Speed up IndexDatabase.accept() by avoiding history lookup for files if unversioned files are allowed by the config.

Author: azakkerman

opengrok-indexer/src/main/java/org/opengrok/indexer/index/IndexDatabase.java

@@ -843,19 +843,20 @@ private boolean accept(File file, AcceptSymlinkRet ret) {
             return true;
         }
 
-        if (HistoryGuru.getInstance().hasHistory(file)) {
-            // versioned files should always be accepted
-            return true;
-        }
 
-        // this is an unversioned file, check if it should be indexed
         RuntimeEnvironment env = RuntimeEnvironment.getInstance();
-        boolean res = !env.isIndexVersionedFilesOnly();
-        if (!res) {
-            LOGGER.log(Level.FINER, "not accepting unversioned {0}",
-                absolutePath);
+        // Lookup history if indexing versioned files only.
+        // Skip the lookup entirely (which is expensive) if unversioned files are allowed
+        if (env.isIndexVersionedFilesOnly()) {
+            if (HistoryGuru.getInstance().hasHistory(file)) {
+                // versioned files should always be accepted
+                return true;
+            }
+            LOGGER.log(Level.FINER, "not accepting unversioned {0}", absolutePath);
+            return false;
         }
-        return res;
+        // unversioned files are allowed
+        return true;
     }
 
     /**