Merge pull request #35 from kyrofa/feature/34/subtree_support

Add ExportSubtree functions for subtree support.

export.go

@@ -29,6 +29,9 @@ type exportWithMapping struct {
 
 	// Method name mapping; key -> struct method, value -> dbus method.
 	mapping map[string]string
+
+	// Whether or not this export is for the entire subtree
+	includeSubtree bool
 }
 
 // Sender is a type which can be used in exported methods to receive the message
@@ -76,6 +79,42 @@ func exportedMethod(export exportWithMapping, name string) reflect.Value {
 	return m
 }
 
+// searchHandlers will look through all registered handlers looking for one
+// to handle the given path. If a verbatim one isn't found, it will check for
+// a subtree registration for the path as well.
+func (conn *Conn) searchHandlers(path ObjectPath) (map[string]exportWithMapping, bool) {
+	conn.handlersLck.RLock()
+	defer conn.handlersLck.RUnlock()
+
+	handlers, ok := conn.handlers[path]
+	if ok {
+		return handlers, ok
+	}
+
+	// If handlers weren't found for this exact path, look for a matching subtree
+	// registration
+	handlers = make(map[string]exportWithMapping)
+	path = path[:strings.LastIndex(string(path), "/")]
+	for len(path) > 0 {
+		var subtreeHandlers map[string]exportWithMapping
+		subtreeHandlers, ok = conn.handlers[path]
+		if ok {
+			for iface, handler := range subtreeHandlers {
+				// Only include this handler if it registered for the subtree
+				if handler.includeSubtree {
+					handlers[iface] = handler
+				}
+			}
+
+			break
+		}
+
+		path = path[:strings.LastIndex(string(path), "/")]
+	}
+
+	return handlers, ok
+}
+
 // handleCall handles the given method call (i.e. looks if it's one of the
 // pre-implemented ones and searches for a corresponding handler if not).
 func (conn *Conn) handleCall(msg *Message) {
@@ -98,37 +137,32 @@ func (conn *Conn) handleCall(msg *Message) {
 	if len(name) == 0 {
 		conn.sendError(errmsgUnknownMethod, sender, serial)
 	}
+
+	// Find the exported handler (if any) for this path
+	handlers, ok := conn.searchHandlers(path)
+	if !ok {
+		conn.sendError(errmsgNoObject, sender, serial)
+		return
+	}
+
 	var m reflect.Value
 	if hasIface {
-		conn.handlersLck.RLock()
-		obj, ok := conn.handlers[path]
-		if !ok {
-			conn.sendError(errmsgNoObject, sender, serial)
-			conn.handlersLck.RUnlock()
-			return
-		}
-		iface := obj[ifaceName]
-		conn.handlersLck.RUnlock()
+		iface := handlers[ifaceName]
 		m = exportedMethod(iface, name)
 	} else {
-		conn.handlersLck.RLock()
-		if _, ok := conn.handlers[path]; !ok {
-			conn.sendError(errmsgNoObject, sender, serial)
-			conn.handlersLck.RUnlock()
-			return
-		}
-		for _, v := range conn.handlers[path] {
+		for _, v := range handlers {
 			m = exportedMethod(v, name)
 			if m.IsValid() {
 				break
 			}
 		}
-		conn.handlersLck.RUnlock()
 	}
+
 	if !m.IsValid() {
 		conn.sendError(errmsgUnknownMethod, sender, serial)
 		return
 	}
+
 	t := m.Type()
 	vs := msg.Body
 	pointers := make([]interface{}, t.NumIn())
@@ -139,27 +173,36 @@ func (conn *Conn) handleCall(msg *Message) {
 		pointers[i] = val.Interface()
 		if tp == reflect.TypeOf((*Sender)(nil)).Elem() {
 			val.Elem().SetString(sender)
+		} else if tp == reflect.TypeOf((*Message)(nil)).Elem() {
+			val.Elem().Set(reflect.ValueOf(*msg))
 		} else {
 			decode = append(decode, pointers[i])
 		}
 	}
+
 	if len(decode) != len(vs) {
 		conn.sendError(errmsgInvalidArg, sender, serial)
 		return
 	}
+
 	if err := Store(vs, decode...); err != nil {
 		conn.sendError(errmsgInvalidArg, sender, serial)
 		return
 	}
+
+	// Extract parameters
 	params := make([]reflect.Value, len(pointers))
 	for i := 0; i < len(pointers); i++ {
 		params[i] = reflect.ValueOf(pointers[i]).Elem()
 	}
+
+	// Call method
 	ret := m.Call(params)
 	if em := ret[t.NumOut()-1].Interface().(*Error); em != nil {
 		conn.sendError(*em, sender, serial)
 		return
 	}
+
 	if msg.Flags&FlagNoReplyExpected == 0 {
 		reply := new(Message)
 		reply.Type = TypeMethodReply
@@ -236,6 +279,10 @@ func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) erro
 // contribute to the dbus signature of the method (i.e. the method is exposed
 // as if the parameters of type Sender were not there).
 //
+// Similarly, any parameters with the type Message are set to the raw message
+// received on the bus. Again, parameters of this type do not contribute to the
+// dbus signature of the method.
+//
 // Every method call is executed in a new goroutine, so the method may be called
 // in multiple goroutines at once.
 //
@@ -256,6 +303,34 @@ func (conn *Conn) Export(v interface{}, path ObjectPath, iface string) error {
 // The keys in the map are the real method names (exported on the struct), and
 // the values are the method names to be exported on DBus.
 func (conn *Conn) ExportWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
+	return conn.exportWithMap(v, mapping, path, iface, false)
+}
+
+// ExportSubtree works exactly like Export but registers the given value for
+// an entire subtree rather under the root path provided.
+//
+// In order to make this useful, one parameter in each of the value's exported
+// methods should be a Message, in which case it will contain the raw message
+// (allowing one to get access to the path that caused the method to be called).
+//
+// Note that more specific export paths take precedence over less specific. For
+// example, a method call using the ObjectPath /foo/bar/baz will call a method
+// exported on /foo/bar before a method exported on /foo.
+func (conn *Conn) ExportSubtree(v interface{}, path ObjectPath, iface string) error {
+	return conn.ExportSubtreeWithMap(v, nil, path, iface)
+}
+
+// ExportSubtreeWithMap works exactly like ExportSubtree but provides the
+// ability to remap method names (e.g. export a lower-case method).
+//
+// The keys in the map are the real method names (exported on the struct), and
+// the values are the method names to be exported on DBus.
+func (conn *Conn) ExportSubtreeWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
+	return conn.exportWithMap(v, mapping, path, iface, true)
+}
+
+// exportWithMap is the worker function for all exports/registrations.
+func (conn *Conn) exportWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string, includeSubtree bool) error {
 	if !path.IsValid() {
 		return fmt.Errorf(`dbus: Invalid path name: "%s"`, path)
 	}
@@ -282,7 +357,7 @@ func (conn *Conn) ExportWithMap(v interface{}, mapping map[string]string, path O
 	}
 
 	// Finally, save this handler
-	conn.handlers[path][iface] = exportWithMapping{export: v, mapping: mapping}
+	conn.handlers[path][iface] = exportWithMapping{export: v, mapping: mapping, includeSubtree: includeSubtree}
 
 	return nil
 }