Replace most typedef with using= (facebook#8751)

Summary:
Old typedef syntax is confusing

Most but not all changes with

    perl -pi -e 's/typedef (.*) ([a-zA-Z0-9_]+);/using $2 = $1;/g' list_of_files
    make format

Pull Request resolved: facebook#8751

Test Plan: existing

Reviewed By: zhichao-cao

Differential Revision: D30745277

Pulled By: pdillinger

fbshipit-source-id: 6f65f0631c3563382d43347896020413cc2366d9

cache/clock_cache.cc

@@ -260,7 +260,7 @@ struct CleanupContext {
 class ClockCacheShard final : public CacheShard {
  public:
   // Hash map type.
-  typedef tbb::concurrent_hash_map<CacheKey, CacheHandle*, CacheKey> HashTable;
+  using HashTable = tbb::concurrent_hash_map<CacheKey, CacheHandle*, CacheKey>;
 
   ClockCacheShard();
   ~ClockCacheShard() override;

db/compaction/compaction_picker_universal.cc

@@ -157,9 +157,9 @@ struct SmallestKeyHeapComparator {
   const Comparator* ucmp_;
 };
 
-typedef std::priority_queue<InputFileInfo, std::vector<InputFileInfo>,
-                            SmallestKeyHeapComparator>
-    SmallestKeyHeap;
+using SmallestKeyHeap =
+    std::priority_queue<InputFileInfo, std::vector<InputFileInfo>,
+                        SmallestKeyHeapComparator>;
 
 // This function creates the heap that is used to find if the files are
 // overlapping during universal compaction when the allow_trivial_move

db/db_impl/db_impl.cc

@@ -3116,7 +3116,7 @@ SnapshotImpl* DBImpl::GetSnapshotImpl(bool is_write_conflict_boundary,
 }
 
 namespace {
-typedef autovector<ColumnFamilyData*, 2> CfdList;
+using CfdList = autovector<ColumnFamilyData*, 2>;
 bool CfdListContains(const CfdList& list, ColumnFamilyData* cfd) {
   for (const ColumnFamilyData* t : list) {
     if (t == cfd) {

db/db_impl/db_impl.h

@@ -1753,7 +1753,7 @@ class DBImpl : public DB {
   // specified value, this flush request is considered to have completed its
   // work of flushing this column family. After completing the work for all
   // column families in this request, this flush is considered complete.
-  typedef std::vector<std::pair<ColumnFamilyData*, uint64_t>> FlushRequest;
+  using FlushRequest = std::vector<std::pair<ColumnFamilyData*, uint64_t>>;
 
   void GenerateFlushRequest(const autovector<ColumnFamilyData*>& cfds,
                             FlushRequest* req);

db/db_test.cc

@@ -2812,7 +2812,7 @@ TEST_F(DBTest, GroupCommitTest) {
 #endif  // TRAVIS
 
 namespace {
-typedef std::map<std::string, std::string> KVMap;
+using KVMap = std::map<std::string, std::string>;
 }
 
 class ModelDB : public DB {

db/forward_iterator.h

@@ -39,8 +39,9 @@ class MinIterComparator {
   const Comparator* comparator_;
 };
 
-typedef std::priority_queue<InternalIterator*, std::vector<InternalIterator*>,
-                            MinIterComparator> MinIterHeap;
+using MinIterHeap =
+    std::priority_queue<InternalIterator*, std::vector<InternalIterator*>,
+                        MinIterComparator>;
 
 /**
  * ForwardIterator is a special type of iterator that only supports Seek()

db/kv_checksum.h

@@ -49,10 +49,10 @@ template <typename T>
 class ProtectionInfoKVOTS;
 
 // Aliases for 64-bit protection infos.
-typedef ProtectionInfo<uint64_t> ProtectionInfo64;
-typedef ProtectionInfoKVOT<uint64_t> ProtectionInfoKVOT64;
-typedef ProtectionInfoKVOTC<uint64_t> ProtectionInfoKVOTC64;
-typedef ProtectionInfoKVOTS<uint64_t> ProtectionInfoKVOTS64;
+using ProtectionInfo64 = ProtectionInfo<uint64_t>;
+using ProtectionInfoKVOT64 = ProtectionInfoKVOT<uint64_t>;
+using ProtectionInfoKVOTC64 = ProtectionInfoKVOTC<uint64_t>;
+using ProtectionInfoKVOTS64 = ProtectionInfoKVOTS<uint64_t>;
 
 template <typename T>
 class ProtectionInfo {

db/malloc_stats.cc

@@ -19,10 +19,10 @@ namespace ROCKSDB_NAMESPACE {
 
 #ifdef ROCKSDB_JEMALLOC
 
-typedef struct {
+struct MallocStatus {
   char* cur;
   char* end;
-} MallocStatus;
+};
 
