lib/db: Refactor to use global list by version (fixes #6372) (#6638)

Group the global list of files by version, instead of having one flat list for all devices. This removes lots of duplicate protocol.Vectors.

Co-authored-by: Jakob Borg <jakob@kastelo.net>

lib/protocol/bep_extensions.go

@@ -23,6 +23,31 @@ const (
 	Version13HelloMagic    uint32 = 0x9F79BC40 // old
 )
 
+// FileIntf is the set of methods implemented by both FileInfo and
+// db.FileInfoTruncated.
+type FileIntf interface {
+	FileSize() int64
+	FileName() string
+	FileLocalFlags() uint32
+	IsDeleted() bool
+	IsInvalid() bool
+	IsIgnored() bool
+	IsUnsupported() bool
+	MustRescan() bool
+	IsReceiveOnlyChanged() bool
+	IsDirectory() bool
+	IsSymlink() bool
+	ShouldConflict() bool
+	HasPermissionBits() bool
+	SequenceNo() int64
+	BlockSize() int
+	FileVersion() Vector
+	FileType() FileInfoType
+	FilePermissions() uint32
+	FileModifiedBy() ShortID
+	ModTime() time.Time
+}
+
 func (m Hello) Magic() uint32 {
 	return HelloMessageMagic
 }
@@ -139,7 +164,7 @@ func (f FileInfo) FileModifiedBy() ShortID {
 
 // WinsConflict returns true if "f" is the one to choose when it is in
 // conflict with "other".
-func (f FileInfo) WinsConflict(other FileInfo) bool {
+func WinsConflict(f, other FileIntf) bool {
 	// If only one of the files is invalid, that one loses.
 	if f.IsInvalid() != other.IsInvalid() {
 		return !f.IsInvalid()
@@ -164,7 +189,7 @@ func (f FileInfo) WinsConflict(other FileInfo) bool {
 
 	// The modification times were equal. Use the device ID in the version
 	// vector as tie breaker.
-	return f.Version.Compare(other.Version) == ConcurrentGreater
+	return f.FileVersion().Compare(other.FileVersion()) == ConcurrentGreater
 }
 
 func (f FileInfo) IsEmpty() bool {

lib/protocol/conflict_test.go

@@ -14,10 +14,10 @@ func TestWinsConflict(t *testing.T) {
 	}
 
 	for _, tc := range testcases {
-		if !tc[0].WinsConflict(tc[1]) {
+		if !WinsConflict(tc[0], tc[1]) {
 			t.Errorf("%v should win over %v", tc[0], tc[1])
 		}
-		if tc[1].WinsConflict(tc[0]) {
+		if WinsConflict(tc[1], tc[0]) {
 			t.Errorf("%v should not win over %v", tc[1], tc[0])
 		}
 	}