libxbps: simplify the algorithm for sorting deps in the transaction.

Rather than using a SIMPLEQ to copy the package dictionary and later on
adding all items into the sorted array, just add the pkg dictionary
into the sorted array directly and removing it from the unsorted array.

This reduces memory usage and greatly sorts all packages that aren't
installed automatically in the correct order in the transaction.

Also added a large comment explaining how the algorithm works and
what it is supposed to do and when.

lib/sortdeps.c

@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2009-2010 Juan Romero Pardines.
+ * Copyright (c) 2009-2011 Juan Romero Pardines.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,50 +30,38 @@
 
 #include <xbps_api.h>
 #include "xbps_api_impl.h"
-#include "queue.h"
-
-struct sorted_dependency {
-	SIMPLEQ_ENTRY(sorted_dependency) chain;
-	prop_dictionary_t dict;
-};
-
-static SIMPLEQ_HEAD(sdep_head, sorted_dependency) sdep_list =
-    SIMPLEQ_HEAD_INITIALIZER(sdep_list);
-
-static struct sorted_dependency *
-find_sorteddep_by_name(const char *pkgname)
-{
-	struct sorted_dependency *sdep = NULL;
-	const char *curpkgname;
-
-	SIMPLEQ_FOREACH(sdep, &sdep_list, chain) {
-		prop_dictionary_get_cstring_nocopy(sdep->dict,
-		    "pkgname", &curpkgname);
-		if (strcmp(pkgname, curpkgname) == 0)
-			return sdep;
-	}
-
-	return NULL;
-}
 
+/*
+ * Sorting algorithm for packages in the transaction dictionary.
+ * The transaction dictionary contains all package dictionaries found from
+ * the repository plist index file in the "unsorted_deps" array.
+ *
+ * When a package has no rundeps or all rundeps are satisfied, the package
+ * dictionary is added into the "packages" array and it is removed from the
+ * "unsorted_deps" array; that means the package has been sorted in the
+ * transaction.
+ *
+ * It will loop until all packages are processed and will check that
+ * the number of packages added into the "packages" array is the same than
+ * it was in the "unsorted_deps" array.
+ */
 int HIDDEN
-xbps_sort_pkg_deps(prop_dictionary_t chaindeps)
+xbps_sort_pkg_deps(prop_dictionary_t transd)
 {
 	prop_array_t sorted, unsorted, rundeps, missingdeps;
 	prop_object_t obj, obj2;
 	prop_object_iterator_t iter, iter2;
-	struct sorted_dependency *sdep;
 	size_t ndeps = 0, rundepscnt = 0, cnt = 0;
 	const char *pkgname, *pkgver, *str;
 	char *pkgnamedep;
 	int rv = 0;
 
-	assert(chaindeps != NULL);
+	assert(transd != NULL);
 
 	/*
 	 * If there are missing dependencies, bail out.
 	 */
-	missingdeps = prop_dictionary_get(chaindeps, "missing_deps");
+	missingdeps = prop_dictionary_get(transd, "missing_deps");
 	if (prop_array_count(missingdeps) > 0) {
 		xbps_dbg_printf("missing dependencies! won't "
 		    "continue sorting\n");
@@ -84,12 +72,20 @@ xbps_sort_pkg_deps(prop_dictionary_t chaindeps)
 	if (sorted == NULL)
 		return ENOMEM;
 
+	/*
+	 * Add sorted packages array into transaction dictionary (empty).
+	 */
+	if (!prop_dictionary_set(transd, "packages", sorted)) {
+		rv = EINVAL;
+		goto out;
+	}
+
 	/*
 	 * All required deps are satisfied (already installed).
 	 */
-	unsorted = prop_dictionary_get(chaindeps, "unsorted_deps");
+	unsorted = prop_dictionary_get(transd, "unsorted_deps");
 	if (prop_array_count(unsorted) == 0) {
-		prop_dictionary_set(chaindeps, "packages", sorted);
+		prop_dictionary_set(transd, "packages", sorted);
 		return 0;
 	}
 	ndeps = prop_array_count(unsorted);
@@ -107,17 +103,14 @@ again:
 		prop_dictionary_get_cstring_nocopy(obj, "pkgname", &pkgname);
 		prop_dictionary_get_cstring_nocopy(obj, "pkgver", &pkgver);
 		xbps_dbg_printf("Sorting package '%s': ", pkgver);
-		if (find_sorteddep_by_name(pkgname) != NULL) {
+
+		if (xbps_find_pkg_in_dict_by_name(transd,
+		    "packages", pkgname)) {
 			xbps_dbg_printf_append("skipping, already queued.\n",
 			    pkgname);
 			continue;
 		}
 
