Fix missing RandomAccessFile::is_mmap_open() override

Fix TerarkZipTableReader FileDescriptor issue

Author: mm304321141

env/io_posix.h

@@ -168,6 +168,7 @@ class PosixMmapReadableFile : public RandomAccessFile {
                         size_t length, const EnvOptions& options);
   ~PosixMmapReadableFile();
   bool use_aio_reads() const final { return use_aio_reads_; }
+  bool is_mmap_open() const final { return true; }
   Status Read(uint64_t offset, size_t n, Slice* result,
               char* scratch) const final;
   Status InvalidateCache(size_t offset, size_t length) final;

port/win/io_win.h

@@ -132,6 +132,8 @@ class WinMmapReadableFile : private WinFileData, public RandomAccessFile {
 
   ~WinMmapReadableFile();
 
+  bool is_mmap_open() const final { return true; }
+
   WinMmapReadableFile(const WinMmapReadableFile&) = delete;
   WinMmapReadableFile& operator=(const WinMmapReadableFile&) = delete;
 

table/terark_zip_table_reader.cc

@@ -1159,7 +1159,7 @@ Status TerarkZipTableReader::Open(RandomAccessFileReader* file,
         (byte_t*)file_data.data() + indexSize + storeSize, recNum);
   }
   subReader_.subIndex_ = 0;
-  // subReader_.storeFD_ = file_->file()->FileDescriptor();
+  subReader_.storeFD_ = file_->file()->FileDescriptor();
   subReader_.storeFileObj_ = file_->file();
   subReader_.storeOffset_ = indexSize;
   subReader_.InitUsePread(tzto_.minPreadLen);