Breaking Change: Introduce new APIs for Entry creation/modification

* Add functions to create, modify Entry

Currently no functions are exposed to create and modify Entry, to
be set in a transaction. Functions Set, SetWithMeta, SetWithDiscard,
SetWithTTL, all are part of Txn struct. These functions internally
create an entry and then call txn.SetEntry. All of Set functions,
set a specific property of Entry apart from key and value. This
restricts us from setting multiple property for same entry such as
meta and TTL.
This PR adds functions to set different properties on an existing
Entry. After setting desired properties, user can call txn.SetEntry
to add entry in the transaction. It also removes entry related functions
from Txn Struct except SetEntry and Set.

* Fix all compilation failure due to above change using
new Entry methods.

* Fix comments from GolangCI.

backup_test.go

@@ -52,7 +52,7 @@ func TestBackupRestore1(t *testing.T) {
 
 	err = db.Update(func(txn *Txn) error {
 		e := entries[0]
-		err := txn.SetWithMeta(e.key, e.val, e.userMeta)
+		err := txn.SetEntry(NewEntry(e.key, e.val).WithMeta(e.userMeta))
 		if err != nil {
 			return err
 		}
@@ -62,7 +62,7 @@ func TestBackupRestore1(t *testing.T) {
 
 	err = db.Update(func(txn *Txn) error {
 		e := entries[1]
-		err := txn.SetWithMeta(e.key, e.val, e.userMeta)
+		err := txn.SetEntry(NewEntry(e.key, e.val).WithMeta(e.userMeta))
 		if err != nil {
 			return err
 		}
@@ -140,20 +140,20 @@ func TestBackupRestore2(t *testing.T) {
 	rawValue := []byte("NotLongValue")
 	N := byte(251)
 	err = db1.Update(func(tx *Txn) error {
-		if err := tx.Set(key1, rawValue); err != nil {
+		if err := tx.SetEntry(NewEntry(key1, rawValue)); err != nil {
 			return err
 		}
-		return tx.Set(key2, rawValue)
+		return tx.SetEntry(NewEntry(key2, rawValue))
 	})
 	if err != nil {
 		t.Fatal(err)
 	}
 	for i := byte(1); i < N; i++ {
 		err = db1.Update(func(tx *Txn) error {
-			if err := tx.Set(append(key1, i), rawValue); err != nil {
+			if err := tx.SetEntry(NewEntry(append(key1, i), rawValue)); err != nil {
 				return err
 			}
-			return tx.Set(append(key2, i), rawValue)
+			return tx.SetEntry(NewEntry(append(key2, i), rawValue))
 		})
 		if err != nil {
 			t.Fatal(err)
@@ -204,10 +204,10 @@ func TestBackupRestore2(t *testing.T) {
 
 	for i := byte(1); i < N; i++ {
 		err = db2.Update(func(tx *Txn) error {
-			if err := tx.Set(append(key1, i), rawValue); err != nil {
+			if err := tx.SetEntry(NewEntry(append(key1, i), rawValue)); err != nil {
 				return err
 			}
-			return tx.Set(append(key2, i), rawValue)
+			return tx.SetEntry(NewEntry(append(key2, i), rawValue))
 		})
 		if err != nil {
 			t.Fatal(err)
@@ -278,7 +278,7 @@ func populateEntries(db *DB, entries []*pb.KV) error {
 	return db.Update(func(txn *Txn) error {
 		var err error
 		for i, e := range entries {
-			if err = txn.Set(e.Key, e.Value); err != nil {
+			if err = txn.SetEntry(NewEntry(e.Key, e.Value)); err != nil {
 				return err
 			}
 			entries[i].Version = 1
@@ -445,8 +445,8 @@ func TestBackupLoadIncremental(t *testing.T) {
 		// pick 5 items to mark as expired.
 		err = db1.Update(func(txn *Txn) error {
 			for _, i := range (ints)[10:15] {
-				if err := txn.SetWithTTL(
-					entries[i].Key, entries[i].Value, -time.Hour); err != nil {
+				entry := NewEntry(entries[i].Key, entries[i].Value).WithTTL(-time.Hour)
+				if err := txn.SetEntry(entry); err != nil {
 					return err
 				}
 				updates[i] = bitDelete // expired
@@ -460,7 +460,8 @@ func TestBackupLoadIncremental(t *testing.T) {
 		// pick 5 items to mark as discard.
 		err = db1.Update(func(txn *Txn) error {
 			for _, i := range ints[15:20] {
-				if err := txn.SetWithDiscard(entries[i].Key, entries[i].Value, 0); err != nil {
+				entry := NewEntry(entries[i].Key, entries[i].Value).WithDiscard()
+				if err := txn.SetEntry(entry); err != nil {
 					return err
 				}
 				updates[i] = bitDiscardEarlierVersions

badger/cmd/bank.go

@@ -131,7 +131,7 @@ func getBalance(txn *badger.Txn, account int) (uint64, error) {
 }
 
