elvish/edit/reader.go
2016-02-23 14:55:56 +01:00

415 lines
9.0 KiB
Go

package edit
import (
"fmt"
"os"
"time"
)
var (
// EscSequenceTimeout is the amount of time within which runes that make up
// an escape sequence are supposed to follow each other. Modern terminal
// emulators send escape sequences very fast, so 10ms is more than
// sufficient. SSH connections on a slow link might be problematic though.
EscSequenceTimeout = 10 * time.Millisecond
)
// Special rune values used in the return value of (*Reader).ReadRune.
const (
// No rune received before specified time.
runeTimeout rune = -1 - iota
// Error occured in AsyncReader. The error is left at the readError field.
runeReadError
)
// Reader converts a stream of runes into a stream of OneRead's.
type Reader struct {
ar *AsyncReader
keyChan chan Key
cprChan chan pos
mouseChan chan mouseEvent
errChan chan error
quit chan struct{}
}
type mouseEvent struct {
pos
down bool
// Number of the button, 0-based. -1 for unknown.
button int
mod Mod
}
// NewReader creates a new Reader on the given terminal file.
func NewReader(f *os.File) *Reader {
rd := &Reader{
NewAsyncReader(f),
make(chan Key),
make(chan pos),
make(chan mouseEvent),
make(chan error),
nil,
}
return rd
}
// KeyChan returns the channel onto which the Reader writes Keys it has read.
func (rd *Reader) KeyChan() <-chan Key {
return rd.keyChan
}
// CPRChan returns the channel onto which the Reader writes CPRs it has read.
func (rd *Reader) CPRChan() <-chan pos {
return rd.cprChan
}
// MouseChan returns the channel onto which the Reader writes mouse events it
// has read.
func (rd *Reader) MouseChan() <-chan mouseEvent {
return rd.mouseChan
}
// ErrorChan returns the channel onto which the Reader writes errors it came
// across during the reading process.
func (rd *Reader) ErrorChan() <-chan error {
return rd.errChan
}
// Run runs the Reader. It blocks until Quit is called and should be called in
// a separate goroutine.
func (rd *Reader) Run() {
runes := rd.ar.Chan()
quit := make(chan struct{})
rd.quit = quit
go rd.ar.Run()
for {
select {
case r := <-runes:
rd.readOne(r)
case <-quit:
return
}
}
}
// Quit terminates the loop of Run.
func (rd *Reader) Quit() {
rd.ar.Quit()
close(rd.quit)
}
// Close releases files associated with the Reader. It does not close the file
// used to create it.
func (rd *Reader) Close() {
rd.ar.Close()
}
// readOne attempts to read one key or CPR, led by a rune already read.
func (rd *Reader) readOne(r rune) {
var k Key
var cpr pos
var mouse mouseEvent
var err error
currentSeq := string(r)
badSeq := func(msg string) {
err = fmt.Errorf("%s: %q", msg, currentSeq)
}
// readRune attempts to read a rune within EscSequenceTimeout. It writes to
// the err and currentSeq variable in the outer scope.
readRune :=
func() rune {
select {
case r := <-rd.ar.Chan():
currentSeq += string(r)
return r
case err = <-rd.ar.ErrorChan():
return runeReadError
case <-time.After(EscSequenceTimeout):
return runeTimeout
}
}
defer func() {
if k != (Key{}) {
select {
case rd.keyChan <- k:
case <-rd.quit:
}
} else if cpr != (pos{}) {
select {
case rd.cprChan <- cpr:
case <-rd.quit:
}
} else if mouse != (mouseEvent{}) {
select {
case rd.mouseChan <- mouse:
case <-rd.quit:
}
}
if err != nil {
select {
case rd.errChan <- err:
case <-rd.quit:
}
}
}()
switch r {
case Tab, Enter, Backspace:
k = Key{r, 0}
case 0x0:
k = Key{'`', Ctrl} // ^@
case 0x1d:
k = Key{'6', Ctrl} // ^^
case 0x1f:
k = Key{'/', Ctrl} // ^_
case 0x1b: // ^[ Escape
r2 := readRune()
if r2 == runeTimeout || r2 == runeReadError {
k = Key{'[', Ctrl}
break
}
switch r2 {
case '[':
// CSI style function key sequence.
r = readRune()
if r == runeTimeout || r == runeReadError {
k = Key{'[', Alt}
return
}
nums := make([]int, 0, 2)
var starter rune
// Read an optional starter.
switch r {
case '<':
starter = r
r = readRune()
case 'M':
// Mouse event.
cb := readRune()
if cb == runeTimeout || cb == runeReadError {
badSeq("Incomplete mouse event")
return
}
cx := readRune()
if cx == runeTimeout || cx == runeReadError {
badSeq("Incomplete mouse event")
return
}
cy := readRune()
if cy == runeTimeout || cy == runeReadError {
badSeq("Incomplete mouse event")
return
}
down := true
button := int(cb & 3)
if button == 3 {
down = false
button = -1
}
mod := mouseModify(int(cb))
mouse = mouseEvent{
pos{int(cy) - 32, int(cx) - 32}, down, button, mod}
return
}
CSISeq:
for {
switch {
case r == ';':
nums = append(nums, 0)
case '0' <= r && r <= '9':
if len(nums) == 0 {
nums = append(nums, 0)
}
cur := len(nums) - 1
nums[cur] = nums[cur]*10 + int(r-'0')
case r == runeTimeout:
// Incomplete CSI.
