*: entry linking and keyword filter

Setting up sibling and parent relationships for entries, so they can be
easier to walk.

Also, making "keyword=value" easier to parse. This helps filtering.

Both of these ready us for checking/validating a hierarchy.

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

hierarchy.go

@@ -35,11 +35,14 @@ func (bp byPos) Swap(i, j int)      { bp[i], bp[j] = bp[j], bp[i] }
 
 // Entry is each component of content in the mtree spec file
 type Entry struct {
-	Pos      int      // order in the spec
+	Parent, Child *Entry   // up, down
-	Raw      string   // file or directory name
+	Prev, Next    *Entry   // left, right
-	Name     string   // file or directory name
+	Set           *Entry   // current `/set` for additional keywords
-	Keywords []string // TODO(vbatts) maybe a keyword typed set of values?
+	Pos           int      // order in the spec
-	Type     EntryType
+	Raw           string   // file or directory name
+	Name          string   // file or directory name
+	Keywords      []string // TODO(vbatts) maybe a keyword typed set of values?
+	Type          EntryType
 }
 
 func (e Entry) String() string {

keywords.go

@@ -9,6 +9,7 @@ import (
 	"hash"
 	"io"
 	"os"
+	"strings"
 
 	"golang.org/x/crypto/ripemd160"
 )
@@ -18,6 +19,53 @@ import (
 // be included for the file entry. Otherwise, empty string.
 type KeywordFunc func(path string, info os.FileInfo) (string, error)
 
+// KeyVal is a "keyword=value"
+type KeyVal string
+
+// Keyword is the mapping to the available keywords
+func (kv KeyVal) Keyword() string {
+	if !strings.Contains(string(kv), "=") {
+		return ""
+	}
+	chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
+	if !strings.Contains(chunks, ".") {
+		return chunks
+	}
+	return strings.SplitN(chunks, ".", 2)[0]
+}
+
+// KeywordSuffix is really only used for xattr, as the keyword is a prefix to
+// the xattr "namespace.key"
+func (kv KeyVal) KeywordSuffix() string {
+	if !strings.Contains(string(kv), "=") {
+		return ""
+	}
+	chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
+	if !strings.Contains(chunks, ".") {
+		return ""
+	}
+	return strings.SplitN(chunks, ".", 2)[1]
+}
+
+// Value is the data/value portion of "keyword=value"
+func (kv KeyVal) Value() string {
+	if !strings.Contains(string(kv), "=") {
+		return ""
+	}
+	return strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[1]
+}
+
+// keywordSelector takes an array of "keyword=value" and filters out that only the set of words
+func keywordSelector(keyval, words []string) []string {
+	retList := []string{}
+	for _, kv := range keyval {
+		if inSlice(KeyVal(kv).Keyword(), words) {
+			retList = append(retList, kv)
+		}
+	}
+	return retList
+}
+
 var (
 	// DefaultKeywords has the several default keyword producers (uid, gid,
 	// mode, nlink, type, size, mtime)
@@ -31,6 +79,7 @@ var (
 		"nlink",
 		"time",
 	}
+	// SetKeywords is the default set of keywords calculated for a `/set` SpecialType
 	SetKeywords = []string{
 		"uid",
 		"gid",

walk.go

@@ -12,12 +12,14 @@ import (
 type ExcludeFunc func(path string, info os.FileInfo) bool
 
 type dhCreator struct {
-	DH        *DirectoryHierarchy
+	DH     *DirectoryHierarchy
-	curSet    []string
+	curSet *Entry
-	depth     int
+	curDir *Entry
-	curDirNum int
+	curEnt *Entry
 }
 
+var defaultSetKeywords = []string{"type=file", "nlink=1", "flags=none", "mode=0664"}
+
 //
 // To be able to do a "walk" that produces an outcome with `/set ...` would
 // need a more linear walk, which this can not ensure.
@@ -36,13 +38,13 @@ func Walk(root string, exlcudes []ExcludeFunc, keywords []string) (*DirectoryHie
 
