Get users' and groups' names via a cache to avoid calling

2006-02-26  Zbigniew Chyla  <mail@zbigniew.chyla.pl>

	Get users' and groups' names via a cache to avoid calling
	getpwuid/getgrgid too often (i.e. many times during single redraw).

	* libnautilus-private/Makefile.am: (libnautilus_private_la_SOURCES):
	Added nautilus-users-groups-cache.[ch]
	* libnautilus-private/nautilus-users-groups-cache.[ch]: New,
	implementation of cache for getpwuid/getgrgid results.
	* libnautilus-private/nautilus-file.c:
	(get_user_name_from_id): removed
	(get_real_name): accept "name + gecos" pair instead of "struct passwd".
	(get_user_and_real_name_from_id): get user name and gecos using
	nautilus_users_cache_* functions instead of using getpwuid directly.
	(nautilus_get_user_names): adjusted to changed signature of get_real_name.
	(nautilus_file_get_group_name): get group name using
	nautilus_groups_cache_get_name instead of using getgrgid directly.
	(nautilus_file_get_owner_as_string): get user name using
	nautilus_users_cache_get_name.

ChangeLog

@@ -1,3 +1,23 @@
+2006-02-26  Zbigniew Chyla  <mail@zbigniew.chyla.pl>
+
+	Get users' and groups' names via a cache to avoid calling
+	getpwuid/getgrgid too often (i.e. many times during single redraw).
+
+	* libnautilus-private/Makefile.am: (libnautilus_private_la_SOURCES):
+	Added nautilus-users-groups-cache.[ch]
+	* libnautilus-private/nautilus-users-groups-cache.[ch]: New,
+	implementation of cache for getpwuid/getgrgid results.
+	* libnautilus-private/nautilus-file.c:
+	(get_user_name_from_id): removed
+	(get_real_name): accept "name + gecos" pair instead of "struct passwd".
+	(get_user_and_real_name_from_id): get user name and gecos using
+	nautilus_users_cache_* functions instead of using getpwuid directly.
+	(nautilus_get_user_names): adjusted to changed signature of get_real_name.
+	(nautilus_file_get_group_name): get group name using
+	nautilus_groups_cache_get_name instead of using getgrgid directly.
+	(nautilus_file_get_owner_as_string): get user name using
+	nautilus_users_cache_get_name.
+
 2006-02-26  Zbigniew Chyla  <mail@zbigniew.chyla.pl>
 
 	Don't add all possible columns to GtkTreeView when initializing

libnautilus-private/Makefile.am

@@ -193,6 +193,8 @@ libnautilus_private_la_SOURCES = \
 	nautilus-undo-transaction.h \
 	nautilus-undo.c \
 	nautilus-undo.h \
+	nautilus-users-groups-cache.c \
+	nautilus-users-groups-cache.h \
 	nautilus-vfs-directory.c \
 	nautilus-vfs-directory.h \
 	nautilus-vfs-file.c \

libnautilus-private/nautilus-file.c

@@ -45,6 +45,7 @@
 #include "nautilus-thumbnails.h"
 #include "nautilus-trash-directory.h"
 #include "nautilus-trash-file.h"
+#include "nautilus-users-groups-cache.h"
 #include "nautilus-vfs-file.h"
 #include "nautilus-saved-search-file.h"
 #include <eel/eel-debug.h>
@@ -3537,30 +3538,15 @@ nautilus_file_set_permissions (NautilusFile *file,
 }
 
 static char *
-get_user_name_from_id (uid_t uid)
-{
-	struct passwd *password_info;
-	
-	/* No need to free result of getpwuid */
-	password_info = getpwuid (uid);
-
-	if (password_info == NULL) {
-		return NULL;
-	}
-	
-	return g_strdup (password_info->pw_name);
-}
-
-static char *
-get_real_name (struct passwd *user)
+get_real_name (const char *name, const char *gecos)
 {
 	char *locale_string, *part_before_comma, *capitalized_login_name, *real_name;
 
-	if (user->pw_gecos == NULL) {
+	if (gecos == NULL) {
 		return NULL;
 	}
 
-	locale_string = eel_str_strip_substring_and_after (user->pw_gecos, ",");
+	locale_string = eel_str_strip_substring_and_after (gecos, ",");
 	if (!g_utf8_validate (locale_string, -1, NULL)) {
 		part_before_comma = g_locale_to_utf8 (locale_string, -1, NULL, NULL, NULL);
 		g_free (locale_string);
@@ -3568,10 +3554,10 @@ get_real_name (struct passwd *user)
 		part_before_comma = locale_string;
 	}
 
