Add new CleanMethod option.

As it was already mentioned several times, the new -Sc behavior in 3.1 is
great, but only when the package cache is not shared.

This option has two possible values : KeepInstalled and KeepCurrent
With KeepCurrent, -Sc will clean packages that are no longer available in
any sync db, rather than packages that are no longer in the local db. The
resulting behavior should be better for shared cache.

Ref :
http://www.archlinux.org/pipermail/pacman-dev/2008-February/011140.html

Signed-off-by: Chantry Xavier <shiningxc@gmail.com>
Signed-off-by: Dan McGee <dan@archlinux.org>

doc/pacman.8.txt

@@ -244,6 +244,9 @@ Sync Options[[SO]]
 	packages that are no longer installed; use two to remove all packages
 	from the cache. In both cases, you will have a yes or no option to
 	remove packages and/or unused downloaded databases.
++
+If you use a network shared cache, see the 'CleanMethod' option in
+linkman:pacman.conf[5].
 
 *-g, \--groups*::
 	Display all the members for each package group specified. If no group

doc/pacman.conf.5.txt

@@ -119,6 +119,15 @@ Options
 	These files refer to files in the package archive, so do not include the
 	leading slash (the RootDir) when specifying them.
 
+*CleanMethod =* KeepInstalled | KeepCurrent::
+	If set to `KeepInstalled` (the default), the '-Sc' operation will clean
+	packages that are no longer installed (not present in the local database).
+	If set to `KeepCurrent`, '-Sc' will clean outdated packages (not present in
+	any sync database).
+	The second behavior is useful when the package cache is shared among
+	multiple machines, where the local databases are usually different, but the
+	sync databases in use could be the same.
+
 *UseSyslog*::
 	Log action messages through syslog(). This will insert log entries into
 	``/var/log/messages'' or equivalent.

src/pacman/conf.h

@@ -65,9 +65,10 @@ typedef struct __config_t {
 	unsigned short chomp; /* I Love Candy! */
 	unsigned short usecolor; /* enable colorful output */
 	unsigned short showsize; /* show individual package sizes */
-	unsigned short totaldownload; /* When downloading, display the amount
-	                                 downloaded, rate, ETA, and percent
-	                                 downloaded of the total download list */
+	/* When downloading, display the amount downloaded, rate, ETA, and percent
+	 * downloaded of the total download list */
+	unsigned short totaldownload;
+	unsigned short cleanmethod; /* select -Sc behavior */
 } config_t;
 
 /* Operations */
@@ -80,6 +81,12 @@ enum {
 	PM_OP_DEPTEST
 };
 
+/* clean method */
+enum {
+	PM_CLEAN_KEEPINST = 0, /* default */
+	PM_CLEAN_KEEPCUR
+};
+
 /* global config variable */
 extern config_t *config;
 

src/pacman/pacman.c

@@ -692,6 +692,16 @@ static int _parseconfig(const char *file, const char *givensection,
 					} else if (strcmp(key, "XferCommand") == 0) {
 						alpm_option_set_xfercommand(ptr);
 						pm_printf(PM_LOG_DEBUG, "config: xfercommand: %s\n", ptr);
+					} else if (strcmp(key, "CleanMethod") == 0) {
+						if (strcmp(ptr, "KeepInstalled") == 0) {
+							config->cleanmethod = PM_CLEAN_KEEPINST;
+						} else if (strcmp(ptr, "KeepCurrent") == 0) {
+							config->cleanmethod = PM_CLEAN_KEEPCUR;
+						} else {
+							pm_printf(PM_LOG_ERROR, _("invalid value for 'CleanMethod' : '%s'\n"), ptr);
+							return(1);
+						}
+						pm_printf(PM_LOG_DEBUG, "config: cleanmethod: %s\n", ptr);
 					} else {
 						pm_printf(PM_LOG_ERROR, _("config file %s, line %d: directive '%s' not recognized.\n"),
 								file, linenum, key);

