Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "trace2/tr2_sid.h"
   3
   4#define TR2_ENVVAR_PARENT_SID "GIT_TR2_PARENT_SID"
   5
   6static struct strbuf tr2sid_buf = STRBUF_INIT;
   7static int tr2sid_nr_git_parents;
   8
   9/*
  10 * Compute a "unique" session id (SID) for the current process.  This allows
  11 * all events from this process to have a single label (much like a PID).
  12 *
  13 * Export this into our environment so that all child processes inherit it.
  14 *
  15 * If we were started by another git instance, use our parent's SID as a
  16 * prefix.  (This lets us track parent/child relationships even if there
  17 * is an intermediate shell process.)
  18 *
  19 * Additionally, count the number of nested git processes.
  20 */
  21static void tr2_sid_compute(void)
  22{
  23        uint64_t us_now;
  24        const char *parent_sid;
  25
  26        if (tr2sid_buf.len)
  27                return;
  28
  29        parent_sid = getenv(TR2_ENVVAR_PARENT_SID);
  30        if (parent_sid && *parent_sid) {
  31                const char *p;
  32                for (p = parent_sid; *p; p++)
  33                        if (*p == '/')
  34                                tr2sid_nr_git_parents++;
  35
  36                strbuf_addstr(&tr2sid_buf, parent_sid);
  37                strbuf_addch(&tr2sid_buf, '/');
  38                tr2sid_nr_git_parents++;
  39        }
  40
  41        us_now = getnanotime() / 1000;
  42        strbuf_addf(&tr2sid_buf, "%" PRIuMAX "-%" PRIdMAX, (uintmax_t)us_now,
  43                    (intmax_t)getpid());
  44
  45        setenv(TR2_ENVVAR_PARENT_SID, tr2sid_buf.buf, 1);
  46}
  47
  48const char *tr2_sid_get(void)
  49{
  50        if (!tr2sid_buf.len)
  51                tr2_sid_compute();
  52
  53        return tr2sid_buf.buf;
  54}
  55
  56int tr2_sid_depth(void)
  57{
  58        if (!tr2sid_buf.len)
  59                tr2_sid_compute();
  60
  61        return tr2sid_nr_git_parents;
  62}
  63
  64void tr2_sid_release(void)
  65{
  66        strbuf_release(&tr2sid_buf);
  67}