[glib/wip/antoniof/fallback-timezone-cache-lookup: 2/3] gtimezone: Set resolved_identifier earlier
- From: António Fernandes <antoniof src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [glib/wip/antoniof/fallback-timezone-cache-lookup: 2/3] gtimezone: Set resolved_identifier earlier
- Date: Wed, 23 Sep 2020 18:23:28 +0000 (UTC)
commit 6f4c45c021258a308ef85fcec59601da58b667b9
Author: António Fernandes <antoniof gnome org>
Date: Wed Sep 23 18:28:40 2020 +0100
gtimezone: Set resolved_identifier earlier
We have been passing a &resolved_identifier address around for multiple
functions to set it. Each function may either:
1. leaving it for the next function to set, if returning early;
2. set it to a duplicate of the passed identifier, if not NULL;
3. get a fallback value and set it, otherwise.
This can be simplified by setting it early to either:
1. a duplicate of the passed identifier, if not NULL;
2. a fallback value, otherwise.
This way we can avoid some unnecessary string duplication and freeing.
Also, on Windows, we avoid calling windows_default_tzname() twice.
But the main motivation for this change is enabling the performance
optimization in the next commit.
glib/gtimezone.c | 86 ++++++++++++++++----------------------------------------
1 file changed, 24 insertions(+), 62 deletions(-)
---
diff --git a/glib/gtimezone.c b/glib/gtimezone.c
index 2e6e3ce88..42a73bd27 100644
--- a/glib/gtimezone.c
+++ b/glib/gtimezone.c
@@ -506,13 +506,11 @@ out:
}
static GBytes*
-zone_info_unix (const gchar *identifier,
- gchar **out_identifier)
+zone_info_unix (const gchar *identifier)
{
gchar *filename;
GMappedFile *file = NULL;
GBytes *zoneinfo = NULL;
- gchar *resolved_identifier = NULL;
const gchar *tzdir;
tzdir = g_getenv ("TZDIR");
@@ -525,8 +523,6 @@ zone_info_unix (const gchar *identifier,
glibc allows both syntaxes, so we should too */
if (identifier != NULL)
{
- resolved_identifier = g_strdup (identifier);
-
if (*identifier == ':')
identifier ++;
@@ -536,10 +532,7 @@ zone_info_unix (const gchar *identifier,
filename = g_build_filename (tzdir, identifier, NULL);
}
else
- {
- filename = g_strdup ("/etc/localtime");
- resolved_identifier = zone_identifier_unix ();
- }
+ filename = g_strdup ("/etc/localtime");
file = g_mapped_file_new (filename, FALSE, NULL);
if (file != NULL)
@@ -551,13 +544,6 @@ zone_info_unix (const gchar *identifier,
g_mapped_file_unref (file);
}
- g_assert (resolved_identifier != NULL);
-
-out:
- if (out_identifier != NULL)
- *out_identifier = g_steal_pointer (&resolved_identifier);
-
- g_free (resolved_identifier);
g_free (filename);
return zoneinfo;
@@ -829,14 +815,11 @@ register_tzi_to_tzi (RegTZI *reg, TIME_ZONE_INFORMATION *tzi)
static guint
rules_from_windows_time_zone (const gchar *identifier,
- gchar **out_identifier,
- TimeZoneRule **rules,
- gboolean copy_identifier)
+ TimeZoneRule **rules)
{
HKEY key;
gchar *subkey = NULL;
gchar *subkey_dynamic = NULL;
- gchar *key_name = NULL;
const gchar *reg_key =
"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones\\";
TIME_ZONE_INFORMATION tzi;
@@ -851,24 +834,14 @@ rules_from_windows_time_zone (const gchar *identifier,
if (GetSystemDirectoryW (winsyspath, MAX_PATH) == 0)
return 0;
- g_assert (copy_identifier == FALSE || out_identifier != NULL);
g_assert (rules != NULL);
- if (copy_identifier)
- *out_identifier = NULL;
-
*rules = NULL;
- key_name = NULL;
if (!identifier)
- key_name = windows_default_tzname ();
- else
- key_name = g_strdup (identifier);
-
- if (!key_name)
return 0;
- subkey = g_strconcat (reg_key, key_name, NULL);
+ subkey = g_strconcat (reg_key, identifier, NULL);
subkey_w = g_utf8_to_utf16 (subkey, -1, NULL, NULL, NULL);
if (subkey_w == NULL)
goto utf16_conv_failed;
@@ -1006,16 +979,9 @@ utf16_conv_failed:
else
(*rules)[rules_num - 1].start_year = (*rules)[rules_num - 2].start_year + 1;
- if (copy_identifier)
- *out_identifier = g_steal_pointer (&key_name);
- else
- g_free (key_name);
-
return rules_num;
}
- g_free (key_name);
-
return 0;
}