 static void GetJemallocStatus(void* mstat_arg, const char* status) {
   MallocStatus* mstat = reinterpret_cast<MallocStatus*>(mstat_arg);

db/pinned_iterators_manager.h

@@ -43,7 +43,7 @@ class PinnedIteratorsManager : public Cleanable {
     }
   }
 
-  typedef void (*ReleaseFunction)(void* arg1);
+  using ReleaseFunction = void (*)(void* arg1);
   void PinPtr(void* ptr, ReleaseFunction release_func) {
     assert(pinning_enabled);
     if (ptr == nullptr) {

env/env_basic_test.cc

@@ -17,8 +17,9 @@
 #include "test_util/testharness.h"
 
 namespace ROCKSDB_NAMESPACE {
-typedef Env* CreateEnvFunc();
 namespace {
+using CreateEnvFunc = Env*();
+
 // These functions are used to create the various environments under which this
 // test can execute. These functions are used to allow the test cases to be
 // created without the Env being initialized, thereby eliminating a potential

include/rocksdb/advanced_options.h

@@ -650,8 +650,8 @@ struct AdvancedColumnFamilyOptions {
   // the tables.
   // Default: empty vector -- no user-defined statistics collection will be
   // performed.
-  typedef std::vector<std::shared_ptr<TablePropertiesCollectorFactory>>
-      TablePropertiesCollectorFactories;
+  using TablePropertiesCollectorFactories =
+      std::vector<std::shared_ptr<TablePropertiesCollectorFactory>>;
   TablePropertiesCollectorFactories table_properties_collector_factories;
 
   // Maximum number of successive merge operations on a key in the memtable.

include/rocksdb/cache.h

@@ -202,9 +202,6 @@ class Cache {
   // takes in a buffer from the NVM cache and constructs an object using
   // it. The callback doesn't have ownership of the buffer and should
   // copy the contents into its own buffer.
-  // typedef std::function<Status(void* buf, size_t size, void** out_obj,
-  //                             size_t* charge)>
-  //    CreateCallback;
   using CreateCallback = std::function<Status(void* buf, size_t size,
                                               void** out_obj, size_t* charge)>;
 

include/rocksdb/cleanable.h

@@ -30,7 +30,7 @@ class Cleanable {
   //
   // Note that unlike all of the preceding methods, this method is
   // not abstract and therefore clients should not override it.
-  typedef void (*CleanupFunction)(void* arg1, void* arg2);
+  using CleanupFunction = void (*)(void* arg1, void* arg2);
   void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
   void DelegateCleanupsTo(Cleanable* other);
   // DoCleanup and also resets the pointers for reuse

include/rocksdb/db.h

@@ -136,8 +136,8 @@ struct GetMergeOperandsOptions {
 // A collections of table properties objects, where
 //  key: is the table's file name.
 //  value: the table properties object of the given table.
-typedef std::unordered_map<std::string, std::shared_ptr<const TableProperties>>
-    TablePropertiesCollection;
+using TablePropertiesCollection =
+    std::unordered_map<std::string, std::shared_ptr<const TableProperties>>;
 
 // A DB is a persistent, versioned ordered map from keys to values.
 // A DB is safe for concurrent access from multiple threads without

include/rocksdb/listener.h

@@ -21,8 +21,8 @@
 
 namespace ROCKSDB_NAMESPACE {
 
-typedef std::unordered_map<std::string, std::shared_ptr<const TableProperties>>
-    TablePropertiesCollection;
+using TablePropertiesCollection =
+    std::unordered_map<std::string, std::shared_ptr<const TableProperties>>;
 
 class DB;
 class ColumnFamilyHandle;

include/rocksdb/memtablerep.h

@@ -51,7 +51,7 @@ class LookupKey;
 class SliceTransform;
 class Logger;
 
-typedef void* KeyHandle;
+using KeyHandle = void*;
 
 extern Slice GetLengthPrefixedSlice(const char* data);
 
@@ -61,7 +61,7 @@ class MemTableRep {
   // concatenated with values.
   class KeyComparator {
    public:
-    typedef ROCKSDB_NAMESPACE::Slice DecodedType;
+    using DecodedType = ROCKSDB_NAMESPACE::Slice;
 
     virtual DecodedType decode_key(const char* key) const {
       // The format of key is frozen and can be treated as a part of the API

include/rocksdb/persistent_cache.h

@@ -24,7 +24,7 @@ namespace ROCKSDB_NAMESPACE {
 // cache interface is specifically designed for persistent read cache.
 class PersistentCache {
  public:
-  typedef std::vector<std::map<std::string, double>> StatsType;
+  using StatsType = std::vector<std::map<std::string, double>>;
 
   virtual ~PersistentCache() {}
 

include/rocksdb/table_properties.h

@@ -26,7 +26,7 @@ namespace ROCKSDB_NAMESPACE {
 //      ++pos) {
 //   ...
 // }
-typedef std::map<std::string, std::string> UserCollectedProperties;
+using UserCollectedProperties = std::map<std::string, std::string>;
 
