Add basic JSON DPM package (ROUGH)

util/json/json.go

@@ -0,0 +1,247 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package json
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+type Operation struct {
+	Op    string      `json:"op"`
+	Path  string      `json:"path"`
+	Value interface{} `json:"value,omitempty"`
+}
+
+type ByPath []Operation
+
+func (a ByPath) Len() int           { return len(a) }
+func (a ByPath) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a ByPath) Less(i, j int) bool { return a[i].Path < a[j].Path }
+
+func NewPatch(op, path string, value interface{}) Operation {
+	return Operation{Op: op, Path: path, Value: value}
+}
+
+// CreatePatch creates a patch as specified in http://jsonpatch.com/
+//
+// 'a' is original, 'b' is the modified document. Both are to be given as json encoded content.
+// The function will return an array of Operations
+//
+// An error will be returned if any of the two documents are invalid.
+func Diff(a, b interface{}) ([]Operation, error) {
+
+	va, oka := a.([]byte)
+	vb, okb := b.([]byte)
+
+	if oka && okb {
+		ia := map[string]interface{}{}
+		ib := map[string]interface{}{}
+		err := json.Unmarshal(va, &ia)
+		if err != nil {
+			return nil, err
+		}
+		err = json.Unmarshal(vb, &ib)
+		if err != nil {
+			return nil, err
+		}
+		return diff(ia, ib, "", []Operation{})
+	}
+
+	ma, oka := a.(map[string]interface{})
+	mb, okb := b.(map[string]interface{})
+
+	if oka && okb {
+		return diff(ma, mb, "", []Operation{})
+	}
+
+	return nil, fmt.Errorf("Invalid input format")
+
+}
+
+// Returns true if the values matches (must be json types)
+// The types of the values must match, otherwise it will always return false
+// If two map[string]interface{} are given, all elements must match.
+func matchesValue(av, bv interface{}) bool {
+	if reflect.TypeOf(av) != reflect.TypeOf(bv) {
+		return false
+	}
+	switch at := av.(type) {
+	case string:
+		bt := bv.(string)
+		if bt == at {
+			return true
+		}
+	case float64:
+		bt := bv.(float64)
+		if bt == at {
+			return true
+		}
+	case bool:
+		bt := bv.(bool)
+		if bt == at {
+			return true
+		}
+	case map[string]interface{}:
+		bt := bv.(map[string]interface{})
+		for key := range at {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		for key := range bt {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		return true
+	case []interface{}:
+		bt := bv.([]interface{})
+		if len(bt) != len(at) {
+			return false
+		}
+		for key := range at {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		for key := range bt {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}
+
+func makePath(path string, newPart interface{}) string {
+	if path == "" {
+		return fmt.Sprintf("/%v", newPart)
+	} else {
+		if strings.HasSuffix(path, "/") {
+			path = path + fmt.Sprintf("%v", newPart)
+		} else {
+			path = path + fmt.Sprintf("/%v", newPart)
+		}
+	}
+	return path
+}
+
+// diff returns the (recursive) difference between a and b as an array of Operations.
+func diff(a, b map[string]interface{}, path string, patch []Operation) ([]Operation, error) {
+	for key, bv := range b {
+		p := makePath(path, key)
+		av, ok := a[key]
+		// value was added
+		if !ok {
+			patch = append(patch, NewPatch("add", p, bv))
+			continue
+		}
+		// If types have changed, replace completely
+		if reflect.TypeOf(av) != reflect.TypeOf(bv) {
+			patch = append(patch, NewPatch("replace", p, bv))
+			continue
+		}
+		// Types are the same, compare values
+		var err error
+		patch, err = handleValues(av, bv, p, patch)
+		if err != nil {
+			return nil, err
+		}
+	}
+	// Now add all deleted values as nil
+	for key := range a {
+		_, found := b[key]
+		if !found {
+			p := makePath(path, key)
+
+			patch = append(patch, NewPatch("remove", p, nil))
+		}
+	}
+	return patch, nil
+}
+
+func handleValues(av, bv interface{}, p string, patch []Operation) ([]Operation, error) {
+	var err error
+	switch at := av.(type) {
+	case map[string]interface{}:
+		bt := bv.(map[string]interface{})
+		patch, err = diff(at, bt, p, patch)
+		if err != nil {
+			return nil, err
+		}
+	case string, float64, bool:
+		if !matchesValue(av, bv) {
+			patch = append(patch, NewPatch("replace", p, bv))
+		}
+	case []interface{}:
+		bt := bv.([]interface{})
+		if len(at) != len(bt) {
+			// arrays are not the same
+			patch = append(patch, compareArray(at, bt, p)...)
+
+		} else {
+			for i, _ := range bt {
+				patch, err = handleValues(at[i], bt[i], makePath(p, i), patch)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+	case nil:
+		switch bv.(type) {
+		case nil:
+			// Both nil, fine.
