147 lines
3.7 KiB
Go
147 lines
3.7 KiB
Go
//go:build wasm
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package terminal
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import (
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"syscall/js"
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)
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type wasmBackend struct {
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width, height int
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inputCh chan []byte
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jsCallbacks []js.Func
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returnEmptyNext bool // Signal to return empty on next Read() for standalone ESC
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}
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const escapeTimeoutMs = 10
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func newBackend() Backend {
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return &wasmBackend{
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width: 80,
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height: 24,
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inputCh: make(chan []byte, 256),
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}
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}
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func (b *wasmBackend) Init() error {
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// Register JS callbacks
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inputCb := js.FuncOf(func(_ js.Value, args []js.Value) any {
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if len(args) > 0 {
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data := make([]byte, args[0].Length())
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js.CopyBytesToGo(data, args[0])
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select {
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case b.inputCh <- data:
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default:
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// Buffer full, drop input
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}
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}
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return nil
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})
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b.jsCallbacks = append(b.jsCallbacks, inputCb)
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js.Global().Set("goTerminalInput", inputCb)
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resizeCb := js.FuncOf(func(_ js.Value, args []js.Value) any {
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if len(args) >= 2 {
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w, h := args[0].Int(), args[1].Int()
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b.width, b.height = w, h
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// Resize handler is set via SetResizeHandler, but we need to store it
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// or have this callback call a method. For simplicity, we'll assign
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// the handler to a struct field if we need dynamic updates,
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// but here we rely on the struct field set by SetResizeHandler.
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// However, SetResizeHandler might be called after Init.
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// See below for corrected flow.
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}
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return nil
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})
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b.jsCallbacks = append(b.jsCallbacks, resizeCb)
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js.Global().Set("goTerminalResize", resizeCb)
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// Initial size query
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if xterm := js.Global().Get("xterm"); !xterm.IsUndefined() {
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b.width = xterm.Get("cols").Int()
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b.height = xterm.Get("rows").Int()
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}
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return nil
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}
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func (b *wasmBackend) Fini() {
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for _, cb := range b.jsCallbacks {
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cb.Release()
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}
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js.Global().Delete("goTerminalInput")
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js.Global().Delete("goTerminalResize")
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}
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func (b *wasmBackend) Size() (int, int) {
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return b.width, b.height
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}
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func (b *wasmBackend) Write(p []byte) error {
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arr := js.Global().Get("Uint8Array").New(len(p))
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js.CopyBytesToJS(arr, p)
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js.Global().Call("goTerminalWrite", arr)
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return nil
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}
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func (b *wasmBackend) Read(stopCh <-chan struct{}) ([]byte, error) {
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// After standalone ESC timeout, return empty to trigger readLoop's ESC emission
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if b.returnEmptyNext {
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b.returnEmptyNext = false
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return nil, nil
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}
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select {
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case data := <-b.inputCh:
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// If we received exactly ESC, wait briefly for more data
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// (in case it's start of escape sequence split across callbacks)
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if len(data) == 1 && data[0] == 0x1b {
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// Use JS setTimeout via a promise-based wait
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moreCh := make(chan []byte, 1)
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// Schedule timeout callback
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var timeoutCb js.Func
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timeoutCb = js.FuncOf(func(_ js.Value, _ []js.Value) any {
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select {
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case moreCh <- nil:
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default:
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}
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timeoutCb.Release()
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return nil
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})
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js.Global().Call("setTimeout", timeoutCb, escapeTimeoutMs)
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// Wait for more data or timeout
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select {
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case more := <-b.inputCh:
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// More data arrived, combine
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return append(data, more...), nil
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case <-moreCh:
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// Timeout, standalone ESC confirmed
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// Signal next Read() to return empty (triggers readLoop standalone ESC logic)
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b.returnEmptyNext = true
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return data, nil
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case <-stopCh:
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return nil, nil
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}
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}
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return data, nil
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case <-stopCh:
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return nil, nil
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}
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}
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func (b *wasmBackend) SetResizeHandler(handler func(width, height int)) {
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// Overwrite the resize callback to include the handler invocation
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// This ensures the handler acts on the latest registration
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resizeCb := js.FuncOf(func(_ js.Value, args []js.Value) any {
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if len(args) >= 2 {
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w, h := args[0].Int(), args[1].Int()
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b.width, b.height = w, h
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handler(w, h)
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}
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return nil
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})
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b.jsCallbacks = append(b.jsCallbacks, resizeCb)
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js.Global().Set("goTerminalResize", resizeCb)
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} |