1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
;;; url-cache.el --- Uniform Resource Locator retrieval tool
;; Copyright (C) 1996, 1997, 1998, 1999, 2004,
;; 2005, 2006, 2007 Free Software Foundation, Inc.
;; Keywords: comm, data, processes, hypermedia
;; 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, 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; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Code:
(require 'url-parse)
(require 'url-util)
(require 'url) ;E.g. for url-configuration-directory.
(defcustom url-cache-directory
(expand-file-name "cache" url-configuration-directory)
"*The directory where cache files should be stored."
:type 'directory
:group 'url-file)
;; Cache manager
(defun url-cache-file-writable-p (file)
"Follows the documentation of `file-writable-p', unlike `file-writable-p'."
(and (file-writable-p file)
(if (file-exists-p file)
(not (file-directory-p file))
(file-directory-p (file-name-directory file)))))
(defun url-cache-prepare (file)
"Makes it possible to cache data in FILE.
Creates any necessary parent directories, deleting any non-directory files
that would stop this. Returns nil if parent directories can not be
created. If FILE already exists as a non-directory, it changes
permissions of FILE or deletes FILE to make it possible to write a new
version of FILE. Returns nil if this can not be done. Returns nil if
FILE already exists as a directory. Otherwise, returns t, indicating that
FILE can be created or overwritten."
(cond
((url-cache-file-writable-p file)
t)
((file-directory-p file)
nil)
(t
(condition-case ()
(or (make-directory (file-name-directory file) t) t)
(error nil)))))
;;;###autoload
(defun url-store-in-cache (&optional buff)
"Store buffer BUFF in the cache."
(if (not (and buff (get-buffer buff)))
nil
(save-current-buffer
(and buff (set-buffer buff))
(let* ((fname (url-cache-create-filename (url-view-url t))))
(if (url-cache-prepare fname)
(let ((coding-system-for-write 'binary))
(write-region (point-min) (point-max) fname nil 5)))))))
;;;###autoload
(defun url-is-cached (url)
"Return non-nil if the URL is cached."
(let* ((fname (url-cache-create-filename url))
(attribs (file-attributes fname)))
(and fname ; got a filename
(file-exists-p fname) ; file exists
(not (eq (nth 0 attribs) t)) ; Its not a directory
(nth 5 attribs)))) ; Can get last mod-time
(defun url-cache-create-filename-human-readable (url)
"Return a filename in the local cache for URL"
(if url
(let* ((url (if (vectorp url) (url-recreate-url url) url))
(urlobj (url-generic-parse-url url))
(protocol (url-type urlobj))
(hostname (url-host urlobj))
(host-components
(cons
(user-real-login-name)
(cons (or protocol "file")
(reverse (split-string (or hostname "localhost")
(eval-when-compile
(regexp-quote ".")))))))
(fname (url-filename urlobj)))
(if (and fname (/= (length fname) 0) (= (aref fname 0) ?/))
(setq fname (substring fname 1 nil)))
(if fname
(let ((slash nil))
(setq fname
(mapconcat
(function
(lambda (x)
(cond
((and (= ?/ x) slash)
(setq slash nil)
"%2F")
((= ?/ x)
(setq slash t)
"/")
(t
(setq slash nil)
(char-to-string x))))) fname ""))))
(setq fname (and fname
(mapconcat
(function (lambda (x)
(if (= x ?~) "" (char-to-string x))))
fname ""))
fname (cond
((null fname) nil)
((or (string= "" fname) (string= "/" fname))
url-directory-index-file)
((= (string-to-char fname) ?/)
(if (string= (substring fname -1 nil) "/")
(concat fname url-directory-index-file)
(substring fname 1 nil)))
(t
(if (string= (substring fname -1 nil) "/")
(concat fname url-directory-index-file)
fname))))
(and fname
(expand-file-name fname
(expand-file-name
(mapconcat 'identity host-components "/")
url-cache-directory))))))
(defun url-cache-create-filename-using-md5 (url)
"Create a cached filename using MD5.
Very fast if you have an `md5' primitive function, suitably fast otherwise."
(require 'md5)
(if url
(let* ((url (if (vectorp url) (url-recreate-url url) url))
(checksum (md5 url))
(urlobj (url-generic-parse-url url))
(protocol (url-type urlobj))
(hostname (url-host urlobj))
(host-components
(cons
(user-real-login-name)
(cons (or protocol "file")
(nreverse
(delq nil
(split-string (or hostname "localhost")
(eval-when-compile
(regexp-quote "."))))))))
(fname (url-filename urlobj)))
(and fname
(expand-file-name checksum
(expand-file-name
(mapconcat 'identity host-components "/")
url-cache-directory))))))
(defcustom url-cache-creation-function 'url-cache-create-filename-using-md5
"*What function to use to create a cached filename."
:type '(choice (const :tag "MD5 of filename (low collision rate)"
:value url-cache-create-filename-using-md5)
(const :tag "Human readable filenames (higher collision rate)"
:value url-cache-create-filename-human-readable)
(function :tag "Other"))
:group 'url-cache)
(defun url-cache-create-filename (url)
(funcall url-cache-creation-function url))
;;;###autoload
(defun url-cache-extract (fnam)
"Extract FNAM from the local disk cache"
(erase-buffer)
(insert-file-contents-literally fnam))
;;;###autoload
(defun url-cache-expired (url mod)
"Return t iff a cached file has expired."
(let* ((urlobj (if (vectorp url) url (url-generic-parse-url url)))
(type (url-type urlobj)))
(cond
(url-standalone-mode
(not (file-exists-p (url-cache-create-filename url))))
((string= type "http")
t)
((member type '("file" "ftp"))
(if (or (equal mod '(0 0)) (not mod))
t
(or (> (nth 0 mod) (nth 0 (current-time)))
(> (nth 1 mod) (nth 1 (current-time))))))
(t nil))))
(provide 'url-cache)
;; arch-tag: 95b050a6-8e81-4f23-8e63-191b9d1d657c
;;; url-cache.el ends here
|
