Support primary and secondary client indexes

Introduces two types of client indexes: primary and secondary. Primary
indexes are verified to no be duplicate at transaction verification,
when enable, otherwise there is no difference between them.

Signed-off-by: Jaime Caamaño Ruiz <jcaamano@redhat.com>

cache/cache.go

@@ -83,9 +83,14 @@ type indexType uint
 
 const (
 	schemaIndexType indexType = iota
-	clientIndexType
+	primaryClientIndexType
+	secondaryClientIndexType
 )
 
+func clientIndexTypeToCacheIndexType(modelIndexType model.IndexType) indexType {
+	return indexType(modelIndexType + 1)
+}
+
 // indexSpec contains details about an index
 type indexSpec struct {
 	index     index
@@ -94,13 +99,17 @@ type indexSpec struct {
 }
 
 func (s indexSpec) isClientIndex() bool {
-	return s.indexType == clientIndexType
+	return s.indexType >= primaryClientIndexType
 }
 
 func (s indexSpec) isSchemaIndex() bool {
 	return s.indexType == schemaIndexType
 }
 
+func (s indexSpec) isPrimaryIndex() bool {
+	return s.indexType < secondaryClientIndexType
+}
+
 // newIndex builds a index from a list of columns
 func newIndexFromColumns(columns ...string) index {
 	sort.Strings(columns)
@@ -372,10 +381,8 @@ func (r *RowCache) IndexExists(row model.Model) error {
 	}
 	uuid := field.(string)
 	for _, indexSpec := range r.indexSpecs {
-		if !indexSpec.isSchemaIndex() {
-			// Given the ordered indexSpecs, we can break here if we reach the
-			// first non schema index
-			break
+		if !indexSpec.isPrimaryIndex() {
+			continue
 		}
 		index := indexSpec.index
 		val, err := valueFromIndex(info, indexSpec.columns)
@@ -1103,7 +1110,8 @@ func newRowCache(name string, dbModel model.DatabaseModel, dataType reflect.Type
 		if _, ok := indexes[index]; ok {
 			continue
 		}
-		spec := indexSpec{index: index, columns: columnKeys, indexType: clientIndexType}
+		indexType := clientIndexTypeToCacheIndexType(clientIndex.Type)
+		spec := indexSpec{index: index, columns: columnKeys, indexType: indexType}
 		r.indexSpecs = append(r.indexSpecs, spec)
 		indexes[index] = spec
 	}

model/client.go

@@ -14,9 +14,22 @@ type ColumnKey struct {
 	Key    interface{}
 }
 
+// IndexType is the type of client index
+type IndexType uint
+
+const (
+	// PrimaryIndexType are client indexes for which uniqueness is optionally
+	// enforced in the context of a specific client instance transaction before
+	// it is sent to the server.
+	PrimaryIndexType IndexType = iota
+	// SecondaryIndexType are indexes for which uniqueness is not enforced.
+	SecondaryIndexType
+)
+
 // ClientIndex defines a client index by a set of columns
 type ClientIndex struct {
 	Columns []ColumnKey
+	Type    IndexType
 }
 
 // ClientDBModel contains the client information needed to build a DatabaseModel
@@ -161,6 +174,7 @@ func copyIndexes(src map[string][]ClientIndex) map[string][]ClientIndex {
 		dst[table] = make([]ClientIndex, 0, len(indexSets))
 		for _, indexSet := range indexSets {
 			indexSetCopy := ClientIndex{
+				Type:    indexSet.Type,
 				Columns: make([]ColumnKey, len(indexSet.Columns)),
 			}
 			copy(indexSetCopy.Columns, indexSet.Columns)