-		sdep = malloc(sizeof(struct sorted_dependency));
-		if (sdep == NULL) {
-			rv = ENOMEM;
-			goto out;
-		}
 		/*
 		 * Packages that don't have deps go unsorted, because
 		 * it doesn't matter.
@@ -126,15 +119,18 @@ again:
 		if (rundeps == NULL || prop_array_count(rundeps) == 0) {
 			xbps_dbg_printf_append("added (no rundeps) into "
 			    "the sorted queue.\n");
-			sdep->dict = prop_dictionary_copy(obj);
+			prop_array_add(sorted, obj);
-			SIMPLEQ_INSERT_TAIL(&sdep_list, sdep, chain);
+			if (!xbps_remove_pkg_from_dict(transd,
+			    "unsorted_deps", pkgname)) {
+				xbps_dbg_printf("can't remove %s from "
+				    "unsorted_deps array!\n", pkgname);
+			}
 			cnt++;
 			continue;
 		}
 		iter2 = prop_array_iterator(rundeps);
 		if (iter2 == NULL) {
 			rv = ENOMEM;
-			free(sdep);
 			goto out;
 		}
 
@@ -148,13 +144,11 @@ again:
 		while ((obj2 = prop_object_iterator_next(iter2)) != NULL) {
 			str = prop_string_cstring_nocopy(obj2);
 			if (str == NULL) {
-				free(sdep);
 				rv = EINVAL;
 				goto out;
 			}
 			pkgnamedep = xbps_get_pkgpattern_name(str);
 			if (pkgnamedep == NULL) {
-				free(sdep);
 				rv = EINVAL;
 				goto out;
 			}
@@ -166,7 +160,8 @@ again:
 			if (xbps_check_is_installed_pkg(str)) {
 				rundepscnt++;
 				xbps_dbg_printf_append("installed.\n");
-			} else if (find_sorteddep_by_name(pkgnamedep) != NULL) {
+			} else if (xbps_find_pkg_in_dict_by_name(transd,
+			    "packages", pkgnamedep)) {
 				xbps_dbg_printf_append("queued.\n");
 				rundepscnt++;
 			} else {
@@ -178,8 +173,12 @@ again:
 
 		/* Add dependency if all its required deps are already added */
 		if (prop_array_count(rundeps) == rundepscnt) {
-			sdep->dict = prop_dictionary_copy(obj);
+			prop_array_add(sorted, obj);
-			SIMPLEQ_INSERT_TAIL(&sdep_list, sdep, chain);
+			if (!xbps_remove_pkg_from_dict(transd,
+			    "unsorted_deps", pkgname)) {
+				xbps_dbg_printf("can't remove %s from "
+				    "unsorted_deps array!\n", pkgname);
+			}
 			xbps_dbg_printf("Added package '%s' to the sorted "
 			    "queue (all rundeps satisfied).\n\n", pkgver);
 			rundepscnt = 0;
@@ -189,33 +188,18 @@ again:
 		xbps_dbg_printf("Unsorted package '%s' has missing "
 		    "rundeps (missing %zu).\n\n", pkgver,
 		    prop_array_count(rundeps) - rundepscnt);
-		free(sdep);
 		rundepscnt = 0;
 	}
-
 	/* Iterate until all deps are processed. */
 	if (cnt < ndeps) {
 		xbps_dbg_printf("Missing required deps! queued: %zu "
 		    "required: %zu.\n", cnt, ndeps);
 		prop_object_iterator_reset(iter);
+		xbps_dbg_printf("total iteratons %zu\n", cnt);
 		goto again;
 	}
 	prop_object_iterator_release(iter);
 
-	/*
-	 * Add all sorted dependencies into the sorted deps array.
-	 */
-	while ((sdep = SIMPLEQ_FIRST(&sdep_list)) != NULL) {
-		if (!prop_array_add(sorted, sdep->dict)) {
-			free(sdep);
-			rv = EINVAL;
-			goto out;
-		}
-		SIMPLEQ_REMOVE(&sdep_list, sdep, sorted_dependency, chain);
-		prop_object_release(sdep->dict);
-		free(sdep);
-	}
-
 	/*
 	 * Sanity check that the array contains the same number of
 	 * objects than the total number of required dependencies.
@@ -224,22 +208,16 @@ again:
 		rv = EINVAL;
 		goto out;
 	}
-
+	/*
-	if (!prop_dictionary_set(chaindeps, "packages", sorted))
+	 * We are done, all packages were sorted... remove the
-		rv = EINVAL;
+	 * temporary array with unsorted packages.
-
+	 */
-	prop_dictionary_remove(chaindeps, "unsorted_deps");
+	prop_dictionary_remove(transd, "unsorted_deps");
 
 out:
-	/*
+	if (rv != 0) {
-	 * Release resources used by temporary sorting.
+		prop_dictionary_remove(transd, "packages");
-	 */
 		prop_object_release(sorted);
-	while ((sdep = SIMPLEQ_FIRST(&sdep_list)) != NULL) {
-		SIMPLEQ_REMOVE(&sdep_list, sdep, sorted_dependency, chain);
-		prop_object_release(sdep->dict);
-		free(sdep);
 	}
-
 	return rv;
 }