/
object.go
73 lines (59 loc) · 1.3 KB
/
object.go
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package jsonmerge
import (
"bytes"
"encoding/json"
"io"
"dario.cat/mergo"
)
type objectMerger struct {
io.Writer
dst map[string]interface{}
}
// NewObjectMerger creates a Merger for JSON objects.
func NewObjectMerger(w io.Writer) Merger {
return &objectMerger{
Writer: w,
dst: make(map[string]interface{}),
}
}
func (merger *objectMerger) NewPage(r io.Reader, isLastPage bool) io.ReadCloser {
return &objectMergerPage{
merger: merger,
Reader: r,
}
}
func (merger *objectMerger) Close() error {
// Marshal to JSON and write to output.
buf, err := json.Marshal(merger.dst)
if err != nil {
return err
}
_, err = merger.Writer.Write(buf)
return err
}
type objectMergerPage struct {
merger *objectMerger
io.Reader
buffer bytes.Buffer
}
func (page *objectMergerPage) Read(p []byte) (int, error) {
// Read into a temporary buffer to be merged and written later.
p = make([]byte, len(p))
n, err := page.Reader.Read(p)
if err != nil {
return 0, err
}
if n == 0 {
return 0, io.EOF
}
_, err = page.buffer.Write(p[:n])
return 0, err
}
func (page *objectMergerPage) Close() error {
var src map[string]interface{}
err := json.Unmarshal(page.buffer.Bytes(), &src)
if err != nil {
return err
}
return mergo.Merge(&page.merger.dst, src, mergo.WithAppendSlice, mergo.WithOverride)
}