 		// handle the /set SpecialType
 		if info.IsDir() {
-			if len(creator.curSet) == 0 {
+			if creator.curSet == nil {
 				// set the initial /set keywords
 				e := Entry{
 					Name:     "/set",
 					Type:     SpecialType,
 					Pos:      len(creator.DH.Entries),
-					Keywords: []string{"type=file", "nlink=1", "flags=none", "mode=0664"},
+					Keywords: keywordSelector(defaultSetKeywords, keywords),
 				}
 				for _, keyword := range SetKeywords {
 					if str, err := KeywordFuncs[keyword](path, info); err == nil && str != "" {
@@ -51,9 +53,9 @@ func Walk(root string, exlcudes []ExcludeFunc, keywords []string) (*DirectoryHie
 						return err
 					}
 				}
-				creator.curSet = e.Keywords
+				creator.curSet = &e
 				creator.DH.Entries = append(creator.DH.Entries, e)
-			} else if len(creator.curSet) > 0 {
+			} else if creator.curSet != nil {
 				// check the attributes of the /set keywords and re-set if changed
 				klist := []string{}
 				for _, keyword := range SetKeywords {
@@ -66,19 +68,20 @@ func Walk(root string, exlcudes []ExcludeFunc, keywords []string) (*DirectoryHie
 
 				needNewSet := false
 				for _, k := range klist {
-					if !inSlice(k, creator.curSet) {
+					if !inSlice(k, creator.curSet.Keywords) {
 						needNewSet = true
 					}
 				}
 
 				if needNewSet {
-					creator.curSet = append([]string{"type=file", "nlink=1", "flags=none", "mode=0664"}, klist...)
+					e := Entry{
-					creator.DH.Entries = append(creator.DH.Entries, Entry{
 						Name:     "/set",
 						Type:     SpecialType,
 						Pos:      len(creator.DH.Entries),
-						Keywords: creator.curSet,
+						Keywords: append(defaultSetKeywords, klist...),
-					})
+					}
+					creator.curSet = &e
+					creator.DH.Entries = append(creator.DH.Entries, e)
 				} else {
 					creator.DH.Entries = append(creator.DH.Entries, Entry{
 						Type: BlankType,
@@ -91,16 +94,30 @@ func Walk(root string, exlcudes []ExcludeFunc, keywords []string) (*DirectoryHie
 		e := Entry{
 			Name: filepath.Base(path),
 			Pos:  len(creator.DH.Entries),
+			Set:  creator.curSet,
 		}
 		for _, keyword := range keywords {
 			if str, err := KeywordFuncs[keyword](path, info); err == nil && str != "" {
-				if !inSlice(str, creator.curSet) {
+				if !inSlice(str, creator.curSet.Keywords) {
 					e.Keywords = append(e.Keywords, str)
 				}
 			} else if err != nil {
 				return err
 			}
 		}
+		if info.IsDir() {
+			if creator.curDir != nil {
+				creator.curDir.Next = &e
+			}
+			e.Prev = creator.curDir
+			creator.curDir = &e
+		} else {
+			if creator.curEnt != nil {
+				creator.curEnt.Next = &e
+			}
+			e.Prev = creator.curEnt
+			creator.curEnt = &e
+		}
 		creator.DH.Entries = append(creator.DH.Entries, e)
 		return nil
 	})
@@ -198,5 +215,4 @@ func readOrderedDirNames(dirname string) ([]string, error) {
 	sort.Strings(names)
 	sort.Strings(dirnames)
 	return append(names, dirnames...), nil
-
 }

walk_test.go

@@ -2,6 +2,7 @@ package mtree
 
 import (
 	"io/ioutil"
+	"log"
 	"testing"
 )
 
@@ -11,6 +12,8 @@ func TestWalk(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	log.Fatalf("%#v", dh)
+
 	fh, err := ioutil.TempFile("", "walk.")
 	if err != nil {
 		t.Fatal(err)