Drop list commands, repurpose implementation as deque

See changelog for rationale behind this.

CHANGELOG.md

 # Changelog
 All notable changes to this project will be documented in this file.
 
+## Unreleased
+
+### Changed
+- Dropped list commands, as the underlying implementation makes it impossible to support all list commands found in official redis. (most notably `linsert`)
+
+  Still, the old implementation makes for an excellent deque. Renamed list commands `lpush`, `lpop`, `rpush`, `rpop`, `rlen` to `deque-push-front`, `deque-pop-front`, `deque-push-back`, `deque-pop-back`, `deque-len`. The underlying data format did not change, only the command names.
+
+  This makes it possible to implement lists properly in the future.
+
+  No-one has been using the list operations, which gives us the opportunity to change the command names.
+
 ## 0.3.2 (2018-08-14)
 ### Added
 - Protection against 1-way network partitions, in which a cluster node

src/Commands.cc

@@ -55,7 +55,7 @@ struct cmdMapInit {
     redis_cmd_map["smembers"] = {RedisCommand::SMEMBERS, CommandType::READ};
     redis_cmd_map["scard"] = {RedisCommand::SCARD, CommandType::READ};
     redis_cmd_map["sscan"] = {RedisCommand::SSCAN, CommandType::READ};
-    redis_cmd_map["llen"] = {RedisCommand::LLEN, CommandType::READ};
+    redis_cmd_map["deque_len"] = {RedisCommand::DEQUE_LEN, CommandType::READ};
     redis_cmd_map["config_get"] = {RedisCommand::CONFIG_GET, CommandType::READ};
     redis_cmd_map["config_getall"] = {RedisCommand::CONFIG_GETALL, CommandType::READ};
     redis_cmd_map["lhget"] = {RedisCommand::LHGET, CommandType::READ};
@@ -79,10 +79,10 @@ struct cmdMapInit {
     redis_cmd_map["sadd"] = {RedisCommand::SADD, CommandType::WRITE};
     redis_cmd_map["srem"] = {RedisCommand::SREM, CommandType::WRITE};
     redis_cmd_map["smove"] = {RedisCommand::SMOVE, CommandType::WRITE};
-    redis_cmd_map["lpush"] = {RedisCommand::LPUSH, CommandType::WRITE};
-    redis_cmd_map["lpop"] = {RedisCommand::LPOP, CommandType::WRITE};
-    redis_cmd_map["rpush"] = {RedisCommand::RPUSH, CommandType::WRITE};
-    redis_cmd_map["rpop"] = {RedisCommand::RPOP, CommandType::WRITE};
+    redis_cmd_map["deque_push_front"] = {RedisCommand::DEQUE_PUSH_FRONT, CommandType::WRITE};
+    redis_cmd_map["deque_pop_front"] = {RedisCommand::DEQUE_POP_FRONT, CommandType::WRITE};
+    redis_cmd_map["deque_push_back"] = {RedisCommand::DEQUE_PUSH_BACK, CommandType::WRITE};
+    redis_cmd_map["deque_pop_back"] = {RedisCommand::DEQUE_POP_BACK, CommandType::WRITE};
     redis_cmd_map["config_set"] = {RedisCommand::CONFIG_SET, CommandType::WRITE};
     redis_cmd_map["lhset"] = {RedisCommand::LHSET, CommandType::WRITE};
     redis_cmd_map["lhdel"] = {RedisCommand::LHDEL, CommandType::WRITE};

src/Commands.hh

@@ -84,11 +84,11 @@ enum class RedisCommand {
   SCARD,
   SSCAN,
 
-  LPUSH,
-  LPOP,
-  RPUSH,
-  RPOP,
-  LLEN,
+  DEQUE_PUSH_FRONT,
+  DEQUE_POP_FRONT,
+  DEQUE_PUSH_BACK,
+  DEQUE_POP_BACK,
+  DEQUE_LEN,
 
