Code to get file/dir completion candidates for a prefix

tools/completion/files.go

@@ -0,0 +1,56 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package completion
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var _ = fmt.Print
+
+type CompleteFilesCallback func(completion_candidate string, abspath string, d fs.DirEntry) error
+
+func complete_files(prefix string, callback CompleteFilesCallback) error {
+	base := "."
+	base_len := len(base) + 1
+	has_cwd_prefix := strings.HasPrefix(prefix, "./")
+	is_abs_path := filepath.IsAbs(prefix)
+	wd := ""
+	if is_abs_path {
+		base = prefix
+		base_len = 0
+		if s, err := os.Stat(prefix); err != nil || !s.IsDir() {
+			base = filepath.Dir(prefix)
+		}
+	} else {
+		wd, _ = os.Getwd()
+	}
+	filepath.WalkDir(base, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return nil
+		}
+		if path == base {
+			return nil
+		}
+		completion_candidate := path
+		abspath := path
+		if is_abs_path {
+			completion_candidate = path[base_len:]
+		} else {
+			abspath = filepath.Join(wd, path)
+			if has_cwd_prefix {
+				completion_candidate = "./" + completion_candidate
+			}
+		}
+		if strings.HasPrefix(completion_candidate, prefix) {
+			return callback(completion_candidate, abspath, d)
+		}
+		return nil
+	})
+
+	return nil
+}