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 const char *gemtext_prefixes[] = {
29 	[LINE_TEXT] = "",
30 	[LINE_TITLE_1] = "# ",
31 	[LINE_TITLE_2] = "## ",
32 	[LINE_TITLE_3] = "### ",
33 	[LINE_ITEM] = "* ",
34 	[LINE_QUOTE] = "> ",
35 	[LINE_PRE_START] = "``` ",
36 	[LINE_PRE_CONTENT] = "",
37 	[LINE_PRE_END] = "```",
38 };
39 
40 static struct timeval tv = { 60, 0 };
41 static struct event timerev;
42 
43 struct mcache {
44 	struct ohash	h;
45 	size_t		npages;
46 	size_t		tot;
47 } mcache;
48 
49 struct mcache_entry {
50 	time_t		 ts;
51 	const char	*parser_name;
52 	int		 trust;
53 	struct evbuffer	*evb;
54 	char		 url[];
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(&mcache.h, url);
64 	if ((e = ohash_remove(&mcache.h, slot)) == NULL)
65 		return;
66 
67 	mcache.npages--;
68 	mcache.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 	treshold = time(NULL) - 15 * 60;
82 
83 	for (e = ohash_first(&mcache.h, &i); e != NULL; e = ohash_next(&mcache.h, &i))
84 		if (e->ts < treshold)
85 			mcache_free_entry(e->url);
86 
87 	evtimer_add(&timerev, &tv);
88 }
89 
90 void
91 mcache_init(void)
92 {
93 	struct ohash_info info = {
94 		.key_offset = offsetof(struct mcache_entry, url),
95 		.calloc = hash_calloc,
96 		.free = hash_free,
97 		.alloc = hash_alloc,
98 	};
99 
100 	ohash_init(&mcache.h, 5, &info);
101 
102 	evtimer_set(&timerev, clean_old_entries, NULL);
103 }
104 
105 int
106 mcache_tab(struct tab *tab)
107 {
108 	struct mcache_entry	*e;
109 	struct line		*line;
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_name = tab->buffer.page.name;
122 	e->trust = tab->trust;
123 	memcpy(e->url, url, l);
124 
125 	if ((e->evb = evbuffer_new()) == NULL)
126 		goto err;
127 
128 	TAILQ_FOREACH(line, &tab->buffer.page.head, lines) {
129 		const char	*text, *alt;
130 		int		 r;
131 
132 		if ((text = line->line) == NULL)
133 			text = "";
134 
135 		if ((alt = line->alt) == NULL)
136 			alt = "";
137 
138 		switch (line->type) {
139 		case LINE_TEXT:
140 		case LINE_TITLE_1:
141 		case LINE_TITLE_2:
142 		case LINE_TITLE_3:
143 		case LINE_ITEM:
144 		case LINE_QUOTE:
145 		case LINE_PRE_START:
146 		case LINE_PRE_CONTENT:
147 		case LINE_PRE_END:
148 			r = evbuffer_add_printf(e->evb, "%s%s\n",
149 			    gemtext_prefixes[line->type], text);
150 			break;
151 
152 		case LINE_LINK:
153 			r = evbuffer_add_printf(e->evb, "=> %s %s\n",
154 			    alt, text);
155 			break;
156 
157 		case LINE_PATCH:
158 		case LINE_PATCH_HDR:
159 		case LINE_PATCH_HUNK_HDR:
160 		case LINE_PATCH_ADD:
161 		case LINE_PATCH_DEL:
162 			/* TODO */
163 			r = -1;
164 			break;
165 
166 		case LINE_COMPL:
167 		case LINE_COMPL_CURRENT:
168 		case LINE_HELP:
169 		case LINE_DOWNLOAD:
170 		case LINE_DOWNLOAD_DONE:
171 		case LINE_DOWNLOAD_INFO:
172 		case LINE_FRINGE:
173 			/* not reached */
174 			abort();
175 		}
176 
177 		if (r == -1)
178 			goto err;
179 	}
180 
181 	/* free any previously cached copies of this page */
182 	mcache_free_entry(url);
183 
184 	slot = ohash_qlookup(&mcache.h, url);
185 	ohash_insert(&mcache.h, slot, e);
186 
187 	mcache.npages++;
188 	mcache.tot += EVBUFFER_LENGTH(e->evb);
189 
190 	if (!evtimer_pending(&timerev, NULL))
191 		evtimer_add(&timerev, &tv);
192 
193 	return 0;
194 
195 err:
196 	if (e->evb != NULL)
197 		evbuffer_free(e->evb);
198 	free(e);
199 	return -1;
200 }
201 
202 int
203 mcache_lookup(const char *url, struct tab *tab)
204 {
205 	struct mcache_entry	*e;
206 	unsigned int		 slot;
207 
208 	slot = ohash_qlookup(&mcache.h, url);
209 	if ((e = ohash_find(&mcache.h, slot)) == NULL)
210 		return 0;
211 
212 	parser_init(tab, gemtext_initparser);
213 	if (!parser_parse(tab, EVBUFFER_DATA(e->evb), EVBUFFER_LENGTH(e->evb)))
214 		goto err;
215 	if (!parser_free(tab))
216 		goto err;
217 
218 	tab->buffer.page.name = e->parser_name;
219 	tab->trust = e->trust;
220 	return 1;
221 
222 err:
223 	parser_free(tab);
224 	erase_buffer(&tab->buffer);
225 	return 0;
226 }
227 
228 void
229 mcache_info(size_t *npages, size_t *tot)
230 {
231 	*npages = mcache.npages;
232 	*tot = mcache.tot;
233 }