Find the hunspell aff and dic files in XDG_DATA_DIRS

Makefile

@@ -4,8 +4,9 @@ CFLAGS = -O2 -Wall
 CFLAGS += $(shell pkg-config --cflags hunspell)
 LDLIBS += $(shell pkg-config --libs hunspell)
 
-huncolor: huncolor.o
+huncolor: huncolor.o xdg_dirs.o
 huncolor.o: huncolor.c
+xdg_dirs.o: xdg_dirs.c
 
 install: huncolor
 	install huncolor $(HOME)/bin

huncolor.c

@@ -1,3 +1,5 @@
+#include "xdg_dirs.h"
+
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -187,7 +189,16 @@ int main(int argc, char **argv)
 	if (isatty(0))
 		exec_less(argv);
 
-	Hunhandle *hunhandle = Hunspell_create(aff_path, dic_path);
+	size_t aff_path_len = find_affix_file(buf, BUFSIZE);
+	size_t dic_path_len = find_dic_file(buf + aff_path_len, BUFSIZE - aff_path_len);
+
+	Hunhandle *hunhandle;
+	if (aff_path_len > 0 && dic_path_len > 0 && aff_path_len + dic_path_len < BUFSIZE) {
+		hunhandle = Hunspell_create(buf, buf + aff_path_len);
+	} else {
+		// fallback to hardcoded paths
+		hunhandle = Hunspell_create(aff_path, dic_path);
+	}
 
 	if (!hunhandle || pipe(fd))
 		exec_less(argv);

xdg_dirs.c

@@ -0,0 +1,53 @@
+#include "xdg_dirs.h"
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#define PATH_BUF_SIZE 128
+
+static int is_regular_file(const char *path) {
+	struct stat st;
+	return (!stat(path, &st) && S_ISREG(st.st_mode));
+}
+
+/// if dst is null or too small, returns the size of buffer needed
+/// returns 0 when fails
+static int find_file(char *dst, size_t dst_len, const char *filename) {
+	char path_buf[PATH_BUF_SIZE];
+
+	const char *dirs = getenv("XDG_DATA_DIRS");
+	if (!dirs) return 0;
+
+	// copy dirs because per getenv manpage you
+	// shouldn't modify the returned string
+	char *dir, *dir_original;
+	dir = dir_original = malloc(strlen(dirs) + 1);
+	strcpy(dir, dirs);
+
+	dir = strtok(dir, ":");
+	while (dir != NULL) {
+		size_t len = snprintf(path_buf, PATH_BUF_SIZE, "%s/hunspell/%s", dir, filename) + 1;
+		if (is_regular_file(path_buf)) {
+			if (dst != NULL && len <= dst_len) strcpy(dst, path_buf);
+			free(dir_original);
+			return len;
+		}
+
+		dir = strtok(NULL, ":");
+	}
+
+	free(dir_original);
+	return 0;
+}
+
+int find_affix_file(char *dst, size_t dst_len) {
+	return find_file(dst, dst_len, "en_US.aff");
+}
+
+int find_dic_file(char *dst, size_t dst_len) {
+	return find_file(dst, dst_len, "en_US.dic");
+}
+

xdg_dirs.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stddef.h>
+
+int find_affix_file(char *dst, size_t dst_len);
+int find_dic_file(char *dst, size_t dst_len);
+