lisp/net/tramp-cache.el

   1 ;;; tramp-cache.el --- file information caching for Tramp
   2
   3 ;; Copyright (C) 2000, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   4
   5 ;; Author: Daniel Pittman <daniel@inanna.danann.net>
   6 ;;         Michael Albinus <michael.albinus@gmx.de>
   7 ;; Keywords: comm, processes
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 3, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, see
  23 ;; <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; An implementation of information caching for remote files.
  28
  29 ;; Each connection, identified by a vector [method user host
  30 ;; localname] or by a process, has a unique cache. We distinguish 3
  31 ;; kind of caches, depending on the key:
  32 ;;
  33 ;; - localname is NIL.  This are reusable properties.  Examples:
  34 ;;   "remote-shell" identifies the POSIX shell to be called on the
  35 ;;   remote host, or "perl" is the command to be called on the remote
  36 ;;   host, when starting a Perl script.  These properties are saved in
  37 ;;   the file `tramp-persistency-file-name'.
  38 ;;
  39 ;; - localname is a string.  This are temporary properties, which are
  40 ;;   related to the file localname is referring to.  Examples:
  41 ;;   "file-exists-p" is t or nile, depending on the file existence, or
  42 ;;   "file-attributes" caches the result of the function
  43 ;;  `file-attributes'.
  44 ;;
  45 ;; - The key is a process.  This are temporary properties related to
  46 ;;   an open connection.  Examples: "scripts" keeps shell script
  47 ;;   definitions already sent to the remote shell, "last-cmd-time" is
  48 ;;   the time stamp a command has been sent to the remote process.
  49
  50 ;;; Code:
  51
  52 ;; Pacify byte-compiler.
  53 (eval-when-compile
  54   (require 'cl)
  55   (autoload 'tramp-message "tramp")
  56   (autoload 'tramp-tramp-file-p "tramp")
  57   ;; We cannot autoload macro `with-parsed-tramp-file-name', it
  58   ;; results in problems of byte-compiled code.
  59   (autoload 'tramp-dissect-file-name "tramp")
  60   (autoload 'tramp-file-name-method "tramp")
  61   (autoload 'tramp-file-name-user "tramp")
  62   (autoload 'tramp-file-name-host "tramp")
  63   (autoload 'tramp-file-name-localname "tramp")
  64   (autoload 'time-stamp-string "time-stamp"))
  65
  66 ;;; -- Cache --
  67
  68 (defvar tramp-cache-data (make-hash-table :test 'equal)
  69   "Hash table for remote files properties.")
  70
  71 (defcustom tramp-persistency-file-name
  72   (cond
  73    ;; GNU Emacs.
  74    ((and (boundp 'user-emacs-directory)
  75          (stringp (symbol-value 'user-emacs-directory))
  76          (file-directory-p (symbol-value 'user-emacs-directory)))
  77     (expand-file-name "tramp" (symbol-value 'user-emacs-directory)))
  78    ((and (not (featurep 'xemacs)) (file-directory-p "~/.emacs.d/"))
  79     "~/.emacs.d/tramp")
  80    ;; XEmacs.
  81    ((and (boundp 'user-init-directory)
  82          (stringp (symbol-value 'user-init-directory))
  83          (file-directory-p (symbol-value 'user-init-directory)))
  84     (expand-file-name "tramp" (symbol-value 'user-init-directory)))
  85    ((and (featurep 'xemacs) (file-directory-p "~/.xemacs/"))
  86     "~/.xemacs/tramp")
  87    ;; For users without `~/.emacs.d/' or `~/.xemacs/'.
  88    (t "~/.tramp"))
  89   "File which keeps connection history for Tramp connections."
  90   :group 'tramp
  91   :type 'file)
  92
  93 (defun tramp-get-file-property (vec file property default)
  94   "Get the PROPERTY of FILE from the cache context of VEC.
  95 Returns DEFAULT if not set."
  96   ;; Unify localname.
  97   (setq vec (copy-sequence vec))
  98   (aset vec 3 (directory-file-name file))
  99   (let* ((hash (or (gethash vec tramp-cache-data)
 100                    (puthash vec (make-hash-table :test 'equal)
 101                             tramp-cache-data)))
 102          (value (if (hash-table-p hash)
 103                     (gethash property hash default)
 104                   default)))
 105     (tramp-message vec 8 "%s %s %s" file property value)
 106     value))
 107
 108 (defun tramp-set-file-property (vec file property value)
 109   "Set the PROPERTY of FILE to VALUE, in the cache context of VEC.
 110 Returns VALUE."
 111   ;; Unify localname.
