Improve completion in tramp-gvfs.el

* lisp/net/tramp-gvfs.el (tramp-zeroconf-parse-device-names):
Renamed from `tramp-zeroconf-parse-service-device-names'.
(tramp-zeroconf-parse-webdav-device-names): Removed.  Code merged
with `tramp-zeroconf-parse-device-names'.
(tramp-gvfs-parse-device-names): New defun.
(top): Use it when `tramp-zeroconf-parse-device-names' is not
applicable.

* lisp/net/tramp.el (tramp-set-completion-function): The argument
could also be a zeroconf service type.

lisp/net/tramp-gvfs.el

@@ -1722,14 +1722,7 @@ be used."
 
 ;; D-Bus zeroconf functions.
 
-(defun tramp-zeroconf-parse-service-device-names (service)
-  "Return a list of (user host) tuples allowed to access."
-  (mapcar
-   (lambda (x)
-     (list nil (zeroconf-service-host x)))
-   (zeroconf-list-services service)))
-
-(defun tramp-zeroconf-parse-webdav-device-names (_ignore)
+(defun tramp-zeroconf-parse-device-names (service)
   "Return a list of (user host) tuples allowed to access."
   (mapcar
    (lambda (x)
@@ -1745,22 +1738,64 @@ be used."
 	   (setq user (match-string 1 (car text))))
 	 (setq text (cdr text)))
        (list user host)))
-   (zeroconf-list-services "_webdav._tcp")))
+   (zeroconf-list-services service)))
+
+(defun tramp-gvfs-parse-device-names (service)
+  "Return a list of (user host) tuples allowed to access.
+This uses \"avahi-browse\" in case D-Bus is not enabled in Avahi."
+  (let ((result
+	 (split-string
+	  (shell-command-to-string (format "avahi-browse -trkp %s" service))
+	  "[\n\r]+" 'omit "^\\+;.*$")))
+    (tramp-compat-delete-dups
+     (mapcar
+      (lambda (x)
+	(let* ((list (split-string x ";"))
+	       (host (nth 6 list))
+	       (port (nth 8 list))
+	       (text (split-string (nth 9 list) "\" \"" 'omit "\""))
+	       user)
+;	  (when (and port (not (string-equal port "0")))
+;	    (setq host (format "%s%s%s" host tramp-prefix-port-regexp port)))
+	  ;; A user is marked in a TXT field like "u=guest".
+	  (while text
+	    (when (string-match "u=\\(.+\\)$" (car text))
+	      (setq user (match-string 1 (car text))))
+	    (setq text (cdr text)))
+	  (list user host)))
+      result))))
 
 ;; Add completion functions for AFP, DAV, DAVS, SFTP and SMB methods.
-(when (and tramp-gvfs-enabled
-	   (member zeroconf-service-avahi (dbus-list-known-names :system)))
+(when tramp-gvfs-enabled
   (zeroconf-init tramp-gvfs-zeroconf-domain)
-  (tramp-set-completion-function
-   "afp" '((tramp-zeroconf-parse-service-device-names "_afpovertcp._tcp")))
-  (tramp-set-completion-function
-   "dav" '((tramp-zeroconf-parse-webdav-device-names "")))
-  (tramp-set-completion-function
-   "davs" '((tramp-zeroconf-parse-webdav-device-names "")))
-  (tramp-set-completion-function
-   "sftp" '((tramp-zeroconf-parse-service-device-names "_workstation._tcp")))
-  (tramp-set-completion-function
-   "smb" '((tramp-zeroconf-parse-service-device-names "_smb._tcp"))))
+  (if (zeroconf-list-service-types)
+      (progn
+	(tramp-set-completion-function
+	 "afp" '((tramp-zeroconf-parse-device-names "_afpovertcp._tcp")))
+	(tramp-set-completion-function
+	 "dav" '((tramp-zeroconf-parse-device-names "_webdav._tcp")))
+	(tramp-set-completion-function
+	 "davs" '((tramp-zeroconf-parse-device-names "_webdav._tcp")))
+	(tramp-set-completion-function
+	 "sftp" '((tramp-zeroconf-parse-device-names "_ssh._tcp")
+		  (tramp-zeroconf-parse-device-names "_workstation._tcp")))
+	(when (member "smb" tramp-gvfs-methods)
+	  (tramp-set-completion-function
+	   "smb" '((tramp-zeroconf-parse-device-names "_smb._tcp")))))
+
+    (when (executable-find "avahi-browse")
+      (tramp-set-completion-function
+       "afp" '((tramp-gvfs-parse-device-names "_afpovertcp._tcp")))
+      (tramp-set-completion-function
+       "dav" '((tramp-gvfs-parse-device-names "_webdav._tcp")))
+      (tramp-set-completion-function
+       "davs" '((tramp-gvfs-parse-device-names "_webdav._tcp")))
+      (tramp-set-completion-function
+       "sftp" '((tramp-gvfs-parse-device-names "_ssh._tcp")
+		(tramp-gvfs-parse-device-names "_workstation._tcp")))
+      (when (member "smb" tramp-gvfs-methods)
+	(tramp-set-completion-function
+	 "smb" '((tramp-gvfs-parse-device-names "_smb._tcp")))))))
 
 
 ;; D-Bus SYNCE functions.

lisp/net/tramp.el

@@ -1765,14 +1765,18 @@ Example:
 	(setcdr v (delete (car v) (cdr v))))
       ;; Check for function and file or registry key.
       (unless (and (functionp (nth 0 (car v)))
-		   (if (string-match "^HKEY_CURRENT_USER" (nth 1 (car v)))
-		       ;; Windows registry.
-		       (and (memq system-type '(cygwin windows-nt))
-			    (zerop
-			     (tramp-call-process
-			      v "reg" nil nil nil "query" (nth 1 (car v)))))
-		     ;; Configuration file.
-		     (file-exists-p (nth 1 (car v)))))
+		   (cond
+		    ;; Windows registry.
+		    ((string-match "^HKEY_CURRENT_USER" (nth 1 (car v)))
+		     (and (memq system-type '(cygwin windows-nt))
+			  (zerop
+			   (tramp-call-process
+			    v "reg" nil nil nil "query" (nth 1 (car v))))))
+		    ;; Zeroconf service type.
+		    ((string-match
+		      "^_[[:alpha:]]+\\._[[:alpha:]]+$" (nth 1 (car v))))
+		    ;; Configuration file.
+		    (t (file-exists-p (nth 1 (car v))))))
 	(setq r (delete (car v) r)))
       (setq v (cdr v)))