[jira] [Created] (FELIX-5286) Pipe commands run in System.in deadlock on single call.

[Jan Winter (JIRA)]

Jan Winter created FELIX-5286:
---------------------------------

             Summary: Pipe commands run in System.in deadlock on single call. 
                 Key: FELIX-5286
                 URL: https://issues.apache.org/jira/browse/FELIX-5286
             Project: Felix
          Issue Type: Bug
          Components: Gogo Runtime
    Affects Versions: gogo.runtime-0.16.4
         Environment: macos
            Reporter: Jan Winter



{code:DeadlockSample.java}
package gogo.runtime.deadlock;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.List;

import org.apache.felix.gogo.runtime.CommandProcessorImpl;
import org.apache.felix.gogo.runtime.threadio.ThreadIOImpl;
import org.apache.felix.service.command.CommandSession;

public class Main {

        public static class DeadlockSample{
                public void produce(){
                        System.out.println(Math.random());
                }
                
                public void consume() throws IOException{
                        List<String> lines = readSysin();
                        
                        if(lines.isEmpty()){
                                System.out.println("'consume' execution is 
catched by thread-name != 'pipe-...': '" + Thread.currentThread().getName() + 
"'");
                                return;
                        }
                        
                        for (String line : lines) {
                                System.out.println("'consume' " + line);
                        }
                }
        }
        
        public static List<String> readSysin() throws IOException {
                final List<String> lines = new LinkedList<String>();

                BufferedReader reader = new BufferedReader(new 
InputStreamReader(System.in));

                String lastLine = null;
                boolean isFirstLine = true;
                boolean hasNoInput = false;

                while (true) {
                        if (hasNoInput) {
                                break;
                        }
                        String line = null;

                        if (isFirstLine) {
                                isFirstLine = false;
                                boolean isSysinAvailable = 
System.in.available() != 0;
                                boolean isPipedGogoThread = 
Thread.currentThread().getName().startsWith("pipe-");
                                
                                if (isSysinAvailable || isPipedGogoThread) {
                                        line = reader.readLine();
                                }
                        } else
                                line = reader.readLine();

                        if (line == null) {
                                hasNoInput = true;
                                
                                boolean isPreviousLineNull = lastLine == null;
                                if(isPreviousLineNull)
                                        continue;
                                
                                switch (lastLine) {
                                case "":
                                case "true":
                                case "false":
                                        lines.remove(lines.size() - 1);
                                        break;
                                default:
                                        continue;
                                }
                                continue;
                        }
                        lines.add(line);
                        lastLine = line;
                }
                return lines;
        }

        public static void main(String[] args) throws Exception {
                ThreadIOImpl tio = new ThreadIOImpl();
                tio.start();
                
                CommandProcessorImpl processor = new CommandProcessorImpl(tio);
                DeadlockSample commands = new DeadlockSample();
                
                processor.addCommand("deadlock", commands, "produce");
                processor.addCommand("deadlock", commands, "consume");
                
                CommandSession session = processor.createSession(System.in, 
System.out, System.err);
                
                session.execute("produce"); // SUCC
                session.execute("consume"); // SUCC
                session.execute("produce | consume"); //SUCC
                
                Thread deadlockThread = new Thread(new Runnable() {
                        
                        @Override
                        public void run() {
                                System.out.println("'consume | consume' pipe 
run in deadlock."); // FAILED
                                try {
                                        session.execute("consume | consume");
                                } catch (Exception e) {
                                        e.printStackTrace();
                                }
                                System.out.println("Never reached :("); // 
DEADLOCK
                        }
                });
                deadlockThread.start();
                
                Thread.sleep(1000);
                System.out.println("Exit bevor 'Never reached :(' line is 
written.");
        }
}
{code}



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