feat(GODT-2582): Deduplication of messages in Recovery Mailbox

When we attempt to recover avoid creating duplicates of existing
recovered messages. We now keep track of the literal hash of all the
messages in the recovered messages folder and if we see we are adding a
known literal, we ignore the new version.

imap/strong_types.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"strconv"
 
-	"github.com/ProtonMail/gluon/internal/utils"
 	"github.com/google/uuid"
 )
 
@@ -13,11 +12,11 @@ type MailboxID string
 type MessageID string
 
 func (l MailboxID) ShortID() string {
-	return utils.ShortID(string(l))
+	return ShortID(string(l))
 }
 
 func (m MessageID) ShortID() string {
-	return utils.ShortID(string(m))
+	return ShortID(string(m))
 }
 
 type InternalMessageID struct {
@@ -31,7 +30,7 @@ func (i InternalMailboxID) ShortID() string {
 }
 
 func (i InternalMessageID) ShortID() string {
-	return utils.ShortID(i.String())
+	return ShortID(i.String())
 }
 
 func (i InternalMailboxID) String() string {

imap/update_mailbox_created.go

@@ -3,8 +3,6 @@ package imap
 import (
 	"fmt"
 	"strings"
-
-	"github.com/ProtonMail/gluon/internal/utils"
 )
 
 type MailboxCreated struct {
@@ -26,6 +24,6 @@ func (u *MailboxCreated) String() string {
 	return fmt.Sprintf(
 		"MailboxCreated: Mailbox.ID = %v, Mailbox.Name = %v",
 		u.Mailbox.ID.ShortID(),
-		utils.ShortID(strings.Join(u.Mailbox.Name, "/")),
+		ShortID(strings.Join(u.Mailbox.Name, "/")),
 	)
 }

imap/update_mailbox_updated.go

@@ -3,8 +3,6 @@ package imap
 import (
 	"fmt"
 	"strings"
-
-	"github.com/ProtonMail/gluon/internal/utils"
 )
 
 type MailboxUpdated struct {
@@ -28,6 +26,6 @@ func (u *MailboxUpdated) String() string {
 	return fmt.Sprintf(
 		"MailboxUpdated: MailboxID = %v, MailboxName = %v",
 		u.MailboxID.ShortID(),
-		utils.ShortID(strings.Join(u.MailboxName, "/")),
+		ShortID(strings.Join(u.MailboxName, "/")),
 	)
 }

imap/utils.go

@@ -0,0 +1,12 @@
+package imap
+
+// ShortID return a string containing a short version of the given ID. Use only for debug display.
+func ShortID(id string) string {
+	const l = 12
+
+	if len(id) < l {
+		return id
+	}
+
+	return id[0:l] + "..."
+}

internal/backend/state_user_interface_impl.go

@@ -2,6 +2,7 @@ package backend
 
 import (
 	"context"
+	"github.com/ProtonMail/gluon/internal/utils"
 
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/internal/db"
@@ -89,3 +90,7 @@ func (s *StateUserInterfaceImpl) GetRecoveryMailboxID() ids.MailboxIDPair {
 		RemoteID:   ids.GluonInternalRecoveryMailboxRemoteID,
 	}
 }
+
+func (s *StateUserInterfaceImpl) GetRecoveredMessageHashesMap() *utils.MessageHashesMap {
+	return s.u.recoveredMessageHashes
+}

internal/backend/user.go

@@ -3,6 +3,7 @@ package backend
 import (
 	"context"
 	"fmt"
+	"github.com/ProtonMail/gluon/internal/utils"
 	"sync"
 
