[gnu-emacs] / lisp / net / tramp-adb.el

;;; tramp-adb.el --- Functions for calling Android Debug Bridge from Tramp

;; Copyright (C) 2011-2013 Free Software Foundation, Inc.

;; Author: Juergen Hoetzel <juergen@archlinux.org>
;; Keywords: comm, processes
;; Package: tramp

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; The Android Debug Bridge "adb" must be installed on your local
;; machine.  If it is not in your $PATH, add the following form into
;; your .emacs:
;;
;;   (setq tramp-adb-program "/path/to/adb")
;;
;; Due to security it is not possible to access non-root devices.

;;; Code:

(require 'tramp)
(require 'time-date)

;; Pacify byte-compiler.
(defvar directory-sep-char)
(defvar dired-move-to-filename-regexp)

(defcustom tramp-adb-program "adb"
  "Name of the Android Debug Bridge program."
  :group 'tramp
  :version "24.4"
  :type 'string)

;;;###tramp-autoload
(defconst tramp-adb-method "adb"
  "*When this method name is used, forward all calls to Android Debug Bridge.")

(defcustom tramp-adb-prompt
  "^\\(?:[[:digit:]]*|?\\)?\\(?:[[:alnum:]]*@[[:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
  "Regexp used as prompt in almquist shell."
  :type 'string
  :version "24.4"
  :group 'tramp)

(defconst tramp-adb-ls-date-regexp
  "[[:space:]][0-9]\\{4\\}-[0-9][0-9]-[0-9][0-9][[:space:]][0-9][0-9]:[0-9][0-9][[:space:]]")

(defconst tramp-adb-ls-toolbox-regexp
  (concat
   "^[[:space:]]*\\([-[:alpha:]]+\\)"   ; \1 permissions
   "[[:space:]]*\\([^[:space:]]+\\)"    ; \2 username
   "[[:space:]]+\\([^[:space:]]+\\)"    ; \3 group
   "[[:space:]]+\\([[:digit:]]+\\)"     ; \4 size
   "[[:space:]]+\\([-[:digit:]]+[[:space:]][:[:digit:]]+\\)" ; \5 date
   "[[:space:]]+\\(.*\\)$"))            ; \6 filename

;;;###tramp-autoload
(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
  '(tramp-set-completion-function
    tramp-adb-method '((tramp-adb-parse-device-names ""))))

;;;###tramp-autoload
(add-to-list 'tramp-foreign-file-name-handler-alist
             (cons 'tramp-adb-file-name-p 'tramp-adb-file-name-handler))

(defconst tramp-adb-file-name-handler-alist
  '((access-file . ignore)
    (add-name-to-file . tramp-adb-handle-copy-file)
    ;; `byte-compiler-base-file-name' performed by default handler.
    ;; `copy-directory' performed by default handler.
    (copy-file . tramp-adb-handle-copy-file)
    (delete-directory . tramp-adb-handle-delete-directory)
    (delete-file . tramp-adb-handle-delete-file)
    ;; `diff-latest-backup-file' performed by default handler.
    (directory-file-name . tramp-handle-directory-file-name)
    (directory-files . tramp-handle-directory-files)
    (directory-files-and-attributes
     . tramp-adb-handle-directory-files-and-attributes)
    (dired-call-process . ignore)
    (dired-compress-file . ignore)
    (dired-uncache . tramp-handle-dired-uncache)
    (expand-file-name . tramp-adb-handle-expand-file-name)
    (file-accessible-directory-p . tramp-handle-file-accessible-directory-p)
    (file-acl . ignore)
    (file-attributes . tramp-adb-handle-file-attributes)
    (file-directory-p . tramp-adb-handle-file-directory-p)
    ;; `file-equal-p' performed by default handler.
    ;; FIXME: This is too sloppy.
    (file-executable-p . tramp-handle-file-exists-p)
    (file-exists-p . tramp-handle-file-exists-p)
    ;; `file-in-directory-p' performed by default handler.
    (file-local-copy . tramp-adb-handle-file-local-copy)
    (file-modes . tramp-handle-file-modes)
    (file-name-all-completions . tramp-adb-handle-file-name-all-completions)
    (file-name-as-directory . tramp-handle-file-name-as-directory)
    (file-name-completion . tramp-handle-file-name-completion)
    (file-name-directory . tramp-handle-file-name-directory)
    (file-name-nondirectory . tramp-handle-file-name-nondirectory)
    ;; `file-name-sans-versions' performed by default handler.
    (file-newer-than-file-p . tramp-handle-file-newer-than-file-p)
    (file-notify-add-watch . tramp-handle-file-notify-add-watch)
    (file-notify-rm-watch . tramp-handle-file-notify-rm-watch)
    (file-ownership-preserved-p . ignore)
    (file-readable-p . tramp-handle-file-exists-p)
    (file-regular-p . tramp-handle-file-regular-p)
    (file-remote-p . tramp-handle-file-remote-p)
    (file-selinux-context . ignore)
    (file-symlink-p . tramp-handle-file-symlink-p)
    (file-truename . tramp-adb-handle-file-truename)
    (file-writable-p . tramp-adb-handle-file-writable-p)
    (find-backup-file-name . tramp-handle-find-backup-file-name)
    ;; `find-file-noselect' performed by default handler.
    ;; `get-file-buffer' performed by default handler.
    (insert-directory . tramp-adb-handle-insert-directory)
    (insert-file-contents . tramp-handle-insert-file-contents)
    (load . tramp-handle-load)
    (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
    (make-directory . tramp-adb-handle-make-directory)
    (make-directory-internal . ignore)
    (make-symbolic-link . ignore)
    (process-file . tramp-adb-handle-process-file)
    (rename-file . tramp-adb-handle-rename-file)
    (set-file-acl . ignore)
    (set-file-modes . tramp-adb-handle-set-file-modes)
    (set-file-selinux-context . ignore)
    (set-file-times . tramp-adb-handle-set-file-times)
    (set-visited-file-modtime . tramp-handle-set-visited-file-modtime)
    (shell-command . tramp-adb-handle-shell-command)
    (start-file-process . tramp-adb-handle-start-file-process)
    (substitute-in-file-name . tramp-handle-substitute-in-file-name)
    (unhandled-file-name-directory . tramp-handle-unhandled-file-name-directory)
    (vc-registered . ignore)
    (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
    (write-region . tramp-adb-handle-write-region))
  "Alist of handler functions for Tramp ADB method.")

