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 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 = { 5 * 60, 0 };
41 static struct event timerev;
42 
43 static struct ohash	h;
44 static size_t		npages;
45 static size_t		tot;
46 
47 struct mcache_entry {
48 	time_t		 ts;
49 	const char	*parser_name;
50 	int		 trust;
51 	struct evbuffer	*evb;
52 	char		 url[];
53 };
54 
55 static void
56 mcache_free_entry(const char *url)
57 {
58 	struct mcache_entry	*e;
59 	unsigned int		 slot;
60 
61 	slot = ohash_qlookup(&h, url);
62 	if ((e = ohash_remove(&h, slot)) == NULL)
63 		return;
64 
65 	npages--;
66 	tot -= EVBUFFER_LENGTH(e->evb);
67 
68 	evbuffer_free(e->evb);
69 	free(e);
70 }
71 
72 static void
73 clean_old_entries(int fd, short ev, void *data)
74 {
75 	struct mcache_entry	*e;
76 	unsigned int		 i;
77 	time_t			 treshold;
78 
79 	/* delete pages older than an hour */
80 	treshold = time(NULL) - 60 * 60;
81 
82 	for (e = ohash_first(&h, &i); e != NULL; e = ohash_next(&h, &i))
83 		if (e->ts < treshold)
84 			mcache_free_entry(e->url);
85 
86 	evtimer_add(&timerev, &tv);
87 }
88 
89 void
90 mcache_init(void)
91 {
92 	struct ohash_info info = {
93 		.key_offset = offsetof(struct mcache_entry, url),
94 		.calloc = hash_calloc,
95 		.free = hash_free,
96 		.alloc = hash_alloc,
97 	};
98 
99 	ohash_init(&h, 5, &info);
100 
101 	evtimer_set(&timerev, clean_old_entries, NULL);
102 }
103 
104 int
105 mcache_tab(struct tab *tab)
106 {
107 	struct mcache_entry	*e;
108 	struct line		*line;
109 	unsigned int		 slot;
110 	size_t			 l, len;
111 	const char		*url;
112 
113 	url = tab->hist_cur->h;
114 	l = strlen(url);
115 	len = sizeof(*e) + l + 1;
116 
117 	if ((e = calloc(1, len)) == NULL)
118 		return -1;
119 	e->ts = time(NULL);
120 	e->parser_name = tab->buffer.page.name;
121 	e->trust = tab->trust;
122 	memcpy(e->url, url, l);
123 
124 	if ((e->evb = evbuffer_new()) == NULL)
125 		goto err;
126 
127 	TAILQ_FOREACH(line, &tab->buffer.page.head, lines) {
128 		const char	*text, *alt;
129 		int		 r;
130 
131 		if ((text = line->line) == NULL)
132 			text = "";
133 
134 		if ((alt = line->alt) == NULL)
135 			alt = "";
136 
137 		switch (line->type) {
138 		case LINE_TEXT:
139 		case LINE_TITLE_1:
140 		case LINE_TITLE_2:
141 		case LINE_TITLE_3:
142 		case LINE_ITEM:
143 		case LINE_QUOTE:
144 		case LINE_PRE_START:
145 		case LINE_PRE_CONTENT:
146 		case LINE_PRE_END:
147 			r = evbuffer_add_printf(e->evb, "%s%s\n",
148 			    gemtext_prefixes[line->type], text);
149 			break;
150 
151 		case LINE_LINK:
152 			r = evbuffer_add_printf(e->evb, "=> %s %s\n",
153 			    alt, text);
154 			break;
155 
156 		case LINE_PATCH:
157 		case LINE_PATCH_HDR:
158 		case LINE_PATCH_HUNK_HDR:
159 		case LINE_PATCH_ADD:
160 		case LINE_PATCH_DEL:
161 			/* TODO */
162 			r = -1;
163 			break;
164 
165 		case LINE_COMPL:
166 		case LINE_COMPL_CURRENT:
167 		case LINE_HELP:
168 		case LINE_DOWNLOAD:
169 		case LINE_DOWNLOAD_DONE:
170 		case LINE_DOWNLOAD_INFO:
171 		case LINE_FRINGE:
172 			/* not reached */
173 			abort();
174 		}
175 
176 		if (r == -1)
177 			goto err;
178 	}
179 
180 	/* free any previously cached copies of this page */
181 	mcache_free_entry(url);
182 
183 	slot = ohash_qlookup(&h, url);
184 	ohash_insert(&h, slot, e);
185 
186 	npages++;
187 	tot += EVBUFFER_LENGTH(e->evb);
188 
189 	if (!evtimer_pending(&timerev, NULL))
190 		evtimer_add(&timerev, &tv);
191 
192 	return 0;
193 
194 err:
195 	if (e->evb != NULL)
196 		evbuffer_free(e->evb);
197 	free(e);
198 	return -1;
199 }
200 
201 int
202 mcache_lookup(const char *url, struct tab *tab)
203 {
204 	struct mcache_entry	*e;
205 	unsigned int		 slot;
206 
207 	slot = ohash_qlookup(&h, url);
208 	if ((e = ohash_find(&h, slot)) == NULL)
209 		return 0;
210 
211 	parser_init(tab, gemtext_initparser);
212 	if (!parser_parse(tab, EVBUFFER_DATA(e->evb), EVBUFFER_LENGTH(e->evb)))
213 		goto err;
214 	if (!parser_free(tab))
215 		goto err;
216 
217 	tab->buffer.page.name = e->parser_name;
218 	tab->trust = e->trust;
219 	return 1;
220 
221 err:
222 	parser_free(tab);
223 	erase_buffer(&tab->buffer);
224 	return 0;
225 }
226 
227 void
228 mcache_info(size_t *r_npages, size_t *r_tot)
229 {
230 	*r_npages = npages;
231 	*r_tot = tot;
232 }