1 files changed, 68 insertions, 0 deletions
diff --git a/filesystem-posix.c b/filesystem-posix.c
new file mode 100644
index 0000000..4913e30
--- /dev/null
+++ b/filesystem-posix.c
@@ -0,0 +1,68 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <errno.h>
+
+// Does this file exist? Returns false for directories.
+static bool fs_file_exists(char const *path) {
+	struct stat statbuf = {0};
+	if (stat(path, &statbuf) != 0)
+		return false;
+	return S_ISREG(statbuf.st_mode);
+}
+
+// Returns a NULL-terminated array of the files in this directory, or NULL if the directory does not exist.
+// When you're done with the file names, call free on each one, then on the array.
+// NOTE: The files aren't returned in any particular order!
+static char **fs_list_directory(char const *dirname) {
+	char **ret = NULL;
+	DIR *dir = opendir(dirname);
+	if (dir) {
+		struct dirent *ent;
+		char **filenames = NULL;
+		size_t nentries = 0;
+		size_t filename_idx = 0;
+
+		while (readdir(dir)) ++nentries;
+		rewinddir(dir);
+		filenames = (char **)calloc(nentries+1, sizeof *filenames);
+
+		while ((ent = readdir(dir))) {
+			if (ent->d_type == DT_REG) {
+				char const *filename = ent->d_name;
+				size_t len = strlen(filename);
+				char *filename_copy = (char *)malloc(len+1);
+				if (!filename_copy) break;
+				strcpy(filename_copy, filename);
+				if (filename_idx < nentries) // this could actually fail if someone creates files between calculating nentries and here. 
+					filenames[filename_idx++] = filename_copy;
+			}
+		}
+		ret = filenames;
+		closedir(dir);
+	}
+	return ret;
+}
+
+static int fs_mkdir(char const *path) {
+	if (mkdir(path, 0755) == 0) {
+		// directory created successfully 
+		return 1;
+	} else if (errno == EEXIST) {
+		struct stat statbuf = {0};
+		if (stat(path, &statbuf) == 0) {
+			if (S_ISDIR(statbuf.st_mode)) {
+				// already exists, and it's a directory 
+				return 0;
+			} else {
+				// already exists, but not a directory 
+				return -1;
+			}
+		} else {
+			return -1;
+		}
+	} else {
+		return -1;
+	}
+}