;; It must be a `defsubst' in order to push the whole code into
;; tramp-loaddefs.el.  Otherwise, there would be recursive autoloading.
;;;###tramp-autoload
(defsubst tramp-adb-file-name-p (filename)
  "Check if it's a filename for ADB."
  (let ((v (tramp-dissect-file-name filename)))
    (string= (tramp-file-name-method v) tramp-adb-method)))

;;;###tramp-autoload
(defun tramp-adb-file-name-handler (operation &rest args)
  "Invoke the ADB handler for OPERATION.
First arg specifies the OPERATION, second arg is a list of arguments to
pass to the OPERATION."
  (let ((fn (assoc operation tramp-adb-file-name-handler-alist)))
    (if fn
        (save-match-data (apply (cdr fn) args))
      (tramp-run-real-handler operation args))))

;;;###tramp-autoload
(defun tramp-adb-parse-device-names (_ignore)
  "Return a list of (nil host) tuples allowed to access."
  (with-timeout (10)
    (with-temp-buffer
      ;; `call-process' does not react on timer under MS Windows.
      ;; That's why we use `start-process'.
      (let ((p (start-process
                tramp-adb-program (current-buffer) tramp-adb-program "devices"))
            result)
        (tramp-compat-set-process-query-on-exit-flag p nil)
        (while (eq 'run (process-status p))
          (sleep-for 0.1))
        (goto-char (point-min))
        (while (search-forward-regexp "^\\(\\S-+\\)[[:space:]]+device$" nil t)
          (add-to-list 'result (list nil (match-string 1))))
        result))))

(defun tramp-adb-handle-expand-file-name (name &optional dir)
  "Like `expand-file-name' for Tramp files."
  ;; If DIR is not given, use DEFAULT-DIRECTORY or "/".
  (setq dir (or dir default-directory "/"))
  ;; Unless NAME is absolute, concat DIR and NAME.
  (unless (file-name-absolute-p name)
    (setq name (concat (file-name-as-directory dir) name)))
  ;; If NAME is not a Tramp file, run the real handler.
  (if (not (tramp-tramp-file-p name))
      (tramp-run-real-handler 'expand-file-name (list name nil))
    ;; Dissect NAME.
    (with-parsed-tramp-file-name name nil
      (unless (tramp-run-real-handler 'file-name-absolute-p (list localname))
        (setq localname (concat "/" localname)))
      ;; Do normal `expand-file-name' (this does "/./" and "/../").
      ;; We bind `directory-sep-char' here for XEmacs on Windows,
      ;; which would otherwise use backslash.  `default-directory' is
      ;; bound, because on Windows there would be problems with UNC
      ;; shares or Cygwin mounts.
      (let ((directory-sep-char ?/)
            (default-directory (tramp-compat-temporary-file-directory)))
        (tramp-make-tramp-file-name
         method user host
         (tramp-drop-volume-letter
          (tramp-run-real-handler
           'expand-file-name (list localname))))))))

(defun tramp-adb-handle-file-directory-p (filename)
  "Like `file-directory-p' for Tramp files."
  (car (file-attributes (file-truename filename))))

;; This is derived from `tramp-sh-handle-file-truename'.  Maybe the
;; code could be shared?
(defun tramp-adb-handle-file-truename (filename)
  "Like `file-truename' for Tramp files."
  (with-parsed-tramp-file-name (expand-file-name filename) nil
    (with-tramp-file-property v localname "file-truename"
      (let ((result nil))                       ; result steps in reverse order
        (tramp-message v 4 "Finding true name for `%s'" filename)
        (let* ((directory-sep-char ?/)
               (steps (tramp-compat-split-string localname "/"))
               (localnamedir (tramp-run-real-handler
                              'file-name-as-directory (list localname)))
               (is-dir (string= localname localnamedir))
               (thisstep nil)
               (numchase 0)
               ;; Don't make the following value larger than
               ;; necessary.  People expect an error message in a
               ;; timely fashion when something is wrong; otherwise
               ;; they might think that Emacs is hung.  Of course,
               ;; correctness has to come first.
               (numchase-limit 20)
               symlink-target)
          (while (and steps (< numchase numchase-limit))
            (setq thisstep (pop steps))
            (tramp-message
             v 5 "Check %s"
             (mapconcat 'identity
                        (append '("") (reverse result) (list thisstep))
                        "/"))
            (setq symlink-target
                  (nth 0 (file-attributes
                          (tramp-make-tramp-file-name
                           method user host
                           (mapconcat 'identity
                                      (append '("")
                                              (reverse result)
                                              (list thisstep))
                                      "/")))))
            (cond ((string= "." thisstep)
                   (tramp-message v 5 "Ignoring step `.'"))
                  ((string= ".." thisstep)
                   (tramp-message v 5 "Processing step `..'")
                   (pop result))
                  ((stringp symlink-target)
                   ;; It's a symlink, follow it.
                   (tramp-message v 5 "Follow symlink to %s" symlink-target)
                   (setq numchase (1+ numchase))
                   (when (file-name-absolute-p symlink-target)
                     (setq result nil))
                   ;; If the symlink was absolute, we'll get a string
                   ;; like "/user@host:/some/target"; extract the
                   ;; "/some/target" part from it.
                   (when (tramp-tramp-file-p symlink-target)
                     (unless (tramp-equal-remote filename symlink-target)
                       (tramp-error
                        v 'file-error
                        "Symlink target `%s' on wrong host" symlink-target))
                     (setq symlink-target localname))
                   (setq steps
                         (append (tramp-compat-split-string
                                  symlink-target "/")
                                 steps)))
                  (t
                   ;; It's a file.
                   (setq result (cons thisstep result)))))
          (when (>= numchase numchase-limit)
            (tramp-error
             v 'file-error
             "Maximum number (%d) of symlinks exceeded" numchase-limit))
          (setq result (reverse result))
          ;; Combine list to form string.
          (setq result
                (if result
                    (mapconcat 'identity (cons "" result) "/")
                  "/"))
          (when (and is-dir (or (string= "" result)
                                (not (string= (substring result -1) "/"))))
            (setq result (concat result "/"))))

