;;; tramp-adb.el --- Functions for calling Android Debug Bridge from Tramp  -*- lexical-binding:t -*-

;; Copyright (C) 2011-2018 Free Software Foundation, Inc.

;; Author: Jürgen Hötzel <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 <https://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)

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

;;;###tramp-autoload
(defcustom tramp-adb-connect-if-not-connected nil
  "Try to run `adb connect' if provided device is not connected currently.
It is used for TCP/IP devices."
  :group 'tramp
  :version "25.1"
  :type 'boolean
  :require 'tramp)

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

;;;###tramp-autoload
(defcustom tramp-adb-prompt
  "^\\(?:[[:digit:]]*|?\\)?\\(?:[[:alnum:]\e;[]*@?[[:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
  "Regexp used as prompt in almquist shell."
  :type 'string
  :version "24.4"
  :group 'tramp
  :require '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:]]"
  "Regexp for date format in ls output.")

(defconst tramp-adb-ls-toolbox-regexp
  (concat
   "^[[:space:]]*\\([-\\.[:alpha:]]+\\)" ; \1 permissions
   "\\(?:[[:space:]]+[[:digit:]]+\\)?"	; links (Android 7/toybox)
   "[[:space:]]*\\([^[:space:]]+\\)"	; \2 username
   "[[:space:]]+\\([^[:space:]]+\\)"	; \3 group
   "[[:space:]]+\\([[:digit:]]+\\)"	; \4 size
   "[[:space:]]+\\([-[:digit:]]+[[:space:]][:[:digit:]]+\\)" ; \5 date
   "[[:space:]]\\(.*\\)$")		; \6 filename
  "Regexp for ls output.")

;;;###tramp-autoload
(add-to-list 'tramp-methods
	     `(,tramp-adb-method
	       (tramp-tmpdir "/data/local/tmp")
               (tramp-default-port 5555)))

;;;###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
(defconst tramp-adb-file-name-handler-alist
  '((access-file . ignore)
    (add-name-to-file . tramp-handle-add-name-to-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-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-handle-file-directory-p)
    (file-equal-p . tramp-handle-file-equal-p)
    ;; 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 . tramp-handle-file-in-directory-p)
    (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-case-insensitive-p . tramp-handle-file-name-case-insensitive-p)
    (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-notify-valid-p . tramp-handle-file-notify-valid-p)
    (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 . tramp-handle-file-selinux-context)
    (file-symlink-p . tramp-handle-file-symlink-p)
    (file-system-info . tramp-adb-handle-file-system-info)
    (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-nearby-temp-file . tramp-handle-make-nearby-temp-file)
    (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)
    (temporary-file-directory . tramp-handle-temporary-file-directory)
    (unhandled-file-name-directory . ignore)
    (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
(tramp-register-foreign-file-name-handler
 'tramp-adb-file-name-p 'tramp-adb-file-name-handler)

;;;###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'.
      ;; We don't know yet whether we need a user or host name for the
      ;; connection vector.  We assume we don't, it will be OK in most
      ;; of the cases.  Otherwise, there might be an additional trace
      ;; buffer, which doesn't hurt.
      (let ((p (start-process
		tramp-adb-program (current-buffer) tramp-adb-program "devices"))
	    (v (make-tramp-file-name :method tramp-adb-method))
	    result)
	(tramp-message v 6 "%s" (mapconcat 'identity (process-command p) " "))
	(process-put p 'adjust-window-size-function 'ignore)
	(set-process-query-on-exit-flag p nil)
	(while (process-live-p p)
	  (accept-process-output p 0.1))
	(accept-process-output p 0.1)
	(tramp-message v 6 "\n%s" (buffer-string))
	(goto-char (point-min))
	(while (search-forward-regexp "^\\(\\S-+\\)[[:space:]]+device$" nil t)
	  (push (list nil (match-string 1)) result))

	;; Replace ":" by "#".
	(mapc
	 (lambda (elt)
	   (setcar
	    (cdr elt)
	    (replace-regexp-in-string
	     ":" tramp-prefix-port-format (car (cdr elt)))))
	 result)
	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 "/../").
      ;; `default-directory' is bound, because on Windows there would
      ;; be problems with UNC shares or Cygwin mounts.
      (let ((default-directory (tramp-compat-temporary-file-directory)))
	(tramp-make-tramp-file-name
	 v (tramp-drop-volume-letter
	    (tramp-run-real-handler 'expand-file-name (list localname))))))))

