consolidate checks whether stdin/stdout is terminal

internal/terminal/stdio.go

@@ -0,0 +1,29 @@
+package terminal
+
+import (
+	"os"
+
+	"golang.org/x/term"
+)
+
+func StdinIsTerminal() bool {
+	return term.IsTerminal(int(os.Stdin.Fd()))
+}
+
+func StdoutIsTerminal() bool {
+	// mintty on windows can use pipes which behave like a posix terminal,
+	// but which are not a terminal handle
+	return term.IsTerminal(int(os.Stdout.Fd())) || StdoutCanUpdateStatus()
+}
+
+func StdoutCanUpdateStatus() bool {
+	return CanUpdateStatus(os.Stdout.Fd())
+}
+
+func StdoutTerminalWidth() int {
+	w, _, err := term.GetSize(int(os.Stdout.Fd()))
+	if err != nil {
+		return 0
+	}
+	return w
+}

internal/terminal/terminal_posix.go

@@ -13,7 +13,7 @@ const (
 	PosixControlClearLine      = "\x1b[2K"
 )
 
-// posixClearCurrentLine removes all characters from the current line and resets the
+// PosixClearCurrentLine removes all characters from the current line and resets the
 // cursor position to the first column.
 func PosixClearCurrentLine(wr io.Writer, _ uintptr) {
 	// clear current line
@@ -24,7 +24,7 @@ func PosixClearCurrentLine(wr io.Writer, _ uintptr) {
 	}
 }
 
-// posixMoveCursorUp moves the cursor to the line n lines above the current one.
+// PosixMoveCursorUp moves the cursor to the line n lines above the current one.
 func PosixMoveCursorUp(wr io.Writer, _ uintptr, n int) {
 	data := []byte(PosixControlMoveCursorHome)
 	data = append(data, bytes.Repeat([]byte(PosixControlMoveCursorUp), n)...)

internal/terminal/terminal_unix.go

@@ -10,13 +10,13 @@ import (
 	"golang.org/x/term"
 )
 
-// clearCurrentLine removes all characters from the current line and resets the
+// ClearCurrentLine removes all characters from the current line and resets the
 // cursor position to the first column.
 func ClearCurrentLine(_ uintptr) func(io.Writer, uintptr) {
 	return PosixClearCurrentLine
 }
 
-// moveCursorUp moves the cursor to the line n lines above the current one.
+// MoveCursorUp moves the cursor to the line n lines above the current one.
 func MoveCursorUp(_ uintptr) func(io.Writer, uintptr, int) {
 	return PosixMoveCursorUp
 }