all: Simultaneously walk fs and db on scan (fixes #2571, fixes #4573) (#4584)

When scanner.Walk detects a change, it now returns the new file info as well as the old file info. It also finds deleted and ignored files while scanning.
Also directory deletions are now always committed to db after their children to prevent temporary failure on remote due to non-empty directory.

lib/protocol/protocol_test.go

@@ -24,6 +24,10 @@ var (
 	quickCfg = &quick.Config{}
 )
 
+const (
+	fileSize = 1 << 40
+)
+
 func TestPing(t *testing.T) {
 	ar, aw := io.Pipe()
 	br, bw := io.Pipe()
@@ -243,12 +247,6 @@ func TestMarshalledIndexMessageSize(t *testing.T) {
 		return
 	}
 
-	const (
-		maxMessageSize = MaxMessageLen
-		fileSize       = 1 << 40
-		blockSize      = BlockSize
-	)
-
 	f := FileInfo{
 		Name:        "a normal length file name withoout any weird stuff.txt",
 		Type:        FileInfoTypeFile,
@@ -256,12 +254,12 @@ func TestMarshalledIndexMessageSize(t *testing.T) {
 		Permissions: 0666,
 		ModifiedS:   time.Now().Unix(),
 		Version:     Vector{Counters: []Counter{{ID: 1 << 60, Value: 1}, {ID: 2 << 60, Value: 1}}},
-		Blocks:      make([]BlockInfo, fileSize/blockSize),
+		Blocks:      make([]BlockInfo, fileSize/BlockSize),
 	}
 
-	for i := 0; i < fileSize/blockSize; i++ {
-		f.Blocks[i].Offset = int64(i) * blockSize
-		f.Blocks[i].Size = blockSize
+	for i := 0; i < fileSize/BlockSize; i++ {
+		f.Blocks[i].Offset = int64(i) * BlockSize
+		f.Blocks[i].Size = BlockSize
 		f.Blocks[i].Hash = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 30, 1, 2}
 	}
 
@@ -271,8 +269,8 @@ func TestMarshalledIndexMessageSize(t *testing.T) {
 	}
 
 	msgSize := idx.ProtoSize()
-	if msgSize > maxMessageSize {
-		t.Errorf("Message size %d bytes is larger than max %d", msgSize, maxMessageSize)
+	if msgSize > MaxMessageLen {
+		t.Errorf("Message size %d bytes is larger than max %d", msgSize, MaxMessageLen)
 	}
 }
 
@@ -400,3 +398,31 @@ func TestCheckConsistency(t *testing.T) {
 		}
 	}
 }
+
+func TestCopyFileInfo(t *testing.T) {
+	f := FileInfo{
+		Name:        "a normal length file name withoout any weird stuff.txt",
+		Type:        FileInfoTypeFile,
+		Size:        fileSize,
+		Permissions: 0666,
+		ModifiedS:   time.Now().Unix(),
+		Version:     Vector{Counters: []Counter{{ID: 1 << 60, Value: 1}, {ID: 2 << 60, Value: 1}}},
+		Blocks:      make([]BlockInfo, fileSize/BlockSize),
+	}
+
+	del := f.DeletedCopy(LocalDeviceID.Short())
+	if f.Deleted {
+		t.Errorf("Source file info was deleted on copy")
+	}
+	if !del.Deleted {
+		t.Errorf("Returned file info was not deleted on copy")
+	}
+
+	inv := f.InvalidatedCopy(LocalDeviceID.Short())
+	if f.Invalid {
+		t.Errorf("Source file info was invalid on copy")
+	}
+	if !inv.Invalid {
+		t.Errorf("Returned file info was not invalid on copy")
+	}
+}