;;; dbus.el --- Elisp bindings for D-Bus.
-;; Copyright (C) 2007-2013 Free Software Foundation, Inc.
+;; Copyright (C) 2007-2014 Free Software Foundation, Inc.
;; Author: Michael Albinus <michael.albinus@gmx.de>
;; Keywords: comm, hardware
;; Declare used subroutines and variables.
(declare-function dbus-message-internal "dbusbind.c")
-(declare-function dbus-init-bus "dbusbind.c")
+(declare-function dbus--init-bus "dbusbind.c")
(defvar dbus-message-type-invalid)
(defvar dbus-message-type-method-call)
(defvar dbus-message-type-method-return)
(defconst dbus-path-dbus "/org/freedesktop/DBus"
"The object path used to talk to the bus itself.")
+(defconst dbus-path-local (concat dbus-path-dbus "/Local")
+ "The object path used in local/in-process-generated messages.")
+
;; Default D-Bus interfaces.
(defconst dbus-interface-dbus "org.freedesktop.DBus"
;; </signal>
;; </interface>
+(defconst dbus-interface-local (concat dbus-interface-dbus ".Local")
+ "An interface whose methods can only be invoked by the local implementation.")
+
+;; <interface name="org.freedesktop.DBus.Local">
+;; <signal name="Disconnected">
+;; <arg name="object_path" type="o"/>
+;; </signal>
+;; </interface>
+
;; Emacs defaults.
(defconst dbus-service-emacs "org.gnu.Emacs"
"The well known service name of Emacs.")
(define-obsolete-variable-alias 'dbus-event-error-hooks
'dbus-event-error-functions "24.3")
-(defvar dbus-event-error-functions nil
+(defvar dbus-event-error-functions '(dbus-notice-synchronous-call-errors)
"Functions to be called when a D-Bus error happens in the event handler.
Every function must accept two arguments, the event and the error variable
caught in `condition-case' by `dbus-error'.")
A key in this hash table is a list (:serial BUS SERIAL), like in
`dbus-registered-objects-table'. BUS is either a Lisp symbol,
`:system' or `:session', or a string denoting the bus address.
-SERIAL is the serial number of the reply message.")
+SERIAL is the serial number of the reply message.
+
+The value of an entry is a cons (STATE . RESULT). STATE can be
+either `:pending' (we are still waiting for the result),
+`:complete' (the result is available) or `:error' (the reply
+message was an error message).")
(defun dbus-call-method-handler (&rest args)
"Handler for reply messages of asynchronous D-Bus message calls.
It calls the function stored in `dbus-registered-objects-table'.
The result will be made available in `dbus-return-values-table'."
- (puthash (list :serial
- (dbus-event-bus-name last-input-event)
- (dbus-event-serial-number last-input-event))
- (if (= (length args) 1) (car args) args)
- dbus-return-values-table))
+ (let* ((key (list :serial
+ (dbus-event-bus-name last-input-event)
+ (dbus-event-serial-number last-input-event)))
+ (result (gethash key dbus-return-values-table)))
+ (when (consp result)
+ (setcar result :complete)
+ (setcdr result (if (= (length args) 1) (car args) args)))))
+
+(defun dbus-notice-synchronous-call-errors (ev er)
+ "Detect errors resulting from pending synchronous calls."
+ (let* ((key (list :serial
+ (dbus-event-bus-name ev)
+ (dbus-event-serial-number ev)))
+ (result (gethash key dbus-return-values-table)))
+ (when (consp result)
+ (setcar result :error)
+ (setcdr result er))))
(defun dbus-call-method (bus service path interface method &rest args)
"Call METHOD on the D-Bus BUS.
(signal 'wrong-type-argument (list 'stringp method)))
(let ((timeout (plist-get args :timeout))
+ (check-interval 0.001)
(key
(apply
'dbus-message-internal dbus-message-type-method-call
- bus service path interface method 'dbus-call-method-handler args)))
+ bus service path interface method 'dbus-call-method-handler args))
+ (result (cons :pending nil)))
;; Wait until `dbus-call-method-handler' has put the result into
;; `dbus-return-values-table'. If no timeout is given, use the
;; default 25". Events which are not from D-Bus must be restored.
;; `read-event' performs a redisplay. This must be suppressed; it
;; hurts when reading D-Bus events asynchronously.
