Fix db_bench

Summary: Adding check for zero size index

Test Plan: ./build_tools/regression_build_test.sh

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20259

table/plain_table_index.cc

@@ -16,15 +16,20 @@ inline uint32_t GetBucketIdFromHash(uint32_t hash, uint32_t num_buckets) {
 }
 }
 
-void PlainTableIndex::InitFromRawData(Slice data) {
+Status PlainTableIndex::InitFromRawData(Slice data) {
-  assert(GetVarint32(&data, &index_size_));
+  if (!GetVarint32(&data, &index_size_)) {
+    return Status::Corruption("Couldn't read the index size!");
+  }
   assert(index_size_ > 0);
-  assert(GetVarint32(&data, &num_prefixes_));
+  if (!GetVarint32(&data, &num_prefixes_)) {
+    return Status::Corruption("Couldn't read the index size!");
+  }
   sub_index_size_ = data.size() - index_size_ * kOffsetLen;
 
   char* index_data_begin = const_cast<char*>(data.data());
   index_ = reinterpret_cast<uint32_t*>(index_data_begin);
   sub_index_ = reinterpret_cast<char*>(index_ + index_size_);
+  return Status::OK();
 }
 
 PlainTableIndex::IndexSearchResult PlainTableIndex::GetOffset(

table/plain_table_index.h

@@ -72,7 +72,7 @@ class PlainTableIndex {
   IndexSearchResult GetOffset(uint32_t prefix_hash,
                               uint32_t* bucket_value) const;
 
-  void InitFromRawData(Slice data);
+  Status InitFromRawData(Slice data);
 
   const char* GetSubIndexBasePtrAndUpperBound(uint32_t offset,
                                               uint32_t* upper_bound) const {

table/plain_table_reader.cc

@@ -236,8 +236,8 @@ Status PlainTableReader::PopulateIndexRecordList(
   }
 
   prefix_hashes->push_back(GetSliceHash(key_prefix_slice));
-  index_.InitFromRawData(index_builder->Finish());
+  auto s = index_.InitFromRawData(index_builder->Finish());
-  return Status::OK();
+  return s;
 }
 
 void PlainTableReader::AllocateAndFillBloom(int bloom_bits_per_key,
@@ -357,7 +357,10 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
       return s;
     }
   } else {
-    index_.InitFromRawData(*index_block);
+    Status s = index_.InitFromRawData(*index_block);
+    if (!s.ok()) {
+      return s;
+    }
   }
 
   if (!index_in_file) {