shared: implement weston_parse_space_separated_list()

This will be useful for parsing config file entries that have several
items on key, like x,y coordinates or a list of flags. Code reading
custom color profiles from weston.ini will use this.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

include/libweston/config-parser.h

@@ -32,6 +32,7 @@ extern "C" {
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <stddef.h>
 
 #define WESTON_CONFIG_FILE_ENV_VAR "WESTON_CONFIG_FILE"
 
@@ -107,6 +108,20 @@ int weston_config_next_section(struct weston_config *config,
 uint32_t
 weston_config_get_binding_modifier(struct weston_config *config, uint32_t default_mod);
 
+/** Container for an array of strings. */
+struct weston_string_array {
+	/** Length of \c array. */
+	size_t len;
+	/** Pointer to an array of strings. */
+	char **array;
+};
+
+void
+weston_string_array_fini(struct weston_string_array *strarr);
+
+struct weston_string_array
+weston_parse_space_separated_list(const char *str);
+
 #ifdef  __cplusplus
 }
 #endif

shared/option-parser.c

@@ -1,5 +1,6 @@
 /*
  * Copyright © 2012 Kristian Høgsberg
+ * Copyright 2025 Collabora, Ltd.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -33,8 +34,10 @@
 #include <assert.h>
 #include <errno.h>
 
+#include <wayland-util.h>
 #include <libweston/config-parser.h>
 #include "string-helpers.h"
+#include "xalloc.h"
 
 static bool
 handle_option(const struct weston_option *option, char *value)
@@ -209,3 +212,71 @@ parse_options(const struct weston_option *options,
 
 	return j;
 }
+
+/** Free string array contents
+ *
+ * Does not free \c strarr itself but resets it.
+ */
+void
+weston_string_array_fini(struct weston_string_array *strarr)
+{
+	size_t i;
+
+	for (i = 0; i < strarr->len; i++)
+		free(strarr->array[i]);
+	free(strarr->array);
+	strarr->len = 0;
+	strarr->array = NULL;
+}
+
+static bool
+is_space_for_split(char c)
+{
+	return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+}
+
+/** Split a string at spaces, tabs, CRs, LFs
+ *
+ * \param str An arbitrary string, can be empty but not NULL.
+ * \return An array of sub-strings. Must be finalized with
+ * weston_string_array_fini().
+ *
+ * Takes the given string, and splits it into items. Empty items are skipped.
+ * The items are returned in the array in the same order they appeared in the
+ * string. Spaces, tabs, newlines or carriage returns will not be present in
+ * the items as they cannot be escaped.
+ */
+struct weston_string_array
+weston_parse_space_separated_list(const char *str)
+{
+	struct wl_array arr;
+	const char *p = str;
+	char **item;
+
+	wl_array_init(&arr);
+
+	while (*p) {
+		const char *end = p;
+		while (*end && !is_space_for_split(*end))
+			end++;
+		size_t len = end - p;
+
+		if (len > 0) {
+			item = wl_array_add(&arr, sizeof *item);
+
+			*item = strndup(p, len);
+			abort_oom_if_null(*item);
+		}
+
+		p = end;
+
+		/* Skip whitespaces */
+		while (*p && is_space_for_split(*p))
+			p++;
+	}
+
+	return (struct weston_string_array){
+		.len = arr.size / sizeof *item,
+		.array = arr.data
+	};
+}

tests/config-parser-test.c

@@ -1,5 +1,6 @@
 /*
  * Copyright © 2013 Intel Corporation
+ * Copyright 2025 Collabora, Ltd.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -924,3 +925,78 @@ TEST(section_from_null)
 
 	return RESULT_OK;
 }
+
+TEST(parse_comma_separated_list)
+{
+	const char *matter;
+	struct weston_string_array strarr;
+
+	matter = "";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 0);
+
+	matter = "   ";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 0);
+
+	matter = " \t    \t \t";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 0);
+
+	matter = "k";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 1);
+	test_assert_str_eq(strarr.array[0], "k");
+	weston_string_array_fini(&strarr);
+
+	matter = " k";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 1);
+	test_assert_str_eq(strarr.array[0], "k");
+	weston_string_array_fini(&strarr);
+
+	matter = "k ";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 1);
+	test_assert_str_eq(strarr.array[0], "k");
+	weston_string_array_fini(&strarr);
+
+	matter = " k ";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 1);
+	test_assert_str_eq(strarr.array[0], "k");
+	weston_string_array_fini(&strarr);
+
+	matter = "kissa kassi";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 2);
+	test_assert_str_eq(strarr.array[0], "kissa");
+	test_assert_str_eq(strarr.array[1], "kassi");
+	weston_string_array_fini(&strarr);
+
+	matter = "kissa\tkassi";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 2);
+	test_assert_str_eq(strarr.array[0], "kissa");
+	test_assert_str_eq(strarr.array[1], "kassi");
+	weston_string_array_fini(&strarr);
+
+	matter = "  kissa\t kassi";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 2);
+	test_assert_str_eq(strarr.array[0], "kissa");
+	test_assert_str_eq(strarr.array[1], "kassi");
+	weston_string_array_fini(&strarr);
+
+	matter = " 4.556\ra bab c \nkoe\t";
+	strarr = weston_parse_space_separated_list(matter);
+	test_assert_u64_eq(strarr.len, 5);
+	test_assert_str_eq(strarr.array[0], "4.556");
+	test_assert_str_eq(strarr.array[1], "a");
+	test_assert_str_eq(strarr.array[2], "bab");
+	test_assert_str_eq(strarr.array[3], "c");
+	test_assert_str_eq(strarr.array[4], "koe");
+	weston_string_array_fini(&strarr);
+
+	return RESULT_OK;
+}