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@@ -0,0 +1,167 @@
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+package jsonmerge
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+
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+import (
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+ "bytes"
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+ "encoding/json"
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+ "fmt"
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+ "reflect"
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+ "strconv"
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+ "strings"
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+)
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+
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+// Merger describes result of merge operation and provides
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+// configuration.
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+type Merger struct {
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+ // Errors is slice of non-critical errors of merge operations
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+ Errors []error
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+ // Replaced is describe replacements
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+ // Key is path in document like
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+ // "prop1.prop2.prop3" for object properties or
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+ // "arr1.1.prop" for arrays
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+ // Value is value of replacemet
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+ Replaced map[string]interface{}
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+ // CopyNonexistent enables setting fields into the result
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+ // which only exist in the patch.
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+ CopyNonexistent bool
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+}
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+
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+func (m *Merger) mergeValue(path []string, patch map[string]interface{}, key string, value interface{}) interface{} {
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+ patchValue, patchHasValue := patch[key]
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+
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+ if !patchHasValue {
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+ return value
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+ }
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+
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+ _, patchValueIsObject := patchValue.(map[string]interface{})
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+
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+ path = append(path, key)
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+ pathStr := strings.Join(path, ".")
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+
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+ if _, ok := value.(map[string]interface{}); ok {
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+ if !patchValueIsObject {
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+ err := fmt.Errorf("patch value must be object for key \"%v\"", pathStr)
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+ m.Errors = append(m.Errors, err)
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+ return value
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+ }
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+
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+ return m.mergeObjects(value, patchValue, path)
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+ }
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+
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+ if _, ok := value.([]interface{}); ok && patchValueIsObject {
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+ return m.mergeObjects(value, patchValue, path)
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+ }
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+
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+ if !reflect.DeepEqual(value, patchValue) {
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+ m.Replaced[pathStr] = patchValue
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+ }
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+
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+ return patchValue
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+}
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+
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+func (m *Merger) mergeObjects(data, patch interface{}, path []string) interface{} {
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+ if patchObject, ok := patch.(map[string]interface{}); ok {
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+ if dataArray, ok := data.([]interface{}); ok {
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+ ret := make([]interface{}, len(dataArray))
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+
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+ for i, val := range dataArray {
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+ ret[i] = m.mergeValue(path, patchObject, strconv.Itoa(i), val)
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+ }
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+
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+ return ret
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+ } else if dataObject, ok := data.(map[string]interface{}); ok {
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+ ret := make(map[string]interface{})
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+
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+ for k, v := range dataObject {
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+ ret[k] = m.mergeValue(path, patchObject, k, v)
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+ }
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+ if m.CopyNonexistent {
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+ for k, v := range patchObject {
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+ if _, ok := dataObject[k]; !ok {
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+ ret[k] = v
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+ }
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+ }
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+ }
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+
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+ return ret
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+ }
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+ }
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+
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+ return data
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+}
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+
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+// Merge merges patch document to data document
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+//
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+// Returning merged document. Result of merge operation can be
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+// obtained from the Merger. Result information is discarded before
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+// merging.
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+func (m *Merger) Merge(data, patch interface{}) interface{} {
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+ m.Replaced = make(map[string]interface{})
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+ m.Errors = make([]error, 0)
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+ return m.mergeObjects(data, patch, nil)
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+}
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+
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+// MergeBytesIndent merges patch document buffer to data document buffer
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+//
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+// Use prefix and indent for set indentation like in json.MarshalIndent
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+//
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+// Returning merged document buffer and error if any.
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+func (m *Merger) MergeBytesIndent(dataBuff, patchBuff []byte, prefix, indent string) (mergedBuff []byte, err error) {
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+ var data, patch, merged interface{}
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+
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+ err = unmarshalJSON(dataBuff, &data)
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+ if err != nil {
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+ err = fmt.Errorf("error in data JSON: %v", err)
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+ return
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+ }
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+
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+ err = unmarshalJSON(patchBuff, &patch)
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+ if err != nil {
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+ err = fmt.Errorf("error in patch JSON: %v", err)
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+ return
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+ }
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+
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+ merged = m.Merge(data, patch)
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+
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+ mergedBuff, err = json.MarshalIndent(merged, prefix, indent)
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+ if err != nil {
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+ err = fmt.Errorf("error writing merged JSON: %v", err)
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+ }
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+
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+ return
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+}
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+
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+// MergeBytes merges patch document buffer to data document buffer
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+//
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+// Returning merged document buffer, merge info and
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+// error if any
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+func (m *Merger) MergeBytes(dataBuff, patchBuff []byte) (mergedBuff []byte, err error) {
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+ var data, patch, merged interface{}
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+
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+ err = unmarshalJSON(dataBuff, &data)
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+ if err != nil {
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+ err = fmt.Errorf("error in data JSON: %v", err)
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+ return
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+ }
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+
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+ err = unmarshalJSON(patchBuff, &patch)
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+ if err != nil {
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+ err = fmt.Errorf("error in patch JSON: %v", err)
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+ return
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+ }
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+
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+ merged = m.Merge(data, patch)
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+
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+ mergedBuff, err = json.Marshal(merged)
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+ if err != nil {
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+ err = fmt.Errorf("error writing merged JSON: %v", err)
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+ }
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+
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+ return
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+}
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+
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+func unmarshalJSON(buff []byte, data interface{}) error {
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+ decoder := json.NewDecoder(bytes.NewReader(buff))
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+ decoder.UseNumber()
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+
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+ return decoder.Decode(data)
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+}
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lijian