convert para_filter to the new scheduler
[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 "sched.h"
24 #include "fd.h"
25 #include "filter.h"
26 #include "error.h"
27 #include "string.h"
28
29 DEFINE_FILTER_ARRAY(filters);
30
31 /**
32 * call the init function of each supported filter
33 *
34 * \param all_filters the array of all supported filters
35 * \sa filter::init
36 */
37 void filter_init(struct filter *all_filters)
38 {
39 struct filter *f;
40
41 for (f = all_filters; f->name; f++)
42 f->init(f);
43 }
44
45 /**
46 * close and destroy a filter callback
47 *
48 * \param fcb the filter callback to close
49 *
50 * This removes \a fcb from the list of filter callbacks and calls
51 * the close callback associated with \a fcb.
52 */
53 static void close_filter_callback(struct filter_callback *fcb)
54 {
55 PARA_NOTICE_LOG("closing filter_callback %p, data: %p\n", fcb, fcb->data);
56 list_del(&fcb->node);
57 fcb->close(fcb);
58 }
59
60 /**
61 * close all callbacks of a filter node
62 *
63 * \param fn the filter node which contains the filter callbacks to be closed
64 *
65 * Call close_filter_callback() for each entry in the filter callback list
66 * of \a fn.
67 */
68 static void close_callbacks(struct filter_node *fn)
69 {
70 struct filter_callback *fcb, *tmp;
71
72 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node)
73 close_filter_callback(fcb);
74 }
75
76 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
77 char *outbuf, size_t outlen)
78 {
79 struct filter_callback *fcb, *tmp;
80 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
81 int ret;
82 if (inlen && fcb->input_cb) {
83 ret = fcb->input_cb(inbuf, inlen, fcb);
84 if (ret < 0) {
85 close_filter_callback(fcb);
86 continue;
87 }
88 }
89 if (!outlen || !fcb->output_cb)
90 continue;
91 ret = fcb->output_cb(outbuf, outlen, fcb);
92 if (ret < 0)
93 close_filter_callback(fcb);
94 }
95 }
96
97 /**
98 * call the convert function of each filter
99 *
100 * This is the core function of the filter subsystem. It loops over the list of
101 * filter nodes determined by \a t 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
108 * success, negative return value on errors (the return value is stored in
109 * t->ret).
110 *
111 * \sa filter_node, filter#convert, filter_callback
112 */
113 void filter_pre_select(__a_unused struct sched *s, struct task *t)
114 {
115 struct filter_chain *fc = t->private_data;
116 struct filter_node *fn;
117 char *ib;
118 size_t *loaded;
119 int conv, conv_total = 0;
120 again:
121 ib = fc->inbuf;
122 loaded = fc->in_loaded;
123 conv = 0;
124 list_for_each_entry(fn, &fc->filters, node) {
125 if (*loaded && fn->loaded < fn->bufsize) {
126 size_t old_fn_loaded = fn->loaded;
127 PARA_DEBUG_LOG("fc %p loaded: %zd, calling %s convert\n",
128 fc, *loaded, fn->filter->name);
129 t->ret = fn->filter->convert(ib, *loaded, fn);
130 if (t->ret < 0)
131 return;
132 call_callbacks(fn, ib, t->ret, fn->buf + old_fn_loaded,
133 fn->loaded - old_fn_loaded);
134 *loaded -= t->ret;
135 conv += t->ret;
136 if (*loaded && t->ret) {
137 PARA_DEBUG_LOG("moving %zd bytes in input buffer for %s filter\n",
138 *loaded, fn->filter->name);
139 memmove(ib, ib + t->ret, *loaded);
140 }
141 }
142 ib = fn->buf;
143 loaded = &fn->loaded;
144 }
145 conv_total += conv;
146 PARA_DEBUG_LOG("reader eof: %d, eof: %d out_loaded: %d, conv: %d, conv_total: %d\n", *fc->reader_eof,
147 fc->eof, *fc->out_loaded, conv, conv_total);
148 if (conv)
149 goto again;
150 t->ret = 1;
151 if (!*fc->reader_eof)
152 return;
153 if (*fc->out_loaded)
154 return;
155 if (*fc->in_loaded && conv_total)
156 return;
157 t->ret = -E_FC_EOF;
158 fc->eof = 1;
159 }
160
161 /**
162 * close all filter nodes and its callbacks
163 *
164 * \param fc the filter chain to close
165 *
166 * For each filter node determined by \a fc, call the close function of each
167 * registered filter callback as well as the close function of the
168 * corresponding filter. Free all resources and destroy all callback lists and
169 * the filter node list.
170 *
171 * \sa filter::close, filter_callback::close
172 */
173 void close_filters(struct filter_chain *fc)
174 {
175 struct filter_node *fn, *tmp;
176
177 if (!fc)
178 return;
179 PARA_DEBUG_LOG("closing filter chain %p\n", fc);
180 list_for_each_entry_safe(fn, tmp, &fc->filters, node) {
181 PARA_NOTICE_LOG("closing %s filter callbacks (fc %p, fn %p)\n", fn->filter->name, fc, fn);
182 close_callbacks(fn);
183 PARA_NOTICE_LOG("closing %s filter (fc %p, fn %p)\n", fn->filter->name, fc, fn);
184 fn->filter->close(fn);
185 list_del(&fn->node);
186 free(fn);
187 }
188 }
189
190 /*
191 * If the filter has a command line parser and options is not NULL, run it.
192 * Returns filter_num on success, negative on errors
193 */
194 static int parse_filter_args(int filter_num, char *options, void **conf)
195 {
196 struct filter *f = &filters[filter_num];
197 int i, argc = 2;
198 char **argv;
199
200 // PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
201 // options? options : "(none)", f->parse_config);
202 if (!f->parse_config)
203 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
204 // PARA_DEBUG_LOG("options: %s\n", options);
205 argc = split_args(options, &argv, " \t");
206 // PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
207 for (i = argc - 1; i >= 0; i--)
208 argv[i + 1] = argv[i];
209 argv[0] = para_strdup(f->name);
210 argc += 1;
211 *conf = f->parse_config(argc, argv);
212 return *conf? filter_num : -E_BAD_FILTER_OPTIONS;
213 }
214
215 /**
216 * check the filter command line options
217 *
218 * \param fa the command line options
219 * \param conf points to the filter configuration upon successful return
220 *
221 * Check if \a fa starts with a the name of a supported filter, followed by
222 * a colon. If yes, call the command line parser of that filter.
223 *
224 * \return On success, the number of the filter is returned and \a conf
225 * is initialized to point to the filter configuration determined by \a fa.
226 * On errors, a negative value is returned.
227 *
228 * Note: If \a fa specifies a filter that has no command line parser success is
229 * returned, and \a conf is initialized to \p NULL.
230 *
231 * \sa filter::parse_config
232 */
233 int check_filter_arg(char *fa, void **conf)
234 {
235 int j;
236
237 *conf = NULL;
238 // PARA_DEBUG_LOG("arg: %s\n", fa);
239 for (j = 0; filters[j].name; j++) {
240 const char *name = filters[j].name;
241 size_t len = strlen(name);
242 char c;
243 if (strlen(fa) < len)
244 continue;
245 if (strncmp(name, fa, len))
246 continue;
247 c = fa[len];
248 if (c && c != ' ')
249 continue;
250 if (c && !filters[j].parse_config)
251 return -E_BAD_FILTER_OPTIONS;
252 return parse_filter_args(j, c? fa + len + 1 :
253 fa + strlen(fa), conf);
254 }
255 return -E_UNSUPPORTED_FILTER;
256 }
257