-	if (!g_utf8_validate (user->pw_name, -1, NULL)) {
-		locale_string = g_locale_to_utf8 (user->pw_name, -1, NULL, NULL, NULL);
+	if (!g_utf8_validate (name, -1, NULL)) {
+		locale_string = g_locale_to_utf8 (name, -1, NULL, NULL, NULL);
 	} else {
-		locale_string = g_strdup (user->pw_name);
+		locale_string = g_strdup (name);
 	}
 	
 	capitalized_login_name = eel_str_capitalize (locale_string);
@@ -3587,7 +3573,7 @@ get_real_name (struct passwd *user)
 
 
 	if (eel_str_is_empty (real_name)
-	    || eel_strcmp (user->pw_name, real_name) == 0
+	    || eel_strcmp (name, real_name) == 0
 	    || eel_strcmp (capitalized_login_name, real_name) == 0) {
 		g_free (real_name);
 		real_name = NULL;
@@ -3601,25 +3587,23 @@ get_real_name (struct passwd *user)
 static char *
 get_user_and_real_name_from_id (uid_t uid)
 {
+	char *name, *gecos;
 	char *real_name, *user_and_real_name;
-	struct passwd *password_info;
 	
-	/* No need to free result of getpwuid */
-	password_info = getpwuid (uid);
+	name = nautilus_users_cache_get_name (uid);
+	gecos = nautilus_users_cache_get_gecos (uid);
 
-	if (password_info == NULL) {
-		return NULL;
-	}
-
-	real_name = get_real_name (password_info);
+	real_name = get_real_name (name, gecos);
 	if (real_name != NULL) {
-		user_and_real_name = g_strdup_printf
-			("%s - %s", password_info->pw_name, real_name);
+		user_and_real_name = g_strdup_printf ("%s - %s", name, real_name);
 	} else {
-		user_and_real_name = g_strdup (password_info->pw_name);
+		user_and_real_name = g_strdup (name);
 	}
 	g_free (real_name);
 
+	g_free (name);
+	g_free (gecos);
+
 	return user_and_real_name;
 }
 
@@ -3893,7 +3877,7 @@ nautilus_get_user_names (void)
 	setpwent ();
 
 	while ((user = getpwent ()) != NULL) {
-		real_name = get_real_name (user);
+		real_name = get_real_name (user->pw_name, user->pw_gecos);
 		if (real_name != NULL) {
 			name = g_strconcat (user->pw_name, "\n", real_name, NULL);
 		} else {
@@ -3939,24 +3923,22 @@ nautilus_file_can_get_group (NautilusFile *file)
 char *
 nautilus_file_get_group_name (NautilusFile *file)
 {
-	struct group *group_info;
+	char *group_name;
 
 	/* Before we have info on a file, the owner is unknown. */
 	if (nautilus_file_info_missing (file, GNOME_VFS_FILE_INFO_FIELDS_IDS)) {
 		return NULL;
 	}
 
-	/* No need to free result of getgrgid */
-	group_info = getgrgid ((gid_t) file->details->info->gid);
-
-	if (group_info != NULL) {
-		return g_strdup (group_info->gr_name);
+	group_name = nautilus_groups_cache_get_name ((gid_t) file->details->info->gid);
+	if (group_name == NULL) {
+		/* In the oddball case that the group name has been set to an id for which
+		 * there is no defined group, return the id in string form.
+		 */
+		group_name = g_strdup_printf ("%d", file->details->info->gid);
 	}
-	
-	/* In the oddball case that the group name has been set to an id for which
-	 * there is no defined group, return the id in string form.
-	 */
-	return g_strdup_printf ("%d", file->details->info->gid);
+
+	return group_name;
 }
 
 /**
@@ -4252,17 +4234,17 @@ nautilus_file_get_owner_as_string (NautilusFile *file, gboolean include_real_nam
 	if (include_real_name) {
 		user_name = get_user_and_real_name_from_id (file->details->info->uid);
 	} else {
-		user_name = get_user_name_from_id (file->details->info->uid);
+		user_name = nautilus_users_cache_get_name (file->details->info->uid);
 	}
 
-	if (user_name != NULL) {
-		return user_name;
+	if (user_name == NULL) {
+		/* In the oddball case that the user name has been set to an id for which
+		 * there is no defined user, return the id in string form.
+		 */
+		user_name = g_strdup_printf ("%d", file->details->info->uid);
 	}
 
