* net/tramp.el (tramp-default-host-alist): New defcustom.

(tramp-find-host): Use it.
(tramp-eshell-directory-change): Moved from tramp-sh.el.  Add to
`eshell-directory-change-hook'.

* net/tramp-adb.el (top): Add adb specific entry in
`tramp-default-host-alist'.
(tramp-adb-file-name-host): Remove function.
(tramp-adb-execute-adb-command, tramp-adb-maybe-open-connection):
Use `tramp-file-name-host' instead of `tramp-adb-file-name-host'.

* net/tramp-sh.el : Move eshell integration code to tramp.el.

lisp/ChangeLog

+2013-01-07  Michael Albinus  <michael.albinus@gmx.de>
+
+	* net/tramp.el (tramp-default-host-alist): New defcustom.
+	(tramp-find-host): Use it.
+	(tramp-eshell-directory-change): Moved from tramp-sh.el.  Add to
+	`eshell-directory-change-hook'.
+
+	* net/tramp-adb.el (top): Add adb specific entry in
+	`tramp-default-host-alist'.
+	(tramp-adb-file-name-host): Remove function.
+	(tramp-adb-execute-adb-command, tramp-adb-maybe-open-connection):
+	Use `tramp-file-name-host' instead of `tramp-adb-file-name-host'.
+
+	* net/tramp-sh.el : Move eshell integration code to tramp.el.
+
 2013-01-06  Jürgen Hötzel  <juergen@archlinux.org>
 
 	* net/tramp-adb.el (tramp-methods): Add `tramp-tmpdir' entry.
@@ -5,7 +20,7 @@
 2013-01-06  Michael Albinus  <michael.albinus@gmx.de>
 
 	* net/tramp-adb.el (tramp-adb-ls-toolbox-regexp): The file size can
-	consist of mor than one digit.
+	consist of more than one digit.
 	(tramp-adb-file-name-handler-alist): Use
 	`tramp-handle-file-exists-p' consistently.
 	(tramp-adb-file-name-handler): Don't tweak `tramp-default-host'.

lisp/net/tramp-adb.el

@@ -66,8 +66,12 @@
    "[[:space:]]+\\(.*\\)$"))		; \6 filename
 
 ;;;###tramp-autoload
-(add-to-list 'tramp-methods `(,tramp-adb-method
-			      (tramp-tmpdir "/data/local/tmp")))
+(add-to-list 'tramp-methods
+	     `(,tramp-adb-method
+	       (tramp-tmpdir "/data/local/tmp")))
+
+;;;###tramp-autoload
+(add-to-list 'tramp-default-host-alist `(,tramp-adb-method nil ""))
 
 ;;;###tramp-autoload
 (eval-after-load 'tramp
@@ -937,17 +941,10 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
 
 ;; Helper functions.
 
-(defun tramp-adb-file-name-host (vec)
-  "Return host component of VEC.
-If it is equal to the default value of `tramp-default-host', `nil' is returned."
-  (let ((host (tramp-file-name-host vec)))
-    (unless (equal host (eval (car (get 'tramp-default-host 'standard-value))))
-      host)))
-
 (defun tramp-adb-execute-adb-command (vec &rest args)
   "Returns nil on success error-output on failure."
-  (when (tramp-adb-file-name-host vec)
-    (setq args (append (list "-s" (tramp-adb-file-name-host vec)) args)))
+  (when (> (length (tramp-file-name-host vec)) 0)
+    (setq args (append (list "-s" (tramp-file-name-host vec)) args)))
   (with-temp-buffer
     (prog1
 	(unless (zerop (apply 'call-process (tramp-adb-program) nil t nil args))
@@ -1048,6 +1045,7 @@ Does not do anything if a connection is already open, but re-opens the
 connection if a previous connection has died for some reason."
   (let* ((buf (tramp-get-connection-buffer vec))
 	 (p (get-buffer-process buf))
+	 (host (tramp-file-name-host vec))
 	 (devices (mapcar 'cadr (tramp-adb-parse-device-names nil))))
     (unless
 	(and p (processp p) (memq (process-status p) '(run open)))
@@ -1055,21 +1053,17 @@ connection if a previous connection has died for some reason."
 	(when (and p (processp p)) (delete-process p))
 	(if (not devices)
 	    (tramp-error vec 'file-error "No device connected"))
-	(if (and (tramp-adb-file-name-host vec)
-		 (not (member (tramp-adb-file-name-host vec) devices)))
-	    (tramp-error
-	     vec 'file-error
-	     "Device %s not connected" (tramp-adb-file-name-host vec)))
-	(if (and (not (eq (length devices) 1))
-		 (not (tramp-adb-file-name-host vec)))
+	(if (and (> (length host) 0) (not (member host devices)))
+	    (tramp-error vec 'file-error "Device %s not connected" host))
+	(if (and (> (length devices) 1) (zerop (length host)))
 	    (tramp-error
 	     vec 'file-error
 	     "Multiple Devices connected: No Host/Device specified"))
 	(with-tramp-progress-reporter vec 3 "Opening adb shell connection"
 	  (let* ((coding-system-for-read 'utf-8-dos) ;is this correct?
 		 (process-connection-type tramp-process-connection-type)
-		 (args (if (tramp-adb-file-name-host vec)
-			   (list "-s" (tramp-adb-file-name-host vec) "shell")
+		 (args (if (> (length host) 0)
+			   (list "-s" host "shell")
 			 (list "shell")))
 		 (p (let ((default-directory
 			    (tramp-compat-temporary-file-directory)))

lisp/net/tramp-sh.el

@@ -5181,34 +5181,6 @@ function cell is returned to be applied on a buffer."
 	 (t
 	  (format "%s <%%s" coding)))))))
 
