elvish/pkg/cli/modes/instant.go
Qi Xiao d2936c06a1 Use a more sophisticated algorithm to distribute widget heights.
This is needed since there can now be an arbitrary number of widgets competing
for vertical space.

- Add a new MaxHeight method to the tk.Widget interface to provide hint on how
  to distribute the height.

- Implement the algorithm in distributeHeight in cli/app.go.
2021-09-05 01:17:46 +01:00

106 lines
2.3 KiB
Go

package modes
import (
"errors"
"src.elv.sh/pkg/cli"
"src.elv.sh/pkg/cli/term"
"src.elv.sh/pkg/cli/tk"
"src.elv.sh/pkg/ui"
)
// Instant is a mode that executes code whenever it changes and shows the
// result.
type Instant interface {
tk.Widget
}
// InstantSpec specifies the configuration for the instant mode.
type InstantSpec struct {
// Key bindings.
Bindings tk.Bindings
// The function to execute code and returns the output.
Execute func(code string) ([]string, error)
}
type instant struct {
InstantSpec
attachedTo tk.CodeArea
textView tk.TextView
lastCode string
lastErr error
}
func (w *instant) Render(width, height int) *term.Buffer {
buf := w.render(width, height)
buf.TrimToLines(0, height)
return buf
}
func (w *instant) MaxHeight(width, height int) int {
return len(w.render(width, height).Lines)
}
func (w *instant) render(width, height int) *term.Buffer {
bb := term.NewBufferBuilder(width).
WriteStyled(modeLine(" INSTANT ", false)).SetDotHere()
if w.lastErr != nil {
bb.Newline().Write(w.lastErr.Error(), ui.FgRed)
}
buf := bb.Buffer()
if len(buf.Lines) < height {
bufTextView := w.textView.Render(width, height-len(buf.Lines))
buf.Extend(bufTextView, false)
}
return buf
}
func (w *instant) Focus() bool { return false }
func (w *instant) Handle(event term.Event) bool {
handled := w.Bindings.Handle(w, event)
if !handled {
handled = w.attachedTo.Handle(event)
}
w.update(false)
return handled
}
func (w *instant) update(force bool) {
code := w.attachedTo.CopyState().Buffer.Content
if code == w.lastCode && !force {
return
}
w.lastCode = code
output, err := w.Execute(code)
w.lastErr = err
if err == nil {
w.textView.MutateState(func(s *tk.TextViewState) {
*s = tk.TextViewState{Lines: output, First: 0}
})
}
}
var errExecutorIsRequired = errors.New("executor is required")
// NewInstant creates a new instant mode.
func NewInstant(app cli.App, cfg InstantSpec) (Instant, error) {
codeArea, err := FocusedCodeArea(app)
if err != nil {
return nil, err
}
if cfg.Execute == nil {
return nil, errExecutorIsRequired
}
if cfg.Bindings == nil {
cfg.Bindings = tk.DummyBindings{}
}
w := instant{
InstantSpec: cfg,
attachedTo: codeArea,
textView: tk.NewTextView(tk.TextViewSpec{Scrollable: true}),
}
w.update(true)
return &w, nil
}