system/dbus: remove builder state leak

This enables external testing of system.I state.

Signed-off-by: Ophestra <cat@gensokyo.uk>

system/dbus/dbus.go

@@ -8,27 +8,31 @@ import (
 )
 
 const (
-	/*SessionBusAddress is the name of the environment variable where the address of the login session message bus is given in.
+	/*
+		SessionBusAddress is the name of the environment variable where the address of the login session message bus is given in.
 
-	If that variable is not set, applications may also try to read the address from the X Window System root window property _DBUS_SESSION_BUS_ADDRESS.
-	The root window property must have type STRING. The environment variable should have precedence over the root window property.
+		If that variable is not set, applications may also try to read the address from the X Window System root window property _DBUS_SESSION_BUS_ADDRESS.
+		The root window property must have type STRING. The environment variable should have precedence over the root window property.
 
-	The address of the login session message bus is given in the DBUS_SESSION_BUS_ADDRESS environment variable.
-	If DBUS_SESSION_BUS_ADDRESS is not set, or if it's set to the string "autolaunch:",
-	the system should use platform-specific methods of locating a running D-Bus session server,
-	or starting one if a running instance cannot be found.
-	Note that this mechanism is not recommended for attempting to determine if a daemon is running.
-	It is inherently racy to attempt to make this determination, since the bus daemon may be started just before or just after the determination is made.
-	Therefore, it is recommended that applications do not try to make this determination for their functionality purposes, and instead they should attempt to start the server.
+		The address of the login session message bus is given in the DBUS_SESSION_BUS_ADDRESS environment variable.
+		If DBUS_SESSION_BUS_ADDRESS is not set, or if it's set to the string "autolaunch:",
+		the system should use platform-specific methods of locating a running D-Bus session server,
+		or starting one if a running instance cannot be found.
+		Note that this mechanism is not recommended for attempting to determine if a daemon is running.
+		It is inherently racy to attempt to make this determination, since the bus daemon may be started just before or just after the determination is made.
+		Therefore, it is recommended that applications do not try to make this determination for their functionality purposes, and instead they should attempt to start the server.
 
-	This package diverges from the specification, as the caller is unlikely to be an X client, or be in a position to autolaunch a dbus server.
-	So a fallback address with a socket located in the well-known default XDG_RUNTIME_DIR formatting is used.*/
+		This package diverges from the specification, as the caller is unlikely to be an X client, or be in a position to autolaunch a dbus server.
+		So a fallback address with a socket located in the well-known default XDG_RUNTIME_DIR formatting is used.
+	*/
 	SessionBusAddress = "DBUS_SESSION_BUS_ADDRESS"
 
-	/*SystemBusAddress is the name of the environment variable where the address of the system message bus is given in.
+	/*
+		SystemBusAddress is the name of the environment variable where the address of the system message bus is given in.
 
-	If that variable is not set, applications should try to connect to the well-known address unix:path=/var/run/dbus/system_bus_socket.
-	Implementations of the well-known system bus should listen on an address that will result in that connection being successful.*/
+		If that variable is not set, applications should try to connect to the well-known address unix:path=/var/run/dbus/system_bus_socket.
+		Implementations of the well-known system bus should listen on an address that will result in that connection being successful.
+	*/
 	SystemBusAddress = "DBUS_SYSTEM_BUS_ADDRESS"
 
 	// FallbackSystemBusAddress is used when [SystemBusAddress] is not set.
@@ -36,28 +40,30 @@ const (
 )
 
 var (
-	addresses   [2]string
+	address     [2]string
 	addressOnce sync.Once
 )
 
+// Address returns the session and system bus addresses copied from environment,
+// or appropriate fallback values if they are not set.
 func Address() (session, system string) {
 	addressOnce.Do(func() {
 		// resolve upstream session bus address
 		if addr, ok := os.LookupEnv(SessionBusAddress); !ok {
 			// fall back to default format
-			addresses[0] = fmt.Sprintf("unix:path=/run/user/%d/bus", os.Getuid())
+			address[0] = fmt.Sprintf("unix:path=/run/user/%d/bus", os.Getuid())
 		} else {
-			addresses[0] = addr
+			address[0] = addr
 		}
 
 		// resolve upstream system bus address
 		if addr, ok := os.LookupEnv(SystemBusAddress); !ok {
 			// fall back to default hardcoded value
-			addresses[1] = FallbackSystemBusAddress
+			address[1] = FallbackSystemBusAddress
 		} else {
-			addresses[1] = addr
+			address[1] = addr
 		}
 	})
 
-	return addresses[0], addresses[1]
+	return address[0], address[1]
 }