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 int
44 mcache_printf(void *d, const char *fmt, ...)
45 {
46 	struct evbuffer *evb = d;
47 	int r;
48 	va_list ap;
49 
50 	va_start(ap, fmt);
51 	r = evbuffer_add_vprintf(evb, fmt, ap);
52 	va_end(ap);
53 
54 	return r;
55 }
56 
57 static void
58 mcache_free_entry(const char *url)
59 {
60 	struct mcache_entry	*e;
61 	unsigned int		 slot;
62 
63 	slot = ohash_qlookup(&h, url);
64 	if ((e = ohash_remove(&h, slot)) == NULL)
65 		return;
66 
67 	npages--;
68 	tot -= EVBUFFER_LENGTH(e->evb);
69 
70 	evbuffer_free(e->evb);
71 	free(e);
72 }
73 
74 static void
75 clean_old_entries(int fd, short ev, void *data)
76 {
77 	struct mcache_entry	*e;
78 	unsigned int		 i;
79 	time_t			 treshold;
80 
81 	/* delete pages older than an hour */
82 	treshold = time(NULL) - 60 * 60;
83 
84 	for (e = ohash_first(&h, &i); e != NULL; e = ohash_next(&h, &i))
85 		if (e->ts < treshold)
86 			mcache_free_entry(e->url);
87 
88 	evtimer_add(&timerev, &tv);
89 }
90 
91 void
92 mcache_init(void)
93 {
94 	struct ohash_info info = {
95 		.key_offset = offsetof(struct mcache_entry, url),
96 		.calloc = hash_calloc,
97 		.free = hash_free,
98 		.alloc = hash_alloc,
99 	};
100 
101 	ohash_init(&h, 5, &info);
102 
103 	evtimer_set(&timerev, clean_old_entries, NULL);
104 }
105 
106 int
107 mcache_tab(struct tab *tab)
108 {
109 	struct mcache_entry	*e;
110 	unsigned int		 slot;
111 	size_t			 l, len;
112 	const char		*url;
113 
114 	url = tab->hist_cur->h;
115 	l = strlen(url);
116 	len = sizeof(*e) + l + 1;
117 
118 	if ((e = calloc(1, len)) == NULL)
119 		return -1;
120 	e->ts = time(NULL);
121 	e->parser = tab->buffer.page.init;
122 	e->trust = tab->trust;
123 	memcpy(e->url, url, l);
124 
125 	if ((e->evb = evbuffer_new()) == NULL)
126 		goto err;
127 
128 	if (!parser_serialize(tab, mcache_printf, e->evb))
129 		goto err;
130 
131 	/* free any previously cached copies of this page */
132 	mcache_free_entry(url);
133 
134 	slot = ohash_qlookup(&h, url);
135 	ohash_insert(&h, slot, e);
136 
137 	npages++;
138 	tot += EVBUFFER_LENGTH(e->evb);
139 
140 	if (!evtimer_pending(&timerev, NULL))
141 		evtimer_add(&timerev, &tv);
142 
143 	return 0;
144 
145 err:
146 	if (e->evb != NULL)
147 		evbuffer_free(e->evb);
148 	free(e);
149 	return -1;
150 }
151 
152 int
153 mcache_lookup(const char *url, struct tab *tab)
154 {
155 	struct mcache_entry	*e;
156 	unsigned int		 slot;
157 
158 	slot = ohash_qlookup(&h, url);
159 	if ((e = ohash_find(&h, slot)) == NULL)
160 		return 0;
161 
162 	parser_init(tab, e->parser);
163 	if (!parser_parse(tab, EVBUFFER_DATA(e->evb), EVBUFFER_LENGTH(e->evb)))
164 		goto err;
165 	if (!parser_free(tab))
166 		goto err;
167 
168 	tab->trust = e->trust;
169 	return 1;
170 
171 err:
172 	parser_free(tab);
173 	erase_buffer(&tab->buffer);
174 	return 0;
175 }
176 
177 void
178 mcache_info(size_t *r_npages, size_t *r_tot)
179 {
180 	*r_npages = npages;
181 	*r_tot = tot;
182 }