- (with-timeout ((if timeout (/ timeout 1000.0) 25))
- (while (eq (gethash key dbus-return-values-table :ignore) :ignore)
- (let ((event (let ((inhibit-redisplay t) unread-command-events)
- (read-event nil nil 0.1))))
- (when (and event (not (ignore-errors (dbus-check-event event))))
- (setq unread-command-events
- (append unread-command-events (list event)))))))
-
- ;; Cleanup `dbus-return-values-table'. Return the result.
- (prog1
- (gethash key dbus-return-values-table)
+
+ ;; Work around bug#16775 by busy-waiting with gradual backoff for
+ ;; dbus calls to complete. A better approach would involve either
+ ;; adding arbitrary wait condition support to read-event or
+ ;; restructuring dbus as a kind of process object. Poll at most
+ ;; about once per second for completion.
+
+ (puthash key result dbus-return-values-table)
+ (unwind-protect
+ (progn
+ (with-timeout ((if timeout (/ timeout 1000.0) 25)
+ (signal 'dbus-error (list "call timed out")))
+ (while (eq (car result) :pending)
+ (let ((event (let ((inhibit-redisplay t) unread-command-events)
+ (read-event nil nil check-interval))))
+ (when event
+ (setf unread-command-events
+ (nconc unread-command-events
+ (cons event nil))))
+ (when (< check-interval 1)
+ (setf check-interval (* check-interval 1.05))))))
+ (when (eq (car result) :error)
+ (signal (cadr result) (cddr result)))
+ (cdr result))
(remhash key dbus-return-values-table))))
;; `dbus-call-method' works non-blocking now.
;; Service.
(or (= dbus-message-type-method-return (nth 2 event))
(= dbus-message-type-error (nth 2 event))
- (stringp (nth 4 event)))
+ (or (stringp (nth 4 event))
+ (null (nth 4 event))))
;; Object path.
(or (= dbus-message-type-method-return (nth 2 event))
(= dbus-message-type-error (nth 2 event))
(nth 1 event) (nth 4 event) (nth 3 event) (cadr err))))
;; Propagate D-Bus error messages.
(run-hook-with-args 'dbus-event-error-functions event err)
- (when (or dbus-debug (= dbus-message-type-error (nth 2 event)))
+ (when dbus-debug
(signal (car err) (cdr err))))))
(defun dbus-event-bus-name (event)
result)
'(:signature "{oa{sa{sv}}}"))))))
+(defun dbus-handle-bus-disconnect ()
+ "React to a bus disconnection.
+BUS is the bus that disconnected. This routine unregisters all
+handlers on the given bus and causes all synchronous calls
+pending at the time of disconnect to fail."
+ (let ((bus (dbus-event-bus-name last-input-event))
+ (keys-to-remove))
+ (maphash
+ (lambda (key value)
+ (when (and (eq (nth 0 key) :serial)
+ (eq (nth 1 key) bus))
+ (run-hook-with-args
+ 'dbus-event-error-functions
+ (list 'dbus-event
+ bus
+ dbus-message-type-error
+ (nth 2 key)
+ nil
+ nil
+ nil
+ nil
+ value)
+ (list 'dbus-error "Bus disconnected" bus))
+ (push key keys-to-remove)))
+ dbus-registered-objects-table)
+ (dolist (key keys-to-remove)
+ (remhash key dbus-registered-objects-table))))
+
+(defun dbus-init-bus (bus &optional private)
+ "Establish the connection to D-Bus BUS.
+
+BUS can be either the symbol `:system' or the symbol `:session', or it
+can be a string denoting the address of the corresponding bus. For
+the system and session buses, this function is called when loading
+`dbus.el', there is no need to call it again.
+
+The function returns a number, which counts the connections this Emacs
+session has established to the BUS under the same unique name (see
+`dbus-get-unique-name'). It depends on the libraries Emacs is linked
+with, and on the environment Emacs is running. For example, if Emacs
+is linked with the gtk toolkit, and it runs in a GTK-aware environment
+like Gnome, another connection might already be established.
+
+When PRIVATE is non-nil, a new connection is established instead of
+reusing an existing one. It results in a new unique name at the bus.
+This can be used, if it is necessary to distinguish from another
+connection used in the same Emacs process, like the one established by
+GTK+. It should be used with care for at least the `:system' and
+`:session' buses, because other Emacs Lisp packages might already use
+this connection to those buses."
+ (dbus--init-bus bus private)
+ (dbus-register-signal
+ bus nil dbus-path-local dbus-interface-local
+ "Disconnected" #'dbus-handle-bus-disconnect))
+
\f
;; Initialize `:system' and `:session' buses. This adds their file
;; descriptors to input_wait_mask, in order to detect incoming