-	/* In the oddball case that the user name has been set to an id for which
-	 * there is no defined user, return the id in string form.
-	 */
-	return g_strdup_printf ("%d", file->details->info->uid);
+	return user_name;
 }
 
 static char *

libnautilus-private/nautilus-users-groups-cache.c

@@ -0,0 +1,277 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*-
+
+   nautilus-users-groups-cache.c: cache of users' and groups' names.
+ 
+   Copyright (C) 2006 Zbigniew Chyla
+  
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+  
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+  
+   You should have received a copy of the GNU General Public
+   License along with this program; if not, write to the
+   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+  
+   Author: Zbigniew Chyla <mail@zbigniew.chyla.pl>
+*/
+
+#include <config.h>
+#include "nautilus-users-groups-cache.h"
+
+#include <glib.h>
+#include <grp.h>
+#include <pwd.h>
+
+
+typedef struct _ExpiringCache ExpiringCache;
+
+/* times in milliseconds */
+#define USERS_CACHE_EXPIRE_TIME   (60 * 1000)
+#define GROUPS_CACHE_EXPIRE_TIME  (60 * 1000)
+
+/* cache of users' names */
+static ExpiringCache *users_cache = NULL;
+
+/* cache of groups' names */
+static ExpiringCache *groups_cache = NULL;
+
+
+/**
+ * Generic implementation of cache with guint keys and values which expire
+ * after specified amount of time.
+ */
+
+typedef gpointer (*ExpiringCacheGetValFunc) (guint key);
+
+
+struct _ExpiringCache
+{
+	/* Expiration time of cached value */
+	time_t expire_time;
+
+	/* Called to obtain a value by a key */
+	ExpiringCacheGetValFunc get_value_func;
+
+	/* Called to destroy a value */
+	GDestroyNotify value_destroy_func;
+
+	/* Stores cached values */
+	GHashTable *cached_values;
+};
+
+
+typedef struct _ExpiringCacheEntry ExpiringCacheEntry;
+
+struct _ExpiringCacheEntry
+{
+	ExpiringCache *cache;
+	guint key;
+	gpointer value;
+};
+
+
+static ExpiringCache *
+expiring_cache_new (time_t expire_time, ExpiringCacheGetValFunc get_value_func,
+                    GDestroyNotify value_destroy_func)
+{
+	ExpiringCache *cache;
+
+	g_return_val_if_fail (get_value_func != NULL, NULL);
+
+	cache = g_new (ExpiringCache, 1);
+	cache->expire_time = expire_time;
+	cache->get_value_func = get_value_func;
+	cache->value_destroy_func = value_destroy_func;
+	cache->cached_values = g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, NULL);
+
+	return cache;
+}
+
+static ExpiringCacheEntry *
+expiring_cache_entry_new (ExpiringCache *cache, guint key, gpointer value)
+{
+	ExpiringCacheEntry *entry;
+
+	entry = g_slice_new (ExpiringCacheEntry);
+	entry->cache = cache;
+	entry->key = key;
+	entry->value = value;
+
+	return entry;
+}
+
+static void
+expiring_cache_entry_destroy (ExpiringCacheEntry *entry)
+{
+	if (entry->cache->value_destroy_func != NULL) {
+		entry->cache->value_destroy_func (entry->value);
+	}
+	g_slice_free (ExpiringCacheEntry, entry);
+}
+
+static gboolean
+cb_cache_entry_expired (ExpiringCacheEntry *entry)
+{
+	g_hash_table_remove (entry->cache->cached_values, GSIZE_TO_POINTER (entry->key));
+	expiring_cache_entry_destroy (entry);
+
+	return FALSE;
+}
+
+static gpointer
+expiring_cache_get_value (ExpiringCache *cache, guint key)
+{
+	ExpiringCacheEntry *entry;
+
+	g_return_val_if_fail (cache != NULL, NULL);
+
+	if (!g_hash_table_lookup_extended (cache->cached_values, GSIZE_TO_POINTER (key),
+	                                   NULL, (gpointer) &entry)) {
+		entry = expiring_cache_entry_new (cache, key, cache->get_value_func (key));
+		g_hash_table_insert (cache->cached_values, GSIZE_TO_POINTER (key), entry);
