feat(wasm): implements CustomQuerier with logic module

The CustomQuerier allow here to call the logic Ask query from a wasm
contract.

app/wasm/query.go

@@ -0,0 +1,43 @@
+package wasm
+
+import (
+	"encoding/json"
+
+	wasmkeeper "github.com/CosmWasm/wasmd/x/wasm/keeper"
+	wasmtypes "github.com/CosmWasm/wasmd/x/wasm/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	logickeeper "github.com/okp4/okp4d/x/logic/keeper"
+	logicwasm "github.com/okp4/okp4d/x/logic/wasm"
+)
+
+// customQuery represents the wasm custom query structure, it is intended to allow wasm contracts to execute queries
+// against the logic modules.
+type customQuery struct {
+	Ask *logicwasm.AskQuery `json:"ask,omitempty"`
+}
+
+// CustomQueryPlugins creates a wasm QueryPlugins containing the custom querier managing wasm contracts queries to the
+// logic module.
+func CustomQueryPlugins(logicKeeper logickeeper.Keeper) *wasmkeeper.QueryPlugins {
+	return &wasmkeeper.QueryPlugins{
+		Custom: makeCustomQuerier(
+			logicwasm.MakeLogicQuerier(logicKeeper),
+		),
+	}
+}
+
+func makeCustomQuerier(logicQuerier logicwasm.LogicQuerier) wasmkeeper.CustomQuerier {
+	return func(ctx sdk.Context, request json.RawMessage) ([]byte, error) {
+		var query customQuery
+		if err := json.Unmarshal(request, &query); err != nil {
+			return nil, sdkerrors.Wrap(sdkerrors.ErrJSONUnmarshal, err.Error())
+		}
+
+		if query.Ask != nil {
+			return logicQuerier.Ask(ctx, query.Ask)
+		}
+
+		return nil, sdkerrors.Wrap(wasmtypes.ErrInvalidMsg, "Unknown Custom query variant")
+	}
+}