 // table properties' human-readable names in the property block.
 struct TablePropertiesNames {

include/rocksdb/transaction_log.h

@@ -14,7 +14,7 @@
 namespace ROCKSDB_NAMESPACE {
 
 class LogFile;
-typedef std::vector<std::unique_ptr<LogFile>> VectorLogPtr;
+using VectorLogPtr = std::vector<std::unique_ptr<LogFile>>;
 
 enum WalFileType {
   /* Indicates that WAL file is in archive directory. WAL files are moved from

include/rocksdb/types.h

@@ -15,7 +15,7 @@ namespace ROCKSDB_NAMESPACE {
 using ColumnFamilyId = uint32_t;
 
 // Represents a sequence number in a WAL file.
-typedef uint64_t SequenceNumber;
+using SequenceNumber = uint64_t;
 
 const SequenceNumber kMinUnCommittedSeq = 1;  // 0 is always committed
 

include/rocksdb/utilities/backup_engine.h

@@ -285,7 +285,7 @@ struct BackupFileInfo {
   uint64_t size;
 };
 
-typedef uint32_t BackupID;
+using BackupID = uint32_t;
 
 struct BackupInfo {
   BackupID backup_id = 0U;

memory/arena.h

@@ -86,7 +86,7 @@ class Arena : public Allocator {
   // Number of bytes allocated in one block
   const size_t kBlockSize;
   // Array of new[] allocated memory blocks
-  typedef std::vector<char*> Blocks;
+  using Blocks = std::vector<char*>;
   Blocks blocks_;
 
   struct MmapInfo {

memory/memory_usage.h

@@ -14,7 +14,7 @@ namespace ROCKSDB_NAMESPACE {
 template <class Key, class Value, class Hash>
 size_t ApproximateMemoryUsage(
     const std::unordered_map<Key, Value, Hash>& umap) {
-  typedef std::unordered_map<Key, Value, Hash> Map;
+  using Map = std::unordered_map<Key, Value, Hash>;
   return sizeof(umap) +
          // Size of all items plus a next pointer for each item.
          (sizeof(typename Map::value_type) + sizeof(void*)) * umap.size() +

memtable/hash_linklist_rep.cc

@@ -22,9 +22,9 @@
 namespace ROCKSDB_NAMESPACE {
 namespace {
 
-typedef const char* Key;
-typedef SkipList<Key, const MemTableRep::KeyComparator&> MemtableSkipList;
-typedef std::atomic<void*> Pointer;
+using Key = const char*;
+using MemtableSkipList = SkipList<Key, const MemTableRep::KeyComparator&>;
+using Pointer = std::atomic<void*>;
 
 // A data structure used as the header of a link list of a hash bucket.
 struct BucketHeader {

memtable/hash_skiplist_rep.cc

@@ -46,7 +46,7 @@ class HashSkipListRep : public MemTableRep {
 
  private:
   friend class DynamicIterator;
-  typedef SkipList<const char*, const MemTableRep::KeyComparator&> Bucket;
+  using Bucket = SkipList<const char*, const MemTableRep::KeyComparator&>;
 
   size_t bucket_size_;
 

memtable/inlineskiplist_test.cc

@@ -19,7 +19,7 @@
 namespace ROCKSDB_NAMESPACE {
 
 // Our test skip list stores 8-byte unsigned integers
-typedef uint64_t Key;
+using Key = uint64_t;
 
 static const char* Encode(const uint64_t* key) {
   return reinterpret_cast<const char*>(key);
@@ -32,7 +32,7 @@ static Key Decode(const char* key) {
 }
 
 struct TestComparator {
-  typedef Key DecodedType;
+  using DecodedType = Key;
 
   static DecodedType decode_key(const char* b) {
     return Decode(b);
@@ -59,7 +59,7 @@ struct TestComparator {
   }
 };
 
