nuts-foundation/go-leia

/*
 * go-leia
 * Copyright (C) 2021 Nuts community
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

package leia

import (
    "encoding/binary"
    "encoding/hex"
    "errors"
    "math"
)

const boltDBFileMode = 0600
const KeyDelimiter = 0x10

// Document represents a JSON document in []byte format
type Document []byte

// ErrInvalidJSON is returned when invalid JSON is parsed
var ErrInvalidJSON = errors.New("invalid json")

// ErrInvalidQuery is returned when a collection is queried with the wrong type
var ErrInvalidQuery = errors.New("invalid query type")

// Reference equals a document hash. In an index, the values are references to docs.
type Reference []byte

// EncodeToString encodes the reference as hex encoded string
func (r Reference) EncodeToString() string {
    return hex.EncodeToString(r)
}

// ByteSize returns the size of the reference, eg: 32 bytes for a sha256
func (r Reference) ByteSize() int {
    return len(r)
}

// Scalar represents a JSON or JSON-LD scalar (string, number, true or false)
type Scalar interface {
    // Bytes returns the byte value
    Bytes() []byte
    // value helps in testing
    value() interface{}
}

type StringScalar string

func (ss StringScalar) Bytes() []byte {
    return []byte(ss)
}

func (ss StringScalar) value() interface{} {
    return string(ss)
}

type BoolScalar bool

func (bs BoolScalar) Bytes() []byte {
    if bs {
        return []byte{1}
    }
    return []byte{0}
}

func (bs BoolScalar) value() interface{} {
    return bool(bs)
}

type Float64Scalar float64

func (fs Float64Scalar) Bytes() []byte {
    var buf [8]byte
    binary.BigEndian.PutUint64(buf[:], math.Float64bits(float64(fs)))
    return buf[:]
}

func (fs Float64Scalar) value() interface{} {
    return float64(fs)
}

// bytesScalar is used internally for the NotNil query
type bytesScalar []byte

func (bs bytesScalar) Bytes() []byte {
    return bs
}

func (bs bytesScalar) value() interface{} {
    return bs.Bytes()
}

// ErrInvalidValue is returned when an invalid value is parsed
var ErrInvalidValue = errors.New("invalid value")

// ParseScalar returns a Scalar based on an interface value. It returns ErrInvalidValue for unsupported values.
func ParseScalar(value interface{}) (Scalar, error) {
    switch castValue := value.(type) {
    case bool:
        return BoolScalar(castValue), nil
    case string:
        return StringScalar(castValue), nil
    case float64:
        return Float64Scalar(castValue), nil
    }

    return nil, ErrInvalidValue
}

// MustParseScalar returns a Scalar based on an interface value. It panics when the value is not supported.
func MustParseScalar(value interface{}) Scalar {
    s, err := ParseScalar(value)
    if err != nil {
        panic(err)
    }
    return s
}