[GitHub] [lucene-solr] uschindler commented on a change in pull request #2052: LUCENE-8982: Make NativeUnixDirectory pure java with FileChannel direct IO flag, and rename to DirectIODirectory

[GitBox <gi...@apache.org>]

uschindler commented on a change in pull request #2052:
URL: https://github.com/apache/lucene-solr/pull/2052#discussion_r558491882



##########
File path: lucene/misc/src/java/org/apache/lucene/misc/store/DirectIODirectory.java
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@@ -307,7 +314,14 @@ public void close() throws IOException {
 
     @Override
     public long getFilePointer() {
-      return filePos + buffer.position();
+      long filePointer = filePos + buffer.position();
+
+      // opening the input and immediately calling getFilePointer without calling readX (and thus refill) first,
+      // will result in negative value equal to bufferSize being returned,
+      // due to the initialization method filePos = -bufferSize used in constructor.
+      assert filePointer == -buffer.capacity() || filePointer >= 0 :
+        "filePointer should either be initial value equal to negative buffer capacity, or larger than or equal to 0";
+      return Math.max(filePointer, 0);

Review comment:
       Thanks, this was driving me crazy when I tried to fix this (I gave up after some beers deep night).




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