(defun tramp-adb-handle-file-system-info (filename)
  "Like `file-system-info' for Tramp files."
  (ignore-errors
    (with-parsed-tramp-file-name (expand-file-name filename) nil
      (tramp-message v 5 "file system info: %s" localname)
      (tramp-adb-send-command
       v (format "df -k %s" (tramp-shell-quote-argument localname)))
      (with-current-buffer (tramp-get-connection-buffer v)
	(goto-char (point-min))
	(forward-line)
	(when (looking-at
	       (concat "[[:space:]]*[^[:space:]]+"
		       "[[:space:]]+\\([[:digit:]]+\\)"
		       "[[:space:]]+\\([[:digit:]]+\\)"
		       "[[:space:]]+\\([[:digit:]]+\\)"))
	  ;; The values are given as 1k numbers, so we must change
	  ;; them to number of bytes.
	  (list (* 1024 (string-to-number (concat (match-string 1) "e0")))
		;; The second value is the used size.  We need the
		;; free size.
		(* 1024 (- (string-to-number (concat (match-string 1) "e0"))
			   (string-to-number (concat (match-string 2) "e0"))))
		(* 1024 (string-to-number (concat (match-string 3) "e0")))))))))

;; 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
      v
      (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* ((steps (split-string localname "/" 'omit))
		 (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
		    (tramp-compat-file-attribute-type
		     (file-attributes
		      (tramp-make-tramp-file-name
		       v (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 (split-string symlink-target "/" 'omit)
				   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))
  (ignore-errors
    (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
      (copy-tree
       (with-tramp-file-property
	   v localname (format "directory-files-and-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.
	     ;; Looks like it does include them in toybox, since Android 6.
	     (unless (re-search-backward "\\.$" nil t)
	       (narrow-to-region (point-max) (point-max))
	       (tramp-adb-send-command
		v (format "%s -d -a -l %s %s"
			  (tramp-adb-get-ls-command v)
			  (tramp-shell-quote-argument
			   (concat (file-name-as-directory localname) "."))
			  (tramp-shell-quote-argument
			   (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)
  "Determine `ls' command at its arguments."
  (with-tramp-connection-property vec "ls"
    (tramp-message vec 5 "Finding a suitable `ls' command")
    (cond
     ;; Support Android derived systems where "ls" command is provided
     ;; by GNU Coreutils. Force "ls" to print one column and set
     ;; time-style to imitate other "ls" flavours.
     ((tramp-adb-send-command-and-check vec "ls --help | grep coreutils")
      "ls -1 --time-style=long-iso")
     ;; Can't disable coloring explicitly for toybox ls command.  We
     ;; also must force "ls" to print just one column.
     ((tramp-adb-send-command-and-check vec "toybox")
      "ls -1")
     ;; On CyanogenMod based system BusyBox is used and "ls" output
     ;; coloring is enabled by default.  So we try to disable it when
     ;; possible.
     ((tramp-adb-send-command-and-check vec "ls --color=never -al /dev/null")
      "ls --color=never")
     (t "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)
		    (replace-regexp-in-string
		     "\\(.\\)"  " -\\1" (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 (bolp) (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))))
    (time-less-p time-b time-a)))

(defun tramp-adb-ls-output-name-less-p (a b)
  "Sort \"ls\" output by name, ascending."
  (if (string-match directory-listing-before-filename-regexp a)
      (let ((posa (match-end 0)))
	(if (string-match directory-listing-before-filename-regexp b)
	    (let ((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-flush-file-properties v (file-name-directory localname))
    (tramp-flush-directory-properties v localname)
    (unless (or (tramp-adb-send-command-and-check
		 v (format "mkdir %s" (tramp-shell-quote-argument localname)))
		(and parents (file-directory-p dir)))
      (tramp-error v 'file-error "Couldn't make directory %s" dir))))

(defun tramp-adb-handle-delete-directory (directory &optional recursive _trash)
  "Like `delete-directory' for Tramp files."
  (setq directory (expand-file-name directory))
  (with-parsed-tramp-file-name (file-truename directory) nil
    (tramp-flush-file-properties v (file-name-directory localname))
    (tramp-flush-directory-properties v localname))
  (with-parsed-tramp-file-name directory nil
    (tramp-flush-file-properties v (file-name-directory localname))
    (tramp-flush-directory-properties 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-properties v (file-name-directory localname))
    (tramp-flush-file-properties 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 (expand-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)
	    (delete-dups
	     (append
	      ;; In older Android versions, "." and ".." are not
	      ;; included.  In newer versions (toybox, since Android
	      ;; 6) they are.  We fix this by `delete-dups'.
	      '("." "..")
	      (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 tramp-file-missing
       "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)
	;; "adb pull ..." does not always return an error code.
	(when (or (tramp-adb-execute-adb-command
		   v "pull" (tramp-compat-file-name-unquote localname) tmpfile)
		  (not (file-exists-p tmpfile)))
	  (ignore-errors (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) (string-to-number "0400" 8))))
      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 mustbenew)
  "Like `write-region' for Tramp files."
  (setq filename (expand-file-name filename))
  (with-parsed-tramp-file-name filename nil
    (when (and mustbenew (file-exists-p filename)
	       (or (eq mustbenew 'excl)
		   (not
		    (y-or-n-p
		     (format "File %s exists; overwrite anyway? " filename)))))
      (tramp-error v 'file-already-exists filename))