+		default:
+			patch = append(patch, NewPatch("add", p, bv))
+		}
+	default:
+		panic(fmt.Sprintf("Unknown type:%T ", av))
+	}
+	return patch, nil
+}
+
+func compareArray(av, bv []interface{}, p string) []Operation {
+	retval := []Operation{}
+	//	var err error
+	for i, v := range av {
+		found := false
+		for _, v2 := range bv {
+			if reflect.DeepEqual(v, v2) {
+				found = true
+			}
+		}
+		if !found {
+			retval = append(retval, NewPatch("remove", makePath(p, i), nil))
+		}
+	}
+
+	for i, v := range bv {
+		found := false
+		for _, v2 := range av {
+			if reflect.DeepEqual(v, v2) {
+				found = true
+			}
+		}
+		if !found {
+			retval = append(retval, NewPatch("add", makePath(p, i), v))
+		}
+	}
+
+	return retval
+}

util/json/merge.go

@@ -0,0 +1,321 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package json
+
+/*import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+func merge(cur, patch *lazyNode) *lazyNode {
+	curDoc, err := cur.intoDoc()
+
+	if err != nil {
+		pruneNulls(patch)
+		return patch
+	}
+
+	patchDoc, err := patch.intoDoc()
+
+	if err != nil {
+		return patch
+	}
+
+	mergeDocs(curDoc, patchDoc)
+
+	return cur
+}
+
+func mergeDocs(doc, patch *partialDoc) {
+	for k, v := range *patch {
+		k := decodePatchKey(k)
+		if v == nil {
+			delete(*doc, k)
+		} else {
+			cur, ok := (*doc)[k]
+
+			if !ok || cur == nil {
+				pruneNulls(v)
+				(*doc)[k] = v
+			} else {
+				(*doc)[k] = merge(cur, v)
+			}
+		}
+	}
+}
+
+func pruneNulls(n *lazyNode) {
+	sub, err := n.intoDoc()
+
+	if err == nil {
+		pruneDocNulls(sub)
+	} else {
+		ary, err := n.intoAry()
+
+		if err == nil {
+			pruneAryNulls(ary)
+		}
+	}
+}
+
+func pruneDocNulls(doc *partialDoc) *partialDoc {
+	for k, v := range *doc {
+		if v == nil {
+			delete(*doc, k)
+		} else {
+			pruneNulls(v)
+		}
+	}
+
+	return doc
+}
+
+func pruneAryNulls(ary *partialArray) *partialArray {
+	newAry := []*lazyNode{}
+
+	for _, v := range *ary {
+		if v != nil {
+			pruneNulls(v)
+			newAry = append(newAry, v)
+		}
+	}
+
+	*ary = newAry
+
+	return ary
+}
+
+var errBadJSONDoc = fmt.Errorf("Invalid JSON Document")
+var errBadJSONPatch = fmt.Errorf("Invalid JSON Patch")
+
+// MergePatch merges the patchData into the docData.
+func MergePatch(docData, patchData []byte) ([]byte, error) {
+	doc := &partialDoc{}
+
+	docErr := json.Unmarshal(docData, doc)
+
+	patch := &partialDoc{}
+
+	patchErr := json.Unmarshal(patchData, patch)
+
+	if _, ok := docErr.(*json.SyntaxError); ok {
+		return nil, errBadJSONDoc
+	}
+
+	if _, ok := patchErr.(*json.SyntaxError); ok {
+		return nil, errBadJSONPatch
+	}
+
+	if docErr == nil && *doc == nil {
+		return nil, errBadJSONDoc
+	}
+
+	if patchErr == nil && *patch == nil {
+		return nil, errBadJSONPatch
+	}
+
+	if docErr != nil || patchErr != nil {
+		// Not an error, just not a doc, so we turn straight into the patch
+		if patchErr == nil {
+			doc = pruneDocNulls(patch)
+		} else {
+			patchAry := &partialArray{}
+			patchErr = json.Unmarshal(patchData, patchAry)
+
+			if patchErr != nil {
+				return nil, errBadJSONPatch
+			}
+
+			pruneAryNulls(patchAry)
+
+			out, patchErr := json.Marshal(patchAry)
+
+			if patchErr != nil {
+				return nil, errBadJSONPatch
+			}
+
+			return out, nil
+		}
+	} else {
+		mergeDocs(doc, patch)
+	}
+
+	return json.Marshal(doc)
+}
+
+// CreateMergePatch creates a merge patch as specified in http://tools.ietf.org/html/draft-ietf-appsawg-json-merge-patch-07
+//
+// 'a' is original, 'b' is the modified document. Both are to be given as json encoded content.
+// The function will return a mergeable json document with differences from a to b.
+//
+// An error will be returned if any of the two documents are invalid.
+func CreateMergePatch(a, b []byte) ([]byte, error) {
+	aI := map[string]interface{}{}
+	bI := map[string]interface{}{}
+	err := json.Unmarshal(a, &aI)
+	if err != nil {
+		return nil, errBadJSONDoc
+	}
+	err = json.Unmarshal(b, &bI)
+	if err != nil {
+		return nil, errBadJSONDoc
+	}
+	dest, err := getDiff(aI, bI)
+	if err != nil {
+		return nil, err
+	}
+	return json.Marshal(dest)
+}
+
+// Returns true if the array matches (must be json types).
+// As is idiomatic for go, an empty array is not the same as a nil array.
+func matchesArray(a, b []interface{}) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	if (a == nil && b != nil) || (a != nil && b == nil) {
+		return false
+	}
+	for i := range a {
+		if !matchesValue(a[i], b[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+// Returns true if the values matches (must be json types)
+// The types of the values must match, otherwise it will always return false
+// If two map[string]interface{} are given, all elements must match.
+func matchesValue(av, bv interface{}) bool {
+	if reflect.TypeOf(av) != reflect.TypeOf(bv) {
+		return false
+	}
+	switch at := av.(type) {
+	case string:
+		bt := bv.(string)
+		if bt == at {
+			return true
+		}
+	case float64:
+		bt := bv.(float64)
+		if bt == at {
+			return true
+		}
+	case bool:
+		bt := bv.(bool)
+		if bt == at {
+			return true
+		}
+	case map[string]interface{}:
+		bt := bv.(map[string]interface{})
+		for key := range at {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		for key := range bt {
+			if !matchesValue(at[key], bt[key]) {
+				return false
+			}
+		}
+		return true
+	case []interface{}:
+		bt := bv.([]interface{})
+		return matchesArray(at, bt)
+	}
+	return false
+}
+
+// getDiff returns the (recursive) difference between a and b as a map[string]interface{}.
+func getDiff(a, b map[string]interface{}) (map[string]interface{}, error) {
+	into := map[string]interface{}{}
+	for key, bv := range b {
+		escapedKey := encodePatchKey(key)
+		av, ok := a[key]
+		// value was added
+		if !ok {
+			into[escapedKey] = bv
+			continue
+		}
+		// If types have changed, replace completely
+		if reflect.TypeOf(av) != reflect.TypeOf(bv) {
+			into[escapedKey] = bv
+			continue
+		}
+		// Types are the same, compare values
+		switch at := av.(type) {
+		case map[string]interface{}:
+			bt := bv.(map[string]interface{})
+			dst := make(map[string]interface{}, len(bt))
+			dst, err := getDiff(at, bt)
+			if err != nil {
+				return nil, err
+			}
+			if len(dst) > 0 {
+				into[escapedKey] = dst
+			}
+		case string, float64, bool:
+			if !matchesValue(av, bv) {
+				into[escapedKey] = bv
+			}
+		case []interface{}:
+			bt := bv.([]interface{})
+			if !matchesArray(at, bt) {
+				into[escapedKey] = bv
+			}
+		case nil:
+			switch bv.(type) {
+			case nil:
+				// Both nil, fine.
