wallet: Add birthday.

Add two new values to the database. One shows the intent to save a
wallet birtday to the database and includes a time. The other is the
wallet's birthday block. While syncing, the wallet will check if there
is an intent to save the birthday and save the block header and height
of the block before the birthday is passed to the database.

internal/prompt/prompt.go

@@ -12,6 +12,7 @@ import (
 	"io"
 	"os"
 	"strings"
+	"time"
 	"unicode"
 
 	"decred.org/dcrwallet/v4/errors"
@@ -367,6 +368,36 @@ func Seed(reader *bufio.Reader) (seed []byte, imported bool, err error) {
 	}
 }
 
+// Birthday prompts for a wallet birthday.
+func Birthday(reader *bufio.Reader) (*time.Time, error) {
+	for {
+		fmt.Printf("Do you have a wallet birthday we should rescan from? (enter date as YYYY-MM-DD, or 'no') [no]: ")
+		reply, err := reader.ReadString('\n')
+		if err != nil {
+			return nil, err
+		}
+		reply = strings.TrimSpace(reply)
+		switch strings.ToLower(reply) {
+		case "", "n", "no":
+			return nil, nil
+		case "y", "yes":
+			continue
+		default:
+		}
+
+		birthday, err := time.Parse("2006-01-02", reply)
+		if err != nil {
+			fmt.Printf("Unable to parse date: %v\n", err)
+			continue
+		}
+		if birthday.After(time.Now()) {
+			fmt.Println("Birthday cannot be in the future.")
+			continue
+		}
+		return &birthday, nil
+	}
+}
+
 // ImportedAccounts prompts for any additional account names and xpubs to
 // import at wallet creation.
 func ImportedAccounts(reader *bufio.Reader, params *chaincfg.Params) (names []string, xpubs []*hdkeychain.ExtendedKey, err error) {

wallet/chainntfns.go

@@ -120,6 +120,7 @@ func (w *Wallet) ChainSwitch(ctx context.Context, forest *SidechainForest, chain
 		}
 
 		if sideChainForkHeight <= tipHeight {
+			birthdayHash, birthdayHeight := w.txStore.Birthday(dbtx)
 			chainTipChanges.DetachedBlocks = make([]*chainhash.Hash, tipHeight-sideChainForkHeight+1)
 			prevChain = make([]*BlockNode, tipHeight-sideChainForkHeight+1)
 			for i := tipHeight; i >= sideChainForkHeight; i-- {
@@ -136,6 +137,14 @@ func (w *Wallet) ChainSwitch(ctx context.Context, forest *SidechainForest, chain
 					return err
 				}
 
+				if birthdayHash != nil && hash == *birthdayHash {
+					if err := w.txStore.SetBirthdayTimeBool(dbtx, true); err != nil {
+						return err
+					}
+					log.Infof("Old birthday block %d (%v) was forked off the network. "+
+						"A new one will be set.", birthdayHeight, birthdayHash)
+				}
+
 				// DetachedBlocks and prevChain are sorted in order of increasing heights.
 				chainTipChanges.DetachedBlocks[i-sideChainForkHeight] = &hash
 				prevChain[i-sideChainForkHeight] = NewBlockNode(header, &hash, filter)
@@ -160,7 +169,9 @@ func (w *Wallet) ChainSwitch(ctx context.Context, forest *SidechainForest, chain
 			}
 		}
 
-		for _, n := range chain {
+		shouldSetBirthday, birthday := w.txStore.BirthdayTime(dbtx)
+
+		for i, n := range chain {
 			if voteVersion(w.chainParams) < n.Header.StakeVersion {
 				log.Warnf("Old vote version detected (v%v), please update your "+
 					"wallet to the latest version.", voteVersion(w.chainParams))
@@ -174,6 +185,30 @@ func (w *Wallet) ChainSwitch(ctx context.Context, forest *SidechainForest, chain
 
