107 lines
2.7 KiB
Go
107 lines
2.7 KiB
Go
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package types
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import (
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"bytes"
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"compress/gzip"
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"database/sql/driver"
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"encoding/json"
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"errors"
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"io/ioutil"
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)
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// GzippedText is a []byte which transparently gzips data being submitted to
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// a database and ungzips data being Scanned from a database.
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type GzippedText []byte
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// Value implements the driver.Valuer interface, gzipping the raw value of
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// this GzippedText.
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func (g GzippedText) Value() (driver.Value, error) {
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b := make([]byte, 0, len(g))
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buf := bytes.NewBuffer(b)
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w := gzip.NewWriter(buf)
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w.Write(g)
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w.Close()
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return buf.Bytes(), nil
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}
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// Scan implements the sql.Scanner interface, ungzipping the value coming off
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// the wire and storing the raw result in the GzippedText.
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func (g *GzippedText) Scan(src interface{}) error {
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var source []byte
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switch src.(type) {
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case string:
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source = []byte(src.(string))
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case []byte:
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source = src.([]byte)
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default:
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return errors.New("Incompatible type for GzippedText")
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}
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reader, err := gzip.NewReader(bytes.NewReader(source))
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defer reader.Close()
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b, err := ioutil.ReadAll(reader)
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if err != nil {
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return err
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}
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*g = GzippedText(b)
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return nil
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}
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// JSONText is a json.RawMessage, which is a []byte underneath.
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// Value() validates the json format in the source, and returns an error if
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// the json is not valid. Scan does no validation. JSONText additionally
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// implements `Unmarshal`, which unmarshals the json within to an interface{}
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type JSONText json.RawMessage
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// MarshalJSON returns the *j as the JSON encoding of j.
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func (j *JSONText) MarshalJSON() ([]byte, error) {
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return *j, nil
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}
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// UnmarshalJSON sets *j to a copy of data
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func (j *JSONText) UnmarshalJSON(data []byte) error {
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if j == nil {
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return errors.New("JSONText: UnmarshalJSON on nil pointer")
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}
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*j = append((*j)[0:0], data...)
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return nil
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}
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// Value returns j as a value. This does a validating unmarshal into another
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// RawMessage. If j is invalid json, it returns an error.
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func (j JSONText) Value() (driver.Value, error) {
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var m json.RawMessage
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var err = j.Unmarshal(&m)
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if err != nil {
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return []byte{}, err
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}
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return []byte(j), nil
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}
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// Scan stores the src in *j. No validation is done.
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func (j *JSONText) Scan(src interface{}) error {
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var source []byte
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switch src.(type) {
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case string:
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source = []byte(src.(string))
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case []byte:
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source = src.([]byte)
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default:
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return errors.New("Incompatible type for JSONText")
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}
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*j = JSONText(append((*j)[0:0], source...))
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return nil
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}
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// Unmarshal unmarshal's the json in j to v, as in json.Unmarshal.
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func (j *JSONText) Unmarshal(v interface{}) error {
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return json.Unmarshal([]byte(*j), v)
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}
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// Pretty printing for JSONText types
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func (j JSONText) String() string {
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return string(j)
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}
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