 112   (setq vec (copy-sequence vec))
 113   (aset vec 3 (directory-file-name file))
 114   (let ((hash (or (gethash vec tramp-cache-data)
 115                   (puthash vec (make-hash-table :test 'equal)
 116                            tramp-cache-data))))
 117     (puthash property value hash)
 118     (tramp-message vec 8 "%s %s %s" file property value)
 119     value))
 120
 121 (defun tramp-flush-file-property (vec file)
 122   "Remove all properties of FILE in the cache context of VEC."
 123   ;; Unify localname.
 124   (setq vec (copy-sequence vec))
 125   (aset vec 3 (directory-file-name file))
 126   (tramp-message vec 8 "%s" file)
 127   (remhash vec tramp-cache-data))
 128
 129 (defun tramp-flush-directory-property (vec directory)
 130   "Remove all properties of DIRECTORY in the cache context of VEC.
 131 Remove also properties of all files in subdirectories."
 132   (let ((directory (directory-file-name directory)))
 133   (tramp-message vec 8 "%s" directory)
 134     (maphash
 135      '(lambda (key value)
 136         (when (and (stringp key)
 137                    (string-match directory (tramp-file-name-localname key)))
 138           (remhash key tramp-cache-data)))
 139      tramp-cache-data)))
 140
 141 ;; Reverting or killing a buffer should also flush file properties.
 142 ;; They could have been changed outside Tramp.  In eshell, "ls" would
 143 ;; not show proper directory contents when a file has been copied or
 144 ;; deleted before.
 145 (defun tramp-flush-file-function ()
 146   "Flush all Tramp cache properties from buffer-file-name."
 147   (let ((bfn (if (stringp (buffer-file-name))
 148                  (buffer-file-name)
 149                default-directory)))
 150     (when (tramp-tramp-file-p bfn)
 151       (let* ((v (tramp-dissect-file-name bfn))
 152              (localname (tramp-file-name-localname v)))
 153         (tramp-flush-file-property v localname)))))
 154
 155 (add-hook 'before-revert-hook 'tramp-flush-file-function)
 156 (add-hook 'eshell-pre-command-hook 'tramp-flush-file-function)
 157 (add-hook 'kill-buffer-hook 'tramp-flush-file-function)
 158 (add-hook 'tramp-cache-unload-hook
 159           '(lambda ()
 160              (remove-hook 'before-revert-hook
 161                           'tramp-flush-file-function)
 162              (remove-hook 'eshell-pre-command-hook
 163                           'tramp-flush-file-function)
 164              (remove-hook 'kill-buffer-hook
 165                           'tramp-flush-file-function)))
 166
 167 ;;; -- Properties --
 168
 169 (defun tramp-get-connection-property (key property default)
 170   "Get the named PROPERTY for the connection.
 171 KEY identifies the connection, it is either a process or a vector.
 172 If the value is not set for the connection, returns DEFAULT."
 173   ;; Unify key by removing localname from vector.  Work with a copy in
 174   ;; order to avoid side effects.
 175   (when (vectorp key)
 176     (setq key (copy-sequence key))
 177     (aset key 3 nil))
 178   (let* ((hash (gethash key tramp-cache-data))
 179          (value (if (hash-table-p hash)
 180                    (gethash property hash default)
 181                  default)))
 182     (tramp-message key 7 "%s %s" property value)
 183     value))
 184
 185 (defun tramp-set-connection-property (key property value)
 186   "Set the named PROPERTY of a connection to VALUE.
 187 KEY identifies the connection, it is either a process or a vector.
 188 PROPERTY is set persistent when KEY is a vector."
 189   ;; Unify key by removing localname from vector.  Work with a copy in
 190   ;; order to avoid side effects.
 191   (when (vectorp key)
 192     (setq key (copy-sequence key))
 193     (aset key 3 nil))
 194   (let ((hash (or (gethash key tramp-cache-data)
 195                   (puthash key (make-hash-table :test 'equal)
 196                             tramp-cache-data))))
 197     (puthash property value hash)
 198     ;; This function is called also during initialization of
 199     ;; tramp-cache.el.  `tramp-message´ is not defined yet at this
 200     ;; time, so we ignore the corresponding error.
 201     (condition-case nil
 202         (tramp-message key 7 "%s %s" property value)
 203       (error nil))
 204     value))
 205
 206 (defun tramp-flush-connection-property (key)
 207   "Remove all properties identified by KEY.
 208 KEY identifies the connection, it is either a process or a vector."
 209   ;; Unify key by removing localname from vector.  Work with a copy in
 210   ;; order to avoid side effects.
 211   (when (vectorp key)
 212     (setq key (copy-sequence key))
 213     (aset key 3 nil))
 214   (remhash key tramp-cache-data))
 215
 216 (defun tramp-cache-print (table)
 217   "Print hash table TABLE."