 			// Add the block hash to the notification.
 			chainTipChanges.AttachedBlocks = append(chainTipChanges.AttachedBlocks, n.Hash)
+
+			if shouldSetBirthday {
+				if n.Header.Timestamp.After(*birthday) {
+					bh := n.Header.PrevBlock
+					if err := w.txStore.SetBirthday(dbtx, &bh, n.Header.Height-1); err != nil {
+						return err
+					}
+					shouldSetBirthday = false
+					if err := w.txStore.UpdateProcessedTxsBlockMarker(dbtx, &bh); err != nil {
+						return err
+					}
+					log.Infof("Set wallet birthday to block %d (%v).",
+						n.Header.Height-1, bh)
+				} else if i == len(chain)-1 {
+					// In the case that the birthday will not be reached,
+					// store a hash for initial sync to start from. Do not
+					// store the tip hash as that will cause w.rescanPoint
+					// to return nil.
+					bh := n.Header.PrevBlock
+					if err := w.txStore.UpdateProcessedTxsBlockMarker(dbtx, &bh); err != nil {
+						return err
+					}
+				}
+			}
 		}
 
 		if relevantTxs != nil {

wallet/rescan.go

@@ -493,3 +493,17 @@ func (w *Wallet) rescanPoint(dbtx walletdb.ReadTx) (*chainhash.Hash, error) {
 	}
 	return &rescanPoint, nil
 }
+
+// SetBirthdayTime sets a time that the birthday block should be set before.
+// The birthday will be set automatically when the wallet sees a block past the
+// birthday time.
+func (w *Wallet) SetBirthdayTime(ctx context.Context, birthday *time.Time) error {
+	const op errors.Op = "wallet.SetBirthdayTime"
+	err := walletdb.Update(ctx, w.db, func(dbtx walletdb.ReadWriteTx) error {
+		return w.txStore.SetBirthdayTime(dbtx, birthday)
+	})
+	if err != nil {
+		return errors.E(op, err)
+	}
+	return nil
+}

wallet/udb/txdb.go

@@ -160,6 +160,8 @@ var (
 	rootHaveCFilters = []byte("havecfilters")
 	rootLastTxsBlock = []byte("lasttxsblock")
 	rootVSPHostIndex = []byte("vsphostindex")
+	rootBirthdayTime = []byte("birthdaytime")
+	rootBirthday     = []byte("birthday")
 )
 
 // The root bucket's mined balance k/v pair records the total balance for all

wallet/udb/txmined.go

@@ -321,6 +321,88 @@ func (s *Store) UpdateProcessedTxsBlockMarker(dbtx walletdb.ReadWriteTx, hash *c
 	return nil
 }
 
