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GDBUS-CODEGEN(1) | User Commands | GDBUS-CODEGEN(1) |
NAME¶
gdbus-codegen - D-Bus code and documentation generatorSYNOPSIS¶
gdbus-codegen [-h, --help]
[--interface-prefix org.project.Prefix]
[--generate-c-code OUTFILES]
[--c-namespace YourProject]
[--c-generate-object-manager] [
--generate-docbook OUTFILES] [
--xml-files FILE]
[--annotate ELEMENT
KEY VALUE]... FILE [FILE...]
DESCRIPTION¶
gdbus-codegen is used to generate code and/or documentation for one or more D-Bus interfaces. The tool reads D-Bus Introspection XML[1] files and generates output files. The tool currently supports generating C code (via --generate-c-code) and Docbook XML (via --generate-docbook).GENERATING C CODE¶
When generating C code, a #GInterface -derived type is generated for each D-Bus interface. Additionally, for every generated type, FooBar, two concrete instantiable types, FooBarProxy and FooBarSkeleton, implementing said interface are also generated. The former is derived from #GDBusProxy and intended for use on the client side while the latter is derived from the #GDBusInterfaceSkeleton type making it easy to export on a #GDBusConnection either directly or via a #GDBusObjectManagerServer instance. The name of each generated C type is derived from the D-Bus interface name stripped with the prefix given with --interface-prefix and with the dots removed and initial characters capitalized. For example, for the D-Bus interface com.acme.Coyote the name used is ComAcmeCoyote. For the D-Bus interface org.project.Bar.Frobnicator with --interface-prefixorg.project., the name used is BarFrobnicator. For methods, signals and properties, if not specified, the name defaults to the name of the method, signal or property. Two forms of the name are used - the CamelCase form and the lower-case form. The CamelCase form is used for the #GType and struct name, while lower-case form is used in function names. The lower-case form is calculated by converting from CamelCase to lower-case and inserting underscores at word boundaries (using certain heuristics). If the value given by the org.gtk.GDBus.C.Name annotation or the --c-namespace option contains an underscore (sometimes called Ugly_Case), then the camel-case name is derived by removing all underscores, and the lower-case name is derived by lower-casing the string. This is useful in some situations where abbreviations are used. For example, if the annotation is used on the interface net.MyCorp.MyApp.iSCSITarget with the value iSCSI_Target the CamelCase form is iSCSITarget while the lower-case form is iscsi_target. If the annotation is used on the method EjectTheiPod with the value Eject_The_iPod, the lower-case form is eject_the_ipod.GENERATING DOCBOOK DOCUMENTATION¶
Each generated Docbook XML file (see the --generate-docbook option for details) is a RefEntry[2] article describing the D-Bus interface.OPTIONS¶
The following options are supported: -h, --helpShow help and exit.
--xml-files FILE
The D-Bus introspection XML file.
--interface-prefix org.project.Prefix.
A prefix to strip from all D-Bus interface names when
calculating the typename for the C binding and the Docbook sortas
attribute[3].
--generate-docbook OUTFILES
Generate Docbook Documentation for each D-Bus interface
and put it in OUTFILES-NAME.xml where NAME is a place-holder for the interface
name, e.g. net.Corp.FooBar and so on.
--generate-c-code OUTFILES
Generate C code for all D-Bus interfaces and put it in
OUTFILES.c and OUTFILES.h.
--c-namespace YourProject
The namespace to use for generated C code. This is
expected to be in CamelCase[4] or Ugly_Case (see above).
--c-generate-object-manager
If this option is passed, suitable #GDBusObject,
#GDBusObjectProxy, #GDBusObjectSkeleton and #GDBusObjectManagerClient
subclasses are generated.