        (tramp-message v 4 "True name of `%s' is `%s'" filename result)
        (tramp-make-tramp-file-name method user host result)))))

(defun tramp-adb-handle-file-attributes (filename &optional id-format)
  "Like `file-attributes' for Tramp files."
  (unless id-format (setq id-format 'integer))
  (ignore-errors
    (with-parsed-tramp-file-name filename nil
      (with-tramp-file-property
          v localname (format "file-attributes-%s" id-format)
        (tramp-adb-barf-unless-okay
         v (format "%s -d -l %s"
                   (tramp-adb-get-ls-command v)
                   (tramp-shell-quote-argument localname)) "")
        (with-current-buffer (tramp-get-buffer v)
          (tramp-adb-sh-fix-ls-output)
          (cdar (tramp-do-parse-file-attributes-with-ls v id-format)))))))

(defun tramp-do-parse-file-attributes-with-ls (vec &optional id-format)
  "Parse `file-attributes' for Tramp files using the ls(1) command."
  (with-current-buffer (tramp-get-buffer vec)
    (goto-char (point-min))
    (let ((file-properties nil))
      (while (re-search-forward tramp-adb-ls-toolbox-regexp nil t)
        (let* ((mod-string (match-string 1))
               (is-dir (eq ?d (aref mod-string 0)))
               (is-symlink (eq ?l (aref mod-string 0)))
               (uid (match-string 2))
               (gid (match-string 3))
               (size (string-to-number (match-string 4)))
               (date (match-string 5))
               (name (match-string 6))
               (symlink-target
                (and is-symlink
                     (cadr (split-string name "\\( -> \\|\n\\)")))))
          (push (list
                 (if is-symlink
                     (car (split-string name "\\( -> \\|\n\\)"))
                   name)
                 (or is-dir symlink-target)
                 1     ;link-count
                 ;; no way to handle numeric ids in Androids ash
                 (if (eq id-format 'integer) 0 uid)
                 (if (eq id-format 'integer) 0 gid)
                 '(0 0)                 ; atime
                 (date-to-time date)    ; mtime
                 '(0 0)                 ; ctime
                 size
                 mod-string
                 ;; fake
                 t 1
                 (tramp-get-device vec))
                file-properties)))
      file-properties)))

(defun tramp-adb-handle-directory-files-and-attributes
  (directory &optional full match nosort id-format)
  "Like `directory-files-and-attributes' for Tramp files."
  (when (file-directory-p directory)
    (with-parsed-tramp-file-name (expand-file-name directory) nil
      (with-tramp-file-property
          v localname (format "directory-files-attributes-%s-%s-%s-%s"
                              full match id-format nosort)
        (tramp-adb-barf-unless-okay
         v (format "%s -a -l %s"
                   (tramp-adb-get-ls-command v)
                   (tramp-shell-quote-argument localname)) "")
        (with-current-buffer (tramp-get-buffer v)
          (tramp-adb-sh-fix-ls-output)
          (let ((result (tramp-do-parse-file-attributes-with-ls
                         v (or id-format 'integer))))
            (when full
              (setq result
                    (mapcar
                     (lambda (x)
                       (cons (expand-file-name (car x) directory) (cdr x)))
                     result)))
            (unless nosort
              (setq result
                    (sort result (lambda (x y) (string< (car x) (car y))))))
            (delq nil
                  (mapcar (lambda (x)
                            (if (or (not match) (string-match match (car x)))
                                x))
                          result))))))))

(defun tramp-adb-get-ls-command (vec)
  (with-tramp-connection-property vec "ls"
    (tramp-message vec 5 "Finding a suitable `ls' command")
    (if (zerop (tramp-adb-command-exit-status
                vec "ls --color=never -al /dev/null"))
        ;; On CyanogenMod based system BusyBox is used and "ls" output
        ;; coloring is enabled by default.  So we try to disable it
        ;; when possible.
        "ls --color=never"
      "ls")))

(defun tramp-adb--gnu-switches-to-ash
  (switches)
  "Almquist shell can't handle multiple arguments.
Convert (\"-al\") to (\"-a\" \"-l\").  Remove arguments like \"--dired\"."
  (split-string
   (apply 'concat
          (mapcar (lambda (s)
                    (tramp-compat-replace-regexp-in-string
                     "\\(.\\)"  " -\\1"
                     (tramp-compat-replace-regexp-in-string "^-" "" s)))
                  ;; FIXME: Warning about removed switches (long and non-dash).
                  (delq nil
                        (mapcar
                         (lambda (s)
                           (and (not (string-match "\\(^--\\|^[^-]\\)" s)) s))
                         switches))))))

