Refactoring & renaming

container/sort.go

@@ -0,0 +1,98 @@
+package container
+
+import (
+	"fmt"
+	"time"
+)
+
+// Sort containers by Created date
+type ByCreated []Container
+
+func (c ByCreated) Len() int      { return len(c) }
+func (c ByCreated) Swap(i, j int) { c[i], c[j] = c[j], c[i] }
+
+func (c ByCreated) Less(i, j int) bool {
+	t1, err := time.Parse(time.RFC3339Nano, c[i].containerInfo.Created)
+	if err != nil {
+		t1 = time.Now()
+	}
+
+	t2, _ := time.Parse(time.RFC3339Nano, c[j].containerInfo.Created)
+	if err != nil {
+		t1 = time.Now()
+	}
+
+	return t1.Before(t2)
+}
+
+func SortByDependencies(containers []Container) ([]Container, error) {
+	sorter := dependencySorter{}
+	return sorter.Sort(containers)
+}
+
+type dependencySorter struct {
+	unvisited []Container
+	marked    map[string]bool
+	sorted    []Container
+}
+
+func (ds *dependencySorter) Sort(containers []Container) ([]Container, error) {
+	ds.unvisited = containers
+	ds.marked = map[string]bool{}
+
+	for len(ds.unvisited) > 0 {
+		if err := ds.visit(ds.unvisited[0]); err != nil {
+			return nil, err
+		}
+	}
+
+	return ds.sorted, nil
+}
+
+func (ds *dependencySorter) visit(c Container) error {
+
+	if _, ok := ds.marked[c.Name()]; ok {
+		return fmt.Errorf("Circular reference to %s", c.Name())
+	}
+
+	// Mark any visited node so that circular references can be detected
+	ds.marked[c.Name()] = true
+	defer delete(ds.marked, c.Name())
+
+	// Recursively visit links
+	for _, linkName := range c.Links() {
+		if linkedContainer := ds.findUnvisited(linkName); linkedContainer != nil {
+			if err := ds.visit(*linkedContainer); err != nil {
+				return err
+			}
+		}
+	}
+
+	// Move container from unvisited to sorted
+	ds.removeUnvisited(c)
+	ds.sorted = append(ds.sorted, c)
+
+	return nil
+}
+
+func (ds *dependencySorter) findUnvisited(name string) *Container {
+	for _, c := range ds.unvisited {
+		if c.Name() == name {
+			return &c
+		}
+	}
+
+	return nil
+}
+
+func (ds *dependencySorter) removeUnvisited(c Container) {
+	var idx int
+	for i := range ds.unvisited {
+		if ds.unvisited[i].Name() == c.Name() {
+			idx = i
+			break
+		}
+	}
+
+	ds.unvisited = append(ds.unvisited[0:idx], ds.unvisited[idx+1:]...)
+}