 func putBalance(txn *badger.Txn, account int, bal uint64) error {
-	return txn.Set(key(account), toSlice(bal))
+	return txn.SetEntry(badger.NewEntry(key(account), toSlice(bal)))
 }
 
 func min(a, b uint64) uint64 {

db.go

@@ -1112,7 +1112,7 @@ func (seq *Sequence) Release() error {
 	err := seq.db.Update(func(txn *Txn) error {
 		var buf [8]byte
 		binary.BigEndian.PutUint64(buf[:], seq.next)
-		return txn.Set(seq.key, buf[:])
+		return txn.SetEntry(NewEntry(seq.key, buf[:]))
 	})
 	if err != nil {
 		return err
@@ -1142,7 +1142,7 @@ func (seq *Sequence) updateLease() error {
 		lease := seq.next + seq.bandwidth
 		var buf [8]byte
 		binary.BigEndian.PutUint64(buf[:], lease)
-		if err = txn.Set(seq.key, buf[:]); err != nil {
+		if err = txn.SetEntry(NewEntry(seq.key, buf[:])); err != nil {
 			return err
 		}
 		seq.leased = lease

db2_test.go

@@ -54,7 +54,7 @@ func TestTruncateVlogWithClose(t *testing.T) {
 	require.NoError(t, err)
 
 	err = db.Update(func(txn *Txn) error {
-		return txn.Set(key(0), data(4055))
+		return txn.SetEntry(NewEntry(key(0), data(4055)))
 	})
 	require.NoError(t, err)
 
@@ -67,7 +67,7 @@ func TestTruncateVlogWithClose(t *testing.T) {
 	require.NoError(t, err)
 	for i := 0; i < 32; i++ {
 		err := db.Update(func(txn *Txn) error {
-			return txn.Set(key(i), data(10))
+			return txn.SetEntry(NewEntry(key(i), data(10)))
 		})
 		require.NoError(t, err)
 	}
@@ -125,7 +125,7 @@ func TestTruncateVlogNoClose(t *testing.T) {
 	}
 	data := fmt.Sprintf("%4055d", 1)
 	err = kv.Update(func(txn *Txn) error {
-		return txn.Set([]byte(key(0)), []byte(data))
+		return txn.SetEntry(NewEntry([]byte(key(0)), []byte(data)))
 	})
 	require.NoError(t, err)
 }
@@ -147,7 +147,7 @@ func TestTruncateVlogNoClose2(t *testing.T) {
 	data := fmt.Sprintf("%10d", 1)
 	for i := 32; i < 64; i++ {
 		err := kv.Update(func(txn *Txn) error {
-			return txn.Set([]byte(key(i)), []byte(data))
+			return txn.SetEntry(NewEntry([]byte(key(i)), []byte(data)))
 		})
 		require.NoError(t, err)
 	}
@@ -205,11 +205,12 @@ func TestBigKeyValuePairs(t *testing.T) {
 		small := make([]byte, 65000)
 
 		txn := db.NewTransaction(true)
-		require.Regexp(t, regexp.MustCompile("Key.*exceeded"), txn.Set(bigK, small))
-		require.Regexp(t, regexp.MustCompile("Value.*exceeded"), txn.Set(small, bigV))
+		require.Regexp(t, regexp.MustCompile("Key.*exceeded"), txn.SetEntry(NewEntry(bigK, small)))
+		require.Regexp(t, regexp.MustCompile("Value.*exceeded"),
+			txn.SetEntry(NewEntry(small, bigV)))
 
-		require.NoError(t, txn.Set(small, small))
-		require.Regexp(t, regexp.MustCompile("Key.*exceeded"), txn.Set(bigK, bigV))
+		require.NoError(t, txn.SetEntry(NewEntry(small, small)))
+		require.Regexp(t, regexp.MustCompile("Key.*exceeded"), txn.SetEntry(NewEntry(bigK, bigV)))
 
 		require.NoError(t, db.View(func(txn *Txn) error {
 			_, err := txn.Get(small)
@@ -225,7 +226,7 @@ func TestBigKeyValuePairs(t *testing.T) {
 
 		saveByKey := func(key string, value []byte) error {
 			return db.Update(func(txn *Txn) error {
-				return txn.Set([]byte(key), value)
+				return txn.SetEntry(NewEntry([]byte(key), value))
 			})
 		}
 
@@ -297,12 +298,12 @@ func TestPushValueLogLimit(t *testing.T) {
 			if i == 4 {
 				v := make([]byte, 2<<30)
 				err := db.Update(func(txn *Txn) error {
-					return txn.Set([]byte(key(i)), v)
+					return txn.SetEntry(NewEntry([]byte(key(i)), v))
 				})
 				require.NoError(t, err)
 			} else {
 				err := db.Update(func(txn *Txn) error {
-					return txn.Set([]byte(key(i)), data)
+					return txn.SetEntry(NewEntry([]byte(key(i)), data))
 				})
 				require.NoError(t, err)
 			}