    ;; We must also flush the cache of the directory, because
    ;; `file-attributes' reads the values from there.
    (tramp-flush-file-properties v (file-name-directory localname))
    (tramp-flush-file-properties 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) (string-to-number "0600" 8))))
      (tramp-run-real-handler
       'write-region (list start end tmpfile append 'no-message lockname))
      (with-tramp-progress-reporter
        v 3 (format-message
             "Moving tmp file `%s' to `%s'" tmpfile filename)
	(unwind-protect
	    (when (tramp-adb-execute-adb-command
		   v "push" tmpfile (tramp-compat-file-name-unquote localname))
	      (tramp-error v 'file-error "Cannot write: `%s'" filename))
	  (delete-file tmpfile)))

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

      ;; Set file modification time.
      (when (or (eq visit t) (stringp visit))
	(set-visited-file-modtime
	 (tramp-compat-file-attribute-modification-time
	  (file-attributes filename))))

      ;; The end.
      (when (and (null noninteractive)
		 (or (eq visit t) (null visit) (stringp visit)))
	(tramp-message v 0 "Wrote %s" filename))
      (run-hooks 'tramp-handle-write-region-hook))))

(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-properties v (file-name-directory localname))
    (tramp-flush-file-properties v localname)
    (tramp-adb-send-command-and-check v (format "chmod %o %s" 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-properties v (file-name-directory localname))
    (tramp-flush-file-properties 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)
      (copy-directory filename newname keep-date t)

    (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 "Copying %s to %s" filename newname)

	  (if (and t1 t2 (tramp-equal-remote filename newname))
	      (let ((l1 (file-remote-p filename 'localname))
		    (l2 (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-properties v (file-name-directory l2))
		(tramp-flush-file-properties v l2)
		;; Short track.
		(tramp-adb-barf-unless-okay
		 v (format
		    "cp -f %s %s"
		    (tramp-shell-quote-argument l1)
		    (tramp-shell-quote-argument l2))
		 "Error 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 (and (file-directory-p newname)
			   (tramp-compat-directory-name-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-properties
		   v (file-name-directory localname))
		  (tramp-flush-file-properties v localname)
		  (when (tramp-adb-execute-adb-command
			 v "push"
			 (tramp-compat-file-name-unquote filename)
			 (tramp-compat-file-name-unquote localname))
		    (tramp-error
		     v 'file-error
		     "Cannot copy `%s' `%s'" filename newname)))))))))

    ;; KEEP-DATE handling.
    (when keep-date
      (set-file-times
       newname
       (tramp-compat-file-attribute-modification-time
	(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))

  (if (file-directory-p filename)
      (progn
	(copy-directory filename newname t t)
	(delete-directory filename 'recursive))

    (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 (file-remote-p filename 'localname))
		    (l2 (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-properties v (file-name-directory l1))
		(tramp-flush-file-properties v l1)
		(tramp-flush-file-properties v (file-name-directory l2))
		(tramp-flush-file-properties v l2)
		;; Short track.
		(tramp-adb-barf-unless-okay
		 v (format
		    "mv -f %s %s"
		    (tramp-shell-quote-argument l1)
		    (tramp-shell-quote-argument l2))
		 "Error renaming %s to %s" filename newname))

	    ;; Rename by copy.
	    (copy-file
	     filename newname ok-if-already-exists 'keep-time 'preserve-uid-gid)
	    (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 v 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 v 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
		  (if (tramp-adb-send-command-and-check
		       v
		       (format "(cd %s; %s)"
			       (tramp-shell-quote-argument localname) command))
		      ;; Set return status accordingly.
		      0 1))
	    ;; We should add the output anyway.
	    (when outbuf
	      (with-current-buffer outbuf
		(insert-buffer-substring (tramp-get-connection-buffer v)))
	      (when (and display (get-buffer-window outbuf t)) (redisplay))))
	;; 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))

      (unless process-file-side-effects
        (tramp-flush-directory-properties 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-compat-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)))
	    (display-message-or-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* ((buffer
	    (if buffer
		(get-buffer-create buffer)
	      ;; BUFFER can be nil.  We use a temporary buffer.
	      (generate-new-buffer tramp-temp-buffer-name)))
	   (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)
	   ;; We do not want to run timers.
	   timer-list timer-idle-list)

