path: add pkgconf_path_prepend API for --with-path

Otherwise, PKG_CONFIG_PATH and PKG_CONFIG_LIBDIR elements would be processed backwards.

Fixes: 384ade5 (path: prepend paths rather than append paths when processing --with-path arguments)
Closes: #250
Signed-off-by: Ariadne Conill <ariadne@dereferenced.org>

cli/main.c

@@ -967,7 +967,7 @@ main(int argc, char *argv[])
 			logfile_arg = pkg_optarg;
 			break;
 		case 42:
-			pkgconf_path_add(pkg_optarg, &dir_list, true);
+			pkgconf_path_prepend(pkg_optarg, &dir_list, true);
 			break;
 		case 43:
 			pkgconf_client_set_prefix_varname(&pkg_client, pkg_optarg);

libpkgconf/libpkgconf.h

@@ -411,6 +411,7 @@ PKGCONF_API void pkgconf_audit_log_dependency(pkgconf_client_t *client, const pk
 
 /* path.c */
 PKGCONF_API void pkgconf_path_add(const char *text, pkgconf_list_t *dirlist, bool filter);
+PKGCONF_API void pkgconf_path_prepend(const char *text, pkgconf_list_t *dirlist, bool filter);
 PKGCONF_API size_t pkgconf_path_split(const char *text, pkgconf_list_t *dirlist, bool filter);
 PKGCONF_API size_t pkgconf_path_build_from_environ(const char *envvarname, const char *fallback, pkgconf_list_t *dirlist, bool filter);
 PKGCONF_API bool pkgconf_path_match_list(const char *path, const pkgconf_list_t *dirlist);

libpkgconf/path.c

@@ -58,6 +58,51 @@ path_list_contains_entry(const char *text, pkgconf_list_t *dirlist)
  * variables.
  */
 
+static pkgconf_path_t *
+prepare_path_node(const char *text, pkgconf_list_t *dirlist, bool filter)
+{
+	pkgconf_path_t *node;
+	char path[PKGCONF_ITEM_SIZE];
+
+	pkgconf_strlcpy(path, text, sizeof path);
+	pkgconf_path_relocate(path, sizeof path);
+
+#ifdef PKGCONF_CACHE_INODES
+	struct stat st;
+
+	if (filter)
+	{
+		if (lstat(path, &st) == -1)
+			return NULL;
+		if (S_ISLNK(st.st_mode))
+		{
+			char pathbuf[PKGCONF_ITEM_SIZE * 4];
+			char *linkdest = realpath(path, pathbuf);
+
+			if (linkdest != NULL && stat(linkdest, &st) == -1)
+				return NULL;
+		}
+		if (path_list_contains_entry(path, dirlist, &st))
+			return NULL;
+	}
+#else
+	if (filter && path_list_contains_entry(path, dirlist))
+		return NULL;
+#endif
+
+	node = calloc(sizeof(pkgconf_path_t), 1);
+	node->path = strdup(path);
+
+#ifdef PKGCONF_CACHE_INODES
+	if (filter) {
+		node->handle_path = (void *)(intptr_t) st.st_ino;
+		node->handle_device = (void *)(intptr_t) st.st_dev;
+	}
+#endif
+
+	return node;
+}
+
 /*
  * !doc
  *
@@ -73,44 +118,31 @@ path_list_contains_entry(const char *text, pkgconf_list_t *dirlist)
 void
 pkgconf_path_add(const char *text, pkgconf_list_t *dirlist, bool filter)
 {
-	pkgconf_path_t *node;
+	pkgconf_path_t *node = prepare_path_node(text, dirlist, filter);
-	char path[PKGCONF_ITEM_SIZE];
+	if (node == NULL)
+		return;
 
-	pkgconf_strlcpy(path, text, sizeof path);
+	pkgconf_node_insert_tail(&node->lnode, node, dirlist);
-	pkgconf_path_relocate(path, sizeof path);
+}
 
-#ifdef PKGCONF_CACHE_INODES
+/*
-	struct stat st;
+ * !doc
-
+ *
-	if (filter)
+ * .. c:function:: void pkgconf_path_prepend(const char *text, pkgconf_list_t *dirlist)
+ *
+ *    Prepends a path node to a path list.  If the path is already in the list, do nothing.
+ *
+ *    :param char* text: The path text to add as a path node.
+ *    :param pkgconf_list_t* dirlist: The path list to add the path node to.
+ *    :param bool filter: Whether to perform duplicate filtering.
+ *    :return: nothing
+ */
+void
+pkgconf_path_prepend(const char *text, pkgconf_list_t *dirlist, bool filter)
 {
-		if (lstat(path, &st) == -1)
+	pkgconf_path_t *node = prepare_path_node(text, dirlist, filter);
+	if (node == NULL)
 		return;
-		if (S_ISLNK(st.st_mode))
-		{
-			char pathbuf[PKGCONF_ITEM_SIZE * 4];
-			char *linkdest = realpath(path, pathbuf);
-
-			if (linkdest != NULL && stat(linkdest, &st) == -1)
-				return;
-		}
-		if (path_list_contains_entry(path, dirlist, &st))
-			return;
-	}
-#else
-	if (filter && path_list_contains_entry(path, dirlist))
-		return;
-#endif
-
-	node = calloc(sizeof(pkgconf_path_t), 1);
-	node->path = strdup(path);
-
-#ifdef PKGCONF_CACHE_INODES
-	if (filter) {
-		node->handle_path = (void *)(intptr_t) st.st_ino;
-		node->handle_device = (void *)(intptr_t) st.st_dev;
-	}
-#endif
 
 	pkgconf_node_insert(&node->lnode, node, dirlist);
 }