Fix unity build with SUPPORT_CLOCK_CACHE (#9309)

Summary:
After https://github.com/facebook/rocksdb/issues/9126

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9309

Test Plan: CI

Reviewed By: ajkr

Differential Revision: D33188902

Pulled By: pdillinger

fbshipit-source-id: 54bf34e33c2b30b1b8dc2a0229e84c194321b606

cache/clock_cache.cc

@@ -228,22 +228,22 @@ struct CacheHandle {
 };
 
 // Key of hash map. We store hash value with the key for convenience.
-struct CacheKey {
+struct ClockCacheKey {
   Slice key;
   uint32_t hash_value;
 
-  CacheKey() = default;
+  ClockCacheKey() = default;
 
-  CacheKey(const Slice& k, uint32_t h) {
+  ClockCacheKey(const Slice& k, uint32_t h) {
     key = k;
     hash_value = h;
   }
 
-  static bool equal(const CacheKey& a, const CacheKey& b) {
+  static bool equal(const ClockCacheKey& a, const ClockCacheKey& b) {
     return a.hash_value == b.hash_value && a.key == b.key;
   }
 
-  static size_t hash(const CacheKey& a) {
+  static size_t hash(const ClockCacheKey& a) {
     return static_cast<size_t>(a.hash_value);
   }
 };
@@ -260,7 +260,8 @@ struct CleanupContext {
 class ClockCacheShard final : public CacheShard {
  public:
   // Hash map type.
-  using HashTable = tbb::concurrent_hash_map<CacheKey, CacheHandle*, CacheKey>;
+  using HashTable =
+      tbb::concurrent_hash_map<ClockCacheKey, CacheHandle*, ClockCacheKey>;
 
   ClockCacheShard();
   ~ClockCacheShard() override;
@@ -559,7 +560,7 @@ bool ClockCacheShard::TryEvict(CacheHandle* handle, CleanupContext* context) {
   if (handle->flags.compare_exchange_strong(flags, 0, std::memory_order_acquire,
                                             std::memory_order_relaxed)) {
     bool erased __attribute__((__unused__)) =
-        table_.erase(CacheKey(handle->key, handle->hash));
+        table_.erase(ClockCacheKey(handle->key, handle->hash));
     assert(erased);
     RecycleHandle(handle, context);
     return true;
@@ -656,13 +657,13 @@ CacheHandle* ClockCacheShard::Insert(
   // relative updates (fetch_add, etc).
   handle->flags.store(flags, std::memory_order_relaxed);
   HashTable::accessor accessor;
-  if (table_.find(accessor, CacheKey(key, hash))) {
+  if (table_.find(accessor, ClockCacheKey(key, hash))) {
     *overwritten = true;
     CacheHandle* existing_handle = accessor->second;
     table_.erase(accessor);
     UnsetInCache(existing_handle, context);
   }
-  table_.insert(HashTable::value_type(CacheKey(key, hash), handle));
+  table_.insert(HashTable::value_type(ClockCacheKey(key, hash), handle));
   if (hold_reference) {
     pinned_usage_.fetch_add(total_charge, std::memory_order_relaxed);
   }
@@ -701,7 +702,7 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
 
 Cache::Handle* ClockCacheShard::Lookup(const Slice& key, uint32_t hash) {
   HashTable::const_accessor accessor;
-  if (!table_.find(accessor, CacheKey(key, hash))) {
+  if (!table_.find(accessor, ClockCacheKey(key, hash))) {
     return nullptr;
   }
   CacheHandle* handle = accessor->second;
@@ -746,7 +747,7 @@ bool ClockCacheShard::EraseAndConfirm(const Slice& key, uint32_t hash,
   MutexLock l(&mutex_);
   HashTable::accessor accessor;
   bool erased = false;
-  if (table_.find(accessor, CacheKey(key, hash))) {
+  if (table_.find(accessor, ClockCacheKey(key, hash))) {
     CacheHandle* handle = accessor->second;
     table_.erase(accessor);
     erased = UnsetInCache(handle, context);