1 /*
2  * Copyright (c) 2022 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "compat.h"
18 
19 #include <sys/time.h>
20 
21 #include <stdlib.h>
22 #include <stdint.h>
23 #include <string.h>
24 #include <time.h>
25 
26 #include "ev.h"
27 #include "hist.h"
28 #include "mcache.h"
29 #include "parser.h"
30 #include "telescope.h"
31 #include "utils.h"
32 #include "xwrapper.h"
33 
34 static struct timeval tv = { 5 * 60, 0 };
35 static unsigned int timeout;
36 
37 static struct ohash	h;
38 static size_t		npages;
39 static size_t		tot;
40 
41 struct mcache_entry {
42 	time_t			 ts;
43 	const struct parser	*parser;
44 	int			 trust;
45 	char			*buf;
46 	size_t			 buflen;
47 	char			 url[];
48 };
49 
50 static void
51 mcache_free_entry(const char *url)
52 {
53 	struct mcache_entry	*e;
54 	unsigned int		 slot;
55 
56 	slot = ohash_qlookup(&h, url);
57 	if ((e = ohash_remove(&h, slot)) == NULL)
58 		return;
59 
60 	npages--;
61 	tot -= e->buflen;
62 
63 	free(e->buf);
64 	free(e);
65 }
66 
67 static void
68 clean_old_entries(int fd, int ev, void *data)
69 {
70 	struct mcache_entry	*e;
71 	unsigned int		 i;
72 	time_t			 threshold;
73 
74 	/* delete pages older than an hour */
75 	threshold = time(NULL) - 60 * 60;
76 
77 	for (e = ohash_first(&h, &i); e != NULL; e = ohash_next(&h, &i))
78 		if (e->ts < threshold)
79 			mcache_free_entry(e->url);
80 
81 	timeout = ev_timer(&tv, clean_old_entries, NULL);
82 }
83 
84 void
85 mcache_init(void)
86 {
87 	struct ohash_info info = {
88 		.key_offset = offsetof(struct mcache_entry, url),
89 		.calloc = hash_calloc,
90 		.free = hash_free,
91 		.alloc = hash_alloc,
92 	};
93 
94 	ohash_init(&h, 5, &info);
95 }
96 
97 int
98 mcache_tab(struct tab *tab)
99 {
100 	struct mcache_entry	*e;
101 	unsigned int		 slot;
102 	size_t			 l, len;
103 	const char		*url;
104 	FILE			*fp;
105 
106 	url = hist_cur(tab->hist);
107 	l = strlen(url);
108 	len = sizeof(*e) + l + 1;
109 
110 	e = xcalloc(1, len);
111 	e->ts = time(NULL);
112 	e->parser = tab->buffer.parser;
113 	e->trust = tab->trust;
114 	memcpy(e->url, url, l);
115 
116 	if ((fp = open_memstream(&e->buf, &e->buflen)) == NULL)
117 		goto err;
118 
119 	if (!parser_serialize(&tab->buffer, fp))
120 		goto err;
121 
122 	fclose(fp);
123 
124 	/* free any previously cached copies of this page */
125 	mcache_free_entry(url);
126 
127 	slot = ohash_qlookup(&h, url);
128 	ohash_insert(&h, slot, e);
129 
130 	npages++;
131 	tot += e->buflen;
132 
133 	if (!ev_timer_pending(timeout))
134 		timeout = ev_timer(&tv, clean_old_entries, NULL);
135 
136 	return 0;
137 
138 err:
139 	if (fp != NULL)
140 		fclose(fp);
141 	if (e->buf != NULL)
142 		free(e->buf);
143 	free(e);
144 	return -1;
145 }
146 
147 int
148 mcache_lookup(const char *url, struct tab *tab)
149 {
150 	struct mcache_entry	*e;
151 	unsigned int		 slot;
152 
153 	slot = ohash_qlookup(&h, url);
154 	if ((e = ohash_find(&h, slot)) == NULL)
155 		return 0;
156 
157 	parser_init(&tab->buffer, e->parser);
158 	if (!parser_parse(&tab->buffer, e->buf, e->buflen))
159 		goto err;
160 	if (!parser_free(tab))
161 		goto err;
162 
163 	tab->trust = e->trust;
164 	return 1;
165 
166 err:
167 	parser_free(tab);
168 	erase_buffer(&tab->buffer);
169 	return 0;
170 }
171 
172 void
173 mcache_info(size_t *r_npages, size_t *r_tot)
174 {
175 	*r_npages = npages;
176 	*r_tot = tot;
177 }