github.com/unigraph-dev/dgraph@v1.1.1-0.20200923154953-8b52b426f765/x/values.go (about)

     1  /*
     2   * Copyright 2017-2018 Dgraph Labs, Inc. and Contributors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package x
    18  
    19  // ValueTypeInfo represents information about the type of values in DirectedEdge/Posting/N-Quad.
    20  type ValueTypeInfo int32
    21  
    22  // Type of a data inside DirectedEdge, Posting or N-Quad
    23  const (
    24  	// ValueUnknown represents an unknown type of value.
    25  	ValueUnknown ValueTypeInfo = iota
    26  	// ValueEmpty represents a value with no UID and no value.
    27  	ValueEmpty
    28  	// ValueUid represents a value with an UID.
    29  	ValueUid
    30  	// ValuePlain represents a plain old value without defined language tag.
    31  	ValuePlain
    32  	// ValueMulti represents a value which is part of a multi-value posting list (like language).
    33  	ValueMulti
    34  )
    35  
    36  // ValueType s a helper function to decide value type of DirectedEdge/Posting/N-Quad.
    37  func ValueType(hasValue, hasLang, hasSpecialId bool) ValueTypeInfo {
    38  	switch {
    39  	case hasValue && hasLang:
    40  		return ValueMulti
    41  	case hasValue && !hasLang:
    42  		return ValuePlain
    43  	case !hasValue && hasSpecialId:
    44  		return ValueEmpty
    45  	case !hasValue && !hasSpecialId:
    46  		return ValueUid
    47  	default:
    48  		return ValueUnknown
    49  	}
    50  }