(defun tramp-adb-handle-insert-directory
  (filename switches &optional _wildcard _full-directory-p)
  "Like `insert-directory' for Tramp files."
  (when (stringp switches)
    (setq switches (tramp-adb--gnu-switches-to-ash (split-string switches))))
  (with-parsed-tramp-file-name (file-truename filename) nil
    (with-current-buffer (tramp-get-buffer v)
      (let ((name (tramp-shell-quote-argument (directory-file-name localname)))
            (switch-d (member "-d" switches))
            (switch-t (member "-t" switches))
            (switches (mapconcat 'identity (remove "-t" switches) " ")))
        (tramp-adb-barf-unless-okay
         v (format "%s %s %s" (tramp-adb-get-ls-command v) switches name)
         "Cannot insert directory listing: %s" filename)
        (unless switch-d
          ;; We insert also filename/. and filename/.., because "ls" doesn't.
          (narrow-to-region (point) (point))
          (ignore-errors
            (tramp-adb-barf-unless-okay
             v (format "%s -d %s %s %s"
                       (tramp-adb-get-ls-command v)
                       switches
                       (concat (file-name-as-directory name) ".")
                       (concat (file-name-as-directory name) ".."))
             "Cannot insert directory listing: %s" filename))
          (widen))
        (tramp-adb-sh-fix-ls-output switch-t)))
    (insert-buffer-substring (tramp-get-buffer v))))

(defun tramp-adb-sh-fix-ls-output (&optional sort-by-time)
  "Insert dummy 0 in empty size columns.
Androids \"ls\" command doesn't insert size column for directories:
Emacs dired can't find files."
  (save-excursion
    ;; Insert missing size.
    (goto-char (point-min))
    (while
        (search-forward-regexp
         "[[:space:]]\\([[:space:]][0-9]\\{4\\}-[0-9][0-9]-[0-9][0-9][[:space:]]\\)" nil t)
      (replace-match "0\\1" "\\1" nil)
      ;; Insert missing "/".
      (when (looking-at "[0-9][0-9]:[0-9][0-9][[:space:]]+$")
        (end-of-line)
        (insert "/")))
    ;; Sort entries.
    (let* ((lines (split-string (buffer-string) "\n" t))
           (sorted-lines
            (sort
             lines
             (if sort-by-time
                 'tramp-adb-ls-output-time-less-p
               'tramp-adb-ls-output-name-less-p))))
      (delete-region (point-min) (point-max))
      (insert "  " (mapconcat 'identity sorted-lines "\n  ")))
    ;; Add final newline.
    (goto-char (point-max))
    (unless (= (point) (line-beginning-position))
      (insert "\n"))))


(defun tramp-adb-ls-output-time-less-p (a b)
  "Sort \"ls\" output by time, descending."
  (let (time-a time-b)
    (string-match tramp-adb-ls-date-regexp a)
    (setq time-a (apply 'encode-time (parse-time-string (match-string 0 a))))
    (string-match tramp-adb-ls-date-regexp b)
    (setq time-b (apply 'encode-time (parse-time-string (match-string 0 b))))
    (tramp-time-less-p time-b time-a)))

(defun tramp-adb-ls-output-name-less-p (a b)
  "Sort \"ls\" output by name, ascending."
  (let (posa posb)
    (string-match dired-move-to-filename-regexp a)
    (setq posa (match-end 0))
    (string-match dired-move-to-filename-regexp b)
    (setq posb (match-end 0))
    (string-lessp (substring a posa) (substring b posb))))

(defun tramp-adb-handle-make-directory (dir &optional parents)
  "Like `make-directory' for Tramp files."
  (setq dir (expand-file-name dir))
  (with-parsed-tramp-file-name dir nil
    (when parents
      (let ((par (expand-file-name ".." dir)))
        (unless (file-directory-p par)
          (make-directory par parents))))
    (tramp-adb-barf-unless-okay
     v (format "mkdir %s" (tramp-shell-quote-argument localname))
     "Couldn't make directory %s" dir)
    (tramp-flush-directory-property v (file-name-directory localname))))

(defun tramp-adb-handle-delete-directory (directory &optional recursive)
  "Like `delete-directory' for Tramp files."
  (setq directory (expand-file-name directory))
  (with-parsed-tramp-file-name directory nil
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-directory-property v localname)
    (tramp-adb-barf-unless-okay
     v (format "%s %s"
               (if recursive "rm -r" "rmdir")
               (tramp-shell-quote-argument localname))
     "Couldn't delete %s" directory)))

(defun tramp-adb-handle-delete-file (filename &optional _trash)
  "Like `delete-file' for Tramp files."
  (setq filename (expand-file-name filename))
  (with-parsed-tramp-file-name filename nil
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-file-property v localname)
    (tramp-adb-barf-unless-okay
     v (format "rm %s" (tramp-shell-quote-argument localname))
     "Couldn't delete %s" filename)))

(defun tramp-adb-handle-file-name-all-completions (filename directory)
  "Like `file-name-all-completions' for Tramp files."
  (all-completions
   filename
   (with-parsed-tramp-file-name directory nil
     (with-tramp-file-property v localname "file-name-all-completions"
       (save-match-data
         (tramp-adb-send-command
          v (format "%s %s"
                    (tramp-adb-get-ls-command v)
                    (tramp-shell-quote-argument localname)))
         (mapcar
          (lambda (f)
            (if (file-directory-p f)
                (file-name-as-directory f)
              f))
          (with-current-buffer (tramp-get-buffer v)
            (delq
             nil
             (mapcar
              (lambda (l) (and (not (string-match  "^[[:space:]]*$" l)) l))
              (split-string (buffer-string) "\n"))))))))))

(defun tramp-adb-handle-file-local-copy (filename)
  "Like `file-local-copy' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (unless (file-exists-p (file-truename filename))
      (tramp-error
       v 'file-error
       "Cannot make local copy of non-existing file `%s'" filename))
    (let ((tmpfile (tramp-compat-make-temp-file filename)))
      (with-tramp-progress-reporter
          v 3 (format "Fetching %s to tmp file %s" filename tmpfile)
        (when (tramp-adb-execute-adb-command v "pull" localname tmpfile)
          (delete-file tmpfile)
          (tramp-error
           v 'file-error "Cannot make local copy of file `%s'" filename))
        (set-file-modes tmpfile (file-modes filename)))
      tmpfile)))