+			default:
+				into[escapedKey] = bv
+			}
+		default:
+			panic(fmt.Sprintf("Unknown type:%T in key %s", av, key))
+		}
+	}
+	// Now add all deleted values as nil
+	for key := range a {
+		_, found := b[key]
+		if !found {
+			into[key] = nil
+		}
+	}
+	return into, nil
+}
+
+// From http://tools.ietf.org/html/rfc6901#section-4 :
+//
+// Evaluation of each reference token begins by decoding any escaped
+// character sequence.  This is performed by first transforming any
+// occurrence of the sequence '~1' to '/', and then transforming any
+// occurrence of the sequence '~0' to '~'.
+
+var (
+	rfc6901Encoder = strings.NewReplacer("~", "~0", "/", "~1")
+	rfc6901Decoder = strings.NewReplacer("~1", "/", "~0", "~")
+)
+
+func decodePatchKey(k string) string {
+	return rfc6901Decoder.Replace(k)
+}
+
+func encodePatchKey(k string) string {
+	return rfc6901Encoder.Replace(k)
+}
+*/

util/json/merge_test.go

@@ -0,0 +1,407 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package json
+
+// import (
+// 	"strings"
+// 	"testing"
+// )
+
+// func mergePatch(doc, patch string) string {
+// 	out, err := MergePatch([]byte(doc), []byte(patch))
+
+// 	if err != nil {
+// 		panic(err)
+// 	}
+
+// 	return string(out)
+// }
+
+// func TestMergePatchReplaceKey(t *testing.T) {
+// 	doc := `{ "title": "hello" }`
+// 	pat := `{ "title": "goodbye" }`
+
+// 	res := mergePatch(doc, pat)
+
+// 	if !compareJSON(pat, res) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// func TestMergePatchIgnoresOtherValues(t *testing.T) {
+// 	doc := `{ "title": "hello", "age": 18 }`
+// 	pat := `{ "title": "goodbye" }`
+
+// 	res := mergePatch(doc, pat)
+
+// 	exp := `{ "title": "goodbye", "age": 18 }`
+
+// 	if !compareJSON(exp, res) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// func TestMergePatchNilDoc(t *testing.T) {
+// 	doc := `{ "title": null }`
+// 	pat := `{ "title": {"foo": "bar"} }`
+
+// 	res := mergePatch(doc, pat)
+
+// 	exp := `{ "title": {"foo": "bar"} }`
+
+// 	if !compareJSON(exp, res) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// func TestMergePatchRecursesIntoObjects(t *testing.T) {
+// 	doc := `{ "person": { "title": "hello", "age": 18 } }`
+// 	pat := `{ "person": { "title": "goodbye" } }`
+
+// 	res := mergePatch(doc, pat)
+
+// 	exp := `{ "person": { "title": "goodbye", "age": 18 } }`
+
+// 	if !compareJSON(exp, res) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// type nonObjectCases struct {
+// 	doc, pat, res string
+// }
+
+// func TestMergePatchReplacesNonObjectsWholesale(t *testing.T) {
+// 	a1 := `[1]`
+// 	a2 := `[2]`
+// 	o1 := `{ "a": 1 }`
+// 	o2 := `{ "a": 2 }`
+// 	o3 := `{ "a": 1, "b": 1 }`
+// 	o4 := `{ "a": 2, "b": 1 }`
+
+// 	cases := []nonObjectCases{
+// 		{a1, a2, a2},
+// 		{o1, a2, a2},
+// 		{a1, o1, o1},
+// 		{o3, o2, o4},
+// 	}
+
+// 	for _, c := range cases {
+// 		act := mergePatch(c.doc, c.pat)
+
+// 		if !compareJSON(c.res, act) {
+// 			t.Errorf("whole object replacement failed")
+// 		}
+// 	}
+// }
+
+// func TestMergePatchReturnsErrorOnBadJSON(t *testing.T) {
+// 	_, err := MergePatch([]byte(`[[[[`), []byte(`1`))
+
+// 	if err == nil {
+// 		t.Errorf("Did not return an error for bad json: %s", err)
+// 	}
+
+// 	_, err = MergePatch([]byte(`1`), []byte(`[[[[`))
+
+// 	if err == nil {
+// 		t.Errorf("Did not return an error for bad json: %s", err)
+// 	}
+// }
+
+// func TestMergePatchReturnsEmptyArrayOnEmptyArray(t *testing.T) {
+// 	doc := `{ "array": ["one", "two"] }`
+// 	pat := `{ "array": [] }`
+
+// 	exp := `{ "array": [] }`
+
+// 	res, err := MergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(exp, string(res)) {
+// 		t.Fatalf("Emtpy array did not return not return as empty array")
+// 	}
+// }
+
+// var rfcTests = []struct {
+// 	target   string
+// 	patch    string
+// 	expected string
+// }{
+// 	// test cases from https://tools.ietf.org/html/rfc7386#appendix-A
+// 	{target: `{"a":"b"}`, patch: `{"a":"c"}`, expected: `{"a":"c"}`},
+// 	{target: `{"a":"b"}`, patch: `{"b":"c"}`, expected: `{"a":"b","b":"c"}`},
+// 	{target: `{"a":"b"}`, patch: `{"a":null}`, expected: `{}`},
+// 	{target: `{"a":"b","b":"c"}`, patch: `{"a":null}`, expected: `{"b":"c"}`},
+// 	{target: `{"a":["b"]}`, patch: `{"a":"c"}`, expected: `{"a":"c"}`},
+// 	{target: `{"a":"c"}`, patch: `{"a":["b"]}`, expected: `{"a":["b"]}`},
+// 	{target: `{"a":{"b": "c"}}`, patch: `{"a": {"b": "d","c": null}}`, expected: `{"a":{"b":"d"}}`},
+// 	{target: `{"a":[{"b":"c"}]}`, patch: `{"a":[1]}`, expected: `{"a":[1]}`},
+// 	{target: `["a","b"]`, patch: `["c","d"]`, expected: `["c","d"]`},
+// 	{target: `{"a":"b"}`, patch: `["c"]`, expected: `["c"]`},
+// 	// {target: `{"a":"foo"}`, patch: `null`, expected: `null`},
+// 	// {target: `{"a":"foo"}`, patch: `"bar"`, expected: `"bar"`},
+// 	{target: `{"e":null}`, patch: `{"a":1}`, expected: `{"a":1,"e":null}`},
+// 	{target: `[1,2]`, patch: `{"a":"b","c":null}`, expected: `{"a":"b"}`},
+// 	{target: `{}`, patch: `{"a":{"bb":{"ccc":null}}}`, expected: `{"a":{"bb":{}}}`},
+// }
+