--annotate ELEMENT KEY VALUE
Used to inject D-Bus annotations into the given XML
files. It can be used with interfaces, methods, signals, properties and
arguments in the following way:
Any UTF-8 string can be used for KEY and VALUE.
gdbus-codegen --c-namespace MyApp \ --generate-c-code myapp-generated \ --annotate "org.project.InterfaceName" \ org.gtk.GDBus.C.Name MyFrobnicator \ --annotate "org.project.InterfaceName:Property" \ bar bat \ --annotate "org.project.InterfaceName.Method()" \ org.freedesktop.DBus.Deprecated true \ --annotate "org.project.InterfaceName.Method()[arg_name]" \ snake hiss \ --annotate "org.project.InterfaceName::Signal" \ cat meow \ --annotate "org.project.InterfaceName::Signal[arg_name]" \ dog wuff \ myapp-dbus-interfaces.xml
SUPPORTED D-BUS ANNOTATIONS¶
The following D-Bus annotations are supported by gdbus-codegen: org.freedesktop.DBus.DeprecatedCan be used on any <interface>, <method>,
<signal> and <property> element to specify that the element is
deprecated if its value is true. Note that this annotation is defined in the
D-Bus specification[1] and can only assume the values true and false.
In particular, you cannot specify the version that the element was deprecated
in nor any helpful deprecation message. Such information should be added to
the element documentation instead.
When generating C code, this annotation is used to add #G_GNUC_DEPRECATED to
generated functions for the element.
When generating Docbook XML, a deprecation warning will appear along the
documentation for the element.
org.gtk.GDBus.Since
Can be used on any <interface>, <method>,
<signal> and <property> element to specify the version (any
free-form string but compared using a version-aware sort function) the element
appeared in.
When generating C code, this field is used to ensure function pointer order for
preserving ABI/API, see the section called “STABILITY
GUARANTEES”.
When generating Docbook XML, the value of this tag appears in the
documentation.
org.gtk.GDBus.DocString
A string with Docbook content for documentation. This
annotation can be used on <interface>, <method>, <signal>,
<property> and <arg> elements.
org.gtk.GDBus.DocString.Short
A string with Docbook content for short/brief
documentation. This annotation can only be used on <interface>
elements.
org.gtk.GDBus.C.Name
Can be used on any <interface>, <method>,
<signal> and <property> element to specify the name to use when
generating C code. The value is expected to be in CamelCase[4] or
Ugly_Case (see above).
org.gtk.GDBus.C.ForceGVariant
If set to a non-empty string, a #GVariant instance will
be used instead of the natural C type. This annotation can be used on any
<arg> and <property> element.
org.gtk.GDBus.C.UnixFD
If set to a non-empty string, the generated code will
include parameters to exchange file descriptors using the #GUnixFDList type.
This annotation can be used on <method> elements.
As an easier alternative to using the org.gtk.GDBus.DocString annotation, note
that parser used by gdbus-codegen parses XML comments in a way similar
to gtk-doc[5]:
Note that @since can be used in any inline documentation bit (e.g. for
interfaces, methods, signals and properties) to set the org.gtk.GDBus.Since
annotation. For the org.gtk.GDBus.DocString annotation (and inline comments),
note that substrings of the form #net.Corp.Bar, net.Corp.Bar.FooMethod(),
#net.Corp.Bar::BarSignal and #net.Corp.InlineDocs:BazProperty are all expanded
to links to the respective interface, method, signal and property.
Additionally, substrings starting with @ and % characters are rendered as
parameter[6] and constant[7] respectively.
If both XML comments and org.gtk.GDBus.DocString or
org.gtk.GDBus.DocString.Short annotations are present, the latter wins.
