequent call to the
+  // |Bind| method. Does not take ownership of |impl|, which must outlive this
+  // object.
+  explicit AssociatedBinding(Interface* impl) : impl_(impl) {
+    stub_.set_sink(impl_);
+  }
+
+  // Constructs a completed associated binding of |impl|. The output |ptr_info|
+  // should be passed through the message pipe endpoint referred to by
+  // |associated_group| to setup the corresponding asssociated interface
+  // pointer. |impl| must outlive this object.
+  AssociatedBinding(Interface* impl,
+                    AssociatedInterfacePtrInfo<Interface>* ptr_info,
+                    AssociatedGroup* associated_group)
+      : AssociatedBinding(impl) {
+    Bind(ptr_info, associated_group);
+  }
+
+  // Constructs a completed associated binding of |impl|. |impl| must outlive
+  // the binding.
+  AssociatedBinding(Interface* impl,
+                    AssociatedInterfaceRequest<Interface> request)
+      : AssociatedBinding(impl) {
+    Bind(request.Pass());
+  }
+
+  ~AssociatedBinding() {}
+
+  // Creates an associated inteface and sets up this object as the
+  // implementation side. The output |ptr_info| should be passed through the
+  // message pipe endpoint referred to by |associated_group| to setup the
+  // corresponding asssociated interface pointer.
+  void Bind(AssociatedInterfacePtrInfo<Interface>* ptr_info,
+            AssociatedGroup* associated_group) {
+    AssociatedInterfaceRequest<Interface> request;
+    associated_group->CreateAssociatedInterface(AssociatedGroup::WILL_PASS_PTR,
+                                                ptr_info, &request);
+    Bind(request.Pass());
+  }
+
+  // Sets up this object as the implementation side of an associated interface.
+  void Bind(AssociatedInterfaceRequest<Interface> request) {
+    internal::ScopedInterfaceEndpointHandle handle =
+        internal::AssociatedInterfaceRequestHelper::PassHandle(&request);
+
+    DCHECK(handle.is_local())
+        << "The AssociatedInterfaceRequest is supposed to be used at the "
+        << "other side of the message pipe.";
+
+    if (!handle.is_valid() || !handle.is_local()) {
+      endpoint_client_.reset();
+      return;
+    }
+
+    endpoint_client_.reset(new internal::InterfaceEndpointClient(
+        handle.Pass(), &stub_,
+        make_scoped_ptr(new typename Interface::RequestValidator_())));
+
+    endpoint_client_->set_connection_error_handler(
+        [this]() { connection_error_handler_.Run(); });
+  }
+
+  // Closes the associated interface. Puts this object into a state where it can
+  // be rebound.
+  void Close() {
+    DCHECK(endpoint_client_);
+    endpoint_client_.reset();
+  }
+
+  // Unbinds and returns the associated interface request so it can be
+  // used in another context, such as on another thread or with a different
+  // implementation. Puts this object into a state where it can be rebound.
+  AssociatedInterfaceRequest<Interface> Unbind() {
+    DCHECK(endpoint_client_);
+
+    AssociatedInterfaceRequest<Interface> request;
+    internal::AssociatedInterfaceRequestHelper::SetHandle(
+        &request, endpoint_client_->PassHandle());
+
+    endpoint_client_.reset();
+
+    return request.Pass();
+  }
+
+  // Sets an error handler that will be called if a connection error occurs.
+  void set_connection_error_handler(const Closure& error_handler) {
+    connection_error_handler_ = error_handler;
+  }
+
+  // Returns the interface implementation that was previously specified.
+  Interface* impl() { return impl_; }
+
+  // Indicates whether the associated binding has been completed.
+  bool is_bound() const { return !!endpoint_client_; }
+
+  // Returns the associated group that this object belongs to. Returns null if
+  // the object is not bound.
+  AssociatedGroup* associated_group() {
+    return endpoint_client_ ? endpoint_client_->associated_group() : nullptr;
+  }
+
+ private:
+  scoped_ptr<internal::InterfaceEndpointClient> endpoint_client_;
+
+  typename Interface::Stub_ stub_;
+  Interface* impl_;
+  Closure connection_error_handler_;
+
+  DISALLOW_COPY_AND_ASSIGN(AssociatedBinding);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_