add file.stat()

compiler/stdlib/os.go

@@ -77,6 +77,40 @@ var osModule = map[string]objects.Object{
 	"start_process":       &objects.UserFunction{Value: osStartProcess}, // start_process(name string, argv array(string), dir string, env array(string)) => imap(process)/error
 	"exec_look_path":      FuncASRSE(exec.LookPath),                     // exec_look_path(file) => string/error
 	"exec":                &objects.UserFunction{Value: osExec},         // exec(name, args...) => command
+	"stat":                &objects.UserFunction{Value: osStat},         // stat(name) => imap(fileinfo)/error
+}
+
+func osStat(args ...objects.Object) (ret objects.Object, err error) {
+	if len(args) != 1 {
+		return nil, objects.ErrWrongNumArguments
+	}
+
+	fname, ok := objects.ToString(args[0])
+	if !ok {
+		return nil, objects.ErrInvalidTypeConversion
+	}
+
+	stat, err := os.Stat(fname)
+	if err != nil {
+		return wrapError(err), nil
+	}
+
+	fstat := &objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			"name":  &objects.String{Value: stat.Name()},
+			"mtime": &objects.Time{Value: stat.ModTime()},
+			"size":  &objects.Int{Value: stat.Size()},
+			"mode":  &objects.Int{Value: int64(stat.Mode())},
+		},
+	}
+
+	if stat.IsDir() {
+		fstat.Value["directory"] = objects.TrueValue
+	} else {
+		fstat.Value["directory"] = objects.FalseValue
+	}
+
+	return fstat, nil
 }
 
 func osCreate(args ...objects.Object) (objects.Object, error) {

compiler/stdlib/os_file.go

@@ -66,6 +66,16 @@ func makeOSFile(file *os.File) *objects.ImmutableMap {
 					return &objects.Int{Value: res}, nil
 				},
 			},
+			// stat() => imap(fileinfo)/error
+			"stat": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					if len(args) != 0 {
+						return nil, objects.ErrWrongNumArguments
+					}
+
+					return osStat(&objects.String{Value: file.Name()})
+				},
+			},
 		},
 	}
 }

compiler/stdlib/os_test.go

@@ -0,0 +1,72 @@
+package stdlib_test
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/d5/tengo/objects"
+)
+
+func TestFileStatArgs(t *testing.T) {
+	module(t, "os").call("stat").expectError()
+}
+
+func TestFileStatFile(t *testing.T) {
+	content := []byte("the quick brown fox jumps over the lazy dog")
+	tf, err := ioutil.TempFile("", "test")
+	if err != nil {
+		t.Logf("could not open tempfile: %s", err)
+		return
+	}
+	defer os.Remove(tf.Name())
+
+	_, err = tf.Write(content)
+	if err != nil {
+		t.Logf("could not write temp content: %s", err)
+		return
+	}
+
+	tf.Close()
+
+	stat, err := os.Stat(tf.Name())
+	if err != nil {
+		t.Logf("could not get tmp file stat: %s", err)
+		return
+	}
+
+	module(t, "os").call("stat", tf.Name()).expect(&objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			"name":      &objects.String{Value: stat.Name()},
+			"mtime":     &objects.Time{Value: stat.ModTime()},
+			"size":      &objects.Int{Value: stat.Size()},
+			"mode":      &objects.Int{Value: int64(stat.Mode())},
+			"directory": objects.FalseValue,
+		},
+	})
+}
+
+func TestFileStatDir(t *testing.T) {
+	td, err := ioutil.TempDir("", "test")
+	if err != nil {
+		t.Logf("could not open tempdir: %s", err)
+		return
+	}
+	defer os.RemoveAll(td)
+
+	stat, err := os.Stat(td)
+	if err != nil {
+		t.Logf("could not get tmp dir stat: %s", err)
+		return
+	}
+
+	module(t, "os").call("stat", td).expect(&objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			"name":      &objects.String{Value: stat.Name()},
+			"mtime":     &objects.Time{Value: stat.ModTime()},
+			"size":      &objects.Int{Value: stat.Size()},
+			"mode":      &objects.Int{Value: int64(stat.Mode())},
+			"directory": objects.TrueValue,
+		},
+	})
+}

docs/stdlib-os.md

@@ -68,6 +68,7 @@ os := import("os")
 - `remove_all(name string) => error `: removes path and any children it contains.
 - `rename(oldpath string, newpath string) => error `: renames (moves) oldpath to newpath.
 - `setenv(key string, value string) => error `: sets the value of the environment variable named by the key.
+- `stat(filename string) => FileInfo/error`: returns a file info structure describing the file
 - `symlink(oldname string newname string) => error `: creates newname as a symbolic link to oldname.
 - `temp_dir() => string `: returns the default directory to use for temporary files.
 - `truncate(name string, size int) => error `: changes the size of the named file.
@@ -98,6 +99,7 @@ file.close()
 - `write(bytes) => int/error`: writes len(b) bytes to the File.
 - `write_string(string) => int/error`: is like 'write', but writes the contents of string s rather than a slice of bytes.
 - `read(bytes) => int/error`: reads up to len(b) bytes from the File.
+- `stat() => FileInfo/error`: returns a file info structure describing the file
 - `chmod(mode int) => error`: changes the mode of the file to mode.
 - `seek(offset int, whence int) => int/error`: sets the offset for the next Read or Write on file to offset, interpreted according to whence: 0 means relative to the origin of the file, 1 means relative to the current offset, and 2 means relative to the end.
 
@@ -131,6 +133,14 @@ cmd := exec.command("echo", ["foo", "bar"])
 output := cmd.output()
 ```
 
+## FileInfo
+
+- `name`: name of the file the info describes
+- `mtime`: time the file was last modified
+- `size`: file size in bytes
+- `mode`: file permissions as in int, comparable to octal permissions
+- `directory`: boolean indicating if the file is a directory
+
 ## Command
 
 - `combined_output() => bytes/error`: runs the command and returns its combined standard output and standard error.