1717package console
1818
1919import (
20+ "errors"
2021 "fmt"
2122 "io"
2223 "io/ioutil"
@@ -26,6 +27,7 @@ import (
2627 "regexp"
2728 "sort"
2829 "strings"
30+ "sync"
2931 "syscall"
3032
3133 "github.com/dop251/goja"
@@ -74,6 +76,13 @@ type Console struct {
7476 histPath string // Absolute path to the console scrollback history
7577 history []string // Scroll history maintained by the console
7678 printer io.Writer // Output writer to serialize any display strings to
79+
80+ interactiveStopped chan struct {}
81+ stopInteractiveCh chan struct {}
82+ signalReceived chan struct {}
83+ stopped chan struct {}
84+ wg sync.WaitGroup
85+ stopOnce sync.Once
7786}
7887
7988// New initializes a JavaScript interpreted runtime environment and sets defaults
@@ -92,19 +101,27 @@ func New(config Config) (*Console, error) {
92101
93102 // Initialize the console and return
94103 console := & Console {
95- client : config .Client ,
96- jsre : jsre .New (config .DocRoot , config .Printer ),
97- prompt : config .Prompt ,
98- prompter : config .Prompter ,
99- printer : config .Printer ,
100- histPath : filepath .Join (config .DataDir , HistoryFile ),
104+ client : config .Client ,
105+ jsre : jsre .New (config .DocRoot , config .Printer ),
106+ prompt : config .Prompt ,
107+ prompter : config .Prompter ,
108+ printer : config .Printer ,
109+ histPath : filepath .Join (config .DataDir , HistoryFile ),
110+ interactiveStopped : make (chan struct {}),
111+ stopInteractiveCh : make (chan struct {}),
112+ signalReceived : make (chan struct {}, 1 ),
113+ stopped : make (chan struct {}),
101114 }
102115 if err := os .MkdirAll (config .DataDir , 0700 ); err != nil {
103116 return nil , err
104117 }
105118 if err := console .init (config .Preload ); err != nil {
106119 return nil , err
107120 }
121+
122+ console .wg .Add (1 )
123+ go console .interruptHandler ()
124+
108125 return console , nil
109126}
110127
@@ -337,9 +354,63 @@ func (c *Console) Evaluate(statement string) {
337354 }
338355 }()
339356 c .jsre .Evaluate (statement , c .printer )
357+
358+ // Avoid exiting Interactive when jsre was interrupted by SIGINT.
359+ c .clearSignalReceived ()
360+ }
361+
362+ // interruptHandler runs in its own goroutine and waits for signals.
363+ // When a signal is received, it interrupts the JS interpreter.
364+ func (c * Console ) interruptHandler () {
365+ defer c .wg .Done ()
366+
367+ // During Interactive, liner inhibits the signal while it is prompting for
368+ // input. However, the signal will be received while evaluating JS.
369+ //
370+ // On unsupported terminals, SIGINT can also happen while prompting.
371+ // Unfortunately, it is not possible to abort the prompt in this case and
372+ // the c.readLines goroutine leaks.
373+ sig := make (chan os.Signal , 1 )
374+ signal .Notify (sig , syscall .SIGINT )
375+ defer signal .Stop (sig )
376+
377+ for {
378+ select {
379+ case <- sig :
380+ c .setSignalReceived ()
381+ c .jsre .Interrupt (errors .New ("interrupted" ))
382+ case <- c .stopInteractiveCh :
383+ close (c .interactiveStopped )
384+ c .jsre .Interrupt (errors .New ("interrupted" ))
385+ case <- c .stopped :
386+ return
387+ }
388+ }
389+ }
390+
391+ func (c * Console ) setSignalReceived () {
392+ select {
393+ case c .signalReceived <- struct {}{}:
394+ default :
395+ }
396+ }
397+
398+ func (c * Console ) clearSignalReceived () {
399+ select {
400+ case <- c .signalReceived :
401+ default :
402+ }
340403}
341404
342- // Interactive starts an interactive user session, where input is propted from
405+ // StopInteractive causes Interactive to return as soon as possible.
406+ func (c * Console ) StopInteractive () {
407+ select {
408+ case c .stopInteractiveCh <- struct {}{}:
409+ case <- c .stopped :
410+ }
411+ }
412+
413+ // Interactive starts an interactive user session, where in.put is propted from
343414// the configured user prompter.
344415func (c * Console ) Interactive () {
345416 var (
@@ -349,15 +420,11 @@ func (c *Console) Interactive() {
349420 inputLine = make (chan string , 1 ) // receives user input
350421 inputErr = make (chan error , 1 ) // receives liner errors
351422 requestLine = make (chan string ) // requests a line of input
352- interrupt = make (chan os.Signal , 1 )
353423 )
354424
355- // Monitor Ctrl-C. While liner does turn on the relevant terminal mode bits to avoid
356- // the signal, a signal can still be received for unsupported terminals. Unfortunately
357- // there is no way to cancel the line reader when this happens. The readLines
358- // goroutine will be leaked in this case.
359- signal .Notify (interrupt , syscall .SIGINT , syscall .SIGTERM )
360- defer signal .Stop (interrupt )
425+ defer func () {
426+ c .writeHistory ()
427+ }()
361428
362429 // The line reader runs in a separate goroutine.
363430 go c .readLines (inputLine , inputErr , requestLine )
@@ -368,7 +435,14 @@ func (c *Console) Interactive() {
368435 requestLine <- prompt
369436
370437 select {
371- case <- interrupt :
438+ case <- c .interactiveStopped :
439+ fmt .Fprintln (c .printer , "node is down, exiting console" )
440+ return
441+
442+ case <- c .signalReceived :
443+ // SIGINT received while prompting for input -> unsupported terminal.
444+ // I'm not sure if the best choice would be to leave the console running here.
445+ // Bash keeps running in this case. node.js does not.
372446 fmt .Fprintln (c .printer , "caught interrupt, exiting" )
373447 return
374448
@@ -476,12 +550,19 @@ func (c *Console) Execute(path string) error {
476550
477551// Stop cleans up the console and terminates the runtime environment.
478552func (c * Console ) Stop (graceful bool ) error {
553+ c .stopOnce .Do (func () {
554+ // Stop the interrupt handler.
555+ close (c .stopped )
556+ c .wg .Wait ()
557+ })
558+
559+ c .jsre .Stop (graceful )
560+ return nil
561+ }
562+
563+ func (c * Console ) writeHistory () error {
479564 if err := ioutil .WriteFile (c .histPath , []byte (strings .Join (c .history , "\n " )), 0600 ); err != nil {
480565 return err
481566 }
482- if err := os .Chmod (c .histPath , 0600 ); err != nil { // Force 0600, even if it was different previously
483- return err
484- }
485- c .jsre .Stop (graceful )
486- return nil
567+ return os .Chmod (c .histPath , 0600 ) // Force 0600, even if it was different previously
487568}
0 commit comments