core: Remove atomic (#266)

2 files changed, 11 insertions, 14 deletions

diff --git a/core/agreement.go b/core/agreement.go
index 13f39ce..cab896c 100644
--- a/core/agreement.go
+++ b/core/agreement.go
@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"math"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
@@ -102,7 +101,7 @@ type agreementData struct {
 type agreement struct {
 	state          agreementState
 	data           *agreementData
-	aID            *atomic.Value
+	aID            types.Position
 	notarySet      map[types.NodeID]struct{}
 	hasOutput      bool
 	lock           sync.RWMutex
@@ -126,7 +125,6 @@ func newAgreement(
 			ID:     ID,
 			leader: leader,
 		},
-		aID:            &atomic.Value{},
 		candidateBlock: make(map[common.Hash]*types.Block),
 		fastForward:    make(chan uint64, 1),
 		authModule:     authModule,
@@ -159,7 +157,7 @@ func (a *agreement) restart(
 		a.state = newInitialState(a.data)
 		a.notarySet = notarySet
 		a.candidateBlock = make(map[common.Hash]*types.Block)
-		a.aID.Store(aID)
+		a.aID = *aID.Clone()
 	}()
 
 	expireTime := time.Now().Add(-10 * time.Second)
@@ -219,7 +217,9 @@ func (a *agreement) clocks() int {
 
 // agreementID returns the current agreementID.
 func (a *agreement) agreementID() types.Position {
-	return a.aID.Load().(types.Position)
+	a.lock.RLock()
+	defer a.lock.RUnlock()
+	return a.aID
 }
 
 // nextState is called at the specific clock time.
diff --git a/core/types/position.go b/core/types/position.go
index d821d16..8e7e852 100644
--- a/core/types/position.go
+++ b/core/types/position.go
@@ -18,15 +18,9 @@
 package types
 
 import (
-	"errors"
 	"fmt"
 )
 
-// ErrComparePositionOnDifferentChains raised when attempting to
-// compare two positions with different chain ID.
-var ErrComparePositionOnDifferentChains = errors.New(
-	"position on different chain")
-
 // Position describes the position in the block lattice of an entity.
 type Position struct {
 	ChainID uint32 `json:"chain_id"`
@@ -42,7 +36,8 @@ func (pos *Position) String() string {
 // are different.
 func (pos *Position) Equal(other *Position) bool {
 	if pos.ChainID != other.ChainID {
-		panic(ErrComparePositionOnDifferentChains)
+		panic(fmt.Errorf("unexpected chainID %d, should be %d",
+			other.ChainID, pos.ChainID))
 	}
 	return pos.Round == other.Round && pos.Height == other.Height
 }
@@ -51,7 +46,8 @@ func (pos *Position) Equal(other *Position) bool {
 // If two blocks on different chain compared by this function, it would panic.
 func (pos *Position) Newer(other *Position) bool {
 	if pos.ChainID != other.ChainID {
-		panic(ErrComparePositionOnDifferentChains)
+		panic(fmt.Errorf("unexpected chainID %d, should be %d",
+			other.ChainID, pos.ChainID))
 	}
 	return pos.Round > other.Round ||
 		(pos.Round == other.Round && pos.Height > other.Height)
@@ -61,7 +57,8 @@ func (pos *Position) Newer(other *Position) bool {
 // If two blocks on different chain compared by this function, it would panic.
 func (pos *Position) Older(other *Position) bool {
 	if pos.ChainID != other.ChainID {
-		panic(ErrComparePositionOnDifferentChains)
+		panic(fmt.Errorf("unexpected chainID %d, should be %d",
+			other.ChainID, pos.ChainID))
 	}
 	return pos.Round < other.Round ||
 		(pos.Round == other.Round && pos.Height < other.Height)