Mojo: Internalize ServiceConnector<>

mojo/public/cpp/shell/service.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_SHELL_SERVICE_H_
-#define MOJO_PUBLIC_SHELL_SERVICE_H_
-
-#include <assert.h>
-
-#include <vector>
-
-#include "mojo/public/cpp/bindings/allocation_scope.h"
-#include "mojo/public/interfaces/shell/shell.mojom.h"
-
-// Utility classes for creating ShellClients that vend service instances.
-// To use define a class that implements your specific server api, e.g. FooImpl
-// to implement a service named Foo. That class must define an empty constructor
-// and the Initialize() method.
-// class FooImpl : public Foo {
-//  public:
-//   FooImpl();
-//   void Initialize();
-//  private:
-//   ServiceConnector<FooImpl>* service_connector_;
-// };
-//
-//
-// To simplify further FooImpl can use the ServiceConnection<> template.
-// class FooImpl : public ServiceConnection<Foo, FooImpl> {
-//  public:
-//   FooImpl();
-//   ...
-//   <Foo implementation>
-// };
-//
-// Instances of FooImpl will be created by a specialized ServiceConnector
-//
-// ServiceConnector<FooImpl>
-//
-// Optionally the classes can be specializeed with a shared context
-// class ServiceConnector<FooImpl, MyContext>
-// and
-// class FooImpl : public ServiceConnection<Foo, FooImpl, MyContext>
-//
-// foo_connector = new ServiceConnector<FooImpl, MyContext>(my_context);
-// instances of FooImpl can call context() and retrieve the value of my_context.
-//
-// Lastly create an Application instance that collects all the
-// ServiceConnectors.
-//
-// Application app(shell_handle);
-// app.AddServiceConnector(new ServiceConnector<FooImpl>);
-//
-//
-// Specialization of ServiceConnector.
-// ServiceImpl: Implementation of Service interface.
-// Context: Optional type of shared context.v
-//
-//
-namespace mojo {
-
-namespace internal {
-class ServiceConnectorBase {
- public:
-  class Owner : public ShellClient {
-   public:
-    Owner(ScopedMessagePipeHandle shell_handle);
-    virtual ~Owner();
-    Shell* shell() { return shell_.get(); }
-    virtual void AddServiceConnector(
-        internal::ServiceConnectorBase* service_connector) = 0;
-    virtual void RemoveServiceConnector(
-        internal::ServiceConnectorBase* service_connector) = 0;
-
-   protected:
-    void set_service_connector_owner(ServiceConnectorBase* service_connector,
-                                     Owner* owner) {
-      service_connector->owner_ = owner;
-    }
-    ShellPtr shell_;
-  };
-  ServiceConnectorBase() : owner_(NULL) {}
-  virtual ~ServiceConnectorBase();
-  Shell* shell() { return owner_->shell(); }
-  virtual void AcceptConnection(const std::string& url,
-                                ScopedMessagePipeHandle client_handle) = 0;
-
- protected:
-  Owner* owner_;
-};
-}  // namespace internal
-
-template <class ServiceImpl, typename Context=void>
-class ServiceConnector : public internal::ServiceConnectorBase {
- public:
-  ServiceConnector(Context* context = NULL) : context_(context) {}
-
-  virtual ~ServiceConnector() {
-    ConnectionList doomed;
-    doomed.swap(connections_);
-    for (typename ConnectionList::iterator it = doomed.begin();
-         it != doomed.end(); ++it) {
-      delete *it;
-    }
-    assert(connections_.empty());  // No one should have added more!
-  }
-
-  virtual void AcceptConnection(const std::string& url,
-                                ScopedMessagePipeHandle handle) MOJO_OVERRIDE {
-    ServiceImpl* impl = BindToPipe(new ServiceImpl(), handle.Pass());
-    impl->set_connector(this);
-
-    connections_.push_back(impl);
-
-    impl->Initialize();
-  }
-
-  void RemoveConnection(ServiceImpl* impl) {
-    // Called from ~ServiceImpl, in response to a connection error.
-    for (typename ConnectionList::iterator it = connections_.begin();
-         it != connections_.end(); ++it) {
-      if (*it == impl) {
-        delete impl;
-        connections_.erase(it);
-        if (connections_.empty())
-          owner_->RemoveServiceConnector(this);
-        return;
-      }
-    }
-  }
-
-  Context* context() const { return context_; }
-
- private:
-  typedef std::vector<ServiceImpl*> ConnectionList;
-  ConnectionList connections_;
-  Context* context_;
-};
-
-// Specialization of ServiceConnection.
-// ServiceInterface: Service interface.
-// ServiceImpl: Subclass of ServiceConnection<...>.
-// Context: Optional type of shared context.
-template <class ServiceInterface, class ServiceImpl, typename Context=void>
-class ServiceConnection : public InterfaceImpl<ServiceInterface> {
- protected:
-  // NOTE: shell() and context() are not available at construction time.
-  // Initialize() will be called once those are available.
-  ServiceConnection() : service_connector_(NULL) {}
-
-  virtual ~ServiceConnection() {}
-
-  virtual void OnConnectionError() MOJO_OVERRIDE {
-    service_connector_->RemoveConnection(static_cast<ServiceImpl*>(this));
-  }
-
-  // Shadow this method in ServiceImpl to perform one-time initialization.
-  // At the time this is called, shell() and context() will be available.
-  // NOTE: No need to call the base class Initialize from your subclass. It
-  // will always be a no-op.
-  void Initialize() {}
-
-  Shell* shell() {
-    return service_connector_->shell();
-  }
-
-  Context* context() const {
-    return service_connector_->context();
-  }
-
- private:
-  friend class ServiceConnector<ServiceImpl, Context>;
-
-  // Called shortly after this class is instantiated.
-  void set_connector(ServiceConnector<ServiceImpl, Context>* connector) {
-    service_connector_ = connector;
-  }
-
-  ServiceConnector<ServiceImpl, Context>* service_connector_;
-};
-
-template <typename Interface>
-inline void ConnectTo(Shell* shell, const std::string& url,
-                      InterfacePtr<Interface>* ptr) {
-  MessagePipe pipe;
-  ptr->Bind(pipe.handle0.Pass());
-
-  AllocationScope scope;
-  shell->Connect(url, pipe.handle1.Pass());
-}
-
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_SHELL_SERVICE_H_