Add `filepath.walk`

core/path/filepath/walk.odin

@@ -0,0 +1,88 @@
+package filepath
+
+import "core:os"
+import "core:sort"
+
+// Walk_Proc is the type of the procedure called for each file or directory visited by 'walk'
+// The 'path' parameter contains the parameter to walk as a prefix (this is the same as info.fullpath except on 'root')
+// The 'info' parameter is the os.File_Info for the named path
+//
+// If there was a problem walking to the file or directory named by path, the incoming error will describe the problem
+// and the procedure can decide how to handle that error (and walk will not descend into that directory)
+// In the case of an error, the info argument will be 0
+// If an error is returned, processing stops
+// The sole exception is if 'skip_dir' is returned as true:
+// 	when 'skip_dir' is invoked on a directory. 'walk' skips directory contents
+// 	when 'skip_dir' is invoked on a non-directory. 'walk' skips the remaining files in the containing directory
+Walk_Proc :: #type proc(info: os.File_Info, in_err: os.Errno) -> (err: os.Errno, skip_dir: bool);
+
+// walk walks the file tree rooted at 'root', calling 'walk_proc' for each file or directory in the tree, including 'root'
+// All errors that happen visiting files and directories are filtered by walk_proc
+// The files are walked in lexical order to make the output deterministic
+// NOTE: Walking large directories can be inefficient due to the lexical sort
+// NOTE: walk does not follow symbolic links
+// NOTE: os.File_Info uses the 'context.temp_allocator' to allocate, and will delete when it is done
+walk :: proc(root: string, walk_proc: Walk_Proc) -> os.Errno {
+	info, err := os.lstat(root, context.temp_allocator);
+	defer os.file_info_delete(info, context.temp_allocator);
+
+	skip_dir: bool;
+	if err != 0 {
+		err, skip_dir = walk_proc(info, err);
+	} else {
+		err, skip_dir = _walk(info, walk_proc);
+	}
+	return 0 if skip_dir else err;
+}
+
+
+@(private)
+_walk :: proc(info: os.File_Info, walk_proc: Walk_Proc) -> (err: os.Errno, skip_dir: bool) {
+	if !info.is_dir {
+		if info.fullpath == "" && info.name == "" {
+			// ignore empty things
+			return;
+		}
+		return walk_proc(info, 0);
+	}
+
+	fis: []os.File_Info;
+	err1: os.Errno;
+	fis, err = read_dir(info.fullpath, context.temp_allocator);
+	defer os.file_info_slice_delete(fis, context.temp_allocator);
+
+	err1, skip_dir = walk_proc(info, err);
+	if err != 0 || err1 != 0 || skip_dir {
+		err = err1;
+		return;
+	}
+
+	for fi in fis {
+		err, skip_dir = _walk(fi, walk_proc);
+		if err != 0 || skip_dir {
+			if !fi.is_dir || !skip_dir {
+				return;
+			}
+		}
+	}
+
+	return;
+}
+
+@(private)
+read_dir :: proc(dir_name: string, allocator := context.temp_allocator) -> ([]os.File_Info, os.Errno) {
+	f, err := os.open(dir_name);
+	if err != 0 {
+		return nil, err;
+	}
+	fis: []os.File_Info;
+	fis, err = os.read_dir(f, -1, allocator);
+	os.close(f);
+	if err != 0 {
+		return nil, err;
+	}
+	sort.quick_sort_proc(fis, proc(a, b: os.File_Info) -> int {
+		return sort.compare_strings(a.name, b.name);
+	});
+	return fis, 0;
+}