(defun tramp-adb-handle-file-writable-p (filename)
  "Like `tramp-sh-handle-file-writable-p'.
But handle the case, if the \"test\" command is not available."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-writable-p"
      (if (tramp-adb-find-test-command v)
          (if (file-exists-p filename)
              (zerop
               (tramp-adb-command-exit-status
                v (format "test -w %s" (tramp-shell-quote-argument localname))))
            (and
             (file-directory-p (file-name-directory filename))
             (file-writable-p (file-name-directory filename))))

        ;; Missing "test" command on Android < 4.
       (let ((rw-path "/data/data"))
         (tramp-message
          v 5
          "Not implemented yet (assuming \"/data/data\" is writable): %s"
          localname)
         (and (>= (length localname) (length rw-path))
              (string= (substring localname 0 (length rw-path))
                       rw-path)))))))

(defun tramp-adb-handle-write-region
  (start end filename &optional append visit lockname confirm)
  "Like `write-region' for Tramp files."
  (setq filename (expand-file-name filename))
  (with-parsed-tramp-file-name filename nil
    (when append
      (tramp-error
       v 'file-error "Cannot append to file using Tramp (`%s')" filename))
    (when (and confirm (file-exists-p filename))
      (unless (y-or-n-p (format "File %s exists; overwrite anyway? "
                                filename))
        (tramp-error v 'file-error "File not overwritten")))
    ;; We must also flush the cache of the directory, because
    ;; `file-attributes' reads the values from there.
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-file-property v localname)
    (let* ((curbuf (current-buffer))
           (tmpfile (tramp-compat-make-temp-file filename)))
      (tramp-run-real-handler
       'write-region
       (list start end tmpfile append 'no-message lockname confirm))
      (with-tramp-progress-reporter
          v 3 (format "Moving tmp file %s to %s" tmpfile filename)
        (unwind-protect
            (when (tramp-adb-execute-adb-command v "push" tmpfile localname)
              (tramp-error v 'file-error "Cannot write: `%s' filename"))
          (delete-file tmpfile)))

      (when (or (eq visit t) (stringp visit))
        (set-visited-file-modtime))

      (unless (equal curbuf (current-buffer))
        (tramp-error
         v 'file-error
         "Buffer has changed from `%s' to `%s'" curbuf (current-buffer))))))

(defun tramp-adb-handle-set-file-modes (filename mode)
  "Like `set-file-modes' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (tramp-flush-file-property v localname)
    (tramp-adb-barf-unless-okay
     v (format "chmod %s %s" (tramp-compat-decimal-to-octal mode) localname)
     "Error while changing file's mode %s" filename)))

(defun tramp-adb-handle-set-file-times (filename &optional time)
  "Like `set-file-times' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (tramp-flush-file-property v localname)
    (let ((time (if (or (null time) (equal time '(0 0)))
                    (current-time)
                  time)))
      (tramp-adb-command-exit-status
       ;; use shell arithmetic because of Emacs integer size limit
       v (format "touch -t $(( %d * 65536 + %d )) %s"
                 (car time) (cadr time)
                 (tramp-shell-quote-argument localname))))))

(defun tramp-adb-handle-copy-file
  (filename newname &optional ok-if-already-exists keep-date
            _preserve-uid-gid _preserve-extended-attributes)
  "Like `copy-file' for Tramp files.
PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
  (setq filename (expand-file-name filename)
        newname (expand-file-name newname))

  (if (file-directory-p filename)
      (tramp-file-name-handler 'copy-directory filename newname keep-date t)
    (with-tramp-progress-reporter
        (tramp-dissect-file-name
         (if (tramp-tramp-file-p filename) filename newname))
        0 (format "Copying %s to %s" filename newname)

      (let ((tmpfile (file-local-copy filename)))

        (if tmpfile
            ;; Remote filename.
            (condition-case err
                (rename-file tmpfile newname ok-if-already-exists)
              ((error quit)
               (delete-file tmpfile)
               (signal (car err) (cdr err))))

          ;; Remote newname.
          (when (file-directory-p newname)
            (setq newname
                  (expand-file-name (file-name-nondirectory filename) newname)))

          (with-parsed-tramp-file-name newname nil
            (when (and (not ok-if-already-exists)
                       (file-exists-p newname))
              (tramp-error v 'file-already-exists newname))

            ;; We must also flush the cache of the directory, because
            ;; `file-attributes' reads the values from there.
            (tramp-flush-file-property v (file-name-directory localname))
            (tramp-flush-file-property v localname)
            (when (tramp-adb-execute-adb-command v "push" filename localname)
              (tramp-error
               v 'file-error "Cannot copy `%s' `%s'" filename newname))))))

    ;; KEEP-DATE handling.
    (when keep-date
      (set-file-times newname (nth 5 (file-attributes filename))))))

(defun tramp-adb-handle-rename-file
  (filename newname &optional ok-if-already-exists)
  "Like `rename-file' for Tramp files."
  (setq filename (expand-file-name filename)
        newname (expand-file-name newname))

  (with-parsed-tramp-file-name
      (if (tramp-tramp-file-p filename) filename newname) nil
    (with-tramp-progress-reporter
        v 0 (format "Renaming %s to %s" newname filename)

      (if (and (tramp-equal-remote filename newname)
               (not (file-directory-p filename)))
          (progn
            (when (and (not ok-if-already-exists)
                       (file-exists-p newname))
              (tramp-error v 'file-already-exists newname))
            ;; We must also flush the cache of the directory, because
            ;; `file-attributes' reads the values from there.
            (tramp-flush-file-property v (file-name-directory localname))
            (tramp-flush-file-property v localname)
            ;; Short track.
            (tramp-adb-barf-unless-okay
             v (format
                "mv %s %s"
                (tramp-file-name-handler 'file-remote-p filename 'localname)
                localname)
             "Error renaming %s to %s" filename newname))