 	"github.com/ProtonMail/gluon/async"
@@ -45,6 +46,8 @@ type user struct {
 	uidValidityGenerator imap.UIDValidityGenerator
 
 	panicHandler async.PanicHandler
+
+	recoveredMessageHashes *utils.MessageHashesMap
 }
 
 func newUser(
@@ -62,6 +65,8 @@ func newUser(
 		return nil, err
 	}
 
+	recoveredMessageHashes := utils.NewMessageHashesMap()
+
 	// Create recovery mailbox if it does not exist
 	recoveryMBox, err := db.WriteResult(ctx, database, func(ctx context.Context, tx *ent.Tx) (*ent.Mailbox, error) {
 		uidValidity, err := uidValidityGenerator.Generate()
@@ -78,7 +83,30 @@ func newUser(
 			Attributes:     imap.NewFlagSet(imap.AttrNoInferiors),
 		}
 
-		return db.GetOrCreateMailbox(ctx, tx, mbox, delimiter, uidValidity)
+		recoveryMBox, err := db.GetOrCreateMailbox(ctx, tx, mbox, delimiter, uidValidity)
+		if err != nil {
+			return nil, err
+		}
+
+		// Pre-fill the message hashes map
+		messages, err := db.GetMailboxMessageIDPairs(ctx, tx.Client(), recoveryMBox.ID)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, m := range messages {
+			literal, err := st.Get(m.InternalID)
+			if err != nil {
+				logrus.WithError(err).Errorf("Failed to load %v for store for recovered message hashes map", m.InternalID)
+				continue
+			}
+
+			if _, err := recoveredMessageHashes.Insert(m.InternalID, literal); err != nil {
+				logrus.WithError(err).Errorf("Failed insert literal for %v into recovered message hashes map", m.InternalID)
+			}
+		}
+
+		return recoveryMBox, nil
 	})
 	if err != nil {
 		return nil, err
@@ -104,6 +132,8 @@ func newUser(
 		uidValidityGenerator: uidValidityGenerator,
 
 		panicHandler: panicHandler,
+
+		recoveredMessageHashes: recoveredMessageHashes,
 	}
 
 	if err := user.deleteAllMessagesMarkedDeleted(ctx); err != nil {

internal/state/actions.go

@@ -201,6 +201,12 @@ func (state *State) actionCreateRecoveredMessage(
 		return err
 	}
 
+	alreadyKnown, err := state.user.GetRecoveredMessageHashesMap().Insert(internalID, literal)
+	if err == nil && alreadyKnown {
+		// Message is already known to us, so we ignore it.
+		return nil
+	}
+
 	if err := state.user.GetStore().SetUnchecked(internalID, bytes.NewReader(literal)); err != nil {
 		return fmt.Errorf("failed to store message literal: %w", err)
 	}
@@ -436,6 +442,8 @@ func (state *State) actionMoveMessagesOutOfRecoveryMailbox(
 			return nil, err
 		}
 
+		state.user.GetRecoveredMessageHashesMap().Erase(oldInternalIDs...)
+
 		updates = append(updates, removeUpdates...)
 	}
 
@@ -470,6 +478,8 @@ func (state *State) actionRemoveMessagesFromMailboxUnchecked(
 		if err := state.user.GetRemote().RemoveMessagesFromMailbox(ctx, remoteIDs, mboxID.RemoteID); err != nil {
 			return err
 		}
+	} else {
+		state.user.GetRecoveredMessageHashesMap().Erase(internalIDs...)
 	}
 
 	updates, err := RemoveMessagesFromMailbox(ctx, tx, mboxID.InternalID, internalIDs)

internal/state/user_interface.go

@@ -2,6 +2,7 @@ package state
 
 import (
 	"context"
+	"github.com/ProtonMail/gluon/internal/utils"
 
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/internal/db"
@@ -31,4 +32,6 @@ type UserInterface interface {
 	GetRecoveryMailboxID() ids.MailboxIDPair
 