@@ -1516,16 +1482,13 @@ parse_identifier_boundaries (gchar **pos, TimeZoneRule *tzr)
*/
static guint
rules_from_identifier (const gchar *identifier,
- gchar **out_identifier,
TimeZoneRule **rules)
{
gchar *pos;
TimeZoneRule tzr;
- g_assert (out_identifier != NULL);
g_assert (rules != NULL);
- *out_identifier = NULL;
*rules = NULL;
if (!identifier)
@@ -1540,7 +1503,6 @@ rules_from_identifier (const gchar *identifier,
if (*pos == 0)
{
- *out_identifier = g_strdup (identifier);
return create_ruleset_from_rule (rules, &tzr);
}
@@ -1560,15 +1522,11 @@ rules_from_identifier (const gchar *identifier,
/* Use US rules, Windows' default is Pacific Standard Time */
if ((rules_num = rules_from_windows_time_zone ("Pacific Standard Time",
- NULL,
- rules,
- FALSE)))
+ rules)))
{
/* We don't want to hardcode our identifier here as
* "Pacific Standard Time", use what was passed in
*/
- *out_identifier = g_strdup (identifier);
-
for (i = 0; i < rules_num - 1; i++)
{
(*rules)[i].std_offset = - tzr.std_offset;
@@ -1589,7 +1547,6 @@ rules_from_identifier (const gchar *identifier,
if (!parse_identifier_boundaries (&pos, &tzr))
return 0;
- *out_identifier = g_strdup (identifier);
return create_ruleset_from_rule (rules, &tzr);
}
@@ -1600,17 +1557,13 @@ parse_footertz (const gchar *footer, size_t footerlen)
gchar *tzstring = g_strndup (footer + 1, footerlen - 2);
GTimeZone *footertz = NULL;
- /* FIXME: it might make sense to modify rules_from_identifier to
- allow NULL to be passed instead of &ident, saving the strdup/free
- pair. The allocation for tzstring could also be avoided by
+ /* FIXME: The allocation for tzstring could be avoided by
passing a gsize identifier_len argument to rules_from_identifier
and changing the code in that function to stop assuming that
identifier is nul-terminated. */
- gchar *ident;
TimeZoneRule *rules;
- guint rules_num = rules_from_identifier (tzstring, &ident, &rules);
+ guint rules_num = rules_from_identifier (tzstring, &rules);
- g_free (ident);
g_free (tzstring);
if (rules_num > 1)
{
@@ -1709,6 +1662,17 @@ g_time_zone_new (const gchar *identifier)
if (time_zones == NULL)
time_zones = g_hash_table_new (g_str_hash, g_str_equal);
+ if (identifier != NULL)
+ resolved_identifier = g_strdup (identifier);
+ else
+ {
+#ifdef G_OS_UNIX
+ resolved_identifier = zone_identifier_unix ();
+#elif defined (G_OS_WIN32)
+ resolved_identifier = windows_default_tzname ();
+#endif
+ }
+
if (identifier)
{
tz = g_hash_table_lookup (time_zones, identifier);
@@ -1716,6 +1680,7 @@ g_time_zone_new (const gchar *identifier)
{
g_atomic_int_inc (&tz->ref_count);
G_UNLOCK (time_zones);
+ g_free (resolved_identifier);
return tz;
}
}
@@ -1726,26 +1691,23 @@ g_time_zone_new (const gchar *identifier)
zone_for_constant_offset (tz, identifier);
if (tz->t_info == NULL &&
- (rules_num = rules_from_identifier (identifier, &resolved_identifier, &rules)))
+ (rules_num = rules_from_identifier (identifier, &rules)))
{
- init_zone_from_rules (tz, rules, rules_num, g_steal_pointer (&resolved_identifier));
+ init_zone_from_rules (tz, rules, rules_num, g_strdup (identifier));
g_free (rules);
}
if (tz->t_info == NULL)
{
#ifdef G_OS_UNIX
- GBytes *zoneinfo = zone_info_unix (identifier, &resolved_identifier);
+ GBytes *zoneinfo = zone_info_unix (identifier);
if (zoneinfo != NULL)
{
init_zone_from_iana_info (tz, zoneinfo, g_steal_pointer (&resolved_identifier));
g_bytes_unref (zoneinfo);
}
#elif defined (G_OS_WIN32)
- if ((rules_num = rules_from_windows_time_zone (identifier,
- &resolved_identifier,
- &rules,
- TRUE)))
+ if ((rules_num = rules_from_windows_time_zone (resolved_identifier, &rules)))
{
init_zone_from_rules (tz, rules, rules_num, g_steal_pointer (&resolved_identifier));
g_free (rules);
@@ -1772,7 +1734,7 @@ g_time_zone_new (const gchar *identifier)
rules[0].start_year = MIN_TZYEAR;
rules[1].start_year = MAX_TZYEAR;
- init_zone_from_rules (tz, rules, 2, windows_default_tzname ());
+ init_zone_from_rules (tz, rules, 2, resolved_identifier);
}
g_free (rules);
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