Further repair parallelism

drive-demuxer.go

@@ -19,6 +19,7 @@ type TopLevel struct {
 	CombinedOutput  string
 	RightOutput     string
 	OpenHandles     chan int
+	OpenDirectories chan int
 	DryRun          bool
 	Bar             *pb.ProgressBar
 }
@@ -297,79 +298,44 @@ func (s *Step) Walk() {
 		rightPath := s.InputPath(child, RIGHT)
 		rightState, err := s.CheckState(rightPath)
 		if err != nil {
-			wg.Add(1)
-			go func(rightPath string) {
-				defer func() {
-					wg.Done()
-				}()
 			log.Printf("Error statting path %s: %s\n", rightPath, err)
 			s.Bar.Increment()
-			}(rightPath)
 			continue
 		} else if rightState == UNKNOWN {
-			wg.Add(1)
-			go func(rightPath string) {
-				defer func() {
-					wg.Done()
-				}()
 			log.Printf("Unknown stat value for path %s\n", rightPath)
 			s.Bar.Increment()
-			}(rightPath)
 			continue
 		} else if rightState == MISSING {
-			wg.Add(1)
-			go func(child string) {
-				defer func() {
-					wg.Done()
-				}()
 			s.SeparateLeft(child)
 			s.Bar.Increment()
-			}(child)
 			continue
 		}
 
 		leftPath := s.InputPath(child, LEFT)
 		leftState, err := s.CheckState(leftPath)
 		if err != nil {
-			wg.Add(1)
-			go func(leftPath string) {
-				defer func() {
-					wg.Done()
-				}()
 			log.Printf("Error statting path %s: %s\n", leftPath, err)
 			s.Bar.Increment()
-			}(leftPath)
 			continue
 		} else if leftState == UNKNOWN {
-			wg.Add(1)
-			go func(leftPath string) {
-				defer func() {
-					wg.Done()
-				}()
 			log.Printf("Unknown stat value for path %s\n", leftPath)
 			s.Bar.Increment()
-			}(leftPath)
 			continue
 		} else if leftState == MISSING {
-			wg.Add(1)
-			go func(child string) {
-				defer func() {
-					wg.Done()
-				}()
 			s.SeparateRight(child)
 			s.Bar.Increment()
-			}(child)
 			continue
 		}
 
 		switch rightState {
 		case FILE:
 			wg.Add(1)
+			if leftState == FILE {
 				go func(child string) {
 					defer func() {
 						wg.Done()
 					}()
-				if leftState == FILE && s.AreFilesIdentical(child) {
+					if s.AreFilesIdentical(child) {
 						s.Combine(child)
 						s.Bar.Increment()
 					} else {
@@ -377,31 +343,32 @@ func (s *Step) Walk() {
 						s.Bar.Increment()
 					}
 				}(child)
+			} else {
+				s.Separate(child)
+				s.Bar.Increment()
+			}
 		case DIRECTORY:
 			if leftState == DIRECTORY {
-				substep := Step{
+				s.OpenDirectories <- 1
-					TopLevel: s.TopLevel,
-					Subpath:  path.Join(s.Subpath, child),
-				}
 				wg.Add(1)
-				go func(child string, substep *Step) {
+				go func(child string) {
 					defer func() {
 						wg.Done()
+						<-s.OpenDirectories
 					}()
+					substep := Step{
+						TopLevel: s.TopLevel,
+						Subpath:  path.Join(s.Subpath, child),
+					}
 					s.MakeCombinedDir(child)
 					substep.Walk()
 					s.RemoveInputDirs(child)
 					s.Bar.Increment()
-				}(child, &substep)
+				}(child)
 			} else {
 				wg.Add(1)
-				go func(child string) {
-					defer func() {
-						wg.Done()
-					}()
 				s.Separate(child)
 				s.Bar.Increment()
-				}(child)
 			}
 		default:
 			panic("Unexpected state")
@@ -414,6 +381,7 @@ func (s *Step) Walk() {
 func main() {
 	settings := TopLevel{
 		OpenHandles:     make(chan int, 450),
+		OpenDirectories: make(chan int, 1000),
 		Bar:             pb.StartNew(1),
 	}
 	flag.StringVar(&settings.LeftInput,