chore: add code of sidetree core go

.golangci.yml

@@ -11,7 +11,7 @@ run:
   tests: true
   build-tags: [""]
   skip-dirs:
-    - pkg/crypto/primitive/bbs12381g2pub/internal/kilic/bls12-381
+    - method/sidetreelongform/sidetree-core/docutil
 
 output:
   format: colored-line-number

doc/json/canonicalizer/canonicalizer.go

@@ -0,0 +1,29 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package canonicalizer
+
+import (
+	"encoding/json"
+
+	"github.com/trustbloc/did-go/doc/json/canonicalizer/internal/jsoncanonicalizer"
+)
+
+// MarshalCanonical is using JCS RFC canonicalization.
+func MarshalCanonical(value interface{}) ([]byte, error) {
+	valueBytes, ok := value.([]byte)
+
+	if !ok {
+		var err error
+
+		valueBytes, err = json.Marshal(value)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return jsoncanonicalizer.Transform(valueBytes)
+}

doc/json/canonicalizer/canonicalizer_test.go

@@ -0,0 +1,43 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package canonicalizer
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestMarshalCanonical(t *testing.T) {
+	t.Run("success", func(t *testing.T) {
+		test := struct {
+			Beta  string `json:"beta"`
+			Alpha string `json:"alpha"`
+		}{
+			Beta:  "beta",
+			Alpha: "alpha",
+		}
+
+		result, err := MarshalCanonical(test)
+		require.NoError(t, err)
+		require.Equal(t, string(result), `{"alpha":"alpha","beta":"beta"}`)
+	})
+
+	t.Run("success - accepts bytes", func(t *testing.T) {
+		result, err := MarshalCanonical([]byte(`{"beta":"beta","alpha":"alpha"}`))
+		require.NoError(t, err)
+		require.Equal(t, string(result), `{"alpha":"alpha","beta":"beta"}`)
+	})
+
+	t.Run("marshal error", func(t *testing.T) {
+		var c chan int
+		result, err := MarshalCanonical(c)
+		require.Error(t, err)
+		require.Empty(t, result)
+		require.Contains(t, err.Error(), "json: unsupported type: chan int")
+	})
+}

doc/json/canonicalizer/internal/jsoncanonicalizer/README.md

@@ -0,0 +1,4 @@
+## JSON Cononicalizer
+
+The files in this folder are copied AS-IS from [Cyberphone JSON Canonicalization Go Library](https://github.com/cyberphone/json-canonicalization/tree/master/go/src/webpki.org/jsoncanonicalizer). 
+The licence details are available at [LICENCE](https://github.com/cyberphone/json-canonicalization/blob/master/LICENSE).

doc/json/canonicalizer/internal/jsoncanonicalizer/es6numfmt.go

@@ -0,0 +1,95 @@
+//
+//  Copyright 2006-2019 WebPKI.org (http://webpki.org).
+//
+//  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
+//
+//      https://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.
+//
+
+// This package converts numbers in IEEE-754 double precision into the
+// format specified for JSON in EcmaScript Version 6 and forward.
+// The core application for this is canonicalization:
+// https://tools.ietf.org/html/draft-rundgren-json-canonicalization-scheme-02
+
+package jsoncanonicalizer
+
+import (
+	"errors"
+	"math"
+	"strconv"
+	"strings"
+)
+
+const invalidPattern uint64 = 0x7ff0000000000000
+
+func NumberToJSON(ieeeF64 float64) (res string, err error) { //nolint:funlen,gocyclo,golint
+	ieeeU64 := math.Float64bits(ieeeF64)
+
+	// Special case: NaN and Infinity are invalid in JSON
+	if (ieeeU64 & invalidPattern) == invalidPattern {
+		return "null", errors.New("Invalid JSON number: " + strconv.FormatUint(ieeeU64, 16))
+	}
+
+	// Special case: eliminate "-0" as mandated by the ES6-JSON/JCS specifications
+	if ieeeF64 == 0 { // Right, this line takes both -0 and 0
+		return "0", nil
+	}
+
+	// Deal with the sign separately
+	var sign string = ""
+
+	if ieeeF64 < 0 {
+		ieeeF64 = -ieeeF64
+		sign = "-"
+	}
+
+	// ES6 has a unique "g" format
+	var format byte = 'e'
+	if ieeeF64 < 1e+21 && ieeeF64 >= 1e-6 {
+		format = 'f'
+	}
+
+	// The following should (in "theory") do the trick:
+	es6Formatted := strconv.FormatFloat(ieeeF64, format, -1, 64)
+
+	// Unfortunately Go version 1.11.4 is a bit buggy with respect to
+	// rounding for -1 precision which is dealt with below.
+	// https://github.com/golang/go/issues/29491
+	exponent := strings.IndexByte(es6Formatted, 'e')
+	//nolint:nestif
+	if exponent > 0 {
+		gform := strconv.FormatFloat(ieeeF64, 'g', 17, 64)
+		if len(gform) == len(es6Formatted) {
+			// "g" occasionally produces another result which also is the correct one
+			es6Formatted = gform
+		}
+		// Go outputs "1e+09" which must be rewritten as "1e+9"
+		if es6Formatted[exponent+2] == '0' {
+			es6Formatted = es6Formatted[:exponent+2] + es6Formatted[exponent+3:]
+		}
+	} else if strings.IndexByte(es6Formatted, '.') < 0 && len(es6Formatted) >= 12 {
+		i := len(es6Formatted)
+		for es6Formatted[i-1] == '0' {
+			i--
+		}
+		if i != len(es6Formatted) {
+			fix := strconv.FormatFloat(ieeeF64, 'f', 0, 64)
+			if fix[i] >= '5' {
+				// "f" with precision 0 occasionally produces another result which also is
+				// the correct one although it must be rounded to match the -1 precision
+				// (which fortunately seems to be correct with respect to trailing zeroes)
+				es6Formatted = fix[:i-1] + string(fix[i-1]+1) + es6Formatted[i:]
+			}
+		}
+	}
+
+	return sign + es6Formatted, nil
+}