   RAW_SCAN,
   RAW_GET_ALL_VERSIONS,

src/Dispatcher.cc

@@ -263,21 +263,21 @@ RedisEncodedResponse RedisDispatcher::dispatchWrite(StagingArea &stagingArea, Re
       if(!st.ok()) return Formatter::fromStatus(st);
       return Formatter::integer(count);
     }
-    case RedisCommand::LPUSH: {
+    case RedisCommand::DEQUE_PUSH_FRONT: {
       if(request.size() < 3) return errArgs(request);
       int64_t length;
       rocksdb::Status st = store.dequePushFront(stagingArea, request[1], request.begin()+2, request.end(), length);
       if(!st.ok()) return Formatter::fromStatus(st);
       return Formatter::integer(length);
     }
-    case RedisCommand::RPUSH: {
+    case RedisCommand::DEQUE_PUSH_BACK: {
       if(request.size() < 3) return errArgs(request);
       int64_t length;
       rocksdb::Status st = store.dequePushBack(stagingArea, request[1], request.begin()+2, request.end(), length);
       if(!st.ok()) return Formatter::fromStatus(st);
       return Formatter::integer(length);
     }
-    case RedisCommand::LPOP: {
+    case RedisCommand::DEQUE_POP_FRONT: {
       if(request.size() != 2) return errArgs(request);
       std::string item;
       rocksdb::Status st = store.dequePopFront(stagingArea, request[1], item);
@@ -285,7 +285,7 @@ RedisEncodedResponse RedisDispatcher::dispatchWrite(StagingArea &stagingArea, Re
       if(!st.ok()) return Formatter::fromStatus(st);
       return Formatter::string(item);
     }
-    case RedisCommand::RPOP: {
+    case RedisCommand::DEQUE_POP_BACK: {
       if(request.size() != 2) return errArgs(request);
       std::string item;
       rocksdb::Status st = store.dequePopBack(stagingArea, request[1], item);
@@ -588,7 +588,7 @@ RedisEncodedResponse RedisDispatcher::dispatchRead(StagingArea &stagingArea, Red
       else newcursor = "next:" + newcursor;
       return Formatter::scan(newcursor, vec);
     }
-    case RedisCommand::LLEN: {
+    case RedisCommand::DEQUE_LEN: {
       if(request.size() != 2) return errArgs(request);
       size_t len;
       rocksdb::Status st = store.dequeLen(stagingArea, request[1], len);

test/e2e.cc

@@ -507,24 +507,24 @@ TEST_F(Raft_e2e, test_many_redis_commands) {
   ASSERT_REPLY(futures[11], 3);
 
   futures.clear();
-  futures.emplace_back(tunnel(leaderID)->exec("lpush", "list_test", "i1", "i2", "i3", "i4"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-push-front", "list_test", "i1", "i2", "i3", "i4"));
   futures.emplace_back(tunnel(leaderID)->exec("exists", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("llen", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("lpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("llen", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("rpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("llen", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-len", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-front", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-len", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-back", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-len", "list_test"));
   futures.emplace_back(tunnel(leaderID)->exec("del", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("llen", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("lpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("rpush", "list_test", "i5", "i6", "i7", "i8"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-len", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-front", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-push-back", "list_test", "i5", "i6", "i7", "i8"));
   futures.emplace_back(tunnel(leaderID)->exec("set", "list_test", "asdf"));
-  futures.emplace_back(tunnel(leaderID)->exec("lpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("rpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("rpop", "list_test"));
-  futures.emplace_back(tunnel(leaderID)->exec("lpop", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-front", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-back", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-back", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-front", "list_test"));
   futures.emplace_back(tunnel(leaderID)->exec("set", "list_test", "asdf"));
-  futures.emplace_back(tunnel(leaderID)->exec("lpop", "list_test"));
+  futures.emplace_back(tunnel(leaderID)->exec("deque-pop-front", "list_test"));
 
   int i = 0;
   ASSERT_REPLY(futures[i++], 4);