Add memcached version and delete commands

README.md

@@ -130,11 +130,11 @@ a distributed log format.
 - [X] stats (partial)
 - [x] append
 - [x] prepend
-- [ ] delete
+- [x] delete
 - [ ] flush_all
 - [x] incr
 - [x] decr
-- [ ] version
+- [x] version
 - [x] quit
 
 API 2.0

helio

@@ -1 +1 @@
-Subproject commit 1b01326ec8689e559dcf4c5be6f328055479e808
+Subproject commit 775f321d8efe9b90fae3fee14b2fcf8364beae7b

src/server/generic_family.cc

@@ -160,6 +160,8 @@ void GenericFamily::Del(CmdArgList args, ConnectionContext* cntx) {
   VLOG(1) << "Del " << ArgS(args, 1);
 
   atomic_uint32_t result{0};
+  bool is_mc = cntx->protocol() == Protocol::MEMCACHE;
+
   auto cb = [&result](const Transaction* t, EngineShard* shard) {
     ArgSlice args = t->ShardArgsInShard(shard->shard_id());
     auto res = OpDel(OpArgs{shard, t->db_index()}, args);
@@ -173,7 +175,18 @@ void GenericFamily::Del(CmdArgList args, ConnectionContext* cntx) {
 
   DVLOG(2) << "Del ts " << transaction->txid();
 
-  (*cntx)->SendLong(result.load(memory_order_release));
+  uint32_t del_cnt = result.load(memory_order_relaxed);
+  if (is_mc) {
+    MCReplyBuilder* mc_builder = static_cast<MCReplyBuilder*>(cntx->reply_builder());
+
+    if (del_cnt == 0) {
+      mc_builder->SendNotFound();
+    } else {
+      mc_builder->SendDirect("DELETED\r\n");
+    }
+  } else {
+    (*cntx)->SendLong(del_cnt);
+  }
 }
 
 void GenericFamily::Ping(CmdArgList args, ConnectionContext* cntx) {

src/server/main_service.cc

@@ -489,6 +489,9 @@ void Service::DispatchMC(const MemcacheParser::Command& cmd, std::string_view va
       strcpy(cmd_name, "SET");
       strcpy(store_opt, "NX");
       break;
+    case MemcacheParser::DELETE:
+      strcpy(cmd_name, "DEL");
+      break;
     case MemcacheParser::INCR:
       strcpy(cmd_name, "INCRBY");
       absl::numbers_internal::FastIntToBuffer(cmd.delta, store_opt);
@@ -512,7 +515,9 @@ void Service::DispatchMC(const MemcacheParser::Command& cmd, std::string_view va
     case MemcacheParser::STATS:
       server_family_.StatsMC(cmd.key, cntx);
       return;
-
+    case MemcacheParser::VERSION:
+      mc_builder->SendDirect(absl::StrCat("VERSION ", gflags::VersionString(), "\r\n"));
+      return;
     default:
       mc_builder->SendClientError("bad command line format");
       return;

src/server/memcache_parser.cc

@@ -22,7 +22,7 @@ MP::CmdType From(string_view token) {
       {"get", MP::GET},       {"gets", MP::GETS},       {"gat", MP::GAT},
       {"gats", MP::GATS},     {"stats", MP::STATS},     {"incr", MP::INCR},
       {"decr", MP::DECR},     {"delete", MP::DELETE},   {"flush_all", MP::FLUSHALL},
-      {"quit", MP::QUIT},
+      {"quit", MP::QUIT},     {"version", MP::VERSION},
   };
 
   auto it = cmd_map.find(token);
@@ -165,7 +165,7 @@ auto MP::Parse(string_view str, uint32_t* consumed, Command* cmd) -> Result {
   }
 
   if (num_tokens == 1) {
-    if (base::_in(cmd->type, {MP::STATS, MP::FLUSHALL, MP::QUIT}))
+    if (base::_in(cmd->type, {MP::STATS, MP::FLUSHALL, MP::QUIT, MP::VERSION}))
       return MP::OK;
     return MP::PARSE_ERROR;
   }

src/server/memcache_parser.h

@@ -31,12 +31,13 @@ class MemcacheParser {
     STATS = 14,
 
     QUIT = 20,
+    VERSION = 21,
 
     // The rest of write commands.
-    DELETE = 21,
-    INCR = 22,
-    DECR = 23,
-    FLUSHALL = 24,
+    DELETE = 31,
+    INCR = 32,
+    DECR = 33,
+    FLUSHALL = 34,
   };
 
   // According to https://github.com/memcached/memcached/wiki/Commands#standard-protocol