-typedef InlineSkipList<TestComparator> TestInlineSkipList;
+using TestInlineSkipList = InlineSkipList<TestComparator>;
 
 class InlineSkipTest : public testing::Test {
  public:

memtable/skiplist_test.cc

@@ -17,7 +17,7 @@
 
 namespace ROCKSDB_NAMESPACE {
 
-typedef uint64_t Key;
+using Key = uint64_t;
 
 struct TestComparator {
   int operator()(const Key& a, const Key& b) const {

memtable/vectorrep.cc

@@ -98,7 +98,7 @@ class VectorRep : public MemTableRep {
 
  private:
   friend class Iterator;
-  typedef std::vector<const char*> Bucket;
+  using Bucket = std::vector<const char*>;
   std::shared_ptr<Bucket> bucket_;
   mutable port::RWMutex rwlock_;
   bool immutable_;

options/cf_options.cc

@@ -479,8 +479,8 @@ static std::unordered_map<std::string, OptionTypeInfo>
         /* not yet supported
         CompressionOptions compression_opts;
         TablePropertiesCollectorFactories table_properties_collector_factories;
-        typedef std::vector<std::shared_ptr<TablePropertiesCollectorFactory>>
-            TablePropertiesCollectorFactories;
+        using TablePropertiesCollectorFactories =
+            std::vector<std::shared_ptr<TablePropertiesCollectorFactory>>;
         UpdateStatus (*inplace_callback)(char* existing_value,
                                          uint34_t* existing_value_size,
                                          Slice delta_value,

options/options_settable_test.cc

@@ -41,7 +41,7 @@ class OptionsSettableTest : public testing::Test {
 };
 
 const char kSpecialChar = 'z';
-typedef std::vector<std::pair<size_t, size_t>> OffsetGap;
+using OffsetGap = std::vector<std::pair<size_t, size_t>>;
 
 void FillWithSpecialChar(char* start_ptr, size_t total_size,
                          const OffsetGap& excluded,

port/port_example.h

@@ -70,7 +70,7 @@ class CondVar {
 //      static void Initializer() { ... do something ...; }
 //      ...
 //      port::InitOnce(&init_control, &Initializer);
-typedef intptr_t OnceType;
+using OnceType = intptr_t;
 #define LEVELDB_ONCE_INIT 0
 extern void InitOnce(port::OnceType*, void (*initializer)());
 

port/port_posix.h

@@ -177,7 +177,7 @@ static inline void AsmVolatilePause() {
 // Returns -1 if not available on this platform
 extern int PhysicalCoreID();
 
-typedef pthread_once_t OnceType;
+using OnceType = pthread_once_t;
 #define LEVELDB_ONCE_INIT PTHREAD_ONCE_INIT
 extern void InitOnce(OnceType* once, void (*initializer)());
 

port/sys_time.h

@@ -23,10 +23,10 @@ namespace ROCKSDB_NAMESPACE {
 namespace port {
 
 // Avoid including winsock2.h for this definition
-typedef struct timeval {
+struct timeval {
   long tv_sec;
   long tv_usec;
-} timeval;
+};
 
 void gettimeofday(struct timeval* tv, struct timezone* tz);
 

port/win/env_win.cc

@@ -53,10 +53,10 @@ static const size_t kSectorSize = 512;
 
 // RAII helpers for HANDLEs
 const auto CloseHandleFunc = [](HANDLE h) { ::CloseHandle(h); };
-typedef std::unique_ptr<void, decltype(CloseHandleFunc)> UniqueCloseHandlePtr;
+using UniqueCloseHandlePtr = std::unique_ptr<void, decltype(CloseHandleFunc)>;
 
 const auto FindCloseFunc = [](HANDLE h) { ::FindClose(h); };
-typedef std::unique_ptr<void, decltype(FindCloseFunc)> UniqueFindClosePtr;
+using UniqueFindClosePtr = std::unique_ptr<void, decltype(FindCloseFunc)>;
 
 void WinthreadCall(const char* label, std::error_code result) {
   if (0 != result.value()) {

port/win/env_win.h

@@ -96,7 +96,7 @@ class WinClock : public SystemClock {
   uint64_t GetPerfCounterFrequency() const { return perf_counter_frequency_; }
 
  private:
-  typedef VOID(WINAPI* FnGetSystemTimePreciseAsFileTime)(LPFILETIME);
+  using FnGetSystemTimePreciseAsFileTime = VOID(WINAPI*)(LPFILETIME);
 
   uint64_t perf_counter_frequency_;
   uint64_t nano_seconds_per_period_;

port/win/port_win.h

@@ -47,7 +47,7 @@
 #undef DeleteFile
 
 #ifndef _SSIZE_T_DEFINED
-typedef SSIZE_T ssize_t;
+using ssize_t = SSIZE_T;
 #endif
 
 // size_t printf formatting named in the manner of C99 standard formatting
@@ -292,7 +292,7 @@ static inline void AsmVolatilePause() {
 extern int PhysicalCoreID();
 
 // For Thread Local Storage abstraction
-typedef DWORD pthread_key_t;
+using pthread_key_t = DWORD;
 
 inline int pthread_key_create(pthread_key_t* key, void (*destructor)(void*)) {
   // Not used