 218   (when (hash-table-p table)
 219     (let (result)
 220       (maphash
 221        '(lambda (key value)
 222           (let ((tmp (format
 223                       "(%s %s)"
 224                       (if (processp key)
 225                           (prin1-to-string (prin1-to-string key))
 226                         (prin1-to-string key))
 227                       (if (hash-table-p value)
 228                           (tramp-cache-print value)
 229                         (if (bufferp value)
 230                             (prin1-to-string (prin1-to-string value))
 231                           (prin1-to-string value))))))
 232             (setq result (if result (concat result " " tmp) tmp))))
 233        table)
 234       result)))
 235
 236 (defun tramp-list-connections ()
 237   "Return a list of all known connection vectors according to `tramp-cache'."
 238     (let (result)
 239       (maphash
 240        '(lambda (key value)
 241           (when (and (vectorp key) (null (aref key 3)))
 242             (add-to-list 'result key)))
 243        tramp-cache-data)
 244       result))
 245
 246 (defun tramp-dump-connection-properties ()
 247   "Write persistent connection properties into file `tramp-persistency-file-name'."
 248   ;; We shouldn't fail, otherwise (X)Emacs might not be able to be closed.
 249   (condition-case nil
 250       (when (and (hash-table-p tramp-cache-data)
 251                  (not (zerop (hash-table-count tramp-cache-data)))
 252                  (stringp tramp-persistency-file-name))
 253         (let ((cache (copy-hash-table tramp-cache-data)))
 254           ;; Remove temporary data.
 255           (maphash
 256            '(lambda (key value)
 257               (if (and (vectorp key) (not (tramp-file-name-localname key)))
 258                   (progn
 259                     (remhash "process-name" value)
 260                     (remhash "process-buffer" value))
 261                 (remhash key cache)))
 262            cache)
 263           ;; Dump it.
 264           (with-temp-buffer
 265             (insert
 266              ";; -*- emacs-lisp -*-"
 267              ;; `time-stamp-string' might not exist in all (X)Emacs flavors.
 268              (condition-case nil
 269                  (progn
 270                    (format
 271                     " <%s %s>\n"
 272                     (time-stamp-string "%02y/%02m/%02d %02H:%02M:%02S")
 273                     tramp-persistency-file-name))
 274                (error "\n"))
 275              ";; Tramp connection history.  Don't change this file.\n"
 276              ";; You can delete it, forcing Tramp to reapply the checks.\n\n"
 277              (with-output-to-string
 278                (pp (read (format "(%s)" (tramp-cache-print cache))))))
 279             (write-region
 280              (point-min) (point-max) tramp-persistency-file-name))))
 281     (error nil)))
 282
 283 (add-hook 'kill-emacs-hook 'tramp-dump-connection-properties)
 284 (add-hook 'tramp-cache-unload-hook
 285           '(lambda ()
 286              (remove-hook 'kill-emacs-hook
 287                           'tramp-dump-connection-properties)))
 288
 289 (defun tramp-parse-connection-properties (method)
 290   "Return a list of (user host) tuples allowed to access for METHOD.
 291 This function is added always in `tramp-get-completion-function'
 292 for all methods.  Resulting data are derived from connection
 293 history."
 294   (let (res)
 295     (maphash
 296      '(lambda (key value)
 297         (if (and (vectorp key)
 298                  (string-equal method (tramp-file-name-method key))
 299                  (not (tramp-file-name-localname key)))
 300             (push (list (tramp-file-name-user key)
 301                         (tramp-file-name-host key))
 302                   res)))
 303      tramp-cache-data)
 304     res))
 305
 306 ;; Read persistent connection history.
 307 (when (and (stringp tramp-persistency-file-name)
 308            (zerop (hash-table-count tramp-cache-data)))
 309   (condition-case err
 310       (with-temp-buffer
 311         (insert-file-contents tramp-persistency-file-name)
 312         (let ((list (read (current-buffer)))
 313               element key item)
 314           (while (setq element (pop list))
 315             (setq key (pop element))
 316             (while (setq item (pop element))
 317               (tramp-set-connection-property key (pop item) (car item))))))
 318     (file-error
 319      ;; Most likely because the file doesn't exist yet.  No message.
 320      (clrhash tramp-cache-data))
 321     (error
 322      ;; File is corrupted.
 323      (message "Tramp persistency file '%s' is corrupted: %s"
 324               tramp-persistency-file-name (error-message-string err))
 325      (clrhash tramp-cache-data))))
 326
 327 (provide 'tramp-cache)
 328
 329 ;; arch-tag: ee1739b7-7628-408c-9b96-d11a74b05d26
 330 ;;; tramp-cache.el ends here