+// func TestMergePatchRFCCases(t *testing.T) {
+// 	for i, c := range rfcTests {
+// 		out := mergePatch(c.target, c.patch)
+
+// 		if !compareJSON(out, c.expected) {
+// 			t.Errorf("case[%d], patch '%s' did not apply properly to '%s'. expected:\n'%s'\ngot:\n'%s'", i, c.patch, c.target, c.expected, out)
+// 		}
+// 	}
+// }
+
+// var rfcFailTests = `
+//      {"a":"foo"}  |   null
+//      {"a":"foo"}  |   "bar"
+// `
+
+// func TestMergePatchFailRFCCases(t *testing.T) {
+// 	tests := strings.Split(rfcFailTests, "\n")
+
+// 	for _, c := range tests {
+// 		if strings.TrimSpace(c) == "" {
+// 			continue
+// 		}
+
+// 		parts := strings.SplitN(c, "|", 2)
+
+// 		doc := strings.TrimSpace(parts[0])
+// 		pat := strings.TrimSpace(parts[1])
+
+// 		out, err := MergePatch([]byte(doc), []byte(pat))
+
+// 		if err != errBadJSONPatch {
+// 			t.Errorf("error not returned properly: %s, %s", err, string(out))
+// 		}
+// 	}
+
+// }
+
+// func TestMergeReplaceKey(t *testing.T) {
+// 	doc := `{ "title": "hello", "nested": {"one": 1, "two": 2} }`
+// 	pat := `{ "title": "goodbye", "nested": {"one": 2, "two": 2}  }`
+
+// 	exp := `{ "title": "goodbye", "nested": {"one": 2}  }`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(exp, string(res)) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// func TestMergeGetArray(t *testing.T) {
+// 	doc := `{ "title": "hello", "array": ["one", "two"], "notmatch": [1, 2, 3] }`
+// 	pat := `{ "title": "hello", "array": ["one", "two", "three"], "notmatch": [1, 2, 3]  }`
+
+// 	exp := `{ "array": ["one", "two", "three"] }`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(exp, string(res)) {
+// 		t.Fatalf("Array was not added")
+// 	}
+// }
+
+// func TestMergeGetObjArray(t *testing.T) {
+// 	doc := `{ "title": "hello", "array": [{"banana": true}, {"evil": false}], "notmatch": [{"one":1}, {"two":2}, {"three":3}] }`
+// 	pat := `{ "title": "hello", "array": [{"banana": false}, {"evil": true}], "notmatch": [{"one":1}, {"two":2}, {"three":3}] }`
+
+// 	exp := `{  "array": [{"banana": false}, {"evil": true}] }`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(exp, string(res)) {
+// 		t.Fatalf("Object array was not added")
+// 	}
+// }
+
+// func TestMergeDeleteKey(t *testing.T) {
+// 	doc := `{ "title": "hello", "nested": {"one": 1, "two": 2} }`
+// 	pat := `{ "title": "hello", "nested": {"one": 1}  }`
+
+// 	exp := `{"nested":{"two":null}}`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	// We cannot use "compareJSON", since Equals does not report a difference if the value is null
+// 	if exp != string(res) {
+// 		t.Fatalf("Key was not removed")
+// 	}
+// }
+
+// func TestMergeEmptyArray(t *testing.T) {
+// 	doc := `{ "array": null }`
+// 	pat := `{ "array": [] }`
+
+// 	exp := `{"array":[]}`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	// We cannot use "compareJSON", since Equals does not report a difference if the value is null
+// 	if exp != string(res) {
+// 		t.Fatalf("Key was not removed")
+// 	}
+// }
+
+// func TestMergeObjArray(t *testing.T) {
+// 	doc := `{ "array": [ {"a": {"b": 2}}, {"a": {"b": 3}} ]}`
+// 	exp := `{}`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(doc))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	// We cannot use "compareJSON", since Equals does not report a difference if the value is null
+// 	if exp != string(res) {
+// 		t.Fatalf("Array was not empty, was " + string(res))
+// 	}
+// }
+
+// func TestMergeComplexMatch(t *testing.T) {
+// 	doc := `{"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4], "nested": {"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4]} }`
+// 	empty := `{}`
+// 	res, err := CreateMergePatch([]byte(doc), []byte(doc))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	// We cannot use "compareJSON", since Equals does not report a difference if the value is null
+// 	if empty != string(res) {
+// 		t.Fatalf("Did not get empty result, was:%s", string(res))
+// 	}
+// }
+
+// func TestMergeComplexAddAll(t *testing.T) {
+// 	doc := `{"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4], "nested": {"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4]} }`
+// 	empty := `{}`
+// 	res, err := CreateMergePatch([]byte(empty), []byte(doc))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(doc, string(res)) {
+// 		t.Fatalf("Did not get everything as, it was:\n%s", string(res))
+// 	}
+// }
+
+// func TestMergeComplexRemoveAll(t *testing.T) {
+// 	doc := `{"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4], "nested": {"hello": "world","t": true ,"f": false, "n": null,"i": 123,"pi": 3.1416,"a": [1, 2, 3, 4]} }`
+// 	exp := `{"a":null,"f":null,"hello":null,"i":null,"n":null,"nested":null,"pi":null,"t":null}`
+// 	empty := `{}`
+// 	res, err := CreateMergePatch([]byte(doc), []byte(empty))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if exp != string(res) {
+// 		t.Fatalf("Did not get result, was:%s", string(res))
+// 	}
+
+// 	// FIXME: Crashes if using compareJSON like this:
+// 	/*
+// 		if !compareJSON(doc, string(res)) {
