Generate Mojom Types in Go

mojo/public/go/application/connection.go

Index: mojo/public/go/application/connection.go
diff --git a/mojo/public/go/application/connection.go b/mojo/public/go/application/connection.go
index f3be55c9a691443630e02d33e3d7bbfe3ffe38db..025bc8a5abd5d5c26e6c07fc97e8089e61c30ed8 100644
--- a/mojo/public/go/application/connection.go
+++ b/mojo/public/go/application/connection.go
@@ -11,6 +11,7 @@ import (
 	"mojo/public/go/system"
 
 	sp "mojo/public/interfaces/application/service_provider"
+	"mojo/public/interfaces/bindings/service_describer"
 )
 
 type connectionInfo struct {
@@ -34,6 +35,10 @@ type ServiceRequest interface {
 	// Name returns the name of requested mojo service.
 	Name() string
 
+	// ServiceDescription returns a service description, which can be queried to
+	// examine the type information of the requested mojo service.

[rudominer, 2015/10/22 21:28:47]

s/of the requested mojo service/of the service associated with this
ServiceRequest./

Also can you say something about what happens if the generation of type
information is
disabled at compilation time. For example say (if this is true) "Some
implementations will
not provide type information and in that case the returned value may be nil."

[alexfandrianto, 2015/10/22 22:58:11]

Done.

+	ServiceDescription() service_describer.ServiceDescription
+
 	// PassMessagePipe passes ownership of the underlying message pipe
 	// handle to the newly created handle object, invalidating the
 	// underlying handle object in the process.
@@ -45,6 +50,10 @@ type ServiceFactory interface {
 	// Name returns the name of provided mojo service.
 	Name() string
 
+	// ServiceDescription returns a service description, which can be queried to
+	// examine the type information of the mojo service.

[rudominer, 2015/10/22 21:28:47]

"of the mojo service associated with this ServiceFactory."

(Sorry, I know I was the one who suggested the previous wording.)

Also as above can you say something about what happens if the generation of type
information is disabled at compilation time. 

[alexfandrianto, 2015/10/22 22:58:11]

Done.

+	ServiceDescription() service_describer.ServiceDescription
+
 	// Create binds an implementation of mojo service to the provided
 	// message pipe and runs it.
 	Create(pipe system.MessagePipeHandle)
@@ -62,6 +71,7 @@ type Connection struct {
 	localServices      *bindings.Stub
 	outgoingConnection *OutgoingConnection
 	isClosed           bool
+	describer          *ServiceDescriberFactory

[rudominer, 2015/10/22 21:28:47]

Please add a comment about what happens when the generation of type information
is disabled.
Is this nil or non-functional?

[alexfandrianto, 2015/10/22 22:58:11]

The ServiceDescriber is functional, but the ServiceDescriptions obtained are
stubs. It's possible to mix and match if the implementer decided to allow a
subset of ServiceDescriptions to generate their type information though.

 }
 
 func newConnection(requestorURL string, services *sp.ServiceProvider_Request, exposedServices *sp.ServiceProvider_Pointer, resolvedURL string) *Connection {
@@ -90,7 +100,7 @@ func newConnection(requestorURL string, services *sp.ServiceProvider_Request, ex
 // Panics if called more than once.
 func (c *Connection) ProvideServices(services ...ServiceFactory) *OutgoingConnection {
 	if c.servicesProvided {
-		panic("ProvideServices can be called only once")
+		panic("ProvideServices or ProvideServicesWithDescriber can be called only once")
 	}
 	c.servicesProvided = true
 	if c.servicesRequest == nil {
@@ -122,6 +132,31 @@ func (c *Connection) ProvideServices(services ...ServiceFactory) *OutgoingConnec
 	return c.outgoingConnection
 }
 
+// ProvideServicesWithDescriber is an alternative to ProvideServices that, in
+// addition to providing the given services, also provides type descriptions of
+// the given services. See ProvideServices for a description of what it does.
+// This method will invoke ProvideServices after appending the ServiceDescriber
+// service to |services|. See service_describer.mojom for a description of the
+// ServiceDescriber interface. Client Mojo applications can choose to connect
+// to this ServiceDescriber interface, which describes the other services listed
+// in |services|.
+// Note that the implementation of ServiceDescriber will make the optional
+// DeclarationData available on all types, and in particular, the names used in
+// .mojom files will be exposed to client applications.
+func (c *Connection) ProvideServicesWithDescriber(services ...ServiceFactory) *OutgoingConnection {
+	if c.servicesProvided {
+		panic("ProvideServices or ProvideServicesWithDescriber can be called only once")
+	}
+	mapping := make(map[string]service_describer.ServiceDescription)
+	for _, service := range services {
+		mapping[service.Name()] = service.ServiceDescription()
+	}
+	c.describer = newServiceDescriberFactory(mapping)
+	servicesWithDescriber := append(services, &service_describer.ServiceDescriber_ServiceFactory{c.describer})
+
+	return c.ProvideServices(servicesWithDescriber...)
+}
+
 // Close closes both incoming and outgoing parts of the connection.
 func (c *Connection) Close() {
 	if c.servicesRequest != nil {
@@ -130,6 +165,9 @@ func (c *Connection) Close() {
 	if c.localServices != nil {
 		c.localServices.Close()
 	}
+	if c.describer != nil {
+		c.describer.Close()
+	}
 	if c.outgoingConnection.remoteServices != nil {
 		c.outgoingConnection.remoteServices.Close_Proxy()
 	}