1a2902477c85d78b2c84739ca5c9d374f5f38a6a
[paraslash.git] / filter_chain.c
1 /*
2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file filter_chain.c Common helper functions for filter input/output. */
8
9 #include <sys/types.h>
10 #include <dirent.h>
11
12 #include "para.h"
13 #include "list.h"
14 #include "sched.h"
15 #include "fd.h"
16 #include "filter.h"
17 #include "error.h"
18 #include "string.h"
19
20 DEFINE_FILTER_ARRAY(filters);
21
22 /**
23 * Call the init function of each supported filter.
24 *
25 * \param all_filters the array of all supported filters.
26 *
27 * \sa filter::init
28 */
29 void filter_init(struct filter *all_filters)
30 {
31 struct filter *f;
32
33 for (f = all_filters; f->name; f++)
34 f->init(f);
35 }
36
37 /**
38 * Close and destroy a filter callback.
39 *
40 * \param fcb The filter callback to close.
41 *
42 * This removes \a fcb from the list of filter callbacks and calls
43 * the close callback associated with \a fcb.
44 */
45 static void close_filter_callback(struct filter_callback *fcb)
46 {
47 PARA_NOTICE_LOG("closing filter_callback %p, data: %p\n", fcb, fcb->data);
48 list_del(&fcb->node);
49 fcb->close(fcb);
50 }
51
52 /**
53 * Close all callbacks of a filter node.
54 *
55 * \param fn The filter node which contains the filter callbacks to be closed.
56 *
57 * Call close_filter_callback() for each entry in the filter callback list
58 * of \a fn.
59 */
60 static void close_callbacks(struct filter_node *fn)
61 {
62 struct filter_callback *fcb, *tmp;
63
64 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
65 PARA_INFO_LOG("closing %s filter callback\n",
66 filters[fn->filter_num].name);
67 close_filter_callback(fcb);
68 }
69 }
70
71 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
72 char *outbuf, size_t outlen)
73 {
74 struct filter_callback *fcb, *tmp;
75 list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
76 int ret;
77 if (inlen && fcb->input_cb) {
78 ret = fcb->input_cb(inbuf, inlen, fcb);
79 if (ret < 0) {
80 close_filter_callback(fcb);
81 continue;
82 }
83 }
84 if (!outlen || !fcb->output_cb)
85 continue;
86 ret = fcb->output_cb(outbuf, outlen, fcb);
87 if (ret < 0)
88 close_filter_callback(fcb);
89 }
90 }
91
92 /**
93 * Call the convert function of each filter.
94 *
95 * \param s Unused.
96 * \param t The task identifying the filter chain.
97 *
98 * This is the core function of the filter subsystem. It loops over the list of
99 * filter nodes determined by \a t and calls the filter's convert function if
100 * there is input available for the filter node in question. If the convert
101 * function consumed some or all of its input data, all registered input
102 * callbacks are called. Similarly, if a convert function produced output, all
103 * registerd output callbacks get called.
104 *
105 * On errors a (negative) error code is stored in t->error.
106 *
107 * \sa filter_node, filter#convert, filter_callback.
108 */
109 void filter_pre_select(__a_unused struct sched *s, struct task *t)
110 {
111 struct filter_chain *fc = container_of(t, struct filter_chain, task);
112 struct filter_node *fn;
113 char *ib;
114 size_t *loaded;
115 int i, conv, conv_total = 0;
116
117 if (fc->output_error && *fc->output_error < 0) {
118 t->error = *fc->output_error;
119 return;
120 }
121 again:
122 ib = fc->inbuf;
123 loaded = fc->in_loaded;
124 conv = 0;
125 FOR_EACH_FILTER_NODE(fn, fc, i) {
126 struct filter *f = filters + fn->filter_num;
127 if (*loaded && fn->loaded < fn->bufsize) {
128 size_t size, old_fn_loaded = fn->loaded;
129 // PARA_DEBUG_LOG("fc %p loaded: %zd, calling %s convert\n",
130 // fc, *loaded, fn->filter->name);
131 t->error = f->convert(ib, *loaded, fn);
132 if (t->error < 0)
133 return;
134 size = t->error;
135 call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
136 fn->loaded - old_fn_loaded);
137 *loaded -= size;
138 conv += size;
139 if (*loaded && size) {
140 // PARA_DEBUG_LOG("moving %zd bytes in input "
141 // "buffer for %s filter\n",
142 // *loaded, fn->filter->name);
143 memmove(ib, ib + size, *loaded);
144 }
145 }
146 ib = fn->buf;
147 loaded = &fn->loaded;
148 }
149 conv_total += conv;
150 // PARA_DEBUG_LOG("eof (in/out/fc): %d/%d/%d out_loaded: %zd, "
151 // "conv: %d, conv_total: %d\n", *fc->input_eof,
152 // fc->output_eof? *fc->output_eof : -42,
153 // fc->eof, *fc->out_loaded, conv, conv_total);
154 if (conv)
155 goto again;
156 if (!*fc->input_error)
157 return;
158 if (*fc->out_loaded)
159 return;
160 if (*fc->in_loaded && conv_total)
161 return;
162 t->error = -E_FC_EOF;
163 }
164
165 /**
166 * Close all filter nodes and their callbacks.
