git/trace2/tr2_sid.c

68 строки
1.5 KiB
C

#include "cache.h"
#include "trace2/tr2_sid.h"
#define TR2_ENVVAR_PARENT_SID "GIT_TR2_PARENT_SID"
static struct strbuf tr2sid_buf = STRBUF_INIT;
static int tr2sid_nr_git_parents;
/*
* Compute a "unique" session id (SID) for the current process. This allows
* all events from this process to have a single label (much like a PID).
*
* Export this into our environment so that all child processes inherit it.
*
* If we were started by another git instance, use our parent's SID as a
* prefix. (This lets us track parent/child relationships even if there
* is an intermediate shell process.)
*
* Additionally, count the number of nested git processes.
*/
static void tr2_sid_compute(void)
{
uint64_t us_now;
const char *parent_sid;
if (tr2sid_buf.len)
return;
parent_sid = getenv(TR2_ENVVAR_PARENT_SID);
if (parent_sid && *parent_sid) {
const char *p;
for (p = parent_sid; *p; p++)
if (*p == '/')
tr2sid_nr_git_parents++;
strbuf_addstr(&tr2sid_buf, parent_sid);
strbuf_addch(&tr2sid_buf, '/');
tr2sid_nr_git_parents++;
}
us_now = getnanotime() / 1000;
strbuf_addf(&tr2sid_buf, "%" PRIuMAX "-%" PRIdMAX, (uintmax_t)us_now,
(intmax_t)getpid());
setenv(TR2_ENVVAR_PARENT_SID, tr2sid_buf.buf, 1);
}
const char *tr2_sid_get(void)
{
if (!tr2sid_buf.len)
tr2_sid_compute();
return tr2sid_buf.buf;
}
int tr2_sid_depth(void)
{
if (!tr2sid_buf.len)
tr2_sid_compute();
return tr2sid_nr_git_parents;
}
void tr2_sid_release(void)
{
strbuf_release(&tr2sid_buf);
}