From 8fe8cb8c27c2f42802fd7b6623b8b284e65adbc7 Mon Sep 17 00:00:00 2001
From: Jan Bartel <janb@webtide.com>
Date: Wed, 2 Dec 2020 10:27:08 +0100
Subject: [PATCH] Issue #5086 Add blocking method for immediate scan.

Signed-off-by: Jan Bartel <janb@webtide.com>
---
 .../java/org/eclipse/jetty/util/Scanner.java  | 29 +++++++++++++++++++
 .../jetty/util/ssl/KeyStoreScanner.java       | 23 +++++++++++++--
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java b/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
index 70fd1fc78276..f9bd609f0959 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java
@@ -611,7 +611,36 @@ public void nudge()
 
         }, 0, TimeUnit.MILLISECONDS);  
     }
+    
+    /**
+     * Get the scanner to perform a scan cycle as soon as possible
+     * and call the Callback when the scan is finished or failed.
+     * 
+     * @param complete called when the scan cycle finishes or fails.
+     */
+    public void scan(Callback complete)
+    {
+        Scheduler s = _scheduler;
+        
+        if (!isRunning() || s == null)
+            complete.failed(new IllegalStateException("Scanner not running"));
+
+        s.schedule(() ->
+        {
+            try
+            {
+                scan();
+                complete.succeeded();
+            }
+            catch (Throwable t)
+            {
+                complete.failed(t);
+            }
 
+        }, 0, TimeUnit.MILLISECONDS);   
+    }
+    
+    
     /**
      * Perform a pass of the scanner and report changes
      */
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/ssl/KeyStoreScanner.java b/jetty-util/src/main/java/org/eclipse/jetty/util/ssl/KeyStoreScanner.java
index 097c4da8f207..46d04a21c923 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/ssl/KeyStoreScanner.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/ssl/KeyStoreScanner.java
@@ -20,8 +20,11 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 
+import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.Scanner;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
 import org.eclipse.jetty.util.annotation.ManagedOperation;
@@ -121,8 +124,24 @@ public void scan()
         if (LOG.isDebugEnabled())
             LOG.debug("scanning");
 
-        _scanner.nudge();
-        _scanner.nudge();
+        try
+        {
+            CountDownLatch complete = new CountDownLatch(2);
+            Callback callback = Callback.from(complete::countDown, t -> 
+            {
+                LOG.warn("Scan fail", t);
+                complete.countDown();
+            });
+
+            _scanner.scan(callback);
+            _scanner.scan(callback);
+            complete.await(10, TimeUnit.SECONDS);
+
+        }
+        catch (Exception e)
+        {
+            throw new RuntimeException(e);
+        }
     }
 
     @ManagedOperation(value = "Reload the SSL Keystore", impact = "ACTION")