vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/tonistiigi/fsutil/diff_containerd.go

@@ -0,0 +1,200 @@
+package fsutil
+
+import (
+	"context"
+	"os"
+	"strings"
+
+	"github.com/tonistiigi/fsutil/types"
+	"golang.org/x/sync/errgroup"
+)
+
+// Everything below is copied from containerd/fs. TODO: remove duplication @dmcgowan
+
+// Const redefined because containerd/fs doesn't build on !linux
+
+// ChangeKind is the type of modification that
+// a change is making.
+type ChangeKind int
+
+const (
+	// ChangeKindAdd represents an addition of
+	// a file
+	ChangeKindAdd ChangeKind = iota
+
+	// ChangeKindModify represents a change to
+	// an existing file
+	ChangeKindModify
+
+	// ChangeKindDelete represents a delete of
+	// a file
+	ChangeKindDelete
+)
+
+// ChangeFunc is the type of function called for each change
+// computed during a directory changes calculation.
+type ChangeFunc func(ChangeKind, string, os.FileInfo, error) error
+
+type currentPath struct {
+	path string
+	f    os.FileInfo
+	//	fullPath string
+}
+
+// doubleWalkDiff walks both directories to create a diff
+func doubleWalkDiff(ctx context.Context, changeFn ChangeFunc, a, b walkerFn) (err error) {
+	g, ctx := errgroup.WithContext(ctx)
+
+	var (
+		c1 = make(chan *currentPath, 128)
+		c2 = make(chan *currentPath, 128)
+
+		f1, f2 *currentPath
+		rmdir  string
+	)
+	g.Go(func() error {
+		defer close(c1)
+		return a(ctx, c1)
+	})
+	g.Go(func() error {
+		defer close(c2)
+		return b(ctx, c2)
+	})
+	g.Go(func() error {
+	loop0:
+		for c1 != nil || c2 != nil {
+			if f1 == nil && c1 != nil {
+				f1, err = nextPath(ctx, c1)
+				if err != nil {
+					return err
+				}
+				if f1 == nil {
+					c1 = nil
+				}
+			}
+
+			if f2 == nil && c2 != nil {
+				f2, err = nextPath(ctx, c2)
+				if err != nil {
+					return err
+				}
+				if f2 == nil {
+					c2 = nil
+				}
+			}
+			if f1 == nil && f2 == nil {
+				continue
+			}
+
+			var f os.FileInfo
+			k, p := pathChange(f1, f2)
+			switch k {
+			case ChangeKindAdd:
+				if rmdir != "" {
+					rmdir = ""
+				}
+				f = f2.f
+				f2 = nil
+			case ChangeKindDelete:
+				// Check if this file is already removed by being
+				// under of a removed directory
+				if rmdir != "" && strings.HasPrefix(f1.path, rmdir) {
+					f1 = nil
+					continue
+				} else if rmdir == "" && f1.f.IsDir() {
+					rmdir = f1.path + string(os.PathSeparator)
+				} else if rmdir != "" {
+					rmdir = ""
+				}
+				f1 = nil
+			case ChangeKindModify:
+				same, err := sameFile(f1, f2)
+				if err != nil {
+					return err
+				}
+				if f1.f.IsDir() && !f2.f.IsDir() {
+					rmdir = f1.path + string(os.PathSeparator)
+				} else if rmdir != "" {
+					rmdir = ""
+				}
+				f = f2.f
+				f1 = nil
+				f2 = nil
+				if same {
+					continue loop0
+				}
+			}
+			if err := changeFn(k, p, f, nil); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+
+	return g.Wait()
+}
+
+func pathChange(lower, upper *currentPath) (ChangeKind, string) {
+	if lower == nil {
+		if upper == nil {
+			panic("cannot compare nil paths")
+		}
+		return ChangeKindAdd, upper.path
+	}
+	if upper == nil {
+		return ChangeKindDelete, lower.path
+	}
+
+	switch i := ComparePath(lower.path, upper.path); {
+	case i < 0:
+		// File in lower that is not in upper
+		return ChangeKindDelete, lower.path
+	case i > 0:
+		// File in upper that is not in lower
+		return ChangeKindAdd, upper.path
+	default:
+		return ChangeKindModify, upper.path
+	}
+}
+
+func sameFile(f1, f2 *currentPath) (same bool, retErr error) {
+	// If not a directory also check size, modtime, and content
+	if !f1.f.IsDir() {
+		if f1.f.Size() != f2.f.Size() {
+			return false, nil
+		}
+
+		t1 := f1.f.ModTime()
+		t2 := f2.f.ModTime()
+		if t1.UnixNano() != t2.UnixNano() {
+			return false, nil
+		}
+	}
+
+	ls1, ok := f1.f.Sys().(*types.Stat)
+	if !ok {
+		return false, nil
+	}
+	ls2, ok := f2.f.Sys().(*types.Stat)
+	if !ok {
+		return false, nil
+	}
+
+	return compareStat(ls1, ls2)
+}
+
+// compareStat returns whether the stats are equivalent,
+// whether the files are considered the same file, and
+// an error
+func compareStat(ls1, ls2 *types.Stat) (bool, error) {
+	return ls1.Mode == ls2.Mode && ls1.Uid == ls2.Uid && ls1.Gid == ls2.Gid && ls1.Devmajor == ls2.Devmajor && ls1.Devminor == ls2.Devminor && ls1.Linkname == ls2.Linkname, nil
+}
+
+func nextPath(ctx context.Context, pathC <-chan *currentPath) (*currentPath, error) {
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case p := <-pathC:
+		return p, nil
+	}
+}