chore: stop treating dirs as having size 128 (#10750)

Resp. directories for the database, and both dirs and symlinks for
`FileInfo.FileSize`. Instead handle it in the UI progress percentage. We
even already have special cases there for deletions, might as well
handle directories just like any other zero-sized needed item there.

This went through the very thorough testing of running it on my laptop,
the migration was applied and it seemed to be working fine after.

---------

Signed-off-by: Simon Frei <freisim93@gmail.com>

lib/protocol/bep_fileinfo.go

@@ -389,16 +389,6 @@ func (f FileInfo) HasPermissionBits() bool {
 	return !f.NoPermissions
 }
 
-func (f FileInfo) FileSize() int64 {
-	if f.Deleted {
-		return 0
-	}
-	if f.IsDirectory() || f.IsSymlink() {
-		return SyntheticDirectorySize
-	}
-	return f.Size
-}
-
 func (f FileInfo) BlockSize() int {
 	if f.RawBlockSize < MinBlockSize {
 		return MinBlockSize

lib/protocol/protocol.go

@@ -56,7 +56,8 @@ const (
 	// DesiredPerFileBlocks is the number of blocks we aim for per file
 	DesiredPerFileBlocks = 2000
 
-	SyntheticDirectorySize = 128
+	// We used to send this size for directories and still accept that for compat.
+	deprecatedSyntheticDirectorySize = 128
 
 	// don't bother compressing messages smaller than this many bytes
 	compressionThreshold = 128
@@ -640,7 +641,7 @@ func checkFileInfoConsistency(f FileInfo) error {
 		// Only files should have blocks
 		return errNonFileHasBlocks
 
-	case f.IsDirectory() && f.Size != 0 && f.Size != SyntheticDirectorySize:
+	case f.IsDirectory() && f.Size != 0 && f.Size != deprecatedSyntheticDirectorySize:
 		// Directories should be size zero or the synthetic directory size
 		return errNonFileHasSize
 

lib/protocol/protocol_test.go

@@ -464,7 +464,7 @@ func TestCheckConsistency(t *testing.T) {
 			fi: FileInfo{
 				Name: "foo",
 				Type: FileInfoTypeDirectory,
-				Size: SyntheticDirectorySize,
+				Size: deprecatedSyntheticDirectorySize,
 			},
 			ok: true,
 		},
@@ -492,7 +492,7 @@ func TestCheckConsistency(t *testing.T) {
 				Name:          "foo",
 				Type:          FileInfoTypeSymlink,
 				SymlinkTarget: []byte("bar"),
-				Size:          SyntheticDirectorySize,
+				Size:          deprecatedSyntheticDirectorySize,
 			},
 			ok: false,
 		},