bug: add a Lamport logical clock to be able to sort bugs by creation time and edit time without having to rely on a timestamp

3 files changed, 12 insertions, 15 deletions

diff --git a/util/lamport.go b/util/lamport.go
index c75e1d15..4d5dcf5b 100644
--- a/util/lamport.go
+++ b/util/lamport.go
@@ -58,9 +58,9 @@ func (l *LamportClock) Time() LamportTime {
 	return LamportTime(atomic.LoadUint64(&l.counter))
 }
 
-// Increment is used to increment and return the value of the lamport clock
+// Increment is used to return the value of the lamport clock and increment it afterwards
 func (l *LamportClock) Increment() LamportTime {
-	return LamportTime(atomic.AddUint64(&l.counter, 1))
+	return LamportTime(atomic.AddUint64(&l.counter, 1) - 1)
 }
 
 // Witness is called to update our local clock if necessary after
diff --git a/util/lamport_test.go b/util/lamport_test.go
index 0bac7d51..de7f1822 100644
--- a/util/lamport_test.go
+++ b/util/lamport_test.go
@@ -38,7 +38,7 @@ func TestLamportClock(t *testing.T) {
 		t.Fatalf("bad time value")
 	}
 
-	if l.Increment() != 1 {
+	if l.Increment() != 0 {
 		t.Fatalf("bad time value")
 	}
 
diff --git a/util/persisted_lamport.go b/util/persisted_lamport.go
index 43a2863c..c8c898e2 100644
--- a/util/persisted_lamport.go
+++ b/util/persisted_lamport.go
@@ -14,7 +14,8 @@ type PersistedLamport struct {
 
 func NewPersistedLamport(filePath string) *PersistedLamport {
 	clock := &PersistedLamport{
-		filePath: filePath,
+		LamportClock: NewLamportClock(),
+		filePath:     filePath,
 	}
 	return clock
 }
@@ -32,21 +33,17 @@ func LoadPersistedLamport(filePath string) (*PersistedLamport, error) {
 	return clock, nil
 }
 
+func (c *PersistedLamport) Increment() (LamportTime, error) {
+	time := c.LamportClock.Increment()
+	return time, c.Write()
+}
+
 func (c *PersistedLamport) Witness(time LamportTime) error {
+	// TODO: rework so that we write only when the clock was actually updated
 	c.LamportClock.Witness(time)
 	return c.Write()
 }
 
-func (c *PersistedLamport) Time() LamportTime {
-	// Equivalent to:
-	//
-	// res = c.LamportClock.Time()
-	// bugClock.Increment()
-	//
-	// ... but thread safe
-	return c.Increment() - 1
-}
-
 func (c *PersistedLamport) read() error {
 	content, err := ioutil.ReadFile(c.filePath)
 	if err != nil {
@@ -76,6 +73,6 @@ func (c *PersistedLamport) Write() error {
 		return err
 	}
 
-	data := []byte(fmt.Sprintf("%d", c.LamportClock.Time()))
+	data := []byte(fmt.Sprintf("%d", c.counter))
 	return ioutil.WriteFile(c.filePath, data, 0644)
 }