aapt2: new method to execAndReturn to collect stdout from a process

brut.j.util/src/main/java/brut/util/OS.java

@@ -19,6 +19,8 @@ package brut.util;
 import brut.common.BrutException;
 import java.io.*;
 import java.util.Arrays;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.logging.Logger;
 
 import org.apache.commons.io.IOUtils;
@@ -100,6 +102,23 @@ public class OS {
         }
     }
 
+    public static String execAndReturn(String[] cmd) {
+        ExecutorService executor = Executors.newCachedThreadPool();
+        try {
+            ProcessBuilder builder = new ProcessBuilder(cmd);
+            builder.redirectErrorStream(true);
+
+            Process process = builder.start();
+            StreamCollector collector = new StreamCollector(process.getInputStream());
+            executor.execute(collector);
+
+            process.waitFor();
+            return collector.get();
+        } catch (IOException | InterruptedException e) {
+            return null;
+        }
+    }
+
     public static File createTempDirectory() throws BrutException {
         try {
             File tmp = File.createTempFile("BRUT", null);
@@ -142,4 +161,37 @@ public class OS {
         private final InputStream mIn;
         private final String mType;
     }
+
+    static class StreamCollector implements Runnable {
+        private final StringBuffer buffer = new StringBuffer();
+        private final InputStream inputStream;
+
+        public StreamCollector(InputStream inputStream) {
+            super();
+            this.inputStream = inputStream;
+        }
+
+        @Override
+        public void run() {
+            BufferedReader reader = null;
+            String line;
+            try {
+                reader = new BufferedReader(new InputStreamReader(inputStream));
+                while ((line = reader.readLine()) != null) {
+                    buffer.append(line).append('\n');
+                }
+            } catch (Exception e) {
+                System.err.println(e);
+            } finally {
+                try {
+                    reader.close();
+                } catch (IOException e) {}
+            }
+
+        }
+
+        public String get() {
+            return buffer.toString();
+        }
+    }
 }