public void end(ShellResponse response) {
// Always leave the status in terminated status if the method succeeds
// Cancelled -> Terminated
// Evaluating -> Terminated
// Terminated -> Terminated
synchronized (lock) {
switch (status) {
case CONSTRUCTED:
case QUEUED:
throw new AssertionError("Should not happen");
case CANCELED:
// We substitute the response
response = ShellResponse.cancelled();
status = Status.TERMINATED;
break;
case EVALUATING:
status = Status.TERMINATED;
break;
case TERMINATED:
throw new IllegalStateException("Cannot end a process already terminated");
}
}
//
caller.end(response);
}
public void execute(ShellProcessContext processContext) {
// Constructed -> Queued
synchronized (lock) {
if (status != Status.CONSTRUCTED) {
throw new IllegalStateException("State was " + status);
}
// Update state
status = Status.QUEUED;
callee = shell.shell.createProcess(request);
caller = processContext;
}
// Create the task
Callable<AsyncProcess> task =
new Callable<AsyncProcess>() {
public AsyncProcess call() throws Exception {
try {
// Cancelled -> Cancelled
// Queued -> Evaluating
ShellResponse response;
synchronized (lock) {
switch (status) {
case CANCELED:
// Do nothing it was canceled in the mean time
response = ShellResponse.cancelled();
break;
case QUEUED:
// Ok we are going to run it
status = Status.EVALUATING;
response = null;
break;
default:
// Just in case but this can only be called by the queue
throw new AssertionError();
}
}
// Execute the process if we are in evalating state
if (response == null) {
// Here the status could already be in status cancelled
// it is a race condition, execution still happens
// but the callback of the callee to the end method will make the process
// terminate and use a cancel response
try {
callee.execute(context);
response = ShellResponse.ok();
} catch (Throwable t) {
response =
ShellResponse.internalError("Unexpected throwable when executing process", t);
}
}
// Make the callback
// Calling terminated twice will have no effect
try {
context.end(response);
} catch (Throwable t) {
// Log it
}
// We return this but we don't really care for now
return AsyncProcess.this;
} finally {
synchronized (shell.lock) {
shell.processes.remove(AsyncProcess.this);
}
}
}
};
//
synchronized (shell.lock) {
if (!shell.closed) {
shell.executor.submit(task);
shell.processes.add(this);
} else {
boolean invokeEnd;
synchronized (lock) {
invokeEnd = status != Status.TERMINATED;
status = Status.TERMINATED;
}
if (invokeEnd) {
caller.end(ShellResponse.cancelled());
}
}
}
}
public String getProperty(String name) {
return caller.getProperty(name);
}
public String readLine(String msg, boolean echo) {
return caller.readLine(msg, echo);
}
public int getWidth() {
return caller.getWidth();
}
