1 #include "a.h"
2 
3 // This code is almost certainly wrong.
4 
5 typedef struct Icache Icache;
6 struct Icache
7 {
8 	char *url;
9 	HTTPHeader hdr;
10 	char *tmpfile;
11 	int fd;
12 	Icache *next;
13 	Icache *prev;
14 	Icache *hash;
15 };
16 
17 enum {
18 	NHASH = 128,
19 	MAXCACHE = 128,
20 };
21 static struct {
22 	Icache *hash[NHASH];
23 	Icache *head;
24 	Icache *tail;
25 	int n;
26 } icache;
27 
28 static Icache*
29 icachefind(char *url)
30 {
31 	int h;
32 	Icache *ic;
33 
34 	h = hash(url) % NHASH;
35 	for(ic=icache.hash[h]; ic; ic=ic->hash){
36 		if(strcmp(ic->url, url) == 0){
37 			/* move to front */
38 			if(ic->prev) {
39 				ic->prev->next = ic->next;
40 				if(ic->next)
41 					ic->next->prev = ic->prev;
42 				else
43 					icache.tail = ic->prev;
44 				ic->prev = nil;
45 				ic->next = icache.head;
46 				icache.head->prev = ic;
47 				icache.head = ic;
48 			}
49 			return ic;
50 		}
51 	}
52 	return nil;
53 }
54 
55 static Icache*
56 icacheinsert(char *url, HTTPHeader *hdr, char *file, int fd)
57 {
58 	int h;
59 	Icache *ic, **l;
60 
61 	if(icache.n == MAXCACHE){
62 		ic = icache.tail;
63 		icache.tail = ic->prev;
64 		if(ic->prev)
65 			ic->prev->next = nil;
66 		else
67 			icache.head = ic->prev;
68 		h = hash(ic->url) % NHASH;
69 		for(l=&icache.hash[h]; *l; l=&(*l)->hash){
70 			if(*l == ic){
71 				*l = ic->hash;
72 				goto removed;
73 			}
74 		}
75 		sysfatal("cannot find ic in cache");
76 	removed:
77 		free(ic->url);
78 		close(ic->fd);
79 		remove(ic->file);
80 		free(ic->file);
81 	}else{
82 		ic = emalloc(sizeof *ic);
83 		icache.n++;
84 	}
85 
86 	ic->url = estrdup(url);
87 	ic->fd = dup(fd, -1);
88 	ic->file = estrdup(file);
89 	ic->hdr = *hdr;
90 	h = hash(url) % NHASH;
91 	ic->hash = icache.hash[h];
92 	icache.hash[h] = ic;
93 	ic->prev = nil;
94 	ic->next = icache.head;
95 	if(ic->next)
96 		ic->next->prev = ic;
97 	else
98 		icache.tail = ic;
99 	return ic;
100 }
101 
102 void
103 icacheflush(char *substr)
104 {
105 	Icache **l, *ic;
106 
107 	for(l=&icache.head; (ic=*l); ) {
108 		if(substr == nil || strstr(ic->url, substr)) {
109 			icache.n--;
110 			*l = ic->next;
111 			free(ic->url);
112 			close(ic->fd);
113 			remove(ic->file);
114 			free(ic->file);
115 			free(ic);
116 		}else
117 			l = &ic->next;
118 	}
119 
120 	if(icache.head) {
121 		icache.head->prev = nil;
122 		for(ic=icache.head; ic; ic=ic->next){
123 			if(ic->next)
124 				ic->next->prev = ic;
125 			else
126 				icache.tail = ic;
127 		}
128 	}else
129 		icache.tail = nil;
130 }
131 
132 int
133 urlfetch(char *url, HTTPHeader hdr)
134 {
135 	Icache *ic;
136 	char buf[50], *host, *path, *p;
137 	int fd, len;
138 
139 	ic = icachefind(url);
140 	if(ic != nil){
141 		*hdr = ic->hdr;
142 		return dup(ic->fd, -1);
143 	}
144 
145 	if(memcmp(url, "http://", 7) != 0){
146 		werrstr("non-http url");
147 		return -1;
148 	}
149 	p = strchr(url+7, '/');
150 	if(p == nil)
151 		p = url+strlen(url);
152 	len = p - (url+7);
153 	host = emalloc(len+1);
154 	memmove(host, url+7, len);
155 	host[len] = 0;
156 	if(*p == 0)
157 		p = "/";
158 
159 	strcpy(buf, "/var/tmp/smugfs.XXXXXX");
160 	fd = opentemp(buf, ORDWR|ORCLOSE);
161 	if(fd < 0)
162 		return -1;
163 	if(httptofile(http, host, req, &hdr, fd) < 0){
164 		free(host);
165 		return -1;
166 	}
167 	free(host);
168 	icacheinsert(url, &hdr, buf, fd);
169 	return fd;
170 }