Merge pull request #731 from stevvooe/snapshot-usage

snapshot: add Usage method to Snapshotter

fs/du.go

@@ -0,0 +1,12 @@
+package fs
+
+type Usage struct {
+	Inodes int64
+	Size   int64
+}
+
+// DiskUsage counts the number of inodes and disk usage for the resources under
+// path.
+func DiskUsage(roots ...string) (Usage, error) {
+	return diskUsage(roots...)
+}

fs/du_unix.go

@@ -0,0 +1,42 @@
+// +build !windows
+
+package fs
+
+import (
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+func diskUsage(roots ...string) (Usage, error) {
+	type inode struct {
+		// TODO(stevvooe): Can probably reduce memory usage by not tracking
+		// device, but we can leave this right for now.
+		dev, ino uint64
+	}
+
+	var (
+		size   int64
+		inodes = map[inode]struct{}{} // expensive!
+	)
+
+	for _, root := range roots {
+		if err := filepath.Walk(root, func(path string, fi os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+
+			stat := fi.Sys().(*syscall.Stat_t)
+			inodes[inode{dev: stat.Dev, ino: stat.Ino}] = struct{}{}
+			size += fi.Size()
+			return nil
+		}); err != nil {
+			return Usage{}, err
+		}
+	}
+
+	return Usage{
+		Inodes: int64(len(inodes)),
+		Size:   size,
+	}, nil
+}

fs/du_windows.go

@@ -0,0 +1,33 @@
+// +build windows
+
+package fs
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func diskUsage(roots ...string) (Usage, error) {
+	var (
+		size int64
+	)
+
+	// TODO(stevvooe): Support inodes (or equivalent) for windows.
+
+	for _, root := range roots {
+		if err := filepath.Walk(root, func(path string, fi os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+
+			size += fi.Size()
+			return nil
+		}); err != nil {
+			return Usage{}, err
+		}
+	}
+
+	return Usage{
+		Size: size,
+	}, nil
+}