4401a06f0f4d5e67ae471b61e6eedcc3d403db1d
[squirrelmail.git] / functions / plugin.php
1 <?php
2
3 /**
4 * plugin.php
5 *
6 * This file provides the framework for a plugin architecture.
7 *
8 * Documentation on how to write plugins might show up some time.
9 *
10 * @copyright &copy; 1999-2006 The SquirrelMail Project Team
11 * @license http://opensource.org/licenses/gpl-license.php GNU Public License
12 * @version $Id$
13 * @package squirrelmail
14 */
15
16 /**
17 * This function adds a plugin.
18 * @param string $name Internal plugin name (ie. delete_move_next)
19 * @return void
20 */
21 function use_plugin ($name) {
22 if (file_exists(SM_PATH . "plugins/$name/setup.php")) {
23 include_once(SM_PATH . "plugins/$name/setup.php");
24 $function = "squirrelmail_plugin_init_$name";
25 if (function_exists($function)) {
26 $function();
27 }
28 }
29 }
30
31 /**
32 * This function executes a hook.
33 * @param string $name Name of hook to fire
34 * @return mixed $data
35 */
36 function do_hook ($name) {
37 global $squirrelmail_plugin_hooks, $currentHookName;
38 $data = func_get_args();
39 $currentHookName = $name;
40
41 if (isset($squirrelmail_plugin_hooks[$name])
42 && is_array($squirrelmail_plugin_hooks[$name])) {
43 foreach ($squirrelmail_plugin_hooks[$name] as $function) {
44 /* Add something to set correct gettext domain for plugin. */
45 if (function_exists($function)) {
46 $function($data);
47 }
48 }
49 }
50
51 $currentHookName = '';
52
53 /* Variable-length argument lists have a slight problem when */
54 /* passing values by reference. Pity. This is a workaround. */
55 return $data;
56 }
57
58 /**
59 * This function executes a hook and allows for parameters to be passed.
60 *
61 * @param string name the name of the hook
62 * @param mixed param the parameters to pass to the hook function
63 * @return mixed the return value of the hook function
64 */
65 function do_hook_function($name,$parm=NULL) {
66 global $squirrelmail_plugin_hooks, $currentHookName;
67 $ret = '';
68 $currentHookName = $name;
69
70 if (isset($squirrelmail_plugin_hooks[$name])
71 && is_array($squirrelmail_plugin_hooks[$name])) {
72 foreach ($squirrelmail_plugin_hooks[$name] as $function) {
73 /* Add something to set correct gettext domain for plugin. */
74 if (function_exists($function)) {
75 $ret = $function($parm);
76 }
77 }
78 }
79
80 $currentHookName = '';
81
82 /* Variable-length argument lists have a slight problem when */
83 /* passing values by reference. Pity. This is a workaround. */
84 return $ret;
85 }
86
87 /**
88 * This function executes a hook, concatenating the results of each
89 * plugin that has the hook defined.
90 *
91 * @param string name the name of the hook
92 * @param mixed parm optional hook function parameters
93 * @return string a concatenation of the results of each plugin function
94 */
95 function concat_hook_function($name,$parm=NULL) {
96 global $squirrelmail_plugin_hooks, $currentHookName;
97 $ret = '';
98 $currentHookName = $name;
99
100 if (isset($squirrelmail_plugin_hooks[$name])
101 && is_array($squirrelmail_plugin_hooks[$name])) {
102 foreach ($squirrelmail_plugin_hooks[$name] as $function) {
103 /* Concatenate results from hook. */
104 if (function_exists($function)) {
105 $ret .= $function($parm);
106 }
107 }
108 }
109
110 $currentHookName = '';
111
112 /* Variable-length argument lists have a slight problem when */
113 /* passing values by reference. Pity. This is a workaround. */
114 return $ret;
115 }
116
117 /**
118 * This function is used for hooks which are to return true or
119 * false. If $priority is > 0, any one or more trues will override
120 * any falses. If $priority < 0, then one or more falses will
121 * override any trues.
122 * Priority 0 means majority rules. Ties will be broken with $tie
123 *
124 * @param string name the hook name
125 * @param mixed parm the parameters for the hook function
126 * @param int priority
127 * @param bool tie
128 * @return bool the result of the function
129 */
130 function boolean_hook_function($name,$parm=NULL,$priority=0,$tie=false) {
131 global $squirrelmail_plugin_hooks, $currentHookName;
132 $yea = 0;
133 $nay = 0;
134 $ret = $tie;
135
136 if (isset($squirrelmail_plugin_hooks[$name]) &&
137 is_array($squirrelmail_plugin_hooks[$name])) {
138
139 /* Loop over the plugins that registered the hook */
140 $currentHookName = $name;
141 foreach ($squirrelmail_plugin_hooks[$name] as $function) {
142 if (function_exists($function)) {
143 $ret = $function($parm);
144 if ($ret) {
145 $yea++;
146 } else {
147 $nay++;
148 }
149 }
150 }
151 $currentHookName = '';
152
153 /* Examine the aftermath and assign the return value appropriately */
154 if (($priority > 0) && ($yea)) {
155 $ret = true;
156 } elseif (($priority < 0) && ($nay)) {
157 $ret = false;
158 } elseif ($yea > $nay) {
159 $ret = true;
160 } elseif ($nay > $yea) {
161 $ret = false;
162 } else {
163 // There's a tie, no action needed.
