Deprecate ItemHandle

Summary:
- `ItemHandle` -> `WriteHandle` codemod in external use cases
- Remove `ItemHandle` from cachelib codebase

Reviewed By: therealgymmy

Differential Revision: D37500348

fbshipit-source-id: 4aaf5bed9b1472064770e8845e2bdbd19af230a4

Author: jiayuebao

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## V17
+In this version, `CacheAllocator::ItemHandle` is removed. Updating to this version will cause compilation error if `ItemHandle` is still used.
+
 ## V16
 
 This version is incompatible with versions below 15. Downgrading from this version directly to a version below 15 will require the cache to be dropped. If you need to downgrade from this version, please make sure you downgrade to version 15 first to avoid dropping the cache.
@@ -8,7 +11,7 @@ This version is incompatible with versions below 15. Downgrading from this versi
 
 This version is incompatible with any previous versions.
 
-Updating to this version may cause compliation error because:
+Updating to this version may cause compilation error because:
 - The following APIs are removed:
 1. CacheAllocator::allocatePermanent_deprecated.
 

cachelib/allocator/CacheAllocator.h

@@ -193,7 +193,9 @@ class CacheAllocator : public CacheBase {
   // safely wraps a pointer to the "const Item"/"Item".
   using ReadHandle = typename Item::ReadHandle;
   using WriteHandle = typename Item::WriteHandle;
-  using ItemHandle = WriteHandle;
+  // Following is deprecated as of allocator version 17 and this line will be
+  // removed at a future date
+  // using ItemHandle = WriteHandle;
   template <typename UserType,
             typename Converter =
                 detail::DefaultUserTypeConverter<Item, UserType>>

cachelib/allocator/CacheVersion.h

@@ -28,7 +28,7 @@ namespace cachelib {
 // then you only need to bump this version.
 // I.e. you're rolling out a new feature that is cache compatible with previous
 // Cachelib instances.
-constexpr uint64_t kCachelibVersion = 16;
+constexpr uint64_t kCachelibVersion = 17;
 
 // Updating this version will cause RAM cache to be dropped for all
 // cachelib users!!! Proceed with care!! You must coordinate with

cachelib/allocator/Util.h

@@ -131,14 +131,14 @@ typename T::WriteHandle allocateAccessible(T& cache,
 // @return      the handle for the item or an invalid handle(nullptr) if the
 //              allocation failed.
 template <typename T>
-typename T::ItemHandle allocateAndReplace(T& cache,
-                                          PoolId poolId,
-                                          typename T::Item::Key key,
-                                          uint32_t size,
-                                          uint32_t ttlSecs = 0) {
+typename T::WriteHandle allocateAndReplace(T& cache,
+                                           PoolId poolId,
+                                           typename T::Item::Key key,
+                                           uint32_t size,
+                                           uint32_t ttlSecs = 0) {
   auto allocHandle = cache.allocate(poolId, key, size, ttlSecs);
   if (!allocHandle) {
-    return typename T::ItemHandle{};
+    return typename T::WriteHandle{};
   }
 
   cache.insertOrReplace(allocHandle);

cachelib/experimental/objcache/Allocator-inl.h

@@ -26,7 +26,7 @@ template <typename ItemHandle, typename Item, typename Cache>
 ItemHandle* objcacheInitializeZeroRefcountHandle(void* handleStorage,
                                                  Item* it,
                                                  Cache& alloc) {
-  return new (handleStorage) typename Cache::ItemHandle{it, alloc};
+  return new (handleStorage) typename Cache::WriteHandle{it, alloc};
 }
 
 // Object-cache's c++ allocator needs to access CacheAllocator directly from
@@ -185,7 +185,7 @@ void* MonotonicBufferResource<CacheDescriptor>::allocateSlow(size_t bytes,
 }
 
 template <typename MonotonicBufferResource, typename Cache>
-std::pair<typename Cache::ItemHandle, MonotonicBufferResource>
+std::pair<typename Cache::WriteHandle, MonotonicBufferResource>
 createMonotonicBufferResource(Cache& cache,
                               PoolId poolId,
                               folly::StringPiece key,
@@ -234,7 +234,7 @@ createMonotonicBufferResource(Cache& cache,
   metadata->buffer = bufferStart;
 
   auto sharedHdl =
-      detail::objcacheInitializeZeroRefcountHandle<typename Cache::ItemHandle>(
+      detail::objcacheInitializeZeroRefcountHandle<typename Cache::WriteHandle>(
           &metadata->itemHandleStorage, hdl.get(), cache);
 
   return {std::move(hdl), MonotonicBufferResource{sharedHdl}};

cachelib/experimental/objcache/Allocator.h

@@ -180,7 +180,7 @@ class AllocatorResource {
 template <typename CacheT>
 struct CacheDescriptor {
   using Cache = CacheT;
-  using ItemHandle = typename CacheT::ItemHandle;
+  using ItemHandle = typename CacheT::WriteHandle;
   using Item = typename CacheT::Item;
   using ChainedItem = typename CacheT::ChainedItem;
 };

cachelib/experimental/objcache/Persistence.h

@@ -32,7 +32,7 @@ namespace objcache {
 template <typename SerializationCallback>
 class PersistorWorker : public PeriodicWorker {
  public:
-  using ItemHandle = CacheAllocator<LruCacheTrait>::ItemHandle;
+  using ItemHandle = CacheAllocator<LruCacheTrait>::WriteHandle;
   using WorkUnit = std::vector<std::pair<ItemHandle, PoolId>>;
   explicit PersistorWorker(SerializationCallback serializationCallback,
                            folly::MPMCQueue<WorkUnit>& queue,
@@ -79,7 +79,7 @@ template <typename ObjectCache>
 class ObjectCachePersistor {
  public:
   using AccessIterator = CacheAllocator<LruCacheTrait>::AccessIterator;
-  using ItemHandle = CacheAllocator<LruCacheTrait>::ItemHandle;
+  using ItemHandle = CacheAllocator<LruCacheTrait>::WriteHandle;
   using WorkUnit = std::vector<std::pair<ItemHandle, PoolId>>;
   using PersistorWorkerObj =
       PersistorWorker<typename ObjectCache::SerializationCallback>;

cachelib/rust/src/cachelib.h

@@ -27,7 +27,7 @@ namespace facebook {
 namespace rust {
 namespace cachelib {
 using LruAllocatorConfig = facebook::cachelib::LruAllocator::Config;
-using LruItemHandle = facebook::cachelib::LruAllocator::ItemHandle;
+using LruItemHandle = facebook::cachelib::LruAllocator::WriteHandle;
 
 std::unique_ptr<facebook::cachelib::CacheAdmin> make_cacheadmin(
     facebook::cachelib::LruAllocator& cache, const std::string& oncall);

website/docs/Cache_Library_User_Guides/Cross_Host_Cache_Persistence.md

@@ -240,7 +240,6 @@ using namespace facebook::cachelib;
 using Cache = cachelib::LruAllocator;
 using CacheConfig = typename Cache::Config;
 using CacheKey = typename Cache::Key;
-using CacheItemHandle = typename Cache::ItemHandle;
 
 // cache config
 CacheConfig config;
@@ -283,7 +282,6 @@ using namespace facebook::cachelib;
 using Cache = cachelib::LruAllocator;
 using CacheConfig = typename Cache::Config;
 using CacheKey = typename Cache::Key;
-using CacheItemHandle = typename Cache::ItemHandle;
 
 // cache config
 CacheConfig config;