src/pacman/sync.c

@@ -133,13 +133,23 @@ static int sync_cleancache(int level)
 		/* incomplete cleanup */
 		DIR *dir;
 		struct dirent *ent;
-		/* Let's vastly improve the way this is done. Before, we went by package
-		 * name. Instead, let's only keep packages we have installed. Open up each
-		 * package and see if it has an entry in the local DB; if not, delete it.
-		 */
+		/* Open up each package and see if it should be deleted,
+		 * depending on the clean method used */
 		printf(_("Cache directory: %s\n"), cachedir);
-		if(!yesno(1, _("Do you want to remove uninstalled packages from cache?"))) {
-			return(0);
+		switch(config->cleanmethod) {
+			case PM_CLEAN_KEEPINST:
+				if(!yesno(1, _("Do you want to remove uninstalled packages from cache?"))) {
+					return(0);
+				}
+				break;
+			case PM_CLEAN_KEEPCUR:
+				if(!yesno(1, _("Do you want to remove outdated packages from cache?"))) {
+					return(0);
+				}
+				break;
+			default:
+				/* this should not happen : the config parsing doesn't set any other value */
+				return(1);
 		}
 		printf(_("removing old packages from cache... "));
 
@@ -153,13 +163,16 @@ static int sync_cleancache(int level)
 		/* step through the directory one file at a time */
 		while((ent = readdir(dir)) != NULL) {
 			char path[PATH_MAX];
-			pmpkg_t *localpkg = NULL, *dbpkg = NULL;
+			int delete = 1;
+			pmpkg_t *localpkg = NULL, *pkg = NULL;
+			alpm_list_t *sync_dbs = alpm_option_get_syncdbs();
+			alpm_list_t *j;
 
 			if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, "..")) {
 				continue;
 			}
 			/* build the full filepath */
-			snprintf(path, PATH_MAX, "%s/%s", cachedir, ent->d_name);
+			snprintf(path, PATH_MAX, "%s%s", cachedir, ent->d_name);
 
 			/* attempt to load the package, skip file on failures as we may have
 			 * files here that aren't valid packages. we also don't need a full
@@ -167,19 +180,39 @@ static int sync_cleancache(int level)
 			if(alpm_pkg_load(path, 0, &localpkg) != 0 || localpkg == NULL) {
 				continue;
 			}
-			/* check if this package is in the local DB */
-			dbpkg = alpm_db_get_pkg(db_local, alpm_pkg_get_name(localpkg));
-			if(dbpkg == NULL) {
-				/* delete package, not present in local DB */
-				unlink(path);
-			} else if(alpm_pkg_vercmp(alpm_pkg_get_version(localpkg),
-							alpm_pkg_get_version(dbpkg)) != 0) {
-				/* delete package, it was found but version differs */
-				unlink(path);
+			switch(config->cleanmethod) {
+				case PM_CLEAN_KEEPINST:
+					/* check if this package is in the local DB */
+					pkg = alpm_db_get_pkg(db_local, alpm_pkg_get_name(localpkg));
+					if(pkg != NULL && alpm_pkg_vercmp(alpm_pkg_get_version(localpkg),
+								alpm_pkg_get_version(pkg)) == 0) {
+						/* package was found in local DB and version matches, keep it */
+						delete = 0;
+					}
+					break;
+				case PM_CLEAN_KEEPCUR:
+					/* check if this package is in a sync DB */
+					for(j = sync_dbs; j && delete; j = alpm_list_next(j)) {
+						pmdb_t *db = alpm_list_getdata(j);
+						pkg = alpm_db_get_pkg(db, alpm_pkg_get_name(localpkg));
+						if(pkg != NULL && alpm_pkg_vercmp(alpm_pkg_get_version(localpkg),
+									alpm_pkg_get_version(pkg)) == 0) {
+							/* package was found in a sync DB and version matches, keep it */
+							delete = 0;
+						}
+					}
+					break;
+				default:
+					/* this should not happen : the config parsing doesn't set any other value */
+					delete = 0;
+					break;
 			}
-			/* else version was the same, so keep the package */
 			/* free the local file package */
 			alpm_pkg_free(localpkg);
+
+			if(delete) {
+				unlink(path);
+			}
 		}
 		printf(_("done.\n"));
 	} else {