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

;; Copyright (C) 2011-2014 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)

(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-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 . tramp-handle-make-symbolic-link)
    (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))
	  (accept-process-output p 0.1))
	(accept-process-output p 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."
  (format
   "%s%s"
   (with-parsed-tramp-file-name (expand-file-name filename) nil
     (tramp-make-tramp-file-name
      method user host
      (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'" localname result)
	  result))))

   ;; Preserve trailing "/".
   (if (string-equal (file-name-nondirectory filename) "") "/" "")))

(defun tramp-adb-handle-file-attributes (filename &optional id-format)
  "Like `file-attributes' for Tramp files."
  (unless id-format (setq id-format 'integer))
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property
	v localname (format "file-attributes-%s" id-format)
      (and
       (tramp-adb-send-command-and-check
	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)
	(with-current-buffer (tramp-get-buffer v)
	  (when (tramp-adb-send-command-and-check
		 v (format "%s -a -l %s"
			   (tramp-adb-get-ls-command v)
			   (tramp-shell-quote-argument localname)))
	    ;; We insert also filename/. and filename/.., because "ls" doesn't.
	    (narrow-to-region (point) (point))
	    (tramp-adb-send-command
	     v (format "%s -d -a -l %s %s"
		       (tramp-adb-get-ls-command v)
		       (concat (file-name-as-directory localname) ".")
		       (concat (file-name-as-directory localname) "..")))
	    (widen))
	  (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 (tramp-adb-send-command-and-check 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-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 directory-listing-before-filename-regexp a)
    (setq posa (match-end 0))
    (string-match directory-listing-before-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-file-property v (file-name-directory localname))
    (tramp-flush-directory-property v 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 -a %s"
		    (tramp-adb-get-ls-command v)
		    (tramp-shell-quote-argument localname)))
	 (mapcar
	  (lambda (f)
	    (if (file-directory-p (expand-file-name f directory))
		(file-name-as-directory f)
	      f))
	  (with-current-buffer (tramp-get-buffer v)
	    (append
	     '("." "..")
	     (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
	 (logior (or (file-modes filename) 0)
		 (tramp-compat-octal-to-decimal "0400"))))
      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)
	      (tramp-adb-send-command-and-check
	       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 (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)))
      (when (and append (file-exists-p filename))
	(copy-file filename tmpfile 'ok)
	(set-file-modes
	 tmpfile
	 (logior (or (file-modes tmpfile) 0)
		 (tramp-compat-octal-to-decimal "0600"))))
      (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-send-command-and-check
     v (format "chmod %s %s" (tramp-compat-decimal-to-octal mode) localname))))

(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-send-command-and-check
       ;; 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))

  (let ((t1 (tramp-tramp-file-p filename))
	(t2 (tramp-tramp-file-p newname)))
    (with-parsed-tramp-file-name (if t1 filename newname) nil
      (with-tramp-progress-reporter
	  v 0 (format "Renaming %s to %s" filename newname)

	(if (and t1 t2
		 (tramp-equal-remote filename newname)
		 (not (file-directory-p filename)))
	    (let ((l1 (tramp-file-name-handler
		       'file-remote-p filename 'localname))
		  (l2 (tramp-file-name-handler
		       'file-remote-p newname 'localname)))
	      (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 l1))
	      (tramp-flush-file-property v l1)
	      (tramp-flush-file-property v (file-name-directory l2))
	      (tramp-flush-file-property v l2)
	      ;; Short track.
	      (tramp-adb-barf-unless-okay
	       v (format "mv %s %s" l1 l2)
	       "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"
    (tramp-adb-send-command-and-check 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-send-command-and-check
  (vec command)
  "Run COMMAND and and check 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
	(zerop (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 (tramp-adb-send-command-and-check 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)

    ;; 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))
	(setq tramp-current-method (tramp-file-name-method vec)
	      tramp-current-user (tramp-file-name-user vec)
	      tramp-current-host (tramp-file-name-host vec)
	      devices (mapcar 'cadr (tramp-adb-parse-device-names nil)))
	(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 (tramp-adb-send-command-and-check 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))))))))

(add-hook 'tramp-unload-hook
	  (lambda ()
	    (unload-feature 'tramp-adb 'force)))

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