ref: 963cfc9a6f6e721f52aa949e6d1af0c3e8dc2ecc
dir: /sys/src/cmd/upas/fs/cache.c/
#include "common.h"
#include <libsec.h>
#include "dat.h"
int
findcache(Mcache *c, Message *m)
{
int i;
for(i = 0; i < c->ntab; i++)
if(c->ctab[i] == m)
return i;
return -1;
}
static void
prcache(Mcache *c, char *prefix)
{
int j;
Message *m;
if(!debug)
return;
for(j = 0; j < c->ntab; j++){
m = c->ctab[j];
dprint("%s%d/%s\t%p\t%d\t%ld\n", prefix, j, m->name, m, m->refs, m->csize);
}
}
/* debugging only */
static void
dupchk(Mcache *c)
{
int i, j;
if(!debug)
return;
for(i = 0; i < c->ntab; i++)
for(j = i + 1; j < c->ntab; j++)
if(c->ctab[i] == c->ctab[j])
goto lose;
return;
lose:
for(j = 0; j < c->ntab; j++)
dprint("%d\t%p %d\t%ld\n", j, c->ctab[j], c->ctab[j]->refs, c->ctab[j]->size);
abort();
}
int
addcache(Mcache *c, Message *m)
{
int i;
if((i = findcache(c, m)) < 0){
if(c->ntab + 1 == nelem(c->ctab))
abort();
i = c->ntab++;
}else{
/* rotate */
if(i == c->ntab - 1)
return i; /* silly shortcut to prevent excessive printage. */
dprint("addcache rotate %d %d\n", i, c->ntab);
prcache(c, "");
memmove(c->ctab + i, c->ctab + i + 1, (c->ntab - i - 1)*sizeof c->ctab[0]);
i = c->ntab - 1;
c->ctab[i] = m;
dupchk(c);
}
dprint("addcache %d %d %p\n", i, c->ntab, m);
c->ctab[i] = m;
return i;
}
static void
notecache(Mailbox *mb, Message *m, long sz)
{
assert(Topmsg(mb, m));
assert(sz >= 0 && sz < Maxmsg);
m->csize += sz;
mb->cached += sz;
addcache(mb, m);
}
static long
cachefree0(Mailbox *mb, Message *m, int force)
{
long sz, i;
Message *s;
if(!force && !mb->fetch)
return 0;
for(s = m->part; s; s = s->next)
cachefree(mb, s, force);
dprint("cachefree: %D %p, %p\n", m->fileid, m, m->start);
if(m->mallocd){
free(m->start);
m->mallocd = 0;
}
if(m->ballocd){
free(m->body);
m->ballocd = 0;
}
if(m->hallocd){
free(m->header);
m->hallocd = 0;
}
for(i = 0; i < nelem(m->references); i++){
free(m->references[i]);
m->references[i] = 0;
}
sz = m->csize;
m->csize = 0;
m->start = 0;
m->end = 0;
m->header = 0;
m->hend = 0;
m->hlen = -1;
m->body = 0;
m->bend = 0;
m->mheader = 0;
m->mhend = 0;
if(mb->decache)
mb->decache(mb, m);
m->decoded = 0;
m->converted = 0;
m->badchars = 0;
m->cstate &= ~(Cheader|Cbody);
if(Topmsg(mb, m))
mb->cached -= sz;
return sz;
}
long
cachefree(Mailbox *mb, Message *m, int force)
{
long sz, i;
sz = cachefree0(mb, m, force);
for(i = 0; i < mb->ntab; i++)
if(m == mb->ctab[i]){
mb->ntab--;
memmove(mb->ctab + i, mb->ctab + i + 1, sizeof m*mb->ntab - i);
dupchk(mb);
break;
}
return sz;
}
enum{
Maxntab = nelem(mbl->ctab) - 10,
};
vlong
sumcache(Mcache *c)
{
int i;
vlong sz;
sz = 0;
for(i = 0; i < c->ntab; i++)
sz += c->ctab[i]->csize;
return sz;
}
int
scancache(Mcache *c)
{
int i;
for(i = 0; i < c->ntab; i++)
if(c->ctab[i]->csize > Maxmsg)
return -1;
return 0;
}
/* debugging only */
static void
chkcsize(Mailbox *mb, vlong sz, vlong sz0)
{
int j;
Mcache *c;
Message *m;
if(sumcache(mb) == mb->cached)
if(scancache(mb) == 0)
return;
eprint("sz0 %lld sz %lld sum %lld sumca %lld\n", sz0, sz, sumcache(mb), mb->cached);
eprint("%lld\n", sumcache(mb));
c = mb;
for(j = 0; j < c->ntab; j++){
m = c->ctab[j];
eprint("%d %p %d %ld %ld\n", j, m, m->refs, m->csize, m->size);
}
abort();
}
/*
* strategy: start with i = 0. while cache exceeds limits,
* find j so that all the [i:j] elements have refs == 0.
