forked from Mirrors/bubbletea
368 lines
10 KiB
Go
368 lines
10 KiB
Go
package tea
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import (
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"errors"
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"fmt"
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"io"
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"unicode/utf8"
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)
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// KeyMsg contains information about a keypress. KeyMsgs are always sent to
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// the program's update function. There are a couple general patterns you could
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// use to check for keypresses:
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//
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// // Switch on the string representation of the key (shorter)
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// switch msg := msg.(type) {
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// case KeyMsg:
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// switch msg.String() {
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// case "enter":
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// fmt.Println("you pressed enter!")
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// case "a":
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// fmt.Println("you pressed a!")
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// }
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// }
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//
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// // Switch on the key type (more foolproof)
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// switch msg := msg.(type) {
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// case KeyMsg:
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// switch msg.Type {
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// case KeyEnter:
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// fmt.Println("you pressed enter!")
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// case KeyRunes:
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// switch string(msg.Runes) {
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// case "a":
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// fmt.Println("you pressed a!")
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// }
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// }
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// }
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//
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// Note that Key.Runes will always contain at least one character, so you can
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// always safely call Key.Runes[0]. In most cases Key.Runes will only contain
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// one character, though certain input method editors (most notably Chinese
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// IMEs) can input multiple runes at once.
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type KeyMsg Key
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// String returns a string representation for a key message. It's safe (and
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// encouraged) for use in key comparison.
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func (k KeyMsg) String() (str string) {
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return Key(k).String()
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}
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// Key contains information about a keypress.
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type Key struct {
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Type KeyType
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Runes []rune
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Alt bool
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}
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// String returns a friendly string representation for a key. It's safe (and
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// encouraged) for use in key comparison.
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//
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// k := Key{Type: KeyEnter}
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// fmt.Println(k)
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// // Output: enter
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//
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func (k Key) String() (str string) {
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if k.Alt {
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str += "alt+"
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}
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if k.Type == KeyRunes {
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str += string(k.Runes)
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return str
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} else if s, ok := keyNames[k.Type]; ok {
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str += s
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return str
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}
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return ""
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}
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// KeyType indicates the key pressed, such as KeyEnter or KeyBreak or KeyCtrlC.
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// All other keys will be type KeyRunes. To get the rune value, check the Rune
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// method on a Key struct, or use the Key.String() method:
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//
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// k := Key{Type: KeyRunes, Runes: []rune{'a'}, Alt: true}
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// if k.Type == KeyRunes {
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//
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// fmt.Println(k.Runes)
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// // Output: a
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//
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// fmt.Println(k.String())
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// // Output: alt+a
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//
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// }
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type KeyType int
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func (k KeyType) String() (str string) {
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if s, ok := keyNames[k]; ok {
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return s
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}
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return ""
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}
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// Control keys. I know we could do this with an iota, but the values are very
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// specific, so we set the values explicitly to avoid any confusion.
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//
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// See also:
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// https://en.wikipedia.org/wiki/C0_and_C1_control_codes
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const (
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keyNUL KeyType = 0 // null, \0
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keySOH KeyType = 1 // start of heading
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keySTX KeyType = 2 // start of text
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keyETX KeyType = 3 // break, ctrl+c
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keyEOT KeyType = 4 // end of transmission
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keyENQ KeyType = 5 // enquiry
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keyACK KeyType = 6 // acknowledge
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keyBEL KeyType = 7 // bell, \a
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keyBS KeyType = 8 // backspace
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keyHT KeyType = 9 // horizontal tabulation, \t
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keyLF KeyType = 10 // line feed, \n
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keyVT KeyType = 11 // vertical tabulation \v
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keyFF KeyType = 12 // form feed \f
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keyCR KeyType = 13 // carriage return, \r
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keySO KeyType = 14 // shift out
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keySI KeyType = 15 // shift in
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keyDLE KeyType = 16 // data link escape
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keyDC1 KeyType = 17 // device control one
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keyDC2 KeyType = 18 // device control two
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keyDC3 KeyType = 19 // device control three
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keyDC4 KeyType = 20 // device control four
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keyNAK KeyType = 21 // negative acknowledge
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keySYN KeyType = 22 // synchronous idle
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keyETB KeyType = 23 // end of transmission block
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keyCAN KeyType = 24 // cancel
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keyEM KeyType = 25 // end of medium
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keySUB KeyType = 26 // substitution
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keyESC KeyType = 27 // escape, \e
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keyFS KeyType = 28 // file separator
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keyGS KeyType = 29 // group separator
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keyRS KeyType = 30 // record separator
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keyUS KeyType = 31 // unit separator
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keySP KeyType = 32 // space
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keyDEL KeyType = 127 // delete. on most systems this is mapped to backspace, I hear
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)
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// Control key aliases.