+// 			t.Fatalf("Did not get everything as, it was:\n%s", string(res))
+// 		}
+// 	*/
+// }
+
+// func TestMergeObjectWithInnerArray(t *testing.T) {
+// 	stateString := `{
+// 	  "OuterArray": [
+// 	    {
+// 		  "InnerArray": [
+// 	        {
+// 	          "StringAttr": "abc123"
+// 	        }
+// 	      ],
+// 	      "StringAttr": "def456"
+// 	    }
+// 	  ]
+// 	}`
+
+// 	patch, err := CreateMergePatch([]byte(stateString), []byte(stateString))
+// 	if err != nil {
+// 		t.Fatal(err)
+// 	}
+
+// 	if string(patch) != "{}" {
+// 		t.Fatalf("Patch should have been {} but was: %v", string(patch))
+// 	}
+// }
+
+// func TestMergeReplaceKeyRequiringEscape(t *testing.T) {
+// 	doc := `{ "title": "hello", "nested": {"title/escaped": 1, "two": 2} }`
+// 	pat := `{ "title": "goodbye", "nested": {"title/escaped": 2, "two": 2}  }`
+
+// 	exp := `{ "title": "goodbye", "nested": {"title~1escaped": 2}  }`
+
+// 	res, err := CreateMergePatch([]byte(doc), []byte(pat))
+
+// 	if err != nil {
+// 		t.Errorf("Unexpected error: %s, %s", err, string(res))
+// 	}
+
+// 	if !compareJSON(exp, string(res)) {
+// 		t.Log(string(res))
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }
+
+// func TestMergePatchReplaceKeyRequiringEscaping(t *testing.T) {
+// 	doc := `{ "obj": { "title/escaped": "hello" } }`
+// 	pat := `{ "obj": { "title~1escaped": "goodbye" } }`
+// 	exp := `{ "obj": { "title/escaped": "goodbye" } }`
+
+// 	res := mergePatch(doc, pat)
+
+// 	if !compareJSON(exp, res) {
+// 		t.Fatalf("Key was not replaced")
+// 	}
+// }

util/json/patch.go

@@ -0,0 +1,601 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package json
+
+/*import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const (
+	eRaw = iota
+	eDoc
+	eAry
+)
+
+const LeftBrace byte = 91 // []byte("[")
+
+type lazyNode struct {
+	raw   *json.RawMessage
+	doc   partialDoc
+	ary   partialArray
+	which int
+}
+
+type operation map[string]*json.RawMessage
+
+// Patch is an ordered collection of operations.
+type Patch []operation
+
+type partialDoc map[string]*lazyNode
+type partialArray []*lazyNode
+
+type container interface {
+	get(key string) (*lazyNode, error)
+	set(key string, val *lazyNode) error
+	add(key string, val *lazyNode) error
+	remove(key string) error
+}
+
+func newLazyNode(raw *json.RawMessage) *lazyNode {
+	return &lazyNode{raw: raw, doc: nil, ary: nil, which: eRaw}
+}
+
+func (n *lazyNode) MarshalJSON() ([]byte, error) {
+	switch n.which {
+	case eRaw:
+		return json.Marshal(n.raw)
+	case eDoc:
+		return json.Marshal(n.doc)
+	case eAry:
+		return json.Marshal(n.ary)
+	default:
+		return nil, fmt.Errorf("Unknown type")
+	}
+}
+
+func (n *lazyNode) UnmarshalJSON(data []byte) error {
+	dest := make(json.RawMessage, len(data))
+	copy(dest, data)
+	n.raw = &dest
+	n.which = eRaw
+	return nil
+}
+
+func (n *lazyNode) intoDoc() (*partialDoc, error) {
+	if n.which == eDoc {
+		return &n.doc, nil
+	}
+
+	err := json.Unmarshal(*n.raw, &n.doc)
+
+	if err != nil {
+		return nil, err
+	}
+
+	n.which = eDoc
+	return &n.doc, nil
+}
+
+func (n *lazyNode) intoAry() (*partialArray, error) {
+	if n.which == eAry {
+		return &n.ary, nil
+	}
+
+	err := json.Unmarshal(*n.raw, &n.ary)
+
+	if err != nil {
+		return nil, err
+	}
+
+	n.which = eAry
+	return &n.ary, nil
+}
+
+func (n *lazyNode) compact() []byte {
+	buf := &bytes.Buffer{}
+
+	err := json.Compact(buf, *n.raw)
+
+	if err != nil {
+		return *n.raw
+	}
+
+	return buf.Bytes()
+}
+
+func (n *lazyNode) tryDoc() bool {
+	err := json.Unmarshal(*n.raw, &n.doc)
+
+	if err != nil {
+		return false
+	}
+
+	n.which = eDoc
+	return true
+}
+
+func (n *lazyNode) tryAry() bool {
+	err := json.Unmarshal(*n.raw, &n.ary)
+
+	if err != nil {
+		return false
+	}
+
+	n.which = eAry
+	return true
+}
+
+func (n *lazyNode) equal(o *lazyNode) bool {
+	if n.which == eRaw {
+		if !n.tryDoc() && !n.tryAry() {
+			if o.which != eRaw {
+				return false
+			}
+
+			return bytes.Equal(n.compact(), o.compact())
+		}
+	}
+
+	if n.which == eDoc {
+		if o.which == eRaw {
+			if !o.tryDoc() {
+				return false
+			}
+		}
+
+		if o.which != eDoc {
+			return false
+		}
+
+		for k, v := range n.doc {
+			ov, ok := o.doc[k]
+
+			if !ok {
+				return false
+			}
+
+			if v == nil && ov == nil {
+				continue
+			}
+
+			if !v.equal(ov) {
+				return false
+			}
+		}
+
+		return true
+	}
+
+	if o.which != eAry && !o.tryAry() {
+		return false
+	}
+
+	if len(n.ary) != len(o.ary) {
+		return false
+	}
+
+	for idx, val := range n.ary {
+		if !val.equal(o.ary[idx]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (o operation) kind() string {
+	if obj, ok := o["op"]; ok {
+		var op string
+
+		err := json.Unmarshal(*obj, &op)
+
+		if err != nil {
+			return "unknown"
+		}
+
+		return op
+	}
+
+	return "unknown"
+}
+
+func (o operation) path() string {
+	if obj, ok := o["path"]; ok {
+		var op string
+
+		err := json.Unmarshal(*obj, &op)
+
+		if err != nil {
+			return "unknown"
+		}
+
+		return op
+	}
+
+	return "unknown"
+}
+
+func (o operation) from() string {
+	if obj, ok := o["from"]; ok {
