rename struct filter_chain_info to filter_chain
[paraslash.git] / filter_chain.c
1 /*
2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file filter_chain.c common helper functions for filter input/output */
20
21 #include "para.h"
22 #include "list.h"
23 #include "filter.h"
24 #include "error.h"
25 #include "string.h"
26
27 DEFINE_FILTER_ARRAY(filters);
28
29 /**
30 * call the init function of each supported filter
31 *
32 * \param all_filters the array of all supported filters
33 * \sa filter::init
34 */
35 void filter_init(struct filter *all_filters)
36 {
37 struct filter *f;
38
39 for (f = all_filters; f->name; f++)
40 f->init(f);
41 }
42
43 /**
44 * close and destroy a filter callback
45 *
46 * \param fcb the filter callback to close
47 *
48 * This removes \a fcb from the list of filter callbacks and calls
49 * the close callback associated with \a fcb.
50 */
51 static void close_filter_callback(struct filter_callback *fcb)
52 {
53 PARA_NOTICE_LOG("closing filter_callback %p, data: %p\n", fcb, fcb->data);
54 list_del(&fcb->node);
55 fcb->close(fcb);
56 }
57
58 /**
59 * close all callbacks of a filter node
60 *
61 * \param fn the filter node which contains the filter callbacks to be closed
62 *
63 * Call close_filter_callback() for each entry in the filter callback list
64 * of \a fn.
65 */
66 static void close_callbacks(struct filter_node *fn)
67 {
68 struct filter_callback *fcb, *tmp;
69
70 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node)
71 close_filter_callback(fcb);
72 }
73
74 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
75 char *outbuf, size_t outlen)
76 {
77 struct filter_callback *fcb, *tmp;
78 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
79 int ret;
80 if (inlen && fcb->input_cb) {
81 ret = fcb->input_cb(inbuf, inlen, fcb);
82 if (ret < 0) {
83 close_filter_callback(fcb);
84 continue;
85 }
86 }
87 if (!outlen || !fcb->output_cb)
88 continue;
89 ret = fcb->output_cb(outbuf, outlen, fcb);
90 if (ret < 0)
91 close_filter_callback(fcb);
92 }
93 }
94
95 /**
96 * call the convert function of each filter
97 *
98 * \param fc the filter chain containing the list of filter nodes.
99 *
100 * This is the core function of the filter subsystem. It loops over the list of
101 * filter nodes determined by \a fc and calls the filter's convert function if
102 * there is input available for the filter node in question. If the convert
103 * function consumed some or all of its input data, all registered input
104 * callbacks are called. Similarly, if a convert function produced output, all
105 * registerd output callbacks get called.
106 *
107 * \return The sum of output bytes produced by the convert functions on success,
108 * negative return value on errors.
109 *
110 * \sa filter_node, filter#convert, filter_callback
111 */
112 int filter_io(struct filter_chain *fc)
113 {
114 struct filter_node *fn;
115 char *ib;
116 size_t *loaded;
117 int conv, conv_total = 0;
118 again:
119 ib = fc->inbuf;
120 loaded = fc->in_loaded;
121 conv = 0;
122 list_for_each_entry(fn, &fc->filters, node) {
123 int ret;
124 if (*loaded && fn->loaded < fn->bufsize) {
125 size_t old_fn_loaded = fn->loaded;
126 PARA_DEBUG_LOG("fc %p loaded: %zd, calling %s convert\n",
127 fc, *loaded, fn->filter->name);
128 ret = fn->filter->convert(ib, *loaded, fn);
129 if (ret < 0) {
130 if (!fc->error)
131 fc->error = -ret;
132 return ret;
133 }
134 call_callbacks(fn, ib, ret, fn->buf + old_fn_loaded,
135 fn->loaded - old_fn_loaded);
136 *loaded -= ret;
137 conv += ret;
138 if (*loaded && ret) {
139 PARA_DEBUG_LOG("moving %zd bytes in input buffer for %s filter\n",
140 *loaded, fn->filter->name);
141 memmove(ib, ib + ret, *loaded);
142 }
143 }
144 ib = fn->buf;
145 loaded = &fn->loaded;
146 }
147 // PARA_DEBUG_LOG("loaded: %d\n", *loaded);
148 conv_total += conv;
149 if (conv)
150 goto again;
151 return conv_total;
152 }
153
154 /**
155 * close all filter nodes and its callbacks
156 *
157 * \param fc the filter chain to close
158 *
159 * For each filter node determined by \a fc, call the close function of each
160 * registered filter callback as well as the close function of the
161 * corresponding filter. Free all resources and destroy all callback lists and
162 * the filter node list.
163 *
164 * \sa filter::close, filter_callback::close
165 */
166 void close_filters(struct filter_chain *fc)
167 {
168 struct filter_node *fn, *tmp;
169
170 if (!fc)
171 return;
172 PARA_DEBUG_LOG("closing filter chain %p\n", fc);
173 list_for_each_entry_safe(fn, tmp, &fc->filters, node) {
174 PARA_NOTICE_LOG("closing %s filter callbacks (fc %p, fn %p)\n", fn->filter->name, fc, fn);
175 close_callbacks(fn);
176 PARA_NOTICE_LOG("closing %s filter (fc %p, fn %p)\n", fn->filter->name, fc, fn);
177 fn->filter->close(fn);
178 list_del(&fn->node);
179 free(fn);
180 }
181 }
182
183 /*
184 * If the filter has a command line parser and options is not NULL, run it.
185 * Returns filter_num on success, negative on errors
186 */
187 static int parse_filter_args(int filter_num, char *options, void **conf)
188 {
189 struct filter *f = &filters[filter_num];
190 int i, argc = 2;
191 char **argv;
192
193 // PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
194 // options? options : "(none)", f->parse_config);
195 if (!f->parse_config)
196 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
197 // PARA_DEBUG_LOG("options: %s\n", options);
198 argc = split_args(options, &argv, " \t");
199 // PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
200 for (i = argc - 1; i >= 0; i--)
201 argv[i + 1] = argv[i];
202 argv[0] = para_strdup(f->name);
203 argc += 1;
204 *conf = f->parse_config(argc, argv);
205 return *conf? filter_num : -E_BAD_FILTER_OPTIONS;
206 }
207
208 /**
209 * check the filter command line options
210 *
211 * \param fa the command line options
212 * \param conf points to the filter configuration upon successful return
213 *
214 * Check if \a fa starts with a the name of a supported filter, followed by
215 * a colon. If yes, call the command line parser of that filter.
216 *
217 * \return On success, the number of the filter is returned and \a conf
218 * is initialized to point to the filter configuration determined by \a fa.
219 * On errors, a negative value is returned.
220 *
221 * Note: If \a fa specifies a filter that has no command line parser success is
222 * returned, and \a conf is initialized to \p NULL.
223 *
224 * \sa filter::parse_config
225 */
226 int check_filter_arg(char *fa, void **conf)
227 {
228 int j;
229
230 *conf = NULL;
231 // PARA_DEBUG_LOG("arg: %s\n", fa);
232 for (j = 0; filters[j].name; j++) {
233 const char *name = filters[j].name;
234 size_t len = strlen(name);
235 char c;
236 if (strlen(fa) < len)
237 continue;
238 if (strncmp(name, fa, len))
239 continue;
240 c = fa[len];
241 if (c && c != ' ')
242 continue;
243 if (c && !filters[j].parse_config)
244 return -E_BAD_FILTER_OPTIONS;
245 return parse_filter_args(j, c? fa + len + 1 :
246 fa + strlen(fa), conf);
247 }
248 return -E_UNSUPPORTED_FILTER;
249 }
250