 	GenerateUIDValidity() (imap.UID, error)
+
+	GetRecoveredMessageHashesMap() *utils.MessageHashesMap
 }

internal/utils/message_hashmap.go

@@ -0,0 +1,61 @@
+package utils
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"github.com/ProtonMail/gluon/imap"
+	"sync"
+)
+
+// MessageHashesMap tracks the hashes for a literal and it's associated internal IMAP ID.
+type MessageHashesMap struct {
+	lock     sync.Mutex
+	idToHash map[imap.InternalMessageID]string
+	hashes   map[string]struct{}
+}
+
+func NewMessageHashesMap() *MessageHashesMap {
+	return &MessageHashesMap{
+		idToHash: make(map[imap.InternalMessageID]string),
+		hashes:   make(map[string]struct{}),
+	}
+}
+
+// Insert inserts the hash of the current message literal into the map and return true if an existing value was already
+// present.
+func (m *MessageHashesMap) Insert(id imap.InternalMessageID, literal []byte) (bool, error) {
+	hash := sha256.New()
+
+	if _, err := hash.Write(literal); err != nil {
+		return false, err
+	}
+
+	literalHash := hash.Sum(nil)
+	literalHashStr := hex.EncodeToString(literalHash)
+
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	if _, ok := m.hashes[literalHashStr]; ok {
+		return true, nil
+	}
+
+	m.idToHash[id] = literalHashStr
+	m.hashes[literalHashStr] = struct{}{}
+
+	return false, nil
+}
+
+// Erase removes the info associated with a given id.
+func (m *MessageHashesMap) Erase(ids ...imap.InternalMessageID) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	for _, id := range ids {
+		if v, ok := m.idToHash[id]; ok {
+			delete(m.hashes, v)
+		}
+
+		delete(m.idToHash, id)
+	}
+}

internal/utils/utils.go

@@ -20,17 +20,6 @@ func NewRandomMessageID() string {
 	return "msg-" + uuid.NewString()
 }
 
-// ShortID return a string containing a short version of the given ID. Use only for debug display.
-func ShortID(id string) string {
-	const l = 12
-
-	if len(id) < l {
-		return id
-	}
-
-	return id[0:l] + "..."
-}
-
 // ErrCause returns the cause of the error, the inner-most error in the wrapped chain.
 func ErrCause(err error) error {
 	cause := err

tests/recovery_mailbox_test.go

@@ -200,6 +200,44 @@ func TestFailedAppendEndsInRecovery(t *testing.T) {
 	})
 }
 
+func TestFailedAppendAreDedupedInRecoveryMailbox(t *testing.T) {
+	runOneToOneTestClientWithAuth(t, defaultServerOptions(t, withConnectorBuilder(&failAppendLabelConnectorBuilder{})), func(client *client.Client, s *testSession) {
+		{
+			status, err := client.Status(ids.GluonRecoveryMailboxName, []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(0), status.Messages)
+		}
+
+		status, err := client.Select("INBOX", false)
+		require.NoError(t, err)
+		require.Equal(t, uint32(0), status.Messages)
+		require.Error(t, doAppendWithClient(client, "INBOX", "To: [email protected]", time.Now()))
+		require.Error(t, doAppendWithClient(client, "INBOX", "To: [email protected]", time.Now()))
+		require.Error(t, doAppendWithClient(client, "INBOX", "To: [email protected]", time.Now()))
+
+		{
+			status, err := client.Status(ids.GluonRecoveryMailboxName, []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(2), status.Messages)
+		}
+		{
+			status, err := client.Status("INBOX", []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(0), status.Messages)
+		}
+
+		{
+			_, err := client.Select(ids.GluonRecoveryMailboxName, false)
+			require.NoError(t, err)
+			// Check that no custom headers are appended to the message.
+			newFetchCommand(t, client).withItems("BODY[]").fetch("1").forSeqNum(1, func(builder *validatorBuilder) {
+				builder.ignoreFlags()
+				builder.wantSection("BODY[]", "To: [email protected]")
+			}).checkAndRequireMessageCount(1)
+		}
+	})
+}
+
 func TestRecoveryMBoxCanBeCopiedOutOfDedup(t *testing.T) {
 	runOneToOneTestClientWithAuth(t, defaultServerOptions(t, withConnectorBuilder(&recoveryDedupConnectorConnectorBuilder{})), func(client *client.Client, s *testSession) {
 		// Insert first message, fails.