X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=getdown%2Fsrc%2Fgetdown%2Fcore%2Fsrc%2Fmain%2Fjava%2Fcom%2Fthreerings%2Fgetdown%2Futil%2FLaunchUtil.java;fp=getdown%2Fsrc%2Fgetdown%2Fcore%2Fsrc%2Fmain%2Fjava%2Fcom%2Fthreerings%2Fgetdown%2Futil%2FLaunchUtil.java;h=ae493bbe8db13a81e523e8760881409fc77e3ba9;hb=6a05eb3f55d97e685f0c723822384633d5636778;hp=f2cd5736e1c2d4298f4e159a6512ac979616c3ca;hpb=d113749a183a3ea8f3f7e22c725511f59f1d833f;p=jalview.git

diff --git a/getdown/src/getdown/core/src/main/java/com/threerings/getdown/util/LaunchUtil.java b/getdown/src/getdown/core/src/main/java/com/threerings/getdown/util/LaunchUtil.java
index f2cd573..ae493bb 100644
--- a/getdown/src/getdown/core/src/main/java/com/threerings/getdown/util/LaunchUtil.java
+++ b/getdown/src/getdown/core/src/main/java/com/threerings/getdown/util/LaunchUtil.java
@@ -9,8 +9,14 @@ import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.Locale;
 
+import javax.xml.bind.DatatypeConverter;
+
+import java.security.MessageDigest;
+
 import static com.threerings.getdown.Log.log;
 
 /**
@@ -125,6 +131,21 @@ public class LaunchUtil
         return vmpath;
     }
 
+    private static String _getMD5FileChecksum (File file) {
+    	// check md5 digest
+    	String algo = "MD5";
+    	String checksum = "";
+    	try {
+    		MessageDigest md = MessageDigest.getInstance(algo);
+    		md.update(Files.readAllBytes(Paths.get(file.getAbsolutePath())));
+    		byte[] digest = md.digest();
+    		checksum = DatatypeConverter.printHexBinary(digest).toUpperCase();
+    	} catch (Exception e) {
+    		System.out.println("Couldn't create "+algo+" digest of "+file.getPath());
+    	}
+    	return checksum;
+    }
+    
     /**
      * Upgrades Getdown by moving an installation managed copy of the Getdown jar file over the
      * non-managed copy (which would be used to run Getdown itself).
@@ -137,9 +158,17 @@ public class LaunchUtil
         // we assume getdown's jar file size changes with every upgrade, this is not guaranteed,
         // but in reality it will, and it allows us to avoid pointlessly upgrading getdown every
         // time the client is updated which is unnecessarily flirting with danger
-        if (!newgd.exists() || newgd.length() == curgd.length()) {
+        if (!newgd.exists())
+        {
             return;
         }
+        
+        if (newgd.length() == curgd.length()) {
+        	if (_getMD5FileChecksum(newgd).equals(_getMD5FileChecksum(curgd)))
+        	{
+				return;
+        	}
+        }
 
         log.info("Updating Getdown with " + newgd + "...");