feat(list): Add BLMove command (#753)

Also update api_status with ZUNION and BRPOPLPUSH
Fixes #751

Signed-off-by: Roman Gershman <roman@dragonflydb.io>

docs/api_status.md

@@ -111,7 +111,7 @@ with respect to Memcached and Redis APIs.
 - [X] List Family
   - [X] BLPOP
   - [X] BRPOP
-  - [ ] BRPOPLPUSH
+  - [X] BRPOPLPUSH
   - [X] LINSERT
   - [X] LPUSHX
   - [X] RPUSHX
@@ -250,12 +250,13 @@ with respect to Memcached and Redis APIs.
 - [X] List Family
   - [X] LMOVE
   - [X] LPOS
+  - [X] BLMOVE
 
 - [ ] Stream Family
   - [ ] XAUTOCLAIM
 
-- [ ] Sorted Set Family
-  - [ ] ZUNION
+- [X] Sorted Set Family
+  - [X] ZUNION
 
 ## Notes
 Some commands were implemented as decorators along the way:

src/server/list_family.cc

@@ -97,6 +97,27 @@ string ListPop(ListDir dir, quicklist* ql) {
   return res;
 }
 
+optional<ListDir> ParseDir(string_view arg) {
+  if (arg == "LEFT") {
+    return ListDir::LEFT;
+  }
+  if (arg == "RIGHT") {
+    return ListDir::RIGHT;
+  }
+
+  return nullopt;
+}
+
+string_view DirToSv(ListDir dir) {
+  switch (dir) {
+    case ListDir::LEFT:
+      return "LEFT"sv;
+    case ListDir::RIGHT:
+      return "RIGHT"sv;
+  }
+  return ""sv;
+}
+
 bool ElemCompare(const quicklistEntry& entry, string_view elem) {
   if (entry.value) {
     return entry.sz == elem.size() &&
@@ -867,6 +888,47 @@ void BRPopLPush(CmdArgList args, ConnectionContext* cntx) {
   }
 }
 
+void BLMove(CmdArgList args, ConnectionContext* cntx) {
+  string_view src = ArgS(args, 1);
+  string_view dest = ArgS(args, 2);
+  string_view timeout_str = ArgS(args, 5);
+
+  float timeout;
+  if (!absl::SimpleAtof(timeout_str, &timeout)) {
+    return (*cntx)->SendError("timeout is not a float or out of range");
+  }
+
+  if (timeout < 0) {
+    return (*cntx)->SendError("timeout is negative");
+  }
+
+  ToUpper(&args[3]);
+  ToUpper(&args[4]);
+
+  optional<ListDir> src_dir = ParseDir(ArgS(args, 3));
+  optional<ListDir> dest_dir = ParseDir(ArgS(args, 4));
+  if (!src_dir || !dest_dir) {
+    return (*cntx)->SendError(kSyntaxErr);
+  }
+
+  BPopPusher bpop_pusher(src, dest, *src_dir, *dest_dir);
+  OpResult<string> op_res = bpop_pusher.Run(cntx->transaction, unsigned(timeout * 1000));
+
+  if (op_res) {
+    return (*cntx)->SendBulkString(*op_res);
+  }
+
+  switch (op_res.status()) {
+    case OpStatus::TIMED_OUT:
+      return (*cntx)->SendNull();
+      break;
+
+    default:
+      return (*cntx)->SendError(op_res.status());
+      break;
+  }
+}
+
 BPopPusher::BPopPusher(string_view pop_key, string_view push_key, ListDir popdir, ListDir pushdir)
     : pop_key_(pop_key), push_key_(push_key), popdir_(popdir), pushdir_(pushdir) {
 }
@@ -890,10 +952,9 @@ OpResult<string> BPopPusher::RunSingle(Transaction* t, time_point tp) {
   auto cb_move = [&](Transaction* t, EngineShard* shard) {
     OpArgs op_args = t->GetOpArgs(shard);
     op_res = OpMoveSingleShard(op_args, pop_key_, push_key_, popdir_, pushdir_);
-    if (op_res) {
-      if (op_args.shard->journal()) {
-        RecordJournal(op_args, "RPOPLPUSH", ArgSlice{pop_key_, push_key_}, 1);
-      }
+    if (op_res && op_args.shard->journal()) {
+      ArgSlice args{pop_key_, push_key_, DirToSv(popdir_), DirToSv(pushdir_)};
+      RecordJournal(op_args, "LMOVE", args, 1);
     }
     return OpStatus::OK;
   };
@@ -1207,24 +1268,13 @@ void ListFamily::LMove(CmdArgList args, ConnectionContext* cntx) {
   ToUpper(&args[3]);
   ToUpper(&args[4]);
 