+		var op string
+
+		err := json.Unmarshal(*obj, &op)
+
+		if err != nil {
+			return "unknown"
+		}
+
+		return op
+	}
+
+	return "unknown"
+}
+
+func (o operation) value() *lazyNode {
+	if obj, ok := o["value"]; ok {
+		return newLazyNode(obj)
+	}
+
+	return nil
+}
+
+func isArray(buf []byte) bool {
+Loop:
+	for _, c := range buf {
+		switch c {
+		case ' ':
+		case '\n':
+		case '\t':
+			continue
+		case '[':
+			return true
+		default:
+			break Loop
+		}
+	}
+
+	return false
+}
+
+func findObject(pd *container, path string) (container, string) {
+	doc := *pd
+
+	split := strings.Split(path, "/")
+
+	parts := split[1 : len(split)-1]
+
+	key := split[len(split)-1]
+
+	var err error
+
+	for _, part := range parts {
+
+		next, ok := doc.get(decodePatchKey(part))
+
+		if next == nil || ok != nil {
+			return nil, ""
+		}
+
+		if isArray(*next.raw) {
+			doc, err = next.intoAry()
+
+			if err != nil {
+				return nil, ""
+			}
+		} else {
+			doc, err = next.intoDoc()
+
+			if err != nil {
+				return nil, ""
+			}
+		}
+	}
+
+	return doc, decodePatchKey(key)
+}
+
+func (d *partialDoc) set(key string, val *lazyNode) error {
+	(*d)[key] = val
+	return nil
+}
+
+func (d *partialDoc) add(key string, val *lazyNode) error {
+	(*d)[key] = val
+	return nil
+}
+
+func (d *partialDoc) get(key string) (*lazyNode, error) {
+	return (*d)[key], nil
+}
+
+func (d *partialDoc) remove(key string) error {
+	_, ok := (*d)[key]
+	if !ok {
+		return fmt.Errorf("Unable to remove nonexistent key: %s", key)
+	}
+
+	delete(*d, key)
+	return nil
+}
+
+func (d *partialArray) set(key string, val *lazyNode) error {
+	if key == "-" {
+		*d = append(*d, val)
+		return nil
+	}
+
+	idx, err := strconv.Atoi(key)
+	if err != nil {
+		return err
+	}
+
+	sz := len(*d)
+	if idx+1 > sz {
+		sz = idx + 1
+	}
+
+	ary := make([]*lazyNode, sz)
+
+	cur := *d
+
+	copy(ary, cur)
+
+	if idx >= len(ary) {
+		return fmt.Errorf("Unable to access invalid index: %d", idx)
+	}
+
+	ary[idx] = val
+
+	*d = ary
+	return nil
+}
+
+func (d *partialArray) add(key string, val *lazyNode) error {
+	if key == "-" {
+		*d = append(*d, val)
+		return nil
+	}
+
+	idx, err := strconv.Atoi(key)
+	if err != nil {
+		return err
+	}
+
+	ary := make([]*lazyNode, len(*d)+1)
+
+	cur := *d
+
+	copy(ary[0:idx], cur[0:idx])
+	ary[idx] = val
+	copy(ary[idx+1:], cur[idx:])
+
+	*d = ary
+	return nil
+}
+
+func (d *partialArray) get(key string) (*lazyNode, error) {
+	idx, err := strconv.Atoi(key)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if idx >= len(*d) {
+		return nil, fmt.Errorf("Unable to access invalid index: %d", idx)
+	}
+
+	return (*d)[idx], nil
+}
+
+func (d *partialArray) remove(key string) error {
+	idx, err := strconv.Atoi(key)
+	if err != nil {
+		return err
+	}
+
+	cur := *d
+
+	if idx >= len(cur) {
+		return fmt.Errorf("Unable to remove invalid index: %d", idx)
+	}
+
+	ary := make([]*lazyNode, len(cur)-1)
+
+	copy(ary[0:idx], cur[0:idx])
+	copy(ary[idx:], cur[idx+1:])
+
+	*d = ary
+	return nil
+
+}
+
+func (p Patch) add(doc *container, op operation) error {
+	path := op.path()
+
+	con, key := findObject(doc, path)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch add operation does not apply: doc is missing path: %s", path)
+	}
+
+	return con.add(key, op.value())
+}
+
+func (p Patch) remove(doc *container, op operation) error {
+	path := op.path()
+
+	con, key := findObject(doc, path)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch remove operation does not apply: doc is missing path: %s", path)
+	}
+
+	return con.remove(key)
+}
+
+func (p Patch) replace(doc *container, op operation) error {
+	path := op.path()
+
+	con, key := findObject(doc, path)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch replace operation does not apply: doc is missing path: %s", path)
+	}
+
+	return con.set(key, op.value())
+}
+
+func (p Patch) move(doc *container, op operation) error {
+	from := op.from()
+
+	con, key := findObject(doc, from)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch move operation does not apply: doc is missing from path: %s", from)
+	}
+
+	val, err := con.get(key)
+	if err != nil {
+		return err
+	}
+
+	err = con.remove(key)
+	if err != nil {
+		return err
+	}
+
+	path := op.path()
+
+	con, key = findObject(doc, path)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch move operation does not apply: doc is missing destination path: %s", path)
+	}
+
+	return con.set(key, val)
+}
+
+func (p Patch) test(doc *container, op operation) error {
+	path := op.path()
+
+	con, key := findObject(doc, path)
+
+	if con == nil {
+		return fmt.Errorf("jsonpatch test operation does not apply: is missing path: %s", path)
+	}
+
+	val, err := con.get(key)
+
+	if err != nil {
+		return err
+	}
+
+	if val == nil {
+		if op.value().raw == nil {
+			return nil
+		} else {
+			return fmt.Errorf("Testing value %s failed", path)
+		}
+	}
+
+	if val.equal(op.value()) {
+		return nil
+	}
+
+	return fmt.Errorf("Testing value %s failed", path)
+}
+
+// Equal indicates if 2 JSON documents have the same structural equality.