badSeq("Incomplete CSI")
return
case r == runeReadError:
// TODO Also complain about incomplte CSI.
return
default: // Treat as a terminator.
break CSISeq
}
r = readRune()
}
if starter == 0 && r == 'R' {
// Cursor position report.
if len(nums) != 2 {
badSeq("bad CPR")
return
}
cpr = pos{nums[0], nums[1]}
} else if starter == '<' && (r == 'm' || r == 'M') {
// SGR-style mouse event.
if len(nums) != 3 {
badSeq("bad SGR mouse event")
return
}
down := r == 'M'
button := nums[0] & 3
mod := mouseModify(nums[0])
mouse = mouseEvent{pos{nums[2], nums[1]}, down, button, mod}
} else {
k = parseCSI(nums, r, currentSeq)
if k == (Key{}) {
badSeq("bad CSI")
}
}
case 'O':
// G3 style function key sequence: read one rune.
r = readRune()
if r == runeTimeout || r == runeReadError {
k = Key{r2, Alt}
return
}
r, ok := g3Seq[r]
if ok {
k = Key{r, 0}
} else {
badSeq("bad G3")
}
default:
k = Key{r2, Alt}
}
default:
// Regular Ctrl sequences.
if 0x1 <= r && r <= 0x1d {
k = Key{r + 0x40, Ctrl}
} else {
k = Key{r, 0}
}
}
}
// G3-style key sequences: \eO followed by exactly one character. For instance,
// \eOP is F1.
var g3Seq = map[rune]rune{
'A': Up, 'B': Down, 'C': Right, 'D': Left,
// F1-F4: xterm, libvte and tmux
'P': F1, 'Q': F2,
'R': F3, 'S': F4,
// Home and End: libvte
'H': Home, 'F': End,
}
// Tables for CSI-style key sequences, which are \e[ followed by a list of
// semicolon-delimited numeric arguments, before being concluded by a
// non-numeric, non-semicolon rune.
// CSI-style key sequences that can be identified based on the ending rune. For
// instance, \e[A is Up.
var keyByLast = map[rune]Key{
'A': Key{Up, 0}, 'B': Key{Down, 0},
'C': Key{Right, 0}, 'D': Key{Left, 0},
'H': Key{Home, 0}, 'F': Key{End, 0},
'Z': Key{Tab, Shift},
}
// CSI-style key sequences ending with '~' and can be identified based on
// the only number argument. For instance, \e[1~ is Home.
var keyByNum0 = map[int]rune{
1: Home, 2: Insert, 3: Delete, 4: End, 5: PageUp, 6: PageDown,
11: F1, 12: F2, 13: F3, 14: F4,
15: F5, 17: F6, 18: F7, 19: F8, 20: F9, 21: F10, 23: F11, 24: F12,
}
// CSI-style key sequences ending with '~', with 27 as the first numeric
// argument. For instance, \e[27;9~ is Tab.
//
// The list is taken blindly from tmux source xterm-keys.c. I don't have a
// keyboard-terminal combination that generate such sequences, but assumably
// some PC keyboard with a numpad can.
var keyByNum2 = map[int]rune{
9: '\t', 13: '\r',
33: '!', 35: '#', 39: '\'', 40: '(', 41: ')', 43: '+', 44: ',', 45: '-',
46: '.',
48: '0', 49: '1', 50: '2', 51: '3', 52: '4', 53: '5', 54: '6', 55: '7',
56: '8', 57: '9',
58: ':', 59: ';', 60: '<', 61: '=', 62: '>', 63: ';',
}
// parseCSI parses a CSI-style key sequence.
func parseCSI(nums []int, last rune, seq string) Key {
if k, ok := keyByLast[last]; ok {
if len(nums) == 0 {
// Unmodified: \e[A (Up)
return k
} else if len(nums) == 2 && nums[0] == 1 {
// Modified: \e[1;5A (Ctrl-Up)
return xtermModify(k, nums[1], seq)
} else {
return Key{}
}
}
if last == '~' {
if len(nums) == 1 || len(nums) == 2 {
if r, ok := keyByNum0[nums[0]]; ok {
k := Key{r, 0}
if len(nums) == 1 {
// Unmodified: \e[5~ (PageUp)
return k
}
// Modified: \e[5;5~ (Ctrl-PageUp)
return xtermModify(k, nums[1], seq)
}
} else if len(nums) == 3 && nums[0] == 27 {
if r, ok := keyByNum2[nums[2]]; ok {
k := Key{r, 0}
return xtermModify(k, nums[1], seq)
}
}
}
return Key{}
}
func xtermModify(k Key, mod int, seq string) Key {
switch mod {
case 0:
// do nothing
case 2:
k.Mod |= Shift
case 3:
k.Mod |= Alt
case 4:
k.Mod |= Shift | Alt
case 5:
k.Mod |= Ctrl
case 6:
k.Mod |= Shift | Ctrl
case 7:
k.Mod |= Alt | Ctrl
case 8:
k.Mod |= Shift | Alt | Ctrl
default:
return Key{}
}
return k
}
func mouseModify(n int) Mod {
var mod Mod
if n&4 != 0 {
mod |= Shift
}
if n&8 != 0 {
mod |= Alt
}
if n&16 != 0 {
mod |= Ctrl
}
return mod
}