misc: panic not ready (#374)

* Panic when config/crs not ready

For those calls to Governace.Configuration
and Governance.CRS without checking
returns, replace those calls with these newly
added helpers:
- utils.GetConfigurationWithPanic
- utils.GetCRSWithPanic

They would check returns, and panic directly
if not ready yet.

* Fix a bug that config is not ready
   when syncing

1 files changed, 61 insertions, 0 deletions

diff --git a/core/utils/utils.go b/core/utils/utils.go
new file mode 100644
index 0000000..3e3803d
--- /dev/null
+++ b/core/utils/utils.go
@@ -0,0 +1,61 @@
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package utils
+
+import (
+	"fmt"
+
+	"github.com/dexon-foundation/dexon-consensus/common"
+	"github.com/dexon-foundation/dexon-consensus/core/types"
+)
+
+type configAccessor interface {
+	Configuration(round uint64) *types.Config
+}
+
+// GetConfigWithPanic is a helper to access configs, and panic when config for
+// that round is not ready yet.
+func GetConfigWithPanic(accessor configAccessor, round uint64,
+	logger common.Logger) *types.Config {
+	if logger != nil {
+		logger.Debug("Calling Governance.Configuration", "round", round)
+	}
+	c := accessor.Configuration(round)
+	if c == nil {
+		panic(fmt.Errorf("configuration is not ready %v", round))
+	}
+	return c
+}
+
+type crsAccessor interface {
+	CRS(round uint64) common.Hash
+}
+
+// GetCRSWithPanic is a helper to access CRS, and panic when CRS for that
+// round is not ready yet.
+func GetCRSWithPanic(accessor crsAccessor, round uint64,
+	logger common.Logger) common.Hash {
+	if logger != nil {
+		logger.Debug("Calling Governance.CRS", "round", round)
+	}
+	crs := accessor.CRS(round)
+	if (crs == common.Hash{}) {
+		panic(fmt.Errorf("CRS is not ready %v", round))
+	}
+	return crs
+
+}