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// Copyright © 2019 The Homeport Team
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
/*
Package term contains convenience functions for terminal related tasks, for
example to get the current terminal width or a reasonable fallback.
*/
package term
import (
"fmt"
"os"
"github.com/mattn/go-isatty"
"github.com/mitchellh/go-ps"
"golang.org/x/term"
)
const (
hideCursor = "\x1b[?25l"
showCursor = "\x1b[?25h"
)
// DefaultTerminalWidth is the default fallback terminal width.
const DefaultTerminalWidth = 80
// DefaultTerminalHeight is the default fallback terminal height.
const DefaultTerminalHeight = 25
// FixedTerminalWidth allows a manual fixed override of the terminal width.
var FixedTerminalWidth = -1
// FixedTerminalHeight allows a manual fixed override of the terminal height.
var FixedTerminalHeight = -1
// GetTerminalWidth return the terminal width (available characters per line)
func GetTerminalWidth() int {
width, _ := GetTerminalSize()
return width
}
// GetTerminalHeight return the terminal height (available lines).
func GetTerminalHeight() int {
_, height := GetTerminalSize()
return height
}
// GetTerminalSize return the terminal size as a width and height tuple. In
// case the terminal size cannot be determined, a reasonable default is
// used: 80x25. A manual override is possible using FixedTerminalWidth
// and FixedTerminalHeight.
func GetTerminalSize() (int, int) {
// In case this is a garden container, disable the terminal size detection
// and fall back to a reasonable assumption that is a bit bigger in size
// than the default terminal fallback dimensions.
if FixedTerminalWidth < 0 && FixedTerminalHeight < 0 && IsGardenContainer() {
FixedTerminalWidth = 120
FixedTerminalHeight = 25
}
// Return user preference (explicit overwrite) of both width and height
if FixedTerminalWidth > 0 && FixedTerminalHeight > 0 {
return FixedTerminalWidth, FixedTerminalHeight
}
width, height, err := term.GetSize(int(os.Stdout.Fd()))
switch {
// Return default fallback value
case err != nil:
return DefaultTerminalWidth, DefaultTerminalHeight
// Return user preference of width, actual value for height
case FixedTerminalWidth > 0:
return FixedTerminalWidth, height
// Return user preference of height, actual value for width
case FixedTerminalHeight > 0:
return width, FixedTerminalHeight
// Return actual determined values
default:
return width, height
}
}
// IsDumbTerminal returns whether the current terminal has a limited feature set
func IsDumbTerminal() bool {
return os.Getenv("TERM") == "dumb"
}
// IsTerminal returns whether this program runs in a terminal and not in a pipe
func IsTerminal() bool {
return isatty.IsTerminal(os.Stdout.Fd()) ||
isatty.IsCygwinTerminal(os.Stdout.Fd())
}
// IsTrueColor returns whether the current terminal supports 24 bit colors
func IsTrueColor() bool {
switch os.Getenv("COLORTERM") {
case "truecolor", "24bit":
return true
default:
return false
}
}
// IsGardenContainer returns whether the current process is started in the
// process tree of garden container (https://github.com/cloudfoundry/garden).
func IsGardenContainer() bool {
if process, err := ps.FindProcess(1); err == nil && process != nil {
switch process.Executable() {
case "garden-init":
return true
}
}
return false
}
// HideCursor sends the ANSI sequence to hide the cursor symbol
func HideCursor() {
fmt.Print(hideCursor)
}
// ShowCursor sends the ANSI sequence to show the cursor symbol
func ShowCursor() {
fmt.Print(showCursor)
}
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