verify: starts of a checking function

tar/verify/verify.go

@@ -1,6 +1,10 @@
 package verify
 
-import "fmt"
+import (
+	"fmt"
+	"os"
+	"time"
+)
 
 // CheckType is how the on disk attributes will be verified against the
 // recorded header information
@@ -15,14 +19,15 @@ const (
 	CheckFileUser
 	CheckFileGroup
 	CheckFileMtime
-	CheckFileDevice
-	CheckFileLink
-	CheckFileCaps
+	CheckFileDevice // major/minor
+	CheckFileLink   // linkname
+	CheckFileCaps   // which is just a subset of xattrs on linux
 )
 
 var (
 	// DefaultChecks is the default for verfication steps against each
-	// storage.VerficationEntry
+	// storage.VerficationEntry.
+	// These may need to vary from platform to platform
 	DefaultChecks = CheckDigest | CheckFileAttributes
 	// CheckFileAttributes are the group of file attribute checks done
 	CheckFileAttributes = CheckFileSize | CheckFileMode | CheckFileUser |
@@ -32,3 +37,26 @@ var (
 	// ErrNotSupportedPlatform is when the platform does not support given features
 	ErrNotSupportedPlatform = fmt.Errorf("platform does not support this feature")
 )
+
+// FileAttrer exposes the functions corresponding to file attribute checks
+type FileAttrer interface {
+	Sizer
+	Moder
+	ModTimer
+	LinkName() string
+}
+
+// Sizer returns the size of the file (see also os.FileInfo)
+type Sizer interface {
+	Size() int64
+}
+
+// Moder returns the mode of the file (see also os.FileInfo)
+type Moder interface {
+	Mode() os.FileMode
+}
+
+// ModTimer returns the mtime of the file (see also os.FileInfo)
+type ModTimer interface {
+	ModTime() time.Time
+}