simplify osx_write_pre_select()
[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 PARA_INFO_LOG("closing %s filter callback\n",
74 fn->filter->name);
75 close_filter_callback(fcb);
76 }
77 }
78
79 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
80 char *outbuf, size_t outlen)
81 {
82 struct filter_callback *fcb, *tmp;
83 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
84 int ret;
85 if (inlen && fcb->input_cb) {
86 ret = fcb->input_cb(inbuf, inlen, fcb);
87 if (ret < 0) {
88 close_filter_callback(fcb);
89 continue;
90 }
91 }
92 if (!outlen || !fcb->output_cb)
93 continue;
94 ret = fcb->output_cb(outbuf, outlen, fcb);
95 if (ret < 0)
96 close_filter_callback(fcb);
97 }
98 }
99
100 /**
101 * call the convert function of each filter
102 *
103 * This is the core function of the filter subsystem. It loops over the list of
104 * filter nodes determined by \a t and calls the filter's convert function if
105 * there is input available for the filter node in question. If the convert
106 * function consumed some or all of its input data, all registered input
107 * callbacks are called. Similarly, if a convert function produced output, all
108 * registerd output callbacks get called.
109 *
110 * \return The sum of output bytes produced by the convert functions on
111 * success, negative return value on errors (the return value is stored in
112 * t->ret).
113 *
114 * \sa filter_node, filter#convert, filter_callback
115 */
116 void filter_pre_select(__a_unused struct sched *s, struct task *t)
117 {
118 struct filter_chain *fc = t->private_data;
119 struct filter_node *fn;
120 char *ib;
121 size_t *loaded;
122 int conv, conv_total = 0;
123
124 t->ret = -E_FC_EOF;
125 if (fc->output_eof && *fc->output_eof)
126 goto err_out;
127 if (fc->input_eof && *fc->input_eof && !*fc->in_loaded)
128 goto err_out;
129 again:
130 ib = fc->inbuf;
131 loaded = fc->in_loaded;
132 conv = 0;
133 list_for_each_entry(fn, &fc->filters, node) {
134 if (*loaded && fn->loaded < fn->bufsize) {
135 size_t old_fn_loaded = fn->loaded;
136 // PARA_DEBUG_LOG("fc %p loaded: %zd, calling %s convert\n",
137 // fc, *loaded, fn->filter->name);
138 t->ret = fn->filter->convert(ib, *loaded, fn);
139 if (t->ret < 0)
140 goto err_out;
141 call_callbacks(fn, ib, t->ret, fn->buf + old_fn_loaded,
142 fn->loaded - old_fn_loaded);
143 *loaded -= t->ret;
144 conv += t->ret;
145 if (*loaded && t->ret) {
146 // PARA_DEBUG_LOG("moving %zd bytes in input "
147 // "buffer for %s filter\n",
148 // *loaded, fn->filter->name);
149 memmove(ib, ib + t->ret, *loaded);
150 }
151 }
152 ib = fn->buf;
153 loaded = &fn->loaded;
154 }
155 conv_total += conv;
156 // PARA_DEBUG_LOG("eof (in/out/fc): %d/%d/%d out_loaded: %zd, "
157 // "conv: %d, conv_total: %d\n", *fc->input_eof,
158 // fc->output_eof? *fc->output_eof : -42,
159 // fc->eof, *fc->out_loaded, conv, conv_total);
160 if (conv)
161 goto again;
162 t->ret = 1;
163 if (!*fc->input_eof)
164 return;
165 if (*fc->out_loaded)
166 return;
167 if (*fc->in_loaded && conv_total)
168 return;
169 t->ret = -E_FC_EOF;
170 err_out:
171 fc->eof = 1;
172 }
173
174 /**
175 * close all filter nodes and its callbacks
176 *
177 * \param fc the filter chain to close
178 *
179 * For each filter node determined by \a fc, call the close function of each
180 * registered filter callback as well as the close function of the
181 * corresponding filter. Free all resources and destroy all callback lists and
182 * the filter node list.
183 *
184 * \sa filter::close, filter_callback::close
185 */
186 void close_filters(struct filter_chain *fc)
187 {
188 struct filter_node *fn, *tmp;
189
190 if (!fc)
191 return;
192 PARA_NOTICE_LOG("closing filter chain %p\n", fc);
193 list_for_each_entry_safe(fn, tmp, &fc->filters, node) {
194 close_callbacks(fn);
195 PARA_INFO_LOG("closing %s filter\n", fn->filter->name);
196 fn->filter->close(fn);
197 list_del(&fn->node);
198 free(fn);
199 }
200 }
201
202 /*
203 * If the filter has a command line parser and options is not NULL, run it.
204 * Returns filter_num on success, negative on errors
205 */
206 static int parse_filter_args(int filter_num, char *options, void **conf)
207 {
208 struct filter *f = &filters[filter_num];
209 int i, argc = 2;
210 char **argv;
211
212 // PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
213 // options? options : "(none)", f->parse_config);
214 if (!f->parse_config)
215 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
216 // PARA_DEBUG_LOG("options: %s\n", options);
217 argc = split_args(options, &argv, " \t");
218 // PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
219 for (i = argc - 1; i >= 0; i--)
220 argv[i + 1] = argv[i];
221 argv[0] = para_strdup(f->name);
222 argc += 1;
223 *conf = f->parse_config(argc, argv);
224 return *conf? filter_num : -E_BAD_FILTER_OPTIONS;
225 }
226
227 /**
228 * check the filter command line options
229 *
230 * \param fa the command line options
231 * \param conf points to the filter configuration upon successful return
232 *
233 * Check if \a fa starts with a the name of a supported filter, followed by
234 * a colon. If yes, call the command line parser of that filter.
235 *
236 * \return On success, the number of the filter is returned and \a conf
237 * is initialized to point to the filter configuration determined by \a fa.
238 * On errors, a negative value is returned.
239 *
240 * Note: If \a fa specifies a filter that has no command line parser success is
241 * returned, and \a conf is initialized to \p NULL.
242 *
243 * \sa filter::parse_config
244 */
245 int check_filter_arg(char *fa, void **conf)
246 {
247 int j;
248
249 *conf = NULL;
250 // PARA_DEBUG_LOG("arg: %s\n", fa);
251 for (j = 0; filters[j].name; j++) {
252 const char *name = filters[j].name;
253 size_t len = strlen(name);
254 char c;
255 if (strlen(fa) < len)
256 continue;
257 if (strncmp(name, fa, len))
258 continue;
259 c = fa[len];
260 if (c && c != ' ')
261 continue;
262 if (c && !filters[j].parse_config)
263 return -E_BAD_FILTER_OPTIONS;
264 return parse_filter_args(j, c? fa + len + 1 :
265 fa + strlen(fa), conf);
266 }
267 return -E_UNSUPPORTED_FILTER;
268 }
269