Kill running preview process after 500ms when focus has changed

Close #1383
Close #1384

1 files changed, 10 insertions, 3 deletions

diff --git a/src/util/util_windows.go b/src/util/util_windows.go
index 41a9a5c7..51715cd8 100644
--- a/src/util/util_windows.go
+++ b/src/util/util_windows.go
@@ -10,13 +10,15 @@ import (
 )
 
 // ExecCommand executes the given command with cmd
-func ExecCommand(command string) *exec.Cmd {
+func ExecCommand(command string, setpgid bool) *exec.Cmd {
 	return ExecCommandWith("cmd", command)
 }
 
 // ExecCommandWith executes the given command with cmd. _shell parameter is
 // ignored on Windows.
-func ExecCommandWith(_shell string, command string) *exec.Cmd {
+// FIXME: setpgid is unused. We set it in the Unix implementation so that we
+// can kill preview process with its child processes at once.
+func ExecCommandWith(_shell string, command string, setpgid bool) *exec.Cmd {
 	cmd := exec.Command("cmd")
 	cmd.SysProcAttr = &syscall.SysProcAttr{
 		HideWindow:    false,
@@ -26,12 +28,17 @@ func ExecCommandWith(_shell string, command string) *exec.Cmd {
 	return cmd
 }
 
+// KillCommand kills the process for the given command
+func KillCommand(cmd *exec.Cmd) error {
+	return cmd.Process.Kill()
+}
+
 // IsWindows returns true on Windows
 func IsWindows() bool {
 	return true
 }
 
-// SetNonBlock executes syscall.SetNonblock on file descriptor
+// SetNonblock executes syscall.SetNonblock on file descriptor
 func SetNonblock(file *os.File, nonblock bool) {
 	syscall.SetNonblock(syscall.Handle(file.Fd()), nonblock)
 }