Issue 355: ProcessHandler configurable executor timeout (#356)

* Issue 355: Allow an application developer to override the default Executor Timeout value

* Issue 355: PR feedback: use int param instead of allowing nulls + 0 timeout means indefinite wait

src/main/java/com/github/kokorin/jaffree/ffmpeg/FFmpeg.java

@@ -59,6 +59,7 @@ public class FFmpeg {
 
     private LogLevel logLevel = LogLevel.INFO;
     private String contextName = null;
+    private Integer executorTimeoutMillis = null;
 
     private final Path executable;
 
@@ -387,6 +388,26 @@ public FFmpeg setContextName(final String contextName) {
         return this;
     }
 
+    /**
+     * Overrides the default {@link com.github.kokorin.jaffree.process.Executor} timeout.
+     * <p>
+     * Most normal use cases will easily complete within the default timeout. It is not recommended
+     * to set an explicit timeout value unless you have actually experienced unwanted timeouts.
+     * <p>
+     * A value of 0 will disable the timeout.
+     * That is, Jaffree will wait indefinitely for the Executor to complete.
+     *
+     * @param executorTimeoutMillis the custom executor timeout in milliseconds
+     * @return this
+     */
+    public FFmpeg setExecutorTimeoutMillis(final int executorTimeoutMillis) {
+        if (executorTimeoutMillis < 0) {
+            throw new IllegalArgumentException("Executor timeout cannot be negative");
+        }
+        this.executorTimeoutMillis = executorTimeoutMillis;
+        return this;
+    }
+
     /**
      * Starts synchronous ffmpeg execution.
      * <p>
@@ -480,11 +501,16 @@ protected ProcessHandler<FFmpegResult> createProcessHandler() {
             helpers.add(progressHelper);
         }
 
-        return new ProcessHandler<FFmpegResult>(executable, contextName)
-                .setStdErrReader(createStdErrReader(outputListener))
-                .setStdOutReader(createStdOutReader())
-                .setHelpers(helpers)
-                .setArguments(buildArguments());
+        ProcessHandler<FFmpegResult> processHandler =
+                new ProcessHandler<FFmpegResult>(executable, contextName)
+                        .setStdErrReader(createStdErrReader(outputListener))
+                        .setStdOutReader(createStdOutReader())
+                        .setHelpers(helpers)
+                        .setArguments(buildArguments());
+        if (executorTimeoutMillis != null) {
+            processHandler.setExecutorTimeoutMillis(executorTimeoutMillis);
+        }
+        return processHandler;
     }
 
     /**

src/main/java/com/github/kokorin/jaffree/process/ProcessHandler.java

@@ -49,8 +49,9 @@ public class ProcessHandler<T> {
     private List<ProcessHelper> helpers = null;
     private Stopper stopper = null;
     private List<String> arguments = Collections.emptyList();
+    private int executorTimeoutMillis = DEFAULT_EXECUTOR_TIMEOUT_MILLIS;
 
-    private static final int EXECUTOR_TIMEOUT_MILLIS = 10_000;
+    private static final int DEFAULT_EXECUTOR_TIMEOUT_MILLIS = 10_000;
     private static final Logger LOGGER = LoggerFactory.getLogger(ProcessHandler.class);
 
     /**
@@ -120,6 +121,20 @@ public synchronized ProcessHandler<T> setArguments(final List<String> arguments)
         return this;
     }
 
+    /**
+     * Overrides the default Executor timeout.
+     * <p>
+     * A value of 0 is interpreted as "wait indefinitely".
+     *
+     * @param executorTimeoutMillis the new Executor timeout in milliseconds
+     */
+    public void setExecutorTimeoutMillis(final int executorTimeoutMillis) {
+        if (executorTimeoutMillis < 0) {
+            throw new IllegalArgumentException("Executor timeout cannot be negative");
+        }
+        this.executorTimeoutMillis = executorTimeoutMillis;
+    }
+
     /**
      * Executes a program.
      * <p>
@@ -180,7 +195,7 @@ protected T interactWithProcess(final Process process) {
             status = process.waitFor();
             LOGGER.info("Process has finished with status: {}", status);
 
-            waitForExecutorToStop(executor, EXECUTOR_TIMEOUT_MILLIS);
+            waitForExecutorToStop(executor, executorTimeoutMillis);
         } catch (InterruptedException e) {
             LOGGER.warn("Process has been interrupted");
             if (stopper != null) {
@@ -308,9 +323,10 @@ private static void waitForExecutorToStop(final Executor executor, final long ti
             throws InterruptedException {
         LOGGER.debug("Waiting for Executor to stop");
 
-        long waitStarted = System.currentTimeMillis();
+        final long waitStarted = System.currentTimeMillis();
         do {
-            if (System.currentTimeMillis() - waitStarted > timeoutMillis) {
+            // Zero timeout means "wait indefinitely"
+            if (timeoutMillis > 0 && System.currentTimeMillis() - waitStarted > timeoutMillis) {
                 LOGGER.warn("Executor hasn't stopped in {} millis, won't wait longer",
                         timeoutMillis);
                 break;