* uncache all the [i:j], reduce ntab by i-j. the tail
* [j+1:ntab] is shifted to [i:ntab], and finally i = i+1.
* we may safely skip the new i, since the condition
* that stopped our scan there still holds.
*/
void
putcache(Mailbox *mb, Message *m)
{
int i, j, k;
vlong sz, sz0;
Message **p;
p = mb->ctab;
sz0 = mb->cached;
dupchk(mb);
for(i = 0;; i++){
sz = mb->cached;
for(j = i;; j++){
if(j >= mb->ntab ||
sz < cachetarg && mb->ntab - (j - i) < Maxntab){
if(j != i)
break;
chkcsize(mb, sz, sz0);
return;
}
if(p[j]->refs > 0)
break;
sz -= p[j]->csize;
}
if(sz == mb->cached){
if(i >= mb->ntab)
break;
continue;
}
for(k = i; k < j; k++)
cachefree0(mb, p[k], 0);
mb->ntab -= j - i;
memmove(p + i, p + j, (mb->ntab - i)*sizeof *p);
}
chkcsize(mb, sz, sz0);
k = 0;
for(i = 0; i < mb->ntab; i++)
k += p[i]->refs > 0;
if((mb->ntab > 1 || k != mb->ntab) && Topmsg(mb, m))
eprint("cache overflow: %D %llud bytes; %d entries\n",
m? m->fileid: 1ll, mb->cached, mb->ntab);
if(k == mb->ntab)
return;
debug = 1; prcache(mb, "");
abort();
}
static int
squeeze(Message *m, uvlong o, long l, int c)
{
char *p, *q, *e;
int n;
q = memchr(m->start + o, c, l);
if(q == nil)
return 0;
n = 0;
e = m->start + o + l;
for(p = q; q < e; q++){
if(*q == c){
n++;
continue;
}
*p++ = *q;
}
return n;
}
void
msgrealloc(Message *m, ulong l)
{
long l0, h0, m0, me, b0;
l0 = m->end - m->start;
m->mallocd = 1;
h0 = m->hend - m->start;
m0 = m->mheader - m->start;
me = m->mhend - m->start;
b0 = m->body - m->start;
assert(h0 >= 0 && m0 >= 0 && me >= 0 && b0 >= 0);
m->start = erealloc(m->start, l + 1);
m->rbody = m->start + b0;
m->rbend = m->end = m->start + l0;
if(!m->hallocd){
m->header = m->start;
m->hend = m->start + h0;
}
if(!m->ballocd){
m->body = m->start + b0;
m->bend = m->start + l0;
}
m->mheader = m->start + m0;
m->mhend = m->start + me;
}
/*
* the way we squeeze out bad characters is exceptionally sneaky.
*/
static int
fetch(Mailbox *mb, Message *m, uvlong o, ulong l)
{
int expand;
long l0, n, sz0;
top:
l0 = m->end - m->start;
assert(l0 >= 0);
dprint("fetch %lud sz %lud o %llud l %lud badchars %d\n", l0, m->size, o, l, m->badchars);
assert(m->badchars < Maxmsg/10);
if(l0 == m->size || o > m->size)
return 0;
expand = 0;
if(o + l > m->size)
l = m->size - o;
if(o + l == m->size)
l += m->ibadchars - m->badchars;
if(o + l > l0){
expand = 1;
msgrealloc(m, o + m->badchars + l);
}
assert(l0 <= o);
sz0 = m->size;
if(mb->fetch(mb, m, o + m->badchars, l) == -1){
logmsg(m, "can't fetch %D %llud %lud", m->fileid, o, l);
m->deleted = Dead;
return -1;
}
if(m->size - sz0)
l += m->size - sz0; /* awful botch for gmail */
if(expand){
/* grumble. poor planning. */
if(m->badchars > 0)
memmove(m->start + o, m->start + o + m->badchars, l);
n = squeeze(m, o, l, 0);
n += squeeze(m, o, l - n, '\r');
if(n > 0){
if(m->ibadchars == 0)
dprint(" %ld more badchars\n", n);
l -= n;
m->badchars += n;
msgrealloc(m, o + l);
}
notecache(mb, m, l);
m->bend = m->rbend = m->end = m->start + o + l;
if(n)
if(o + l + n == m->size && m->cstate&Cidx){
dprint(" redux %llud %ld\n", o + l, n);
o += l;
l = n;
goto top;
}
}else
eprint("unhandled case in fetch\n");
*m->end = 0;
return 0;
}
void
cachehash(Mailbox *mb, Message *m)
{
// fprint(2, "cachehash %P\n", mpair(mb, m));
if(m->whole == m->whole->whole)
