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Rewrite ZipOS

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This reduces the virtual memory usage of Emacs for me by 30%. We now
have a simpler implementation that uses read(), rather mmap()ing the
whole executable.
This commit is contained in:
Justine Tunney 2023-10-03 07:27:25 -07:00
parent ff77f2a6af
commit b01282e23e
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GPG key ID: BE714B4575D6E328
21 changed files with 408 additions and 421 deletions
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42
libc/runtime/zipos-find.c
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@ -24,11 +24,11 @@
#include "libc/sysv/errfuns.h"
#include "libc/zip.internal.h"
static ssize_t __zipos_match(struct Zipos *z, struct ZiposUri *name, int len,
int i) {
size_t cfile = z->index[i];
const char *zname = ZIP_CFILE_NAME(z->map + cfile);
int zsize = ZIP_CFILE_NAMESIZE(z->map + cfile);
static int __zipos_match(struct Zipos *z, struct ZiposUri *name, int len,
int i) {
int cfile = z->index[i];
const char *zname = ZIP_CFILE_NAME(z->cdir + cfile);
int zsize = ZIP_CFILE_NAMESIZE(z->cdir + cfile);
if ((len == zsize || (len + 1 == zsize && zname[len] == '/')) &&
!memcmp(name->path, zname, len)) {
return cfile;
@ -40,7 +40,7 @@ static ssize_t __zipos_match(struct Zipos *z, struct ZiposUri *name, int len,
}
}
ssize_t __zipos_scan(struct Zipos *zipos, struct ZiposUri *name) {
int __zipos_scan(struct Zipos *zipos, struct ZiposUri *name) {
// strip trailing slash from search name
int len = name->len;
@ -55,12 +55,12 @@ ssize_t __zipos_scan(struct Zipos *zipos, struct ZiposUri *name) {
// binary search for leftmost name in central directory
int l = 0;
int r = zipos->records;
int r = zipos->cnt;
while (l < r) {
int m = (l & r) + ((l ^ r) >> 1); // floor((a+b)/2)
const char *xp = ZIP_CFILE_NAME(zipos->map + zipos->index[m]);
const char *xp = ZIP_CFILE_NAME(zipos->cdir + zipos->index[m]);
const char *yp = name->path;
int xn = ZIP_CFILE_NAMESIZE(zipos->map + zipos->index[m]);
int xn = ZIP_CFILE_NAMESIZE(zipos->cdir + zipos->index[m]);
int yn = len;
int n = MIN(xn, yn);
int c;
@ -78,25 +78,25 @@ ssize_t __zipos_scan(struct Zipos *zipos, struct ZiposUri *name) {
}
}
if (l < zipos->records) {
if (l < zipos->cnt) {
int dx;
size_t cfile = zipos->index[l];
const char *zname = ZIP_CFILE_NAME(zipos->map + cfile);
int zsize = ZIP_CFILE_NAMESIZE(zipos->map + cfile);
int cfile = zipos->index[l];
const char *zname = ZIP_CFILE_NAME(zipos->cdir + cfile);
int zsize = ZIP_CFILE_NAMESIZE(zipos->cdir + cfile);
if (zsize > len && (dx = '/' - (zname[len] & 255))) {
// since the index is asciibetical, we need to specially handle
// the case where, when searching for a directory, regular files
// exist whose names share the same prefix as the directory name.
dx = dx > +1 ? +1 : dx;
dx = dx < -1 ? -1 : dx;
for (l += dx; 0 <= l && l < zipos->records; l += dx) {
ssize_t cf;
for (l += dx; 0 <= l && l < zipos->cnt; l += dx) {
int cf;
if ((cf = __zipos_match(zipos, name, len, l)) != -1) {
return cf;
}
cfile = zipos->index[l];
zname = ZIP_CFILE_NAME(zipos->map + cfile);
zsize = ZIP_CFILE_NAMESIZE(zipos->map + cfile);
zname = ZIP_CFILE_NAME(zipos->cdir + cfile);
zsize = ZIP_CFILE_NAMESIZE(zipos->cdir + cfile);
if (zsize < len || (len && zname[len - 1] != name->path[len - 1])) {
break;
}
@ -112,8 +112,8 @@ ssize_t __zipos_scan(struct Zipos *zipos, struct ZiposUri *name) {
}
// support code for open(), stat(), and access()
ssize_t __zipos_find(struct Zipos *zipos, struct ZiposUri *name) {
ssize_t cf;
int __zipos_find(struct Zipos *zipos, struct ZiposUri *name) {
int cf;
if ((cf = __zipos_scan(zipos, name)) == -1) {
// test if parent component exists that isn't a directory
char *p;
@ -121,7 +121,7 @@ ssize_t __zipos_find(struct Zipos *zipos, struct ZiposUri *name) {
name->path[name->len = p - name->path] = 0;
if ((cf = __zipos_scan(zipos, name)) != -1 &&
cf != ZIPOS_SYNTHETIC_DIRECTORY &&
!S_ISDIR(GetZipCfileMode(zipos->map + cf))) {
!S_ISDIR(GetZipCfileMode(zipos->cdir + cf))) {
return enotdir();
}
}
@ -130,7 +130,7 @@ ssize_t __zipos_find(struct Zipos *zipos, struct ZiposUri *name) {
// test if we're opening "foo/" and "foo" isn't a directory
if (cf != ZIPOS_SYNTHETIC_DIRECTORY && //
name->len && name->path[name->len - 1] == '/' &&
!S_ISDIR(GetZipCfileMode(zipos->map + cf))) {
!S_ISDIR(GetZipCfileMode(zipos->cdir + cf))) {
return enotdir();
}
return cf;