-  ListDir src_dir;
-  ListDir dest_dir;
-  if (src_dir_str == "LEFT") {
-    src_dir = ListDir::LEFT;
-  } else if (src_dir_str == "RIGHT") {
-    src_dir = ListDir::RIGHT;
-  } else {
-    return (*cntx)->SendError(kSyntaxErr);
-  }
-  if (dest_dir_str == "LEFT") {
-    dest_dir = ListDir::LEFT;
-  } else if (dest_dir_str == "RIGHT") {
-    dest_dir = ListDir::RIGHT;
-  } else {
+  optional<ListDir> src_dir = ParseDir(src_dir_str);
+  optional<ListDir> dest_dir = ParseDir(dest_dir_str);
+  if (!src_dir || !dest_dir) {
     return (*cntx)->SendError(kSyntaxErr);
   }
 
-  MoveGeneric(cntx, src, dest, src_dir, dest_dir);
+  MoveGeneric(cntx, src, dest, *src_dir, *dest_dir);
 }
 
 void ListFamily::BPopGeneric(ListDir dir, CmdArgList args, ConnectionContext* cntx) {
@@ -1364,7 +1414,9 @@ void ListFamily::Register(CommandRegistry* registry) {
       << CI{"LSET", CO::WRITE | CO::DENYOOM, 4, 1, 1, 1}.HFUNC(LSet)
       << CI{"LTRIM", CO::WRITE, 4, 1, 1, 1}.HFUNC(LTrim)
       << CI{"LREM", CO::WRITE, 4, 1, 1, 1}.HFUNC(LRem)
-      << CI{"LMOVE", CO::WRITE | CO::DENYOOM | CO::NO_AUTOJOURNAL, 5, 1, 2, 1}.HFUNC(LMove);
+      << CI{"LMOVE", CO::WRITE | CO::DENYOOM | CO::NO_AUTOJOURNAL, 5, 1, 2, 1}.HFUNC(LMove)
+      << CI{"BLMOVE", CO::WRITE | CO::DENYOOM | CO::NO_AUTOJOURNAL | CO::BLOCKING, 6, 1, 2, 1}
+             .SetHandler(BLMove);
 }
 
 }  // namespace dfly

src/server/list_family_test.cc

@@ -759,4 +759,17 @@ TEST_F(ListFamilyTest, BRPopLPushTwoShards) {
   // the atomicity and causes the first bug as well.
 }
 
+TEST_F(ListFamilyTest, BLMove) {
+  EXPECT_THAT(Run({"blmove", "x", "y", "right", "right", "0.05"}), ArgType(RespExpr::NIL));
+  ASSERT_EQ(0, NumWatched());
+
+  EXPECT_THAT(Run({"lpush", "x", "val1"}), IntArg(1));
+  EXPECT_THAT(Run({"lpush", "y", "val2"}), IntArg(1));
+
+  EXPECT_EQ(Run({"blmove", "x", "y", "right", "left", "0.01"}), "val1");
+  auto resp = Run({"lrange", "y", "0", "-1"});
+  ASSERT_THAT(resp, ArrLen(2));
+  ASSERT_THAT(resp.GetVec(), ElementsAre("val1", "val2"));
+}
+
 }  // namespace dfly