https://github.com/git/git
Revision 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC, committed by Johannes Schindelin on 22 March 2023, 16:58:29 UTC
In http.c, the run_active_slot() function allows the given "slot" to make progress by calling step_active_slots() in a loop repeatedly, and the loop is not left until the request held in the slot completes. Ages ago, we used to use the slot->in_use member to get out of the loop, which misbehaved when the request in "slot" completes (at which time, the result of the request is copied away from the slot, and the in_use member is cleared, making the slot ready to be reused), and the "slot" gets reused to service a different request (at which time, the "slot" becomes in_use again, even though it is for a different request). The loop terminating condition mistakenly thought that the original request has yet to be completed. Today's code, after baa7b67d (HTTP slot reuse fixes, 2006-03-10) fixed this issue, uses a separate "slot->finished" member that is set in run_active_slot() to point to an on-stack variable, and the code that completes the request in finish_active_slot() clears the on-stack variable via the pointer to signal that the particular request held by the slot has completed. It also clears the in_use member (as before that fix), so that the slot itself can safely be reused for an unrelated request. One thing that is not quite clean in this arrangement is that, unless the slot gets reused, at which point the finished member is reset to NULL, the member keeps the value of &finished, which becomes a dangling pointer into the stack when run_active_slot() returns. Clear the finished member before the control leaves the function, which has a side effect of unconfusing compilers like recent GCC 12 that is over-eager to warn against such an assignment. Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Tip revision: 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC
http.c: clear the 'finished' member once we are done with it
http.c: clear the 'finished' member once we are done with it
Tip revision: 5843080
csum-file.h
#ifndef CSUM_FILE_H
#define CSUM_FILE_H
#include "hash.h"
struct progress;
/* A SHA1-protected file */
struct hashfile {
int fd;
int check_fd;
unsigned int offset;
git_hash_ctx ctx;
off_t total;
struct progress *tp;
const char *name;
int do_crc;
uint32_t crc32;
unsigned char buffer[8192];
};
/* Checkpoint */
struct hashfile_checkpoint {
off_t offset;
git_hash_ctx ctx;
};
void hashfile_checkpoint(struct hashfile *, struct hashfile_checkpoint *);
int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *);
/* finalize_hashfile flags */
#define CSUM_CLOSE 1
#define CSUM_FSYNC 2
#define CSUM_HASH_IN_STREAM 4
struct hashfile *hashfd(int fd, const char *name);
struct hashfile *hashfd_check(const char *name);
struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp);
int finalize_hashfile(struct hashfile *, unsigned char *, unsigned int);
void hashwrite(struct hashfile *, const void *, unsigned int);
void hashflush(struct hashfile *f);
void crc32_begin(struct hashfile *);
uint32_t crc32_end(struct hashfile *);
/*
* Returns the total number of bytes fed to the hashfile so far (including ones
* that have not been written out to the descriptor yet).
*/
static inline off_t hashfile_total(struct hashfile *f)
{
return f->total + f->offset;
}
static inline void hashwrite_u8(struct hashfile *f, uint8_t data)
{
hashwrite(f, &data, sizeof(data));
}
static inline void hashwrite_be32(struct hashfile *f, uint32_t data)
{
data = htonl(data);
hashwrite(f, &data, sizeof(data));
}
static inline size_t hashwrite_be64(struct hashfile *f, uint64_t data)
{
data = htonll(data);
hashwrite(f, &data, sizeof(data));
return sizeof(data);
}
#endif
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