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 <stdlib.h>
20 #include <stdint.h>
21 #include <string.h>
22 
23 #include "telescope.h"
24 #include "mcache.h"
25 #include "parser.h"
26 #include "utils.h"
27 
28 static struct timeval tv = { 5 * 60, 0 };
29 static struct event timerev;
30 
31 static struct ohash	h;
32 static size_t		npages;
33 static size_t		tot;
34 
35 struct mcache_entry {
36 	time_t		 ts;
37 	parserfn	 parser;
38 	int		 trust;
39 	struct evbuffer	*evb;
40 	char		 url[];
41 };
42 
43 static void
44 mcache_free_entry(const char *url)
45 {
46 	struct mcache_entry	*e;
47 	unsigned int		 slot;
48 
49 	slot = ohash_qlookup(&h, url);
50 	if ((e = ohash_remove(&h, slot)) == NULL)
51 		return;
52 
53 	npages--;
54 	tot -= EVBUFFER_LENGTH(e->evb);
55 
56 	evbuffer_free(e->evb);
57 	free(e);
58 }
59 
60 static void
61 clean_old_entries(int fd, short ev, void *data)
62 {
63 	struct mcache_entry	*e;
64 	unsigned int		 i;
65 	time_t			 treshold;
66 
67 	/* delete pages older than an hour */
68 	treshold = time(NULL) - 60 * 60;
69 
70 	for (e = ohash_first(&h, &i); e != NULL; e = ohash_next(&h, &i))
71 		if (e->ts < treshold)
72 			mcache_free_entry(e->url);
73 
74 	evtimer_add(&timerev, &tv);
75 }
76 
77 void
78 mcache_init(void)
79 {
80 	struct ohash_info info = {
81 		.key_offset = offsetof(struct mcache_entry, url),
82 		.calloc = hash_calloc,
83 		.free = hash_free,
84 		.alloc = hash_alloc,
85 	};
86 
87 	ohash_init(&h, 5, &info);
88 
89 	evtimer_set(&timerev, clean_old_entries, NULL);
90 }
91 
92 int
93 mcache_tab(struct tab *tab)
94 {
95 	struct mcache_entry	*e;
96 	unsigned int		 slot;
97 	size_t			 l, len;
98 	const char		*url;
99 
100 	url = tab->hist_cur->h;
101 	l = strlen(url);
102 	len = sizeof(*e) + l + 1;
103 
104 	if ((e = calloc(1, len)) == NULL)
105 		return -1;
106 	e->ts = time(NULL);
107 	e->parser = tab->buffer.page.init;
108 	e->trust = tab->trust;
109 	memcpy(e->url, url, l);
110 
111 	if ((e->evb = evbuffer_new()) == NULL)
112 		goto err;
113 
114 	if (!parser_serialize(tab, e->evb))
115 		goto err;
116 
117 	/* free any previously cached copies of this page */
118 	mcache_free_entry(url);
119 
120 	slot = ohash_qlookup(&h, url);
121 	ohash_insert(&h, slot, e);
122 
123 	npages++;
124 	tot += EVBUFFER_LENGTH(e->evb);
125 
126 	if (!evtimer_pending(&timerev, NULL))
127 		evtimer_add(&timerev, &tv);
128 
129 	return 0;
130 
131 err:
132 	if (e->evb != NULL)
133 		evbuffer_free(e->evb);
134 	free(e);
135 	return -1;
136 }
137 
138 int
139 mcache_lookup(const char *url, struct tab *tab)
140 {
141 	struct mcache_entry	*e;
142 	unsigned int		 slot;
143 
144 	slot = ohash_qlookup(&h, url);
145 	if ((e = ohash_find(&h, slot)) == NULL)
146 		return 0;
147 
148 	parser_init(tab, e->parser);
149 	if (!parser_parse(tab, EVBUFFER_DATA(e->evb), EVBUFFER_LENGTH(e->evb)))
150 		goto err;
151 	if (!parser_free(tab))
152 		goto err;
153 
154 	tab->trust = e->trust;
155 	return 1;
156 
157 err:
158 	parser_free(tab);
159 	erase_buffer(&tab->buffer);
160 	return 0;
161 }
162 
163 void
164 mcache_info(size_t *r_npages, size_t *r_tot)
165 {
166 	*r_npages = npages;
167 	*r_tot = tot;
168 }