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git/trace2/tr2_sysenv.c
SZEDER Gábor e4b75d6a1d trace2: rename environment variables to GIT_TRACE2*
For an environment variable that is supposed to be set by users, the
GIT_TR2* env vars are just too unclear, inconsistent, and ugly.

Most of the established GIT_* environment variables don't use
abbreviations, and in case of the few that do (GIT_DIR,
GIT_COMMON_DIR, GIT_DIFF_OPTS) it's quite obvious what the
abbreviations (DIR and OPTS) stand for.  But what does TR stand for?
Track, traditional, trailer, transaction, transfer, transformation,
transition, translation, transplant, transport, traversal, tree,
trigger, truncate, trust, or ...?!

The trace2 facility, as the '2' suffix in its name suggests, is
supposed to eventually supercede Git's original trace facility.  It's
reasonable to expect that the corresponding environment variables
follow suit, and after the original GIT_TRACE variables they are
called GIT_TRACE2; there is no such thing is 'GIT_TR'.

All trace2-specific config variables are, very sensibly, in the
'trace2' section, not in 'tr2'.

OTOH, we don't gain anything at all by omitting the last three
characters of "trace" from the names of these environment variables.

So let's rename all GIT_TR2* environment variables to GIT_TRACE2*,
before they make their way into a stable release.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-28 10:20:34 -07:00

128 lines
3.5 KiB
C

#include "cache.h"
#include "config.h"
#include "dir.h"
#include "tr2_sysenv.h"
/*
* Each entry represents a trace2 setting.
* See Documentation/technical/api-trace2.txt
*/
struct tr2_sysenv_entry {
const char *env_var_name;
const char *git_config_name;
char *value;
unsigned int getenv_called : 1;
};
/*
* This table must match "enum tr2_sysenv_variable" in tr2_sysenv.h.
*
* The strings in this table are constant and must match the published
* config and environment variable names as described in the documentation.
*
* We do not define entries for the GIT_TRACE2_PARENT_* environment
* variables because they are transient and used to pass information
* from parent to child git processes, rather than settings.
*/
/* clang-format off */
static struct tr2_sysenv_entry tr2_sysenv_settings[] = {
[TR2_SYSENV_CFG_PARAM] = { "GIT_TRACE2_CONFIG_PARAMS",
"trace2.configparams" },
[TR2_SYSENV_DST_DEBUG] = { "GIT_TRACE2_DST_DEBUG",
"trace2.destinationdebug" },
[TR2_SYSENV_NORMAL] = { "GIT_TRACE2",
"trace2.normaltarget" },
[TR2_SYSENV_NORMAL_BRIEF] = { "GIT_TRACE2_BRIEF",
"trace2.normalbrief" },
[TR2_SYSENV_EVENT] = { "GIT_TRACE2_EVENT",
"trace2.eventtarget" },
[TR2_SYSENV_EVENT_BRIEF] = { "GIT_TRACE2_EVENT_BRIEF",
"trace2.eventbrief" },
[TR2_SYSENV_EVENT_NESTING] = { "GIT_TRACE2_EVENT_NESTING",
"trace2.eventnesting" },
[TR2_SYSENV_PERF] = { "GIT_TRACE2_PERF",
"trace2.perftarget" },
[TR2_SYSENV_PERF_BRIEF] = { "GIT_TRACE2_PERF_BRIEF",
"trace2.perfbrief" },
};
/* clang-format on */
static int tr2_sysenv_cb(const char *key, const char *value, void *d)
{
int k;
if (!starts_with(key, "trace2."))
return 0;
for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++) {
if (!strcmp(key, tr2_sysenv_settings[k].git_config_name)) {
free(tr2_sysenv_settings[k].value);
tr2_sysenv_settings[k].value = xstrdup(value);
return 0;
}
}
return 0;
}
/*
* Load Trace2 settings from the system config (usually "/etc/gitconfig"
* unless we were built with a runtime-prefix). These are intended to
* define the default values for Trace2 as requested by the administrator.
*
* Then override with the Trace2 settings from the global config.
*/
void tr2_sysenv_load(void)
{
if (ARRAY_SIZE(tr2_sysenv_settings) != TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_settings size is wrong");
read_very_early_config(tr2_sysenv_cb, NULL);
}
/*
* Return the value for the requested Trace2 setting from these sources:
* the system config, the global config, and the environment.
*/
const char *tr2_sysenv_get(enum tr2_sysenv_variable var)
{
if (var >= TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_get invalid var '%d'", var);
if (!tr2_sysenv_settings[var].getenv_called) {
const char *v = getenv(tr2_sysenv_settings[var].env_var_name);
if (v && *v) {
free(tr2_sysenv_settings[var].value);
tr2_sysenv_settings[var].value = xstrdup(v);
}
tr2_sysenv_settings[var].getenv_called = 1;
}
return tr2_sysenv_settings[var].value;
}
/*
* Return a friendly name for this setting that is suitable for printing
* in an error messages.
*/
const char *tr2_sysenv_display_name(enum tr2_sysenv_variable var)
{
if (var >= TR2_SYSENV_MUST_BE_LAST)
BUG("tr2_sysenv_get invalid var '%d'", var);
return tr2_sysenv_settings[var].env_var_name;
}
void tr2_sysenv_release(void)
{
int k;
for (k = 0; k < ARRAY_SIZE(tr2_sysenv_settings); k++)
free(tr2_sysenv_settings[k].value);
}