EXAMPLE¶
Consider the following D-Bus Introspection XML.<node> <interface name="net.Corp.MyApp.Frobber"> <method name="HelloWorld"> <arg name="greeting" direction="in" type="s"/> <arg name="response" direction="out" type="s"/> </method> <signal name="Notification"> <arg name="icon_blob" type="ay"/> <arg name="height" type="i"/> <arg name="messages" type="as"/> </signal> <property name="Verbose" type="b" access="readwrite"/> </interface> </node>
gdbus-codegen --generate-c-code myapp-generated \ --c-namespace MyApp \ --interface-prefix net.corp.MyApp. \ net.Corp.MyApp.Frobber.xml
/* GType macros for the three generated types */ #define MY_APP_TYPE_FROBBER (my_app_frobber_get_type ()) #define MY_APP_TYPE_FROBBER_SKELETON (my_app_frobber_skeleton_get_type ()) #define MY_APP_TYPE_FROBBER_PROXY (my_app_frobber_proxy_get_type ()) typedef struct _MyAppFrobber MyAppFrobber; /* Dummy typedef */ typedef struct { GTypeInterface parent_iface; /* Signal handler for the ::notification signal */ void (*notification) (MyAppFrobber *proxy, GVariant *icon_blob, gint height, const gchar* const *messages); /* Signal handler for the ::handle-hello-world signal */ gboolean (*handle_hello_world) (MyAppFrobber *proxy, GDBusMethodInvocation *invocation, const gchar *greeting); } MyAppFrobberIface; /* Asynchronously calls HelloWorld() */ void my_app_frobber_call_hello_world (MyAppFrobber *proxy, const gchar *greeting, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data); gboolean my_app_frobber_call_hello_world_finish (MyAppFrobber *proxy, gchar **out_response, GAsyncResult *res, GError **error); /* Synchronously calls HelloWorld(). Blocks calling thread. */ gboolean my_app_frobber_call_hello_world_sync (MyAppFrobber *proxy, const gchar *greeting, gchar **out_response, GCancellable *cancellable, GError **error); /* Completes handling the HelloWorld() method call */ void my_app_frobber_complete_hello_world (MyAppFrobber *object, GDBusMethodInvocation *invocation, const gchar *response); /* Emits the ::notification signal / Notification() D-Bus signal */ void my_app_frobber_emit_notification (MyAppFrobber *object, GVariant *icon_blob, gint height, const gchar* const *messages); /* Gets the :verbose GObject property / Verbose D-Bus property. * Does no blocking I/O. */ gboolean my_app_frobber_get_verbose (MyAppFrobber *object); /* Sets the :verbose GObject property / Verbose D-Bus property. * Does no blocking I/O. */ void my_app_frobber_set_verbose (MyAppFrobber *object, gboolean value); /* Gets the interface info */ GDBusInterfaceInfo *my_app_frobber_interface_info (void); /* Creates a new skeleton object, ready to be exported */ MyAppFrobber *my_app_frobber_skeleton_new (void); /* Client-side proxy constructors. * * Additionally, _new_for_bus(), _new_for_bus_finish() and * _new_for_bus_sync() proxy constructors are also generated. */ void my_app_frobber_proxy_new (GDBusConnection *connection, GDBusProxyFlags flags, const gchar *name, const gchar *object_path, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data); MyAppFrobber * my_app_frobber_proxy_new_finish (GAsyncResult *res, GError **error); MyAppFrobber * my_app_frobber_proxy_new_sync (GDBusConnection *connection, GDBusProxyFlags flags, const gchar *name, const gchar *object_path, GCancellable *cancellable, GError **error);
Client | Server | |
Types | Use MyAppFrobberProxy | Any type implementing the MyAppFrobber interface |
Methods | Use m_a_f_hello_world() to call. | Receive via the handle_hello_world() signal handler. Complete the call with m_a_f_complete_hello_world() |
Signals | Connect to the ::notification GObject signal. | Use m_a_f_emit_notification() to emit signal. |
Properties (Reading) | Use m_a_f_get_verbose() or :verbose. | Implement #GObject's get_property() vfunc. |
Properties (writing) | Use m_a_f_set_verbose() or :verbose. | Implement #GObject's set_property() vfunc. |
Client-side usage¶