henter(PATH(mb->id, Qmbox), m->name,
(Qid){PATH(m->id, Qdir), 0, QTDIR}, m, mb);
else
henter(PATH(m->whole->id, Qdir), m->name,
(Qid){PATH(m->id, Qdir), 0, QTDIR}, m, mb);
henter(PATH(m->id, Qdir), "xxx",
(Qid){PATH(m->id, Qmax), 0, QTFILE}, m, mb); /* sleezy speedup */
}
void
newcachehash(Mailbox *mb, Message *m, int doplumb)
{
if(doplumb)
mailplumb(mb, m, 0);
else
if(insurecache(mb, m) == 0)
msgdecref(mb, m);
/* avoid cachehash on error? */
cachehash(mb, m);
}
static char *itab[] = {
"idx",
"stale",
"header",
"body"
};
char*
cstate(Message *m)
{
char *p, *e;
int i, s;
static char buf[64];
s = m->cstate;
p = e = buf;
e += sizeof buf;
for(i = 0; i < 8; i++)
if(s & 1<<i)
if(i < nelem(itab))
p = seprint(p, e, "%s ", itab[i]);
if(p > buf)
p--;
p[0] = 0;
return buf;
}
static int
middlecache(Mailbox *mb, Message *m)
{
int y;
y = 0;
while(!Topmsg(mb, m)){
m = m->whole;
if((m->cstate & Cbody) == 0)
y = 1;
}
if(y == 0)
return 0;
dprint("middlecache %d [%D] %lud %lud\n", m->id, m->fileid, m->end - m->start, m->size);
return cachebody(mb, m);
}
int
cacheheaders(Mailbox *mb, Message *m)
{
char *p, *e;
int r;
ulong o;
if(!mb->fetch || m->cstate&Cheader)
return 0;
if(!Topmsg(mb, m))
return middlecache(mb, m);
dprint("cacheheaders %d %D\n", m->id, m->fileid);
if(m->size < 10000)
r = fetch(mb, m, 0, m->size);
else for(r = 0; (o = m->end - m->start) < m->size; ){
if((r = fetch(mb, m, o, 4096)) < 0)
break;
p = m->start + o;
if(o)
p--;
for(e = m->end - 2; p < e; p++){
p = memchr(p, '\n', e - p);
if(p == nil)
break;
if(p[1] == '\n' || (p[1] == '\r' && p[2] == '\n'))
goto found;
}
}
if(r < 0)
return -1;
found:
parseheaders(mb, m, mb->addfrom, 0);
return 0;
}
void
digestmessage(Mailbox *mb, Message *m)
{
assert(m->digest == 0);
m->digest = emalloc(SHA1dlen);
sha1((uchar*)m->start, m->end - m->start, m->digest, nil);
if(mtreeisdup(mb, m)){
logmsg(m, "dup detected");
m->deleted = Dup; /* no dups allowed */
}else
mtreeadd(mb, m);
dprint("%d %#A\n", m->id, m->digest);
}
int
cachebody(Mailbox *mb, Message *m)
{
ulong o;
while(!Topmsg(mb, m))
m = m->whole;
if(!mb->fetch || m->cstate&Cbody)
return 0;
o = m->end - m->start;
dprint("cachebody %d [%D] %lud %lud %s\n", m->id, m->fileid, o, m->size, cstate(m));
if(o < m->size)
if(fetch(mb, m, o, m->size - o) < 0)
return -1;
if((m->cstate&Cidx) == 0){
assert(m->ibadchars == 0);
if(m->badchars > 0)
dprint("reducing size %ld %ld\n", m->size, m->size - m->badchars);
m->size -= m->badchars; /* sneaky */
m->ibadchars = m->badchars;
}
if(m->digest == 0)
digestmessage(mb, m);
if(m->lines == 0)
m->lines = countlines(m);
parse(mb, m, mb->addfrom, 0);
dprint(" →%s\n", cstate(m));
return 0;
}
int
cacheidx(Mailbox *mb, Message *m)
{
if(m->cstate & Cidx)
return 0;
if(cachebody(mb, m) == -1)
return -1;
m->cstate |= Cidxstale|Cidx;
return 0;
}
static int
countparts(Message *m)
{
Message *p;
if(m->nparts == 0)
for(p = m->part; p; p = p->next){
countparts(p);
m->nparts++;
}
return m->nparts;
}
int
insurecache(Mailbox *mb, Message *m)
{
if(m->deleted || !m->inmbox)
return -1;
msgincref(m);
cacheidx(mb, m);
if((m->cstate & Cidx) == 0){
logmsg(m, "%s: can't cache: %s: %r", mb->path, m->name);
msgdecref(mb, m);
return -1;
}
if(m->digest == 0)
sysfatal("digest?");
countparts(m);
return 0;
}