+// SetBirthday sets a birthday block and hash. It also sets the birthday time
+// should be set bool to false.
+//
+// [0:32]  Block header hash (32 bytes)
+// [32:36] Birthday block height (4 bytes)
+func (s *Store) SetBirthday(dbtx walletdb.ReadWriteTx, blockHash *chainhash.Hash, height uint32) error {
+	ns := dbtx.ReadWriteBucket(wtxmgrBucketKey)
+	err := s.setBirthday(ns, blockHash, height)
+	if err != nil {
+		return err
+	}
+	return s.setBirthdayTimeBool(ns, false)
+}
+
+func (s *Store) setBirthday(ns walletdb.ReadWriteBucket, blockHash *chainhash.Hash, height uint32) error {
+	v := make([]byte, chainhash.HashSize+4)
+	copy(v[:], blockHash[:])
+	byteOrder.PutUint32(v[chainhash.HashSize:], uint32(height))
+	return ns.Put(rootBirthday, v)
+}
+
+// Birthday returns the currently set wallet birthday block hash and height. If
+// not set a nil hash is returned.
+func (s *Store) Birthday(dbtx walletdb.ReadTx) (*chainhash.Hash, uint32) {
+	ns := dbtx.ReadBucket(wtxmgrBucketKey)
+	v := ns.Get(rootBirthday)
+	if len(v) != chainhash.HashSize+4 {
+		return nil, 0
+	}
+	var h chainhash.Hash
+	copy(h[:], v[:chainhash.HashSize])
+	return &h, byteOrder.Uint32(v[chainhash.HashSize:])
+}
+
+// SetBirthdayTime sets a time that the birthday should be set from. Also sets
+// the bool that decides if the birthday should be set to true.
+//
+// [0:1] should set bool (1 byte)
+// [1:9] Birthday time (8 bytes)
+func (s *Store) SetBirthdayTime(dbtx walletdb.ReadWriteTx, birthday *time.Time) error {
+	ns := dbtx.ReadWriteBucket(wtxmgrBucketKey)
+	v := make([]byte, 1+8)
+	v[0] = 1 // true
+	byteOrder.PutUint64(v[1:], uint64(birthday.Unix()))
+	return ns.Put(rootBirthdayTime, v)
+}
+
+// SetBirthdayTimeBool sets only the bool that decides if the birthday should
+// be set. Will error if the birthday time was never set.
+func (s *Store) SetBirthdayTimeBool(dbtx walletdb.ReadWriteTx, shouldSet bool) error {
+	ns := dbtx.ReadWriteBucket(wtxmgrBucketKey)
+	return s.setBirthdayTimeBool(ns, shouldSet)
+}
+
+func (s *Store) setBirthdayTimeBool(ns walletdb.ReadWriteBucket, shouldSet bool) error {
+	v := ns.Get(rootBirthdayTime)
+	if len(v) != 1+8 {
+		return errors.New("birthday time never set")
+	}
+	vcopy := make([]byte, 1+8)
+	copy(vcopy, v)
+	if shouldSet {
+		vcopy[0] = 1
+	} else {
+		vcopy[0] = 0
+	}
+	return ns.Put(rootBirthdayTime, vcopy)
+}
+
+// BirthdayTime returns whether the birthday should be set and what a time it
+// should be set before.
+func (s *Store) BirthdayTime(dbtx walletdb.ReadTx) (shouldSet bool, birthday *time.Time) {
+	ns := dbtx.ReadBucket(wtxmgrBucketKey)
+	v := ns.Get(rootBirthdayTime)
+	if len(v) != 1+8 {
+		return false, nil
+	}
+	shouldSet = v[0] == 1
+	t := time.Unix(int64(byteOrder.Uint64(v[1:])), 0)
+	return shouldSet, &t
+}
+
 // IsMissingMainChainCFilters returns whether all compact filters for main chain
 // blocks have been recorded to the database after the upgrade which began to
 // require them to extend the main chain.  If compact filters are missing, they

walletsetup.go

@@ -13,6 +13,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"decred.org/dcrwallet/v4/errors"
 	"decred.org/dcrwallet/v4/internal/loader"
@@ -125,6 +126,7 @@ func createWallet(ctx context.Context, cfg *config) error {
 	var importedAccountNames []string
 	var importedAccountXpubs []*hdkeychain.ExtendedKey
 	var err error
+	var birthday *time.Time
 	c := make(chan struct{}, 1)
 	go func() {
 		defer func() { c <- struct{}{} }()
@@ -164,6 +166,18 @@ func createWallet(ctx context.Context, cfg *config) error {
 		// script which provide scripted input to create wallets to
 		// continue working.
 
+		// Ask for a birthday if the wallet was created from seed. If
+		// the wallet is new the birthday is now.
+		if imported {
+			birthday, err = prompt.Birthday(r)
+			if err != nil {
+				return
+			}
+		} else {
+			bd := time.Now()
+			birthday = &bd
+		}
+
 		// Prompt for any additional xpubs to import as watching-only accounts.
 		importedAccountNames, importedAccountXpubs, err = prompt.ImportedAccounts(
 			r, activeNet.Params)
@@ -213,6 +227,10 @@ func createWallet(ctx context.Context, cfg *config) error {
 		}
 	}
 
+	if birthday != nil {
+		w.SetBirthdayTime(ctx, birthday)
+	}
+
 	err = loader.UnloadWallet()
 	if err != nil {
 		return err