+		g_timeout_add (cache->expire_time, (GSourceFunc) cb_cache_entry_expired, entry);
+	}
+
+	return entry->value;
+}
+
+
+/*
+ * Cache of users' names based on ExpiringCache.
+ */
+
+typedef struct _UserInfo UserInfo;
+
+struct _UserInfo {
+	char *name;
+	char *gecos;
+};
+
+
+static UserInfo *
+user_info_new (struct passwd *password_info)
+{
+	UserInfo *uinfo;
+
+	if (password_info != NULL) {
+		uinfo = g_slice_new (UserInfo);
+		uinfo->name = g_strdup (password_info->pw_name);
+		uinfo->gecos = g_strdup (password_info->pw_gecos);
+	} else {
+		uinfo = NULL;
+	}
+
+	return uinfo;
+}
+
+static void
+user_info_free (UserInfo *uinfo)
+{
+	if (uinfo != NULL) {
+		g_free (uinfo->name);
+		g_free (uinfo->gecos);
+		g_slice_free (UserInfo, uinfo);
+	}
+}
+
+static gpointer
+users_cache_get_value (guint key)
+{
+	return user_info_new (getpwuid (key));
+}
+
+static UserInfo *
+get_cached_user_info(guint uid)
+{
+	if (users_cache == NULL) {
+		users_cache = expiring_cache_new (USERS_CACHE_EXPIRE_TIME, users_cache_get_value,
+		                                  (GDestroyNotify) user_info_free);
+	}
+
+	return expiring_cache_get_value (users_cache, uid);
+}
+
+/**
+ * nautilus_users_cache_get_name:
+ *
+ * Returns name of user with given uid (using cached data if possible) or
+ * NULL in case a user with given uid can't be found.
+ *
+ * Returns: Newly allocated string or NULL.
+ */
+char *
+nautilus_users_cache_get_name (uid_t uid)
+{
+	UserInfo *uinfo;
+
+	uinfo = get_cached_user_info (uid);
+	if (uinfo != NULL) {
+		return g_strdup (uinfo->name);
+	} else {
+		return NULL;
+	}
+}
+
+/**
+ * nautilus_users_cache_get_gecos:
+ *
+ * Returns gecos of user with given uid (using cached data if possible) or
+ * NULL in case a user with given uid can't be found.
+ *
+ * Returns: Newly allocated string or NULL.
+ */
+char *
+nautilus_users_cache_get_gecos (uid_t uid)
+{
+	UserInfo *uinfo;
+
+	uinfo = get_cached_user_info (uid);
+	if (uinfo != NULL) {
+		return g_strdup (uinfo->gecos);
+	} else {
+		return NULL;
+	}
+}
+
+/*
+ * Cache of groups' names based on ExpiringCache.
+ */
+
+static gpointer
+groups_cache_get_value (guint key)
+{
+	struct group *group_info;
+
+	group_info = getgrgid (GPOINTER_TO_SIZE (key));
+	if (group_info != NULL) {
+		return g_strdup (group_info->gr_name);
+	} else {
+		return NULL;
+	}
+}
+
+
+/**
+ * nautilus_groups_cache_get_name:
+ *
+ * Returns name of group with given gid (using cached data if possible) or
+ * NULL in case a group with given gid can't be found.
+ *
+ * Returns: Newly allocated string or NULL.
+ */
+char *
+nautilus_groups_cache_get_name (gid_t gid)
+{
+	if (groups_cache == NULL) {
+		groups_cache = expiring_cache_new (GROUPS_CACHE_EXPIRE_TIME, groups_cache_get_value, g_free);
+	}
+
+	return g_strdup (expiring_cache_get_value (groups_cache, gid));
+}

libnautilus-private/nautilus-users-groups-cache.h

@@ -0,0 +1,34 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*-
+
+   nautilus-users-groups-cache.h: cache of users' and groups' names.
+ 
+   Copyright (C) 2006 Zbigniew Chyla
+  
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+  
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+  
+   You should have received a copy of the GNU General Public
+   License along with this program; if not, write to the
+   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+  
+   Author: Zbigniew Chyla <mail@zbigniew.chyla.pl>
+*/
+
+#ifndef NAUTILUS_USERS_GROUPS_CACHE_H
+#define NAUTILUS_USERS_GROUPS_CACHE_H
+
+#include <sys/types.h>
+
+char *nautilus_users_cache_get_name (uid_t uid);
+char *nautilus_users_cache_get_gecos (uid_t uid);
+char *nautilus_groups_cache_get_name (gid_t gid);
+
+#endif /* NAUTILUS_USERS_GROUPS_CACHE_H */