+func Equal(a, b []byte) bool {
+	ra := make(json.RawMessage, len(a))
+	copy(ra, a)
+	la := newLazyNode(&ra)
+
+	rb := make(json.RawMessage, len(b))
+	copy(rb, b)
+	lb := newLazyNode(&rb)
+
+	return la.equal(lb)
+}
+
+// DecodePatch decodes the passed JSON document as an RFC 6902 patch.
+func DecodePatch(buf []byte) (Patch, error) {
+	var p Patch
+
+	err := json.Unmarshal(buf, &p)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return p, nil
+}
+
+// Apply mutates a JSON document according to the patch, and returns the new
+// document.
+func (p Patch) Apply(doc []byte) ([]byte, error) {
+	return p.ApplyIndent(doc, "")
+}
+
+// ApplyIndent mutates a JSON document according to the patch, and returns the new
+// document indented.
+func (p Patch) ApplyIndent(doc []byte, indent string) ([]byte, error) {
+	var pd container
+	if doc[0] == LeftBrace {
+		pd = &partialArray{}
+	} else {
+		pd = &partialDoc{}
+	}
+
+	err := json.Unmarshal(doc, pd)
+
+	if err != nil {
+		return nil, err
+	}
+
+	err = nil
+
+	for _, op := range p {
+		switch op.kind() {
+		case "add":
+			err = p.add(&pd, op)
+		case "remove":
+			err = p.remove(&pd, op)
+		case "replace":
+			err = p.replace(&pd, op)
+		case "move":
+			err = p.move(&pd, op)
+		case "test":
+			err = p.test(&pd, op)
+		default:
+			err = fmt.Errorf("Unexpected kind: %s", op.kind())
+		}
+
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if indent != "" {
+		return json.MarshalIndent(pd, "", indent)
+	}
+
+	return json.Marshal(pd)
+}
+*/

util/json/patch_test.go

@@ -0,0 +1,311 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package json
+
+// import (
+// 	"bytes"
+// 	"encoding/json"
+// 	"fmt"
+// 	"reflect"
+// 	"testing"
+// )
+
+// func reformatJSON(j string) string {
+// 	buf := new(bytes.Buffer)
+
+// 	json.Indent(buf, []byte(j), "", "  ")
+
+// 	return buf.String()
+// }
+
+// func compareJSON(a, b string) bool {
+// 	// return Equal([]byte(a), []byte(b))
+
+// 	var obj_a, obj_b map[string]interface{}
+// 	json.Unmarshal([]byte(a), &obj_a)
+// 	json.Unmarshal([]byte(b), &obj_b)
+
+// 	// fmt.Printf("Comparing %#v\nagainst %#v\n", obj_a, obj_b)
+// 	return reflect.DeepEqual(obj_a, obj_b)
+// }
+
+// func applyPatch(doc, patch string) (string, error) {
+// 	obj, err := DecodePatch([]byte(patch))
+
+// 	if err != nil {
+// 		panic(err)
+// 	}
+
+// 	out, err := obj.Apply([]byte(doc))
+
+// 	if err != nil {
+// 		return "", err
+// 	}
+
+// 	return string(out), nil
+// }
+
+// type Case struct {
+// 	doc, patch, result string
+// }
+
+// var Cases = []Case{
+// 	{
+// 		`{ "foo": "bar"}`,
+// 		`[
+//          { "op": "add", "path": "/baz", "value": "qux" }
+//      ]`,
+// 		`{
+//        "baz": "qux",
+//        "foo": "bar"
+//      }`,
+// 	},
+// 	{
+// 		`{ "foo": [ "bar", "baz" ] }`,
+// 		`[
+//      { "op": "add", "path": "/foo/1", "value": "qux" }
+//     ]`,
+// 		`{ "foo": [ "bar", "qux", "baz" ] }`,
+// 	},
+// 	{
+// 		`{ "baz": "qux", "foo": "bar" }`,
+// 		`[ { "op": "remove", "path": "/baz" } ]`,
+// 		`{ "foo": "bar" }`,
+// 	},
+// 	{
+// 		`{ "foo": [ "bar", "qux", "baz" ] }`,
+// 		`[ { "op": "remove", "path": "/foo/1" } ]`,
+// 		`{ "foo": [ "bar", "baz" ] }`,
+// 	},
+// 	{
+// 		`{ "baz": "qux", "foo": "bar" }`,
+// 		`[ { "op": "replace", "path": "/baz", "value": "boo" } ]`,
+// 		`{ "baz": "boo", "foo": "bar" }`,
+// 	},
+// 	{
+// 		`{
+//      "foo": {
+//        "bar": "baz",
+//        "waldo": "fred"
+//      },
+//      "qux": {
+//        "corge": "grault"
+//      }
+//    }`,
+// 		`[ { "op": "move", "from": "/foo/waldo", "path": "/qux/thud" } ]`,
+// 		`{
+//      "foo": {
+//        "bar": "baz"
+//      },
+//      "qux": {
+//        "corge": "grault",
+//        "thud": "fred"
+//      }
+//    }`,
+// 	},
+// 	{
+// 		`{ "foo": [ "all", "grass", "cows", "eat" ] }`,
+// 		`[ { "op": "move", "from": "/foo/1", "path": "/foo/3" } ]`,
+// 		`{ "foo": [ "all", "cows", "eat", "grass" ] }`,
+// 	},
+// 	{
+// 		`{ "foo": "bar" }`,
+// 		`[ { "op": "add", "path": "/child", "value": { "grandchild": { } } } ]`,
+// 		`{ "foo": "bar", "child": { "grandchild": { } } }`,
+// 	},
+// 	{
+// 		`{ "foo": ["bar"] }`,
+// 		`[ { "op": "add", "path": "/foo/-", "value": ["abc", "def"] } ]`,
+// 		`{ "foo": ["bar", ["abc", "def"]] }`,
+// 	},
+// 	{
+// 		`{ "foo": "bar", "qux": { "baz": 1, "bar": null } }`,
+// 		`[ { "op": "remove", "path": "/qux/bar" } ]`,
