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Replace EFF_RDONLY by EFF_PRIVATE

Browse source 
Read-only was a bit of a misnomer: you could write to the table by
obtaining a pointer into it from ef_ptr(), you just couldn't write to
the backing file.

Semantic changes:

* ef_flush() is now allowed when the table is file-backed or privately
  mapped.  Before, it had to be file-backed.  Flushing a privately
  mapped table does nothing, just like flushing a read-only table did.

* ef_write() is now allowed when the table is file-backed or fully
  cached.  Before, it had to be file-backed and not read-only.
  Writing to a privately mapped file-backed table doesn't write to the
  file.

* ef_extend() is not implemented for privately mapped tables, just
  like it wasn't implemented for read-only tables.
This commit is contained in:
Markus Armbruster 2008-02-21 21:04:11 +01:00
parent ef71897051
commit f8dcb7b07b
3 changed files with 28 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

30
src/lib/common/file.c
View file

@ -73,7 +73,7 @@ ef_open(int type, int how)
if (CANT_HAPPEN(ep->fd >= 0))
return 0;
oflags = O_RDWR;
if (how & EFF_RDONLY)
if (how & EFF_PRIVATE)
oflags = O_RDONLY;
if (how & EFF_CREATE)
oflags |= O_CREAT | O_TRUNC;
@ -85,7 +85,7 @@ ef_open(int type, int how)
return 0;
}
lock.l_type = how & EFF_RDONLY ? F_RDLCK : F_WRLCK;
lock.l_type = how & EFF_PRIVATE ? F_RDLCK : F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0;
if (fcntl(fd, F_SETLK, &lock) == -1) {
@ -177,7 +177,8 @@ ef_close(int type)
}
/*
* Flush file-backed table TYPE (EF_SECTOR, ...) to disk.
* Flush table TYPE (EF_SECTOR, ...) to disk.
* Does nothing if the table is privately mapped.
* Return non-zero on success, zero on failure.
*/
int
@ -188,6 +189,8 @@ ef_flush(int type)
if (ef_check(type) < 0)
return 0;
ep = &empfile[type];
if (ep->flags & EFF_PRIVATE)
return 1; /* nothing to do */
if (CANT_HAPPEN(ep->fd < 0))
return 0;
/*
@ -196,7 +199,7 @@ ef_flush(int type)
* allowed only with EFF_MEM. Assume the whole cash is dirty
* then.
*/
if (!(ep->flags & EFF_RDONLY) && (ep->flags & EFF_MEM))
if (ep->flags & EFF_MEM)
return do_write(ep, ep->cache, ep->baseid, ep->cids) >= 0;
return 1;
@ -311,7 +314,8 @@ do_write(struct empfile *ep, void *buf, int id, int count)
int n, ret;
char *p;
if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
if (CANT_HAPPEN(ep->fd < 0 || (ep->flags & EFF_PRIVATE)
|| id < 0 || count < 0))
return -1;
if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
@ -339,9 +343,10 @@ do_write(struct empfile *ep, void *buf, int id, int count)
}
/*
* Write element ID into file-backed table TYPE from buffer FROM.
* Write element ID into table TYPE from buffer FROM.
* FIXME pass buffer size!
* Write through cache straight to disk.
* If table is file-backed and not privately mapped, write through
* cache straight to disk.
* Cannot write beyond the end of fully cached table (flags & EFF_MEM).
* Can write at the end of partially cached table.
* Return non-zero on success, zero on failure.
@ -355,12 +360,16 @@ ef_write(int type, int id, void *from)
if (ef_check(type) < 0)
return 0;
ep = &empfile[type];
if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
return 0;
if (ep->prewrite)
ep->prewrite(id, from);
if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
return 0; /* not implemented */
if (do_write(ep, from, id, 1) < 0)
return 0;
if (!(ep->flags & EFF_PRIVATE)) {
if (do_write(ep, from, id, 1) < 0)
return 0;
}
if (id >= ep->baseid && id < ep->baseid + ep->cids) {
/* update the cache if necessary */
to = ep->cache + (id - ep->baseid) * ep->size;
@ -376,6 +385,7 @@ ef_write(int type, int id, void *from)
/*
* Extend the file-backed table TYPE by COUNT elements.
* Can't extend privately mapped tables.
* Return non-zero on success, zero on failure.
*/
int
@ -390,6 +400,8 @@ ef_extend(int type, int count)
ep = &empfile[type];
if (CANT_HAPPEN(ep->fd < 0 || count < 0))
return 0;
if (CANT_HAPPEN(ep->flags & EFF_PRIVATE))
return 0; /* not implemented */
tmpobj = calloc(1, ep->size);
id = ep->fids;