        ;; Rename by copy.
        (copy-file filename newname ok-if-already-exists t t)
        (delete-file filename)))))

(defun tramp-adb-handle-process-file
  (program &optional infile destination display &rest args)
  "Like `process-file' for Tramp files."
  ;; The implementation is not complete yet.
  (when (and (numberp destination) (zerop destination))
    (error "Implementation does not handle immediate return"))

  (with-parsed-tramp-file-name default-directory nil
    (let (command input tmpinput stderr tmpstderr outbuf ret)
      ;; Compute command.
      (setq command (mapconcat 'tramp-shell-quote-argument
                               (cons program args) " "))
      ;; Determine input.
      (if (null infile)
          (setq input "/dev/null")
        (setq infile (expand-file-name infile))
        (if (tramp-equal-remote default-directory infile)
            ;; INFILE is on the same remote host.
            (setq input (with-parsed-tramp-file-name infile nil localname))
          ;; INFILE must be copied to remote host.
          (setq input (tramp-make-tramp-temp-file v)
                tmpinput (tramp-make-tramp-file-name method user host input))
          (copy-file infile tmpinput t)))
      (when input (setq command (format "%s <%s" command input)))

      ;; Determine output.
      (cond
       ;; Just a buffer.
       ((bufferp destination)
        (setq outbuf destination))
       ;; A buffer name.
       ((stringp destination)
        (setq outbuf (get-buffer-create destination)))
       ;; (REAL-DESTINATION ERROR-DESTINATION)
       ((consp destination)
        ;; output.
        (cond
         ((bufferp (car destination))
          (setq outbuf (car destination)))
         ((stringp (car destination))
          (setq outbuf (get-buffer-create (car destination))))
         ((car destination)
          (setq outbuf (current-buffer))))
        ;; stderr.
        (cond
         ((stringp (cadr destination))
          (setcar (cdr destination) (expand-file-name (cadr destination)))
          (if (tramp-equal-remote default-directory (cadr destination))
              ;; stderr is on the same remote host.
              (setq stderr (with-parsed-tramp-file-name
                               (cadr destination) nil localname))
            ;; stderr must be copied to remote host.  The temporary
            ;; file must be deleted after execution.
            (setq stderr (tramp-make-tramp-temp-file v)
                  tmpstderr (tramp-make-tramp-file-name
                             method user host stderr))))
         ;; stderr to be discarded.
         ((null (cadr destination))
          (setq stderr "/dev/null"))))
       ;; 't
       (destination
        (setq outbuf (current-buffer))))
      (when stderr (setq command (format "%s 2>%s" command stderr)))

      ;; Send the command.  It might not return in time, so we protect
      ;; it.  Call it in a subshell, in order to preserve working
      ;; directory.
      (condition-case nil
          (progn
            (setq ret 0)
            (tramp-adb-barf-unless-okay
             v (format "(cd %s; %s)"
                       (tramp-shell-quote-argument localname) command)
             "")
            ;; We should show the output anyway.
            (when outbuf
              (with-current-buffer outbuf
                (insert-buffer-substring (tramp-get-connection-buffer v)))
              (when display (display-buffer outbuf))))
        ;; When the user did interrupt, we should do it also.  We use
        ;; return code -1 as marker.
        (quit
         (kill-buffer (tramp-get-connection-buffer v))
         (setq ret -1))
        ;; Handle errors.
        (error
         (kill-buffer (tramp-get-connection-buffer v))
         (setq ret 1)))

      ;; Provide error file.
      (when tmpstderr (rename-file tmpstderr (cadr destination) t))

      ;; Cleanup.  We remove all file cache values for the connection,
      ;; because the remote process could have changed them.
      (when tmpinput (delete-file tmpinput))

      ;; `process-file-side-effects' has been introduced with GNU
      ;; Emacs 23.2.  If set to `nil', no remote file will be changed
      ;; by `program'.  If it doesn't exist, we assume its default
      ;; value 't'.
      (unless (and (boundp 'process-file-side-effects)
                   (not (symbol-value 'process-file-side-effects)))
        (tramp-flush-directory-property v ""))

      ;; Return exit status.
      (if (equal ret -1)
          (keyboard-quit)
        ret))))

(defun tramp-adb-handle-shell-command
  (command &optional output-buffer error-buffer)
  "Like `shell-command' for Tramp files."
  (let* ((asynchronous (string-match "[ \t]*&[ \t]*\\'" command))
         ;; We cannot use `shell-file-name' and `shell-command-switch',
         ;; they are variables of the local host.
         (args (list "sh" "-c" (substring command 0 asynchronous)))
         current-buffer-p
         (output-buffer
          (cond
           ((bufferp output-buffer) output-buffer)
           ((stringp output-buffer) (get-buffer-create output-buffer))
           (output-buffer
            (setq current-buffer-p t)
            (current-buffer))
           (t (get-buffer-create
               (if asynchronous
                   "*Async Shell Command*"
                 "*Shell Command Output*")))))
         (error-buffer
          (cond
           ((bufferp error-buffer) error-buffer)
           ((stringp error-buffer) (get-buffer-create error-buffer))))
         (buffer
          (if (and (not asynchronous) error-buffer)
              (with-parsed-tramp-file-name default-directory nil
                (list output-buffer (tramp-make-tramp-temp-file v)))
            output-buffer))
         (p (get-buffer-process output-buffer)))

    ;; Check whether there is another process running.  Tramp does not
    ;; support 2 (asynchronous) processes in parallel.
    (when p
      (if (yes-or-no-p "A command is running.  Kill it? ")
          (ignore-errors (kill-process p))
        (tramp-user-error p "Shell command in progress")))

    (if current-buffer-p
        (progn
          (barf-if-buffer-read-only)
          (push-mark nil t))
      (with-current-buffer output-buffer
        (setq buffer-read-only nil)
        (erase-buffer)))