+// 		`{ "foo": "bar", "qux": { "baz": 1 } }`,
+// 	},
+// 	{
+// 		`{ "foo": "bar" }`,
+// 		`[ { "op": "add", "path": "/baz", "value": null } ]`,
+// 		`{ "baz": null, "foo": "bar" }`,
+// 	},
+// 	{
+// 		`{ "foo": ["bar"]}`,
+// 		`[ { "op": "replace", "path": "/foo/0", "value": "baz"}]`,
+// 		`{ "foo": ["baz"]}`,
+// 	},
+// 	{
+// 		`{ "foo": ["bar","baz"]}`,
+// 		`[ { "op": "replace", "path": "/foo/0", "value": "bum"}]`,
+// 		`{ "foo": ["bum","baz"]}`,
+// 	},
+// 	{
+// 		`{ "foo": ["bar","qux","baz"]}`,
+// 		`[ { "op": "replace", "path": "/foo/1", "value": "bum"}]`,
+// 		`{ "foo": ["bar", "bum","baz"]}`,
+// 	},
+// 	{
+// 		`[ {"foo": ["bar","qux","baz"]}]`,
+// 		`[ { "op": "replace", "path": "/0/foo/0", "value": "bum"}]`,
+// 		`[ {"foo": ["bum","qux","baz"]}]`,
+// 	},
+// }
+
+// type BadCase struct {
+// 	doc, patch string
+// }
+
+// var MutationTestCases = []BadCase{
+// 	{
+// 		`{ "foo": "bar", "qux": { "baz": 1, "bar": null } }`,
+// 		`[ { "op": "remove", "path": "/qux/bar" } ]`,
+// 	},
+// 	{
+// 		`{ "foo": "bar", "qux": { "baz": 1, "bar": null } }`,
+// 		`[ { "op": "replace", "path": "/qux/baz", "value": null } ]`,
+// 	},
+// }
+
+// var BadCases = []BadCase{
+// 	{
+// 		`{ "foo": "bar" }`,
+// 		`[ { "op": "add", "path": "/baz/bat", "value": "qux" } ]`,
+// 	},
+// 	{
+// 		`{ "a": { "b": { "d": 1 } } }`,
+// 		`[ { "op": "remove", "path": "/a/b/c" } ]`,
+// 	},
+// 	{
+// 		`{ "a": { "b": { "d": 1 } } }`,
+// 		`[ { "op": "move", "from": "/a/b/c", "path": "/a/b/e" } ]`,
+// 	},
+// 	{
+// 		`{ "a": { "b": [1] } }`,
+// 		`[ { "op": "remove", "path": "/a/b/1" } ]`,
+// 	},
+// 	{
+// 		`{ "a": { "b": [1] } }`,
+// 		`[ { "op": "move", "from": "/a/b/1", "path": "/a/b/2" } ]`,
+// 	},
+// }
+
+// func TestAllCases(t *testing.T) {
+// 	for _, c := range Cases {
+// 		out, err := applyPatch(c.doc, c.patch)
+
+// 		if err != nil {
+// 			t.Errorf("Unable to apply patch: %s", err)
+// 		}
+
+// 		if !compareJSON(out, c.result) {
+// 			t.Errorf("Patch did not apply. Expected:\n%s\n\nActual:\n%s",
+// 				reformatJSON(c.result), reformatJSON(out))
+// 		}
+// 	}
+
+// 	for _, c := range MutationTestCases {
+// 		out, err := applyPatch(c.doc, c.patch)
+
+// 		if err != nil {
+// 			t.Errorf("Unable to apply patch: %s", err)
+// 		}
+
+// 		if compareJSON(out, c.doc) {
+// 			t.Errorf("Patch did not apply. Original:\n%s\n\nPatched:\n%s",
+// 				reformatJSON(c.doc), reformatJSON(out))
+// 		}
+// 	}
+
+// 	for _, c := range BadCases {
+// 		_, err := applyPatch(c.doc, c.patch)
+
+// 		if err == nil {
+// 			t.Errorf("Patch should have failed to apply but it did not")
+// 		}
+// 	}
+// }
+
+// type TestCase struct {
+// 	doc, patch string
+// 	result     bool
+// 	failedPath string
+// }
+
+// var TestCases = []TestCase{
+// 	{
+// 		`{
+// 			"baz": "qux",
+// 			"foo": [ "a", 2, "c" ]
+// 		}`,
+// 		`[
+// 			{ "op": "test", "path": "/baz", "value": "qux" },
+// 			{ "op": "test", "path": "/foo/1", "value": 2 }
+// 		]`,
+// 		true,
+// 		"",
+// 	},
+// 	{
+// 		`{ "baz": "qux" }`,
+// 		`[ { "op": "test", "path": "/baz", "value": "bar" } ]`,
+// 		false,
+// 		"/baz",
+// 	},
+// 	{
+// 		`{
+// 			"baz": "qux",
+// 			"foo": ["a", 2, "c"]
+// 		}`,
+// 		`[
+// 			{ "op": "test", "path": "/baz", "value": "qux" },
+// 			{ "op": "test", "path": "/foo/1", "value": "c" }
+// 		]`,
+// 		false,
+// 		"/foo/1",
+// 	},
+// 	{
+// 		`{ "baz": "qux" }`,
+// 		`[ { "op": "test", "path": "/foo", "value": 42 } ]`,
+// 		false,
+// 		"/foo",
+// 	},
+// 	{
+// 		`{ "baz": "qux" }`,
+// 		`[ { "op": "test", "path": "/foo", "value": null } ]`,
+// 		true,
+// 		"",
+// 	},
+// 	{
+// 		`{ "baz/foo": "qux" }`,
+// 		`[ { "op": "test", "path": "/baz~1foo", "value": "qux"} ]`,
+// 		true,
+// 		"",
+// 	},
+// }
+
+// func TestAllTest(t *testing.T) {
+// 	for _, c := range TestCases {
+// 		_, err := applyPatch(c.doc, c.patch)
+
+// 		if c.result && err != nil {
+// 			t.Errorf("Testing failed when it should have passed: %s", err)
+// 		} else if !c.result && err == nil {
+// 			t.Errorf("Testing passed when it should have faild: %s", err)
+// 		} else if !c.result {
+// 			expected := fmt.Sprintf("Testing value %s failed", c.failedPath)
+// 			if err.Error() != expected {
+// 				t.Errorf("Testing failed as expected but invalid message: expected [%s], got [%s]", expected, err)
+// 			}
+// 		}
+// 	}
+// }