-;;; Integration of eshell.el:
-
-(eval-when-compile
-  (defvar eshell-path-env))
-
-;; eshell.el keeps the path in `eshell-path-env'.  We must change it
-;; when `default-directory' points to another host.
-(defun tramp-eshell-directory-change ()
-  "Set `eshell-path-env' to $PATH of the host related to `default-directory'."
-  (setq eshell-path-env
-	(if (file-remote-p default-directory)
-	    (with-parsed-tramp-file-name default-directory nil
-	      (mapconcat
-	       'identity
-	       (tramp-get-remote-path v)
-	       ":"))
-	  (getenv "PATH"))))
-
-(eval-after-load "esh-util"
-  '(progn
-     (tramp-eshell-directory-change)
-     (add-hook 'eshell-directory-change-hook
-	       'tramp-eshell-directory-change)
-     (add-hook 'tramp-unload-hook
-	       (lambda ()
-		 (remove-hook 'eshell-directory-change-hook
-			      'tramp-eshell-directory-change)))))
-
 (add-hook 'tramp-unload-hook
 	  (lambda ()
 	    (unload-feature 'tramp-sh 'force)))

lisp/net/tramp.el

@@ -381,6 +381,22 @@ Useful for su and sudo methods mostly."
   :group 'tramp
   :type 'string)
 
+;;;###tramp-autoload
+(defcustom tramp-default-host-alist nil
+  "Default host to use for specific method/user pairs.
+This is an alist of items (METHOD USER HOST).  The first matching item
+specifies the host to use for a file name which does not specify a
+host.  METHOD and HOST are regular expressions or nil, which is
+interpreted as a regular expression which always matches.  If no entry
+matches, the variable `tramp-default-host' takes effect.
+
+If the file name does not specify the method, lookup is done using the
+empty string for the method name."
+  :group 'tramp
+  :type '(repeat (list (choice :tag "Method regexp" regexp sexp)
+		       (choice :tag "  User regexp" regexp sexp)
+		       (choice :tag "    Host name" string (const nil)))))
+
 (defcustom tramp-default-proxies-alist nil
   "Route to be followed for specific host/user pairs.
 This is an alist of items (HOST USER PROXY).  The first matching
@@ -918,7 +934,7 @@ See `tramp-file-name-structure' for more explanations.")
 This regexp should match partial Tramp file names only.
 
 Please note that the entry in `file-name-handler-alist' is made when
-this file (tramp.el) is loaded.  This means that this variable must be set
+this file \(tramp.el\) is loaded.  This means that this variable must be set
 before loading tramp.el.  Alternatively, `file-name-handler-alist' can be
 updated after changing this variable.
 
@@ -1163,6 +1179,15 @@ This is USER, if non-nil. Otherwise, do a lookup in
   "Return the right host string to use.
 This is HOST, if non-nil. Otherwise, it is `tramp-default-host'."
   (or (and (> (length host) 0) host)
+      (let ((choices tramp-default-host-alist)
+	    lhost item)
+	(while choices
+	  (setq item (pop choices))
+	  (when (and (string-match (or (nth 0 item) "") (or method ""))
+		     (string-match (or (nth 1 item) "") (or user "")))
+	    (setq lhost (nth 2 item))
+	    (setq choices nil)))
+	lhost)
       tramp-default-host))
 
 (defun tramp-dissect-file-name (name &optional nodefault)
@@ -3861,6 +3886,34 @@ Only works for Bourne-like shells."
 				      t t result)))
 	result))))
 
+;;; Integration of eshell.el:
+
+(eval-when-compile
+  (defvar eshell-path-env))
+
+;; eshell.el keeps the path in `eshell-path-env'.  We must change it
+;; when `default-directory' points to another host.
+(defun tramp-eshell-directory-change ()
+  "Set `eshell-path-env' to $PATH of the host related to `default-directory'."
+  (setq eshell-path-env
+	(if (file-remote-p default-directory)
+	    (with-parsed-tramp-file-name default-directory nil
+	      (mapconcat
+	       'identity
+	       (tramp-get-connection-property v "remote-path" nil)
+	       ":"))
+	  (getenv "PATH"))))
+
+(eval-after-load "esh-util"
+  '(progn
+     (tramp-eshell-directory-change)
+     (add-hook 'eshell-directory-change-hook
+	       'tramp-eshell-directory-change)
+     (add-hook 'tramp-unload-hook
+	       (lambda ()
+		 (remove-hook 'eshell-directory-change-hook
+			      'tramp-eshell-directory-change)))))
+
 ;; Checklist for `tramp-unload-hook'
 ;; - Unload all `tramp-*' packages
 ;; - Reset `file-name-handler-alist'