    (if (and (not current-buffer-p) (integerp asynchronous))
        (prog1
            ;; Run the process.
            (apply 'start-file-process "*Async Shell*" buffer args)
          ;; Display output.
          (pop-to-buffer output-buffer)
          (setq mode-line-process '(":%s"))
          (shell-mode))

      (prog1
          ;; Run the process.
          (apply 'process-file (car args) nil buffer nil (cdr args))
        ;; Insert error messages if they were separated.
        (when (listp buffer)
          (with-current-buffer error-buffer
            (insert-file-contents (cadr buffer)))
          (delete-file (cadr buffer)))
        (if current-buffer-p
            ;; This is like exchange-point-and-mark, but doesn't
            ;; activate the mark.  It is cleaner to avoid activation,
            ;; even though the command loop would deactivate the mark
            ;; because we inserted text.
            (goto-char (prog1 (mark t)
                         (set-marker (mark-marker) (point)
                                     (current-buffer))))
          ;; There's some output, display it.
          (when (with-current-buffer output-buffer (> (point-max) (point-min)))
            (if (functionp 'display-message-or-buffer)
                (tramp-compat-funcall 'display-message-or-buffer output-buffer)
              (pop-to-buffer output-buffer))))))))

;; We use BUFFER also as connection buffer during setup.  Because of
;; this, its original contents must be saved, and restored once
;; connection has been setup.
(defun tramp-adb-handle-start-file-process (name buffer program &rest args)
  "Like `start-file-process' for Tramp files."
  (with-parsed-tramp-file-name default-directory nil
    ;; When PROGRAM is nil, we should provide a tty.  This is not
    ;; possible here.
    (unless (stringp program)
      (tramp-error v 'file-error "PROGRAM must be a string"))

    (let ((command
           (format "cd %s; %s"
                   (tramp-shell-quote-argument localname)
                   (mapconcat 'tramp-shell-quote-argument
                              (cons program args) " ")))
          (tramp-process-connection-type
           (or (null program) tramp-process-connection-type))
          (bmp (and (buffer-live-p buffer) (buffer-modified-p buffer)))
          (name1 name)
          (i 0))

      (unless buffer
        ;; BUFFER can be nil.  We use a temporary buffer.
        (setq buffer (generate-new-buffer tramp-temp-buffer-name)))
      (while (get-process name1)
        ;; NAME must be unique as process name.
        (setq i (1+ i)
              name1 (format "%s<%d>" name i)))
      (setq name name1)
      ;; Set the new process properties.
      (tramp-set-connection-property v "process-name" name)
      (tramp-set-connection-property v "process-buffer" buffer)

      (with-current-buffer (tramp-get-connection-buffer v)
        (unwind-protect
            ;; We catch this event.  Otherwise, `start-process' could
            ;; be called on the local host.
            (save-excursion
              (save-restriction
                ;; Activate narrowing in order to save BUFFER
                ;; contents.  Clear also the modification time;
                ;; otherwise we might be interrupted by
                ;; `verify-visited-file-modtime'.
                (let ((buffer-undo-list t)
                      (buffer-read-only nil)
                      (mark (point)))
                  (clear-visited-file-modtime)
                  (narrow-to-region (point-max) (point-max))
                  ;; We call `tramp-adb-maybe-open-connection', in
                  ;; order to cleanup the prompt afterwards.
                  (tramp-adb-maybe-open-connection v)
                  (widen)
                  (delete-region mark (point))
                  (narrow-to-region (point-max) (point-max))
                  ;; Send the command.
                  (let ((tramp-adb-prompt (regexp-quote command)))
                    (tramp-adb-send-command v command))
                  (let ((p (tramp-get-connection-process v)))
                    ;; Set query flag and process marker for this
                    ;; process.  We ignore errors, because the process
                    ;; could have finished already.
                    (ignore-errors
                      (tramp-compat-set-process-query-on-exit-flag p t)
                      (set-marker (process-mark p) (point)))
                    ;; Return process.
                    p))))

          ;; Save exit.
          (if (string-match tramp-temp-buffer-name (buffer-name))
              (ignore-errors
                (set-process-buffer (tramp-get-connection-process v) nil)
                (kill-buffer (current-buffer)))
            (set-buffer-modified-p bmp))
          (tramp-set-connection-property v "process-name" nil)
          (tramp-set-connection-property v "process-buffer" nil))))))

;; Helper functions.

(defun tramp-adb-execute-adb-command (vec &rest args)
  "Returns nil on success error-output on failure."
  (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 'tramp-call-process tramp-adb-program nil t nil args))
          (buffer-string))
      (tramp-message vec 6 "%s" (buffer-string)))))

(defun tramp-adb-find-test-command (vec)
  "Checks, whether the ash has a builtin \"test\" command.
This happens for Android >= 4.0."
  (with-tramp-connection-property vec "test"
    (zerop (tramp-adb-command-exit-status vec "type test"))))

;; Connection functions

(defun tramp-adb-send-command (vec command)
  "Send the COMMAND to connection VEC."
  (tramp-adb-maybe-open-connection vec)
  (tramp-message vec 6 "%s" command)
  (tramp-send-string vec command)
  ;; fixme: Race condition
  (tramp-adb-wait-for-output (tramp-get-connection-process vec))
  (with-current-buffer (tramp-get-connection-buffer vec)
    (save-excursion
      (goto-char (point-min))
      ;; We can't use stty to disable echo of command.
      (delete-matching-lines (regexp-quote command))
      ;; When the local machine is W32, there are still trailing ^M.
      ;; There must be a better solution by setting the correct coding
      ;; system, but this requires changes in core Tramp.
      (goto-char (point-min))
      (while (re-search-forward "\r+$" nil t)
        (replace-match "" nil nil)))))