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const (
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KeyNull KeyType = keyNUL
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KeyBreak KeyType = keyETX
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KeyEnter KeyType = keyCR
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KeyBackspace KeyType = keyDEL
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KeyTab KeyType = keyHT
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KeySpace KeyType = keySP
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KeyEsc KeyType = keyESC
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KeyEscape KeyType = keyESC
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KeyCtrlAt KeyType = keyNUL // ctrl+@
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KeyCtrlA KeyType = keySOH
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KeyCtrlB KeyType = keySTX
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KeyCtrlC KeyType = keyETX
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KeyCtrlD KeyType = keyEOT
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KeyCtrlE KeyType = keyENQ
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KeyCtrlF KeyType = keyACK
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KeyCtrlG KeyType = keyBEL
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KeyCtrlH KeyType = keyBS
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KeyCtrlI KeyType = keyHT
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KeyCtrlJ KeyType = keyLF
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KeyCtrlK KeyType = keyVT
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KeyCtrlL KeyType = keyFF
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KeyCtrlM KeyType = keyCR
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KeyCtrlN KeyType = keySO
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KeyCtrlO KeyType = keySI
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KeyCtrlP KeyType = keyDLE
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KeyCtrlQ KeyType = keyDC1
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KeyCtrlR KeyType = keyDC2
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KeyCtrlS KeyType = keyDC3
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KeyCtrlT KeyType = keyDC4
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KeyCtrlU KeyType = keyNAK
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KeyCtrlV KeyType = keySYN
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KeyCtrlW KeyType = keyETB
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KeyCtrlX KeyType = keyCAN
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KeyCtrlY KeyType = keyEM
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KeyCtrlZ KeyType = keySUB
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KeyCtrlOpenBracket KeyType = keyESC // ctrl+[
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KeyCtrlBackslash KeyType = keyFS // ctrl+\
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KeyCtrlCloseBracket KeyType = keyGS // ctrl+]
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KeyCtrlCaret KeyType = keyRS // ctrl+^
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KeyCtrlUnderscore KeyType = keyUS // ctrl+_
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KeyCtrlQuestionMark KeyType = keyDEL // ctrl+?
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)
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// Other keys.
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const (
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KeyRunes KeyType = -(iota + 1)
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KeyUp
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KeyDown
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KeyRight
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KeyLeft
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KeyShiftTab
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KeyHome
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KeyEnd
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KeyPgUp
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KeyPgDown
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KeyDelete
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)
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// Mapping for control keys to friendly consts.
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var keyNames = map[KeyType]string{
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keyNUL: "ctrl+@", // also ctrl+`
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keySOH: "ctrl+a",
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keySTX: "ctrl+b",
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keyETX: "ctrl+c",
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keyEOT: "ctrl+d",
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keyENQ: "ctrl+e",
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keyACK: "ctrl+f",
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keyBEL: "ctrl+g",
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keyBS: "ctrl+h",
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keyHT: "tab", // also ctrl+i
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keyLF: "ctrl+j",
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keyVT: "ctrl+k",
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keyFF: "ctrl+l",
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keyCR: "enter",
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keySO: "ctrl+n",
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keySI: "ctrl+o",
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keyDLE: "ctrl+p",
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keyDC1: "ctrl+q",
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keyDC2: "ctrl+r",
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keyDC3: "ctrl+s",
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keyDC4: "ctrl+t",
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keyNAK: "ctrl+u",
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keySYN: "ctrl+v",
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keyETB: "ctrl+w",
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keyCAN: "ctrl+x",
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keyEM: "ctrl+y",
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keySUB: "ctrl+z",
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keyESC: "esc",
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keyFS: "ctrl+\\",
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keyGS: "ctrl+]",
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keyRS: "ctrl+^",
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keyUS: "ctrl+_",
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keySP: "space",
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keyDEL: "backspace",
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KeyRunes: "runes",
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KeyUp: "up",
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KeyDown: "down",
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KeyRight: "right",
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KeyLeft: "left",
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KeyShiftTab: "shift+tab",
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KeyHome: "home",
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KeyEnd: "end",
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KeyPgUp: "pgup",
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KeyPgDown: "pgdown",
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}
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// Mapping for sequences to consts.
