forked from toolshed/abra
134 lines
3.6 KiB
Go
134 lines
3.6 KiB
Go
package tea
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import (
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"io"
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"os"
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"os/exec"
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)
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// execMsg is used internally to run an ExecCommand sent with Exec.
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type execMsg struct {
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cmd ExecCommand
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fn ExecCallback
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}
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// Exec is used to perform arbitrary I/O in a blocking fashion, effectively
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// pausing the Program while execution is running and resuming it when
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// execution has completed.
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//
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// Most of the time you'll want to use ExecProcess, which runs an exec.Cmd.
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//
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// For non-interactive i/o you should use a Cmd (that is, a tea.Cmd).
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func Exec(c ExecCommand, fn ExecCallback) Cmd {
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return func() Msg {
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return execMsg{cmd: c, fn: fn}
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}
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}
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// ExecProcess runs the given *exec.Cmd in a blocking fashion, effectively
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// pausing the Program while the command is running. After the *exec.Cmd exists
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// the Program resumes. It's useful for spawning other interactive applications
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// such as editors and shells from within a Program.
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//
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// To produce the command, pass an *exec.Cmd and a function which returns
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// a message containing the error which may have occurred when running the
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// ExecCommand.
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//
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// type VimFinishedMsg struct { err error }
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//
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// c := exec.Command("vim", "file.txt")
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//
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// cmd := ExecProcess(c, func(err error) Msg {
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// return VimFinishedMsg{err: err}
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// })
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//
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// Or, if you don't care about errors, you could simply:
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//
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// cmd := ExecProcess(exec.Command("vim", "file.txt"), nil)
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//
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// For non-interactive i/o you should use a Cmd (that is, a tea.Cmd).
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func ExecProcess(c *exec.Cmd, fn ExecCallback) Cmd {
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return Exec(wrapExecCommand(c), fn)
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}
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// ExecCallback is used when executing an *exec.Command to return a message
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// with an error, which may or may not be nil.
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type ExecCallback func(error) Msg
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// ExecCommand can be implemented to execute things in a blocking fashion in
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// the current terminal.
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type ExecCommand interface {
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Run() error
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SetStdin(io.Reader)
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SetStdout(io.Writer)
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SetStderr(io.Writer)
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}
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// wrapExecCommand wraps an exec.Cmd so that it satisfies the ExecCommand
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// interface so it can be used with Exec.
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func wrapExecCommand(c *exec.Cmd) ExecCommand {
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return &osExecCommand{Cmd: c}
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}
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// osExecCommand is a layer over an exec.Cmd that satisfies the ExecCommand
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// interface.
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type osExecCommand struct{ *exec.Cmd }
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// SetStdin sets stdin on underlying exec.Cmd to the given io.Reader.
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func (c *osExecCommand) SetStdin(r io.Reader) {
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// If unset, have the command use the same input as the terminal.
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if c.Stdin == nil {
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c.Stdin = r
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}
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}
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// SetStdout sets stdout on underlying exec.Cmd to the given io.Writer.
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func (c *osExecCommand) SetStdout(w io.Writer) {
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// If unset, have the command use the same output as the terminal.
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if c.Stdout == nil {
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c.Stdout = w
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}
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}
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// SetStderr sets stderr on the underlying exec.Cmd to the given io.Writer.
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func (c *osExecCommand) SetStderr(w io.Writer) {
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// If unset, use stderr for the command's stderr
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if c.Stderr == nil {
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c.Stderr = w
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}
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}
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// exec runs an ExecCommand and delivers the results to the program as a Msg.
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func (p *Program) exec(c ExecCommand, fn ExecCallback) {
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if err := p.ReleaseTerminal(); err != nil {
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// If we can't release input, abort.
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if fn != nil {
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go p.Send(fn(err))
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}
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return
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}
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c.SetStdin(p.input)
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c.SetStdout(p.output)
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c.SetStderr(os.Stderr)
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// Execute system command.
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if err := c.Run(); err != nil {
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p.renderer.resetLinesRendered()
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_ = p.RestoreTerminal() // also try to restore the terminal.
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if fn != nil {
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go p.Send(fn(err))
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}
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return
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}
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// Maintain the existing output from the command
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p.renderer.resetLinesRendered()
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// Have the program re-capture input.
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err := p.RestoreTerminal()
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if fn != nil {
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go p.Send(fn(err))
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}
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}
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