164 }
165 return $ret;
166 }
167 // If the code gets here, there was a problem - no hooks, etc.
168 return NULL;
169 }
170
171 /**
172 * This function checks whether the user's USER_AGENT is known to
173 * be broken. If so, returns true and the plugin is invisible to the
174 * offending browser.
175 * *** THIS IS A TEST FOR JAVASCRIPT SUPPORT ***
176 * FIXME: This function needs to have its name changed!
177 *
178 * @return bool whether this browser properly supports JavaScript
179 * @deprecated use checkForJavascript() since 1.5.1
180 */
181 function soupNazi(){
182 return !checkForJavascript();
183 }
184
185 /**
186 * Check if plugin is enabled
187 * @param string $plugin_name plugin name
188 * @since 1.5.1
189 * @return boolean
190 */
191 function is_plugin_enabled($plugin_name) {
192 global $plugins;
193
194 /**
195 * check if variable is empty. if var is not set, php empty
196 * returns true without error notice.
197 *
198 * then check if it is an array
199 */
200 if (empty($plugins) || ! is_array($plugins))
201 return false;
202
203 if ( in_array($plugin_name,$plugins) ) {
204 return true;
205 } else {
206 return false;
207 }
208 }
209
210 /**
211 * Check a plugin's version.
212 *
213 * Returns TRUE if the given plugin is installed,
214 * activated and is at minimum version $a.$b.$c.
215 * If any one of those conditions fails, FALSE
216 * will be returned (careful of plugins that are
217 * sufficiently versioned but are not activated).
218 *
219 * By overriding the default value of $force_inclusion,
220 * this function will attempt to grab versioning
221 * information from the given plugin even if it
222 * is not activated (plugin still has to be
223 * unpackaged and set in place in the plugins
224 * directory). Use with care - some plugins
225 * might break SquirrelMail when this is used.
226 *
227 * Note that this function assumes plugin
228 * versioning is consistently applied in the same
229 * fashion that SquirrelMail versions are, with the
230 * exception that an applicable SquirrelMail
231 * version may be appended to the version number
232 * (which will be ignored herein). That is, plugin
233 * version number schemes are expected in the following
234 * format: 1.2.3, or 1.2.3-1.4.0.
235 *
236 * Any characters after the third number are discarded,
237 * so formats such as the following will also work,
238 * although extra information about beta versions can
239 * possibly confuse the desired results of the version
240 * check: 1.2.3-beta4, 1.2.3.RC2, and so forth.
241 *
242 * @since 1.5.2
243 *
244 * @param string plugin_name name of the plugin to
245 * check; must precisely
246 * match the plugin
247 * directory name
248 * @param int a major version number
249 * @param int b minor version number
250 * @param int c release number
251 * @param bool force_inclusion try to get version info
252 * for plugins not activated?
253 * (default FALSE)
254 *
255 * @return bool
256 *
257 */
258 function check_plugin_version($plugin_name,
259 $a = 0, $b = 0, $c = 0,
260 $force_inclusion = FALSE)
261 {
262
263 $info_function = $plugin_name . '_info';
264 $version_function = $plugin_name . '_version';
265 $plugin_info = array();
266 $plugin_version = FALSE;
267
268
269 // first attempt to find the plugin info function, wherein
270 // the plugin version should be available
271 //
272 if (function_exists($info_function))
273 $plugin_info = $info_function();
274 else if ($force_inclusion
275 && file_exists(SM_PATH . 'plugins/' . $plugin_name . '/setup.php'))
276 {
277 include_once(SM_PATH . 'plugins/' . $plugin_name . '/setup.php');
278 if (function_exists($info_function))
279 $plugin_info = $info_function();
280 }
281 if (!empty($plugin_info['version']))
282 $plugin_version = $plugin_info['version'];
283
284
285 // otherwise, look for older version function
286 //
287 if (!$plugin_version && function_exists($version_function))
288 $plugin_version = $version_function();
289
290
291 if (!$plugin_version) return FALSE;
292
293
294 // now massage version number into something we understand
295 //
296 $plugin_version = trim(preg_replace(array('/[^0-9.]+.*$/', '/[^0-9.]/'),
297 '', $plugin_version),
298 '.');
299 $plugin_version = explode('.', $plugin_version);
300 if (!isset($plugin_version[0])) $plugin_version[0] = 0;
301 if (!isset($plugin_version[1])) $plugin_version[1] = 0;
302 if (!isset($plugin_version[2])) $plugin_version[2] = 0;
303 // sm_print_r($plugin_version);
304
305
306 // now test the version number
307 //
308 if ($plugin_version[0] < $a ||
309 ($plugin_version[0] == $a && $plugin_version[1] < $b) ||
310 ($plugin_version[0] == $a && $plugin_version[1] == $b && $plugin_version[2] < $c))
311 return FALSE;
312
313
314 return TRUE;
315
316 }
317