167 *
168 * \param fc The filter chain to close.
169 *
170 * For each filter node determined by \a fc, call the close function of each
171 * registered filter callback as well as the close function of the
172 * corresponding filter. Free all resources and destroy all callback lists and
173 * the filter node list.
174 *
175 * \sa filter::close, filter_callback::close
176 */
177 void close_filters(struct filter_chain *fc)
178 {
179 struct filter_node *fn;
180 int i;
181
182 if (!fc)
183 return;
184 PARA_NOTICE_LOG("closing filter chain %p\n", fc);
185 FOR_EACH_FILTER_NODE(fn, fc, i) {
186 struct filter *f = filters + fn->filter_num;
187 close_callbacks(fn);
188 PARA_INFO_LOG("closing %s filter\n", f->name);
189 f->close(fn);
190 }
191 free(fc->filter_nodes);
192 }
193
194 /*
195 * If the filter has a command line parser and options is not NULL, run it.
196 * Returns filter_num on success, negative on errors
197 */
198 static int parse_filter_args(int filter_num, char *options, void **conf)
199 {
200 struct filter *f = &filters[filter_num];
201 int i, argc = 2;
202 char **argv;
203
204 // PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
205 // options? options : "(none)", f->parse_config);
206 if (!f->parse_config)
207 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
208 // PARA_DEBUG_LOG("options: %s\n", options);
209 argc = split_args(options, &argv, " \t");
210 // PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
211 for (i = argc - 1; i >= 0; i--)
212 argv[i + 1] = argv[i];
213 argv[0] = para_strdup(f->name);
214 argc += 1;
215 *conf = f->parse_config(argc, argv);
216 free(argv[0]);
217 free(argv);
218 return *conf? filter_num : -E_BAD_FILTER_OPTIONS;
219 }
220
221 /**
222 * Check the filter command line options.
223 *
224 * \param fa The command line options.
225 * \param conf Points to the filter configuration upon successful return.
226 *
227 * Check if \a fa starts with a the name of a supported filter, followed by
228 * a colon. If yes, call the command line parser of that filter.
229 *
230 * \return On success, the number of the filter is returned and \a conf
231 * is initialized to point to the filter configuration determined by \a fa.
232 * On errors, a negative value is returned.
233 *
234 * Note: If \a fa specifies a filter that has no command line parser success is
235 * returned, and \a conf is initialized to \p NULL.
236 *
237 * \sa filter::parse_config
238 */
239 int check_filter_arg(char *fa, void **conf)
240 {
241 int j;
242
243 *conf = NULL;
244 // PARA_DEBUG_LOG("arg: %s\n", fa);
245 for (j = 0; filters[j].name; j++) {
246 const char *name = filters[j].name;
247 size_t len = strlen(name);
248 char c;
249 if (strlen(fa) < len)
250 continue;
251 if (strncmp(name, fa, len))
252 continue;
253 c = fa[len];
254 if (c && c != ' ')
255 continue;
256 if (c && !filters[j].parse_config)
257 return -E_BAD_FILTER_OPTIONS;
258 return parse_filter_args(j, c? fa + len + 1 :
259 fa + strlen(fa), conf);
260 }
261 return -E_UNSUPPORTED_FILTER;
262 }
263