      (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
		      (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-flush-connection-property v "process-name")
	  (tramp-flush-connection-property v "process-buffer"))))))

(defun tramp-adb-get-device (vec)
  "Return full host name from VEC to be used in shell execution.
E.g. a host name \"192.168.1.1#5555\" returns \"192.168.1.1:5555\"
     a host name \"R38273882DE\" returns \"R38273882DE\"."
  ;; Sometimes this is called before there is a connection process
  ;; yet.  In order to work with the connection cache, we flush all
  ;; unwanted entries first.
  (tramp-flush-connection-properties nil)
  (with-tramp-connection-property (tramp-get-connection-process vec) "device"
    (let* ((host (tramp-file-name-host vec))
	   (port (tramp-file-name-port-or-default vec))
	   (devices (mapcar 'cadr (tramp-adb-parse-device-names nil))))
      (replace-regexp-in-string
       tramp-prefix-port-format ":"
       (cond ((member host devices) host)
	     ;; This is the case when the host is connected to the default port.
	     ((member (format "%s%s%d" host tramp-prefix-port-format port)
		      devices)
	      (format "%s:%d" host port))
	     ;; An empty host name shall be mapped as well, when there
	     ;; is exactly one entry in `devices'.
	     ((and (zerop (length host)) (= (length devices) 1))
	      (car devices))
	     ;; Try to connect device.
	     ((and tramp-adb-connect-if-not-connected
		   (not (zerop (length host)))
		   (not (tramp-adb-execute-adb-command
                         vec "connect"
                         (replace-regexp-in-string
                          tramp-prefix-port-format ":" host))))
	      ;; When new device connected, running other adb command (e.g.
	      ;; adb shell) immediately will fail.  To get around this
	      ;; problem, add sleep 0.1 second here.
	      (sleep-for 0.1)
	      host)
	     (t (tramp-error
		 vec 'file-error "Could not find device %s" host)))))))

(defun tramp-adb-execute-adb-command (vec &rest args)
  "Returns nil on success error-output on failure."
  (when (and (> (length (tramp-file-name-host vec)) 0)
	     ;; The -s switch is only available for ADB device commands.
	     (not (member (car args) '("connect" "disconnect"))))
    (setq args (append (list "-s" (tramp-adb-get-device vec)) args)))
  (with-temp-buffer
    (prog1
	(unless
	    (zerop
	     (apply 'tramp-call-process vec 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 check its exit status.
Sends `echo $?' along with the COMMAND for checking the exit
status.  If COMMAND is nil, just sends `echo $?'.  Returns nil if
the exit status is not equal 0, and t otherwise."
  (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-get-connection-property proc "prompt" 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-get-connection-property proc "prompt" tramp-adb-prompt)
		(point-at-eol) t)
           (forward-line 1)
           (delete-region (point-min) (point)))
	  (goto-char (point-max))
	  (re-search-backward
	   (tramp-get-connection-property proc "prompt" 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-get-connection-property proc "prompt" tramp-adb-prompt)
	   timeout)
	(tramp-error
	 proc 'file-error
	 "[[Remote prompt `%s' not found]]"
	 (tramp-get-connection-property proc "prompt" 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."
  (let* ((buf (tramp-get-connection-buffer vec))
	 (p (get-buffer-process buf))
	 (host (tramp-file-name-host vec))
	 (user (tramp-file-name-user vec))
         (device (tramp-adb-get-device vec)))

    ;; 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 (process-live-p p)
      (save-match-data
	(when (and p (processp p)) (delete-process p))
	(if (zerop (length device))
	    (tramp-error vec 'file-error "Device %s not connected" host))
	(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" device "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)))
		 (prompt (md5 (concat (prin1-to-string process-environment)
				      (current-time-string)))))
	    (tramp-message
	     vec 6 "%s" (mapconcat 'identity (process-command p) " "))
	    ;; Wait for initial prompt.
	    (tramp-adb-wait-for-output p 30)
	    (unless (process-live-p p)
	      (tramp-error  vec 'file-error "Terminated!"))
	    (process-put p 'vector vec)
	    (process-put p 'adjust-window-size-function 'ignore)
	    (set-process-query-on-exit-flag p nil)

	    ;; Change prompt.
	    (tramp-set-connection-property
	     p "prompt" (regexp-quote (format "///%s#$" prompt)))
	    (tramp-adb-send-command
	     vec (format "PS1=\"///\"\"%s\"\"#$\"" prompt))

	    ;; 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-flush-file-property vec "" "su-command-p")
		(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))

	    ;; Set connection-local variables.
	    (tramp-set-connection-local-variables vec)

	    ;; Mark it as connected.
	    (tramp-set-connection-property p "connected" t)))))))

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

(provide 'tramp-adb)

;;; tramp-adb.el ends here