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// 11 february 2014
package ui
import (
"runtime"
)
// Go sets up the UI environment and pulses Ready.
// If initialization fails, Go returns an error and Ready is not pulsed.
// Otherwise, Go does not return to its caller until Stop is pulsed, at which point Go() will return nil.
// After Go() returns, you cannot call future ui functions/methods meaningfully.
// Pulsing Stop will cause Go() to return immediately; the programmer is responsible for cleaning up (for instance, hiding open Windows) beforehand.
//
// It is not safe to call ui.Go() in a goroutine. It must be called directly from main(). This means if your code calls other code-modal servers (such as http.ListenAndServe()), they must be run from goroutines. (This is due to limitations in various OSs, such as Mac OS X.)
//
// Go() does not process the command line for flags (that is, it does not call flag.Parse()), nor does package ui add any of the underlying toolkit's supported command-line flags.
// If you must, and if the toolkit also has environment variable equivalents to these flags (for instance, GTK+), use those instead.
func Go() error {
runtime.LockOSThread()
if err := uiinit(); err != nil {
return err
}
Ready <- struct{}{}
close(Ready)
ui()
return nil
}
// Ready is pulsed when Go() is ready to begin accepting requests to the safe methods.
// Go() will wait for something to receive on Ready, then Ready will be closed.
var Ready = make(chan struct{})
// Stop should be pulsed when you are ready for Go() to return.
// Pulsing Stop will cause Go() to return immediately; the programmer is responsible for cleaning up (for instance, hiding open Windows) beforehand.
// Do not pulse Stop more than once.
var Stop = make(chan struct{})
// This function is a simple helper functionn that basically pushes the effect of a function call for later. This allows the selected safe Window methods to be safe.
// TODO make sure this acts sanely if called from uitask itself
func touitask(f func()) {
done := make(chan struct{})
defer close(done)
go func() { // to avoid locking uitask itself
done2 := make(chan struct{}) // make the chain uitask <- f <- uitask to avoid deadlocks
defer close(done2)
uitask <- func() {
f()
done2 <- struct{}{}
}
done <- <-done2
}()
<-done
}
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