Undo the hash algorithm additions; retain flag checks

lib/model/model.go

@@ -637,11 +637,10 @@ nextFolder:
 	for _, folder := range cm.Folders {
 		cfg := m.folderCfgs[folder.ID]
 
-		if _, err := protocol.HashAlgorithmFromFlagBits(folder.Flags); err != nil {
-			// The hash algorithm failed to deserialize, so it's not SHA256
-			// (the only acceptable algorithm).
-			l.Warnf("Device %v: %v", deviceID, err)
-			cfg.Invalid = err.Error() + " from " + deviceID.String()
+		if folder.Flags&^protocol.FlagFolderAll != 0 {
+			// There are flags set that we don't know what they mean. Scary!
+			l.Warnf("Device %v: unknown flags for folder %s", deviceID, folder.ID)
+			cfg.Invalid = fmt.Sprintf("Unknown flags from device %v", deviceID)
 			m.cfg.SetFolder(cfg)
 			if srv := m.folderRunners[folder.ID]; srv != nil {
 				srv.setError(fmt.Errorf(cfg.Invalid))

lib/protocol/hashalgorithm.go

@@ -1,54 +0,0 @@
-// Copyright (C) 2016 The Protocol Authors.
-
-package protocol
-
-import "fmt"
-
-type HashAlgorithm int
-
-const (
-	SHA256 HashAlgorithm = iota
-)
-
-func (h HashAlgorithm) String() string {
-	switch h {
-	case SHA256:
-		return "sha256"
-	default:
-		return "unknown"
-	}
-}
-
-// FlagBits returns the bits that we should or into the folder flag field to
-// indicate the hash algorithm.
-func (h HashAlgorithm) FlagBits() uint32 {
-	switch h {
-	case SHA256:
-		return FolderHashSHA256 << FolderHashShiftBits
-	default:
-		panic("unknown hash algorithm")
-	}
-}
-
-func (h *HashAlgorithm) UnmarshalText(bs []byte) error {
-	switch string(bs) {
-	case "sha256":
-		*h = SHA256
-		return nil
-	}
-	return fmt.Errorf("Unknown hash algorithm %q", string(bs))
-}
-
-func (h *HashAlgorithm) MarshalText() ([]byte, error) {
-	return []byte(h.String()), nil
-}
-
-func HashAlgorithmFromFlagBits(flags uint32) (HashAlgorithm, error) {
-	algo := flags >> FolderHashShiftBits & FolderHashMask
-	switch algo {
-	case FolderHashSHA256:
-		return SHA256, nil
-	default:
-		return 0, fmt.Errorf("Unknown hash algorithm %d", algo)
-	}
-}

lib/protocol/hashalgorithm_test.go

@@ -1,35 +0,0 @@
-// Copyright (C) 2016 The Protocol Authors.
-
-package protocol
-
-import "testing"
-
-/*
-   0                   1                   2                   3
-    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-   |                       Reserved                  | Hash  |D|P|R|
-   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-*/
-func TestHashAlgorithmFromFlagBits(t *testing.T) {
-	// SHA256 is algorithm zero, shifted three bits to the left (for clarity,
-	// I know it doesn't actually do anything).
-
-	sha256 := uint32(0 << 3)
-
-	h, err := HashAlgorithmFromFlagBits(sha256)
-	if err != nil {
-		t.Error(err)
-	}
-	if h != SHA256 {
-		t.Error("Zero should have unmarshalled as SHA256")
-	}
-
-	// Any other algorithm is unknown
-	unknown := uint32(1 << 3)
-
-	_, err = HashAlgorithmFromFlagBits(unknown)
-	if err == nil {
-		t.Error("Unknown algo should not have unmarshalled")
-	}
-}

lib/protocol/protocol.go

@@ -66,13 +66,7 @@ const (
 	FlagFolderReadOnly     uint32 = 1 << 0
 	FlagFolderIgnorePerms         = 1 << 1
 	FlagFolderIgnoreDelete        = 1 << 2
-
-	// The folder hash algorithm IDs, to be put in the flags field by shifting
-	// left FolderHashShiftBits. 1 through 15 currently reserved.
-
-	FolderHashSHA256    = 0
-	FolderHashMask      = 15
-	FolderHashShiftBits = 3
+	FlagFolderAll                 = 1<<3 - 1
 )
 
 // ClusterConfigMessage.Folders.Devices flags