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var sequences = map[string]KeyType{
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"\x1b[A": KeyUp,
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"\x1b[B": KeyDown,
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"\x1b[C": KeyRight,
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"\x1b[D": KeyLeft,
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}
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// Mapping for hex codes to consts. Unclear why these won't register as
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// sequences.
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var hexes = map[string]Key{
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"1b5b5a": {Type: KeyShiftTab},
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"1b5b337e": {Type: KeyDelete},
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"1b0d": {Type: KeyEnter, Alt: true},
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"1b7f": {Type: KeyBackspace, Alt: true},
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"1b5b48": {Type: KeyHome},
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"1b5b377e": {Type: KeyHome}, // urxvt
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"1b5b313b3348": {Type: KeyHome, Alt: true},
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"1b1b5b377e": {Type: KeyHome, Alt: true}, // urxvt
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"1b5b46": {Type: KeyEnd},
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"1b5b387e": {Type: KeyEnd}, // urxvt
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"1b5b313b3346": {Type: KeyEnd, Alt: true},
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"1b1b5b387e": {Type: KeyEnd, Alt: true}, // urxvt
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"1b5b357e": {Type: KeyPgUp},
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"1b5b353b337e": {Type: KeyPgUp, Alt: true},
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"1b1b5b357e": {Type: KeyPgUp, Alt: true}, // urxvt
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"1b5b367e": {Type: KeyPgDown},
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"1b5b363b337e": {Type: KeyPgDown, Alt: true},
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"1b1b5b367e": {Type: KeyPgDown, Alt: true}, // urxvt
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"1b5b313b3341": {Type: KeyUp, Alt: true},
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"1b5b313b3342": {Type: KeyDown, Alt: true},
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"1b5b313b3343": {Type: KeyRight, Alt: true},
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"1b5b313b3344": {Type: KeyLeft, Alt: true},
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// Powershell
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"1b4f41": {Type: KeyUp, Alt: false},
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"1b4f42": {Type: KeyDown, Alt: false},
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"1b4f43": {Type: KeyRight, Alt: false},
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"1b4f44": {Type: KeyLeft, Alt: false},
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}
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// readInput reads keypress and mouse input from a TTY and returns a message
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// containing information about the key or mouse event accordingly.
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func readInput(input io.Reader) (Msg, error) {
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var buf [256]byte
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// Read and block
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numBytes, err := input.Read(buf[:])
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if err != nil {
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return nil, err
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}
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// See if it's a mouse event. For now we're parsing X10-type mouse events
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// only.
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mouseEvent, err := parseX10MouseEvent(buf[:numBytes])
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if err == nil {
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return MouseMsg(mouseEvent), nil
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}
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// Is it a special sequence, like an arrow key?
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if k, ok := sequences[string(buf[:numBytes])]; ok {
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return KeyMsg(Key{Type: k}), nil
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}
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// Some of these need special handling
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hex := fmt.Sprintf("%x", buf[:numBytes])
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if k, ok := hexes[hex]; ok {
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return KeyMsg(k), nil
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}
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// Is the alt key pressed? The buffer will be prefixed with an escape
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// sequence if so.
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if numBytes > 1 && buf[0] == 0x1b {
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// Now remove the initial escape sequence and re-process to get the
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// character being pressed in combination with alt.
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c, _ := utf8.DecodeRune(buf[1:])
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if c == utf8.RuneError {
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return nil, errors.New("could not decode rune after removing initial escape")
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}
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return KeyMsg(Key{Alt: true, Type: KeyRunes, Runes: []rune{c}}), nil
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}
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var runes []rune
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b := buf[:numBytes]
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// Translate input into runes. In most cases we'll receive exactly one
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// rune, but there are cases, particularly when an input method editor is
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// used, where we can receive multiple runes at once.
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for i, w := 0, 0; i < len(b); i += w {
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r, width := utf8.DecodeRune(b[i:])
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if r == utf8.RuneError {
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return nil, errors.New("could not decode rune")
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}
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runes = append(runes, r)
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w = width
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}
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if len(runes) == 0 {
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return nil, errors.New("receied 0 runes from input")
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} else if len(runes) > 1 {
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// We received multiple runes, so we know this isn't a control
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// character, sequence, and so on.
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return KeyMsg(Key{Type: KeyRunes, Runes: runes}), nil
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}
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// Is the first rune a control character?
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r := KeyType(runes[0])
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if numBytes == 1 && r <= keyUS || r == keyDEL {
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return KeyMsg(Key{Type: r}), nil
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}
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// Welp, it's just a regular, ol' single rune
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return KeyMsg(Key{Type: KeyRunes, Runes: runes}), nil
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}
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