index: cleanup and formalizing key formats into their own types

Change-Id: I36aaa74ee7a4349bb00c1ac06285d4c43f4c61bc

lib/go/camli/index/index.go

@@ -127,6 +127,30 @@ func New(s IndexStorage) *Index {
 	}
 }
 
+type prefixIter struct {
+	Iterator
+	prefix string
+}
+
+func (p *prefixIter) Next() bool {
+	v := p.Iterator.Next()
+	if v && !strings.HasPrefix(p.Key(), p.prefix) {
+		return false
+	}
+	return v
+}
+
+func (x *Index) queryPrefix(key *keyType, args ...interface{}) *prefixIter {
+	return x.queryPrefixString(key.Prefix(args...))
+}
+
+func (x *Index) queryPrefixString(prefix string) *prefixIter {
+	return &prefixIter{
+		prefix:   prefix,
+		Iterator: x.s.Find(prefix),
+	}
+}
+
 func (x *Index) GetRecentPermanodes(dest chan *search.Result, owner *blobref.BlobRef, limit int) os.Error {
 	defer close(dest)
 	// TODO(bradfitz): this will need to be a context wrapper too, like storage
@@ -141,13 +165,10 @@ func (x *Index) GetRecentPermanodes(dest chan *search.Result, owner *blobref.Blo
 
 	sent := 0
 	var seenPermanode dupSkipper
-	prefix := pipes("recpn", keyId, "")
-	it := x.s.Find(prefix)
+
+	it := x.queryPrefix(keyRecentPermanode, keyId)
 	defer it.Close()
 	for it.Next() {
-		if !strings.HasPrefix(it.Key(), prefix) {
-			break
-		}
 		permaStr := it.Value()
 		parts := strings.SplitN(it.Key(), "|", 4)
 		if len(parts) != 4 {
@@ -191,12 +212,9 @@ func (x *Index) GetOwnerClaims(permaNode, owner *blobref.BlobRef) (cl search.Cla
 		return nil, err
 	}
 	prefix := pipes("claim", permaNode, keyId, "")
-	it := x.s.Find(prefix)
+	it := x.queryPrefixString(prefix)
 	defer it.Close()
 	for it.Next() {
-		if !strings.HasPrefix(it.Key(), prefix) {
-			break
-		}
 		keyPart := strings.Split(it.Key(), "|")
 		valPart := strings.Split(it.Value(), "|")
 		if len(keyPart) < 5 || len(valPart) < 3 {
@@ -257,13 +275,10 @@ func (x *Index) PermanodeOfSignerAttrValue(signer *blobref.BlobRef, attr, val st
 	if err != nil {
 		return nil, err
 	}
-	prefix := pipes("signerattrvalue", keyId, urle(attr), urle(val), "")
-	it := x.s.Find(prefix)
+	it := x.queryPrefixString(pipes("signerattrvalue", keyId, urle(attr), urle(val), ""))
 	defer it.Close()
 	if it.Next() {
-		if strings.HasPrefix(it.Key(), prefix) {
-			return blobref.Parse(it.Value()), nil
-		}
+		return blobref.Parse(it.Value()), nil
 	}
 	return nil, os.ENOENT
 }

lib/go/camli/index/keys.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2011 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package index
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type keyType struct {
+	name  string
+	parts []keyPart
+}
+
+func (k *keyType) Prefix(args ...interface{}) string {
+	var buf bytes.Buffer
+	buf.WriteString(k.name)
+	for _, arg := range args {
+		buf.WriteString("|")
+		// TODO(bradfitz): verify the type matches
+		if s, ok := arg.(string); ok {
+			buf.WriteString(s)
+		} else {
+			buf.WriteString(arg.(fmt.Stringer).String())
+		}
+	}
+	buf.WriteString("|")
+	return buf.String()
+}
+
+type keyPart struct {
+	name string
+	typ  partType
+}
+
+type partType int
+
+const (
+	typeKeyId partType = iota // PGP key id
+	typeTime
+	typeReverseTime // time prepended with "rt" + each numeric digit reversed from '9'
+	typeBlobRef
+)
+
+var (
+	keyRecentPermanode = &keyType{
+		"recpn",
+		[]keyPart{
+			{"owner", typeKeyId},
+			{"modtime", typeReverseTime},
+			{"claim", typeBlobRef},
+		},
+	}
+)

lib/go/camli/index/keys_test.go

@@ -0,0 +1,27 @@
+/*
+Copyright 2011 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package index
+
+import (
+	"testing"
+)
+
+func TestKeyPrefix(t *testing.T) {
+	if g, e := keyRecentPermanode.Prefix("ABC"), "recpn|ABC|"; g != e {
+		t.Errorf("recpn = %q; want %q", g, e)
+	}
+}

lib/go/camli/index/receive.go

@@ -121,6 +121,7 @@ func (ix *Index) populateClaim(br *blobref.BlobRef, ss *schema.Superset, sniffer
 
 	bm.Set("signerkeyid:"+vr.CamliSigner.String(), verifiedKeyId)
 
+	// TODO(bradfitz): use keyRecentPermanode here instead of pipes() with "recpn".
 	recentKey := pipes("recpn", verifiedKeyId, reverseTimeString(ss.ClaimDate), br)
 	bm.Set(recentKey, pnbr.String())