impl/memory: Implement Queries

service/datastore/index.go

Index: service/datastore/index.go
diff --git a/service/datastore/index.go b/service/datastore/index.go
index 0f1aaca469903e6cef8ba46bda5073dbb22f61f9..44cb172bd05fa2c340a958a48598b5a6d1f521bf 100644
--- a/service/datastore/index.go
+++ b/service/datastore/index.go
@@ -18,6 +18,13 @@ const (
 	DESCENDING                = true
 )
 
+func (i IndexDirection) String() string {
+	if i == ASCENDING {
+		return "ASCENDING"
+	}
+	return "DESCENDING"
+}
+
 type IndexColumn struct {
 	Property  string
 	Direction IndexDirection
@@ -39,6 +46,55 @@ type IndexDefinition struct {
 	SortBy   []IndexColumn
 }
 
+func (id *IndexDefinition) Equal(o *IndexDefinition) bool {
+	if id.Kind != o.Kind || id.Ancestor != o.Ancestor || len(id.SortBy) != len(o.SortBy) {
+		return false
+	}
+	for i, col := range id.SortBy {
+		if col != o.SortBy[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// NormalizeOrder returns the normalized SortBy value for this IndexDefinition.
+// This is just appending __key__ if it's not explicitly the last field in this
+// IndexDefinition.
+func (id *IndexDefinition) Normalize() *IndexDefinition {
+	if len(id.SortBy) > 0 && id.SortBy[len(id.SortBy)-1].Property == "__key__" {
+		return id
+	}
+	ret := *id
+	ret.SortBy = make([]IndexColumn, len(id.SortBy), len(id.SortBy)+1)
+	copy(ret.SortBy, id.SortBy)
+	ret.SortBy = append(ret.SortBy, IndexColumn{Property: "__key__"})
+	return &ret
+}
+
+func (id *IndexDefinition) GetFullSortOrder() []IndexColumn {
+	id = id.Normalize()
+	if !id.Ancestor {
+		return id.SortBy
+	}
+	ret := make([]IndexColumn, 0, len(id.SortBy)+1)
+	ret = append(ret, IndexColumn{Property: "__ancestor__"})
+	return append(ret, id.SortBy...)
+}
+
+func (id *IndexDefinition) PrepForIdxTable() *IndexDefinition {
+	return id.Normalize().Flip()
+}
+
+func (id *IndexDefinition) Flip() *IndexDefinition {
+	ret := *id
+	ret.SortBy = make([]IndexColumn, 0, len(id.SortBy))
+	for i := len(id.SortBy) - 1; i >= 0; i-- {
+		ret.SortBy = append(ret.SortBy, id.SortBy[i])
+	}
+	return &ret
+}
+
 // Yeah who needs templates, right?
 // <flames>This is fine.</flames>
 
@@ -119,7 +175,7 @@ func (i *IndexDefinition) Compound() bool {
 		return false
 	}
 	for _, sb := range i.SortBy {
-		if sb.Property == "" {
+		if sb.Property == "" || sb.Property == "__ancestor__" {
 			return false
 		}
 	}
@@ -147,11 +203,3 @@ func (i *IndexDefinition) String() string {
 	}
 	return ret.String()
 }
-
-func IndexBuiltinQueryPrefix() []byte {
-	return []byte{0}
-}
-
-func IndexComplexQueryPrefix() []byte {
-	return []byte{1}
-}