Fix handling of end of user records

Summary: This addresses some broken logic that didn't need to exist. For all files, if the index record is before user records, or after, and we can always trust that it if after, then it marks the end of user records data.

Reviewed By: hanghu

Differential Revision: D64150620

fbshipit-source-id: 61b40ed6e5b72fc538b6eccf9a84ade23c3dfd8e

vrs/FileFormat.cpp

@@ -111,20 +111,9 @@ void FileHeader::enableFrontIndexRecordSupport() {
 
 int64_t FileHeader::getEndOfUserRecordsOffset(int64_t fileSize) const {
   if (looksLikeAVRSFile()) {
-    switch (fileFormatVersion.get()) {
-      case kOriginalFileFormatVersion:
-        // index record always in the back, firstUserRecordOffset is 0
-        if (indexRecordOffset.get() > 0) {
-          return min<int64_t>(fileSize, indexRecordOffset.get());
-        }
-        break;
-      case kFrontIndexFileFormatVersion:
-      case kZstdFormatVersion:
-        // index maybe before or after the user records, and firstUserRecordOffset should be valid.
-        if (indexRecordOffset.get() > 0 && indexRecordOffset.get() > firstUserRecordOffset.get()) {
-          return min<int64_t>(fileSize, indexRecordOffset.get());
-        }
-        break;
+    // index maybe before or after the user records
+    if (indexRecordOffset.get() > firstUserRecordOffset.get()) {
+      return min<int64_t>(fileSize, indexRecordOffset.get());
     }
   }
   return fileSize;

vrs/RecordFileReader.cpp

@@ -507,10 +507,8 @@ const vector<int64_t>& RecordFileReader::getRecordBoundaries() const {
       }
       lastOffset = r.fileOffset;
     }
-    int64_t fileSize = file_->getTotalSize();
-    recordBoundaries_.emplace_back(
-        endOfUserRecordsOffset_ < fileSize ? endOfUserRecordsOffset_ : fileSize);
-    if (sortNeeded || recordBoundaries_.back() < lastOffset) {
+    recordBoundaries_.emplace_back(endOfUserRecordsOffset_);
+    if (sortNeeded) {
       sort(recordBoundaries_.begin(), recordBoundaries_.end());
     }
   }