You can use the generated proxy type with the generated constructors:MyAppFrobber *proxy; GError *error; error = NULL; proxy = my_app_frobber_proxy_new_for_bus_sync ( G_BUS_TYPE_SESSION, G_DBUS_PROXY_FLAGS_NONE, "net.Corp.MyApp", /* bus name */ "/net/Corp/MyApp/SomeFrobber", /* object */ NULL, /* GCancellable* */ &error); /* do stuff with proxy */ g_object_unref (proxy);
Server-side usage¶
The generated MyAppFrobber interface is designed so it is easy to implement it in a #GObject subclass. For example, to handle HelloWorld() method invocations, set the vfunc for handle_hello_hello_world() in the MyAppFrobberIface structure. Similary, to handle the net.Corp.MyApp.Frobber:Verbose property override the :verbose #GObject property from the subclass. To emit a signal, use e.g. my_app_emit_signal() or g_signal_emit_by_name(). Instead of subclassing, it is often easier to use the generated MyAppFrobberSkeleton subclass. To handle incoming method calls, use g_signal_connect() with the ::handle-* signals and instead of overriding #GObject 's get_property() and set_property() vfuncs, use g_object_get() and g_object_set() or the generated property getters and setters (the generated class has an internal property bag implementation).static gboolean on_handle_hello_world (MyAppFrobber *interface, GDBusMethodInvocation *invocation, const gchar *greeting, gpointer user_data) { if (g_strcmp0 (greeting, "Boo") != 0) { gchar *response; response = g_strdup_printf ("Word! You said `%s'.", greeting); my_app_complete_hello_world (interface, invocation, response); g_free (response); } else { g_dbus_method_invocation_return_error (invocation, MY_APP_ERROR, MY_APP_ERROR_NO_WHINING, "Hey, %s, there will be no whining!", g_dbus_method_invocation_get_sender (invocation)); } return TRUE; } [...] interface = my_app_frobber_skeleton_new (); my_app_frobber_set_verbose (interface, TRUE); g_signal_connect (interface, "handle-hello-world", G_CALLBACK (on_handle_hello_world), some_user_data); [...] error = NULL; if (!g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (interface), connection, "/path/of/dbus_object", &error)) { /* handle error */ }
C TYPE MAPPING¶
Scalar types (type-strings and and and gchar*, gchar** and so on. Everything else is mapped to the #GVariant type. This automatic mapping can be turned off by using the annotation org.gtk.GDBus.C.ForceGVariant - if used then a #GVariant is always exchanged instead of the corresponding native C type. This annotation may be convenient to use when using bytestrings (type-stringSTABILITY GUARANTEES¶
The generated C functions are guaranteed to not change their ABI that is, if a method, signal or property does not change its signature in the introspection XML, the generated C functions will not change its C ABI either. The ABI of the generated instance and class structures will be preserved as well. The ABI of the generated #GType s will be preserved only if the org.gtk.GDBus.Since annotation is used judiciously — this is because the VTable for the #GInterface relies on functions pointers for signal handlers. Specifically, if a D-Bus method, property or signal or is added to a D-Bus interface, then ABI of the generated #GInterface type is preserved if, and only if, each added method, property signal is annotated with they org.gtk.GDBus.Since annotation using a greater version number than previous versions. The generated C code currently happens to be annotated with gtk-doc[5] / GObject Introspection[9] comments / annotations. The layout and contents might change in the future so no guarantees about e.g. SECTION usage etc. is given. While the generated Docbook for D-Bus interfaces isn't expected to change, no guarantees are given at this point. It is important to note that the generated code should not be checked into revision control systems, nor it should be included in distributed source archives.BUGS¶
Please send bug reports to either the distribution bug tracker or the upstream bug tracker at https://bugzilla.gnome.org/enter_bug.cgi?product=glib.SEE ALSO¶
gdbus(1)NOTES¶
- 1.
- D-Bus Introspection XML
- 2.
- RefEntry
- 3.
- sortas attribute
- 4.
- CamelCase
- 5.
- gtk-doc
- 6.
- parameter
- 7.
- constant
- 8.
- org.freedesktop.DBus.Properties.Set
- 9.
- GObject Introspection
GIO |