Mojo Example that demos the difference between providing and requesting an interface

examples/indirect_service/indirect_integer_service.cc

Index: examples/indirect_service/indirect_integer_service.cc
diff --git a/examples/indirect_service/indirect_integer_service.cc b/examples/indirect_service/indirect_integer_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8eeb17de6e796b6f9678b6d760f5dc196a0c70c1
--- /dev/null
+++ b/examples/indirect_service/indirect_integer_service.cc
@@ -0,0 +1,76 @@
+// 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.
+
+#include "examples/indirect_service/indirect_service_demo.mojom.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_connection.h"
+#include "mojo/public/cpp/application/application_delegate.h"
+#include "mojo/public/cpp/application/application_runner.h"
+#include "mojo/public/cpp/application/interface_factory_impl.h"
+
+namespace mojo {
+namespace examples {
+
+class IndirectIntegerServiceImpl :
+    public InterfaceImpl<IndirectIntegerService> {
+ public:
+  IndirectIntegerServiceImpl() {}
+  virtual ~IndirectIntegerServiceImpl() {}

[yzshen1, 2014/11/20 18:17:17]

Please use
~xxxx() override {}  // without virtual, but with override.

[hansmuller, 2014/11/20 19:27:59]

Done.

+
+  virtual void Set(IntegerServicePtr service) override;

[yzshen1, 2014/11/20 18:17:17]

style nit: no need to have 'virtual'.  (This was a recent change..)

[hansmuller, 2014/11/20 19:27:59]

Done.

+  virtual void Get(InterfaceRequest<IntegerService> service) override;
+
+  IntegerService* integer_service() {
+    return integer_service_.get();
+  }
+
+private:
+  IntegerServicePtr integer_service_;
+};
+
+class DelegatingIntegerServiceImpl : public InterfaceImpl<IntegerService> {

[Aaron Boodman, 2014/11/20 07:21:58]

I think it is possible to use jamesr's new bindings fanciness to avoid this
class, and just bind the incoming InterfaceRequests in Get() more directly to
integer_service_. But I haven't thought it through, it's just a feeling.

[yzshen1, 2014/11/20 18:17:17]

+1

[hansmuller, 2014/11/20 19:27:59]

I applied your suggestion - IndirectIntegerServiceImpl now implements
IntegerService (too).  Each request for an IntegerService Binds to the one
IndirectIntegerServiceImpl. Much simpler!

+ public:
+  DelegatingIntegerServiceImpl(IndirectIntegerServiceImpl* delegate)

[yzshen1, 2014/11/20 18:17:17]

explicit, please.

+      : delegate_(delegate) {
+  }
+  virtual ~DelegatingIntegerServiceImpl() {}
+
+  virtual void Increment(const Callback<void(int32_t)>& callback) override {
+    delegate_->integer_service()->Increment(callback);
+  }
+
+ private:
+  IndirectIntegerServiceImpl* delegate_;
+};
+
+void IndirectIntegerServiceImpl::Set(IntegerServicePtr service) {
+  integer_service_ = service.Pass();
+}
+
+void IndirectIntegerServiceImpl::Get(InterfaceRequest<IntegerService> service) {
+  BindToRequest(new DelegatingIntegerServiceImpl(this), &service);
+}
+
+class IndirectIntegerServiceAppDelegate : public ApplicationDelegate {
+ public:
+  virtual bool ConfigureIncomingConnection(
+      ApplicationConnection* connection) override {
+    connection->AddService(&indirect_integer_service_factory_);
+    return true;
+  }
+
+ private:
+  InterfaceFactoryImpl<IndirectIntegerServiceImpl>
+      indirect_integer_service_factory_;
+};
+
+}  // namespace examples
+}  // namespace mojo
+
+MojoResult MojoMain(MojoHandle shell_handle) {
+  mojo::ApplicationRunner runner(
+      new mojo::examples::IndirectIntegerServiceAppDelegate);
+  return runner.Run(shell_handle);
+}
+