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 "utils.h"
31 
32 static struct timeval tv = { 5 * 60, 0 };
33 static unsigned int timeout;
34 
35 static struct ohash	h;
36 static size_t		npages;
37 static size_t		tot;
38 
39 struct mcache_entry {
40 	time_t		 ts;
41 	parserfn	 parser;
42 	int		 trust;
43 	char		*buf;
44 	size_t		 buflen;
45 	char		 url[];
46 };
47 
48 static void
49 mcache_free_entry(const char *url)
50 {
51 	struct mcache_entry	*e;
52 	unsigned int		 slot;
53 
54 	slot = ohash_qlookup(&h, url);
55 	if ((e = ohash_remove(&h, slot)) == NULL)
56 		return;
57 
58 	npages--;
59 	tot -= e->buflen;
60 
61 	free(e->buf);
62 	free(e);
63 }
64 
65 static void
66 clean_old_entries(int fd, int ev, void *data)
67 {
68 	struct mcache_entry	*e;
69 	unsigned int		 i;
70 	time_t			 treshold;
71 
72 	/* delete pages older than an hour */
73 	treshold = time(NULL) - 60 * 60;
74 
75 	for (e = ohash_first(&h, &i); e != NULL; e = ohash_next(&h, &i))
76 		if (e->ts < treshold)
77 			mcache_free_entry(e->url);
78 
79 	timeout = ev_timer(&tv, clean_old_entries, NULL);
80 }
81 
82 void
83 mcache_init(void)
84 {
85 	struct ohash_info info = {
86 		.key_offset = offsetof(struct mcache_entry, url),
87 		.calloc = hash_calloc,
88 		.free = hash_free,
89 		.alloc = hash_alloc,
90 	};
91 
92 	ohash_init(&h, 5, &info);
93 }
94 
95 int
96 mcache_tab(struct tab *tab)
97 {
98 	struct mcache_entry	*e;
99 	unsigned int		 slot;
100 	size_t			 l, len;
101 	const char		*url;
102 	FILE			*fp;
103 
104 	url = hist_cur(tab->hist);
105 	l = strlen(url);
106 	len = sizeof(*e) + l + 1;
107 
108 	if ((e = calloc(1, len)) == NULL)
109 		return -1;
110 	e->ts = time(NULL);
111 	e->parser = tab->buffer.page.init;
112 	e->trust = tab->trust;
113 	memcpy(e->url, url, l);
114 
115 	if ((fp = open_memstream(&e->buf, &e->buflen)) == NULL)
116 		goto err;
117 
118 	if (!parser_serialize(tab, fp))
119 		goto err;
120 
121 	fclose(fp);
122 
123 	/* free any previously cached copies of this page */
124 	mcache_free_entry(url);
125 
126 	slot = ohash_qlookup(&h, url);
127 	ohash_insert(&h, slot, e);
128 
129 	npages++;
130 	tot += e->buflen;
131 
132 	if (!ev_timer_pending(timeout))
133 		timeout = ev_timer(&tv, clean_old_entries, NULL);
134 
135 	return 0;
136 
137 err:
138 	if (fp != NULL)
139 		fclose(fp);
140 	if (e->buf != NULL)
141 		free(e->buf);
142 	free(e);
143 	return -1;
144 }
145 
146 int
147 mcache_lookup(const char *url, struct tab *tab)
148 {
149 	struct mcache_entry	*e;
150 	unsigned int		 slot;
151 
152 	slot = ohash_qlookup(&h, url);
153 	if ((e = ohash_find(&h, slot)) == NULL)
154 		return 0;
155 
156 	parser_init(tab, e->parser);
157 	if (!parser_parse(tab, e->buf, e->buflen))
158 		goto err;
159 	if (!parser_free(tab))
160 		goto err;
161 
162 	tab->trust = e->trust;
163 	return 1;
164 
165 err:
166 	parser_free(tab);
167 	erase_buffer(&tab->buffer);
168 	return 0;
169 }
170 
171 void
172 mcache_info(size_t *r_npages, size_t *r_tot)
173 {
174 	*r_npages = npages;
175 	*r_tot = tot;
176 }