(defun tramp-adb-command-exit-status
  (vec command)
  "Run COMMAND and return its exit status.
Sends `echo $?' along with the COMMAND for checking the exit status.  If
COMMAND is nil, just sends `echo $?'.  Returns the exit status found."
  (tramp-adb-send-command
   vec (if command
           (format "%s; echo tramp_exit_status $?" command)
         "echo tramp_exit_status $?"))
  (with-current-buffer (tramp-get-connection-buffer vec)
    (goto-char (point-max))
    (unless (re-search-backward "tramp_exit_status [0-9]+" nil t)
      (tramp-error
       vec 'file-error "Couldn't find exit status of `%s'" command))
    (skip-chars-forward "^ ")
    (prog1
        (read (current-buffer))
      (let (buffer-read-only)
        (delete-region (match-beginning 0) (point-max))))))

(defun tramp-adb-barf-unless-okay (vec command fmt &rest args)
  "Run COMMAND, check exit status, throw error if exit status not okay.
FMT and ARGS are passed to `error'."
  (unless (zerop (tramp-adb-command-exit-status vec command))
    (apply 'tramp-error vec 'file-error fmt args)))

(defun tramp-adb-wait-for-output (proc &optional timeout)
  "Wait for output from remote command."
  (unless (buffer-live-p (process-buffer proc))
    (delete-process proc)
    (tramp-error proc 'file-error "Process `%s' not available, try again" proc))
  (with-current-buffer (process-buffer proc)
    (if (tramp-wait-for-regexp proc timeout tramp-adb-prompt)
        (let (buffer-read-only)
          (goto-char (point-min))
          ;; ADB terminal sends "^H" sequences.
          (when (re-search-forward "<\b+" (point-at-eol) t)
            (forward-line 1)
            (delete-region (point-min) (point)))
          ;; Delete the prompt.
         (goto-char (point-min))
         (when (re-search-forward tramp-adb-prompt (point-at-eol) t)
           (forward-line 1)
           (delete-region (point-min) (point)))
          (goto-char (point-max))
          (re-search-backward tramp-adb-prompt nil t)
          (delete-region (point) (point-max)))
      (if timeout
          (tramp-error
           proc 'file-error
           "[[Remote adb prompt `%s' not found in %d secs]]"
           tramp-adb-prompt timeout)
        (tramp-error
         proc 'file-error
         "[[Remote prompt `%s' not found]]" tramp-adb-prompt)))))

(defun tramp-adb-maybe-open-connection (vec)
  "Maybe open a connection VEC.
Does not do anything if a connection is already open, but re-opens the
connection if a previous connection has died for some reason."
  (tramp-check-proper-method-and-host vec)

  (let* ((buf (tramp-get-connection-buffer vec))
         (p (get-buffer-process buf))
         (host (tramp-file-name-host vec))
         (user (tramp-file-name-user vec))
         (devices (mapcar 'cadr (tramp-adb-parse-device-names nil))))

    ;; Maybe we know already that "su" is not supported.  We cannot
    ;; use a connection property, because we have not checked yet
    ;; whether it is still the same device.
    (when (and user (not (tramp-get-file-property vec "" "su-command-p" t)))
      (tramp-error vec 'file-error "Cannot switch to user `%s'" user))

    (unless
        (and p (processp p) (memq (process-status p) '(run open)))
      (save-match-data
        (when (and p (processp p)) (delete-process p))
        (if (not devices)
            (tramp-error vec 'file-error "No device connected"))
        (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 (> (length host) 0)
                           (list "-s" host "shell")
                         (list "shell")))
                 (p (let ((default-directory
                            (tramp-compat-temporary-file-directory)))
                      (apply 'start-process (tramp-get-connection-name vec) buf
                             tramp-adb-program args))))
            (tramp-message
             vec 6 "%s" (mapconcat 'identity (process-command p) " "))
            ;; Wait for initial prompt.
            (tramp-adb-wait-for-output p 30)
            (unless (eq 'run (process-status p))
              (tramp-error  vec 'file-error "Terminated!"))
            (tramp-set-connection-property p "vector" vec)
            (tramp-compat-set-process-query-on-exit-flag p nil)

            ;; Check whether the properties have been changed.  If
            ;; yes, this is a strong indication that we must expire all
            ;; connection properties.  We start again.
            (tramp-message vec 5 "Checking system information")
            (tramp-adb-send-command
             vec "echo \\\"`getprop ro.product.model` `getprop ro.product.version` `getprop ro.build.version.release`\\\"")
            (let ((old-getprop
                   (tramp-get-connection-property vec "getprop" nil))
                  (new-getprop
                   (tramp-set-connection-property
                    vec "getprop"
                    (with-current-buffer (tramp-get-connection-buffer vec)
                      ;; Read the expression.
                      (goto-char (point-min))
                      (read (current-buffer))))))
              (when (and (stringp old-getprop)
                         (not (string-equal old-getprop new-getprop)))
                (tramp-message
                 vec 3
                 "Connection reset, because remote host changed from `%s' to `%s'"
                 old-getprop new-getprop)
                (tramp-cleanup-connection vec t)
                (tramp-adb-maybe-open-connection vec)))

            ;; Change user if indicated.
            (when user
              (tramp-adb-send-command vec (format "su %s" user))
              (unless (zerop (tramp-adb-command-exit-status vec nil))
                (delete-process p)
                (tramp-set-file-property vec "" "su-command-p" nil)
                (tramp-error
                 vec 'file-error "Cannot switch to user `%s'" user)))

            ;; Set "remote-path" connection property.  This is needed
            ;; for eshell.
            (tramp-adb-send-command vec "echo \\\"$PATH\\\"")
            (tramp-set-connection-property
             vec "remote-path"
             (split-string
              (with-current-buffer (tramp-get-connection-buffer vec)
                ;; Read the expression.
                (goto-char (point-min))
                (read (current-buffer)))
              ":" 'omit-nulls))))))))

(provide 'tramp-adb)
;;; tramp-adb.el ends here