github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/store/types/uuid.go (about)

     1  // Copyright 2019 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package types
    16  
    17  import (
    18  	"bytes"
    19  	"context"
    20  
    21  	"github.com/google/uuid"
    22  
    23  	"github.com/dolthub/dolt/go/store/hash"
    24  )
    25  
    26  const (
    27  	uuidNumBytes = 16
    28  )
    29  
    30  // UUIDHashedFromValues generates a UUID from the first 16 byes of the hash.Hash
    31  // generated from serialized |vals|.
    32  func UUIDHashedFromValues(nbf *NomsBinFormat, vals ...Value) (UUID, error) {
    33  	w := binaryNomsWriter{make([]byte, 4), 0}
    34  	for _, v := range vals {
    35  		if v == nil || v.Kind() == NullKind {
    36  			continue
    37  		}
    38  		if err := v.writeTo(&w, nbf); err != nil {
    39  			return [16]byte{}, err
    40  		}
    41  	}
    42  
    43  	h := hash.Of(w.data())
    44  	id, err := uuid.FromBytes(h[:uuidNumBytes])
    45  	return UUID(id), err
    46  }
    47  
    48  type UUID uuid.UUID
    49  
    50  func (v UUID) Value(ctx context.Context) (Value, error) {
    51  	return v, nil
    52  }
    53  
    54  func (v UUID) Equals(other Value) bool {
    55  	return v == other
    56  }
    57  
    58  func (v UUID) Less(nbf *NomsBinFormat, other LesserValuable) (bool, error) {
    59  	if v2, ok := other.(UUID); ok {
    60  		return bytes.Compare(v[:], v2[:]) < 0, nil
    61  	}
    62  	return UUIDKind < other.Kind(), nil
    63  }
    64  
    65  func (v UUID) Hash(nbf *NomsBinFormat) (hash.Hash, error) {
    66  	return getHash(v, nbf)
    67  }
    68  
    69  func (v UUID) isPrimitive() bool {
    70  	return true
    71  }
    72  
    73  func (v UUID) WalkValues(ctx context.Context, cb ValueCallback) error {
    74  	return nil
    75  }
    76  
    77  func (v UUID) WalkRefs(nbf *NomsBinFormat, cb RefCallback) error {
    78  	return nil
    79  }
    80  
    81  func (v UUID) typeOf() (*Type, error) {
    82  	return PrimitiveTypeMap[UUIDKind], nil
    83  }
    84  
    85  func (v UUID) Kind() NomsKind {
    86  	return UUIDKind
    87  }
    88  
    89  func (v UUID) valueReadWriter() ValueReadWriter {
    90  	return nil
    91  }
    92  
    93  func (v UUID) writeTo(w nomsWriter, nbf *NomsBinFormat) error {
    94  	id := UUID(v)
    95  	byteSl := id[:]
    96  	err := UUIDKind.writeTo(w, nbf)
    97  
    98  	if err != nil {
    99  		return err
   100  	}
   101  
   102  	w.writeRaw(byteSl)
   103  	return nil
   104  }
   105  
   106  func (v UUID) readFrom(_ *NomsBinFormat, b *binaryNomsReader) (Value, error) {
   107  	id := b.ReadUUID()
   108  	return UUID(id), nil
   109  }
   110  
   111  func (v UUID) skip(nbf *NomsBinFormat, b *binaryNomsReader) {
   112  	b.skipBytes(uuidNumBytes)
   113  }
   114  
   115  func (v UUID) String() string {
   116  	return uuid.UUID(v).String()
   117  }
   118  
   119  func (v UUID) HumanReadableString() string {
   120  	return v.String()
   121  }