Commit 6a31c819 authored by Michael Albinus's avatar Michael Albinus
Browse files

* dbus.texi (Type Conversion): Extend for D-Bus compound types.

(Errors and Events): Mention wrong-type-argument error.
parent 87cf1a39
2007-12-21 Michael Albinus <michael.albinus@gmx.de>
* dbus.texi (Type Conversion): Extend for D-Bus compound types.
(Errors and Events): Mention wrong-type-argument error.
2007-12-21 Alex Schroeder <alex@gnu.org>
* rcirc.texi: Changed single spaces after sentence end to double
......
......@@ -238,7 +238,7 @@ D-Bus method calls and signals accept usually several arguments as
parameters, either as input parameter, or as output parameter. Every
argument belongs to a D-Bus type.
Such arguments must be mapped between the the value encoded as a D-Bus
Such arguments must be mapped between the value encoded as a D-Bus
type, and the corresponding type of Lisp objects. The mapping is
applied Lisp object @expansion{} D-Bus type for input parameters, and
D-Bus type @expansion{} Lisp object for output parameters.
......@@ -247,8 +247,7 @@ D-Bus type @expansion{} Lisp object for output parameters.
@section Input parameters.
Input parameters for D-Bus methods and signals occur as arguments of a
Lisp function call. Only some primitive Lisp types are supported in
the current implementation. The following mapping to D-Bus types is
Lisp function call. The following mapping to D-Bus types is
applied, when the corresponding D-Bus message is created:
@example
......@@ -260,30 +259,90 @@ applied, when the corresponding D-Bus message is created:
@item integer @tab @expansion{} @tab DBUS_TYPE_INT32
@item float @tab @expansion{} @tab DBUS_TYPE_DOUBLE
@item string @tab @expansion{} @tab DBUS_TYPE_STRING
@item list @tab @expansion{} @tab DBUS_TYPE_ARRAY
@end multitable
@end example
Other Lisp objects, like symbols or hash tables, are not accepted as
input parameter.
If it is necessary to use another D-Bus type, a corresponding type
symbol can be preceeded to the corresponding Lisp object. Basic D-Bus
types are represented by the type symbols `:byte', `:boolean',
`:int16', `:uint16', `:int32', `:uint32', `:int64', `:uint64',
`:double', `:string', `:object-path' and `:signature'.
@noindent
Other Lisp types, especially lists, are not supported (yet).
Example:
@lisp
(dbus-call-method ... @var{NUMBER} @var{STRING})
@end lisp
is equivalent to
@lisp
(dbus-call-method ... :uint32 @var{NUMBER} :string @var{STRING})
@end lisp
but different to
@lisp
(dbus-call-method ... :int32 @var{NUMBER} :signature @var{STRING})
@end lisp
A D-Bus compound type is always represented as list. The car of this
list can be the type symbol `:array', `:variant', `:struct' or
`:dict-entry', which would result in a corresponding D-Bus container.
`:array' is optional, because this is the default compoud type for a
list.
The objects being elements of the list are checked according to the
D-Bus compound type rules.
@itemize
@item An array must contain only elements of the same D-Bus type.
@item A variant must contain only one single element.
@item A dictionary entry must be element of an array, and it must
contain only a key-value pair of two element, with a basic type key.
@item There is no restriction for structs.
@end itemize
@noindent
Example:
@lisp
(dbus-send-signal ...
:object-path STRING '(:variant :boolean BOOL)
'(:array NUMBER NUMBER) '(:array BOOL :boolean BOOL)
'(:struct BOOL :boolean BOOL BOOL
(:array NUMBER NUMBER) (:array BOOL BOOL))
'(:struct NUMBER NUMBER) '((:dict-entry NUMBER (NUMBER)))
'(:array (:dict-entry NUMBER :int32 NUMBER)))
@end lisp
@section Output parameters.
Output parameters of D-Bus methods and signals are mapped to Lisp
objects. This mapping is more powerful than the one for input
parameters, i.e., more D-Bus types are supported by the current
implementation.
objects.
@example
@multitable {DBUS_TYPE_OBJECT_PATH} {@expansion{}} {@code{t} or @code{nil}}
@item D-Bus type @tab @tab Lisp type
@item
@item DBUS_TYPE_BOOLEAN @tab @expansion{} @tab @code{t} or @code{nil}
@item DBUS_TYPE_BYTE @tab @expansion{} @tab
@item DBUS_TYPE_UINT16 @tab @expansion{} @tab number
@item DBUS_TYPE_INT32 @tab @expansion{} @tab number
@item DBUS_TYPE_UINT32 @tab @expansion{} @tab number
@item DBUS_TYPE_INT32 @tab @expansion{} @tab number
@item DBUS_TYPE_UINT64 @tab @expansion{} @tab number
@item DBUS_TYPE_INT64 @tab @expansion{} @tab number
@item DBUS_TYPE_DOUBLE @tab @expansion{} @tab float
@item DBUS_TYPE_STRING @tab @expansion{} @tab string
@item DBUS_TYPE_OBJECT_PATH @tab @expansion{} @tab string
@item DBUS_TYPE_SIGNATURE @tab @expansion{} @tab string
@item DBUS_TYPE_ARRAY @tab @expansion{} @tab list
@item DBUS_TYPE_VARIANT @tab @expansion{} @tab list
@item DBUS_TYPE_STRUCT @tab @expansion{} @tab list
......@@ -498,6 +557,11 @@ result of a preceding @code{dbus-register-signal} call.
@cindex errors
@cindex events
Input parameters of @code{dbus-call-method} and
@code{dbus-register-signal} are checked for correct D-Bus types. If
there is a type mismatch, the Lisp error @code{wrong-type-argument}
@code{D-Bus ARG} is raised.
All errors raised by D-Bus are signaled with the error symbol
@code{dbus-error}. As usual, such an error can be trapped with a
@code{condition-case} form. If possible, error messages from D-Bus
......
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