decoder_test.go

// Copyright (c) 2021-2025 Dell Inc. or its subsidiaries.  All rights reserved.
// Licensed to You under the Apache License, Version 2.0.   See the LICENSE file for more details.
package jsonstream_test

/*
Modifications
Copyright (c) 2021, Dell Inc  Michael Brown

Original
Copyright (c) 2020, Dave Cheney <dave@cheney.net>
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
Modified from Dave Cheney's original:
 - Our use case is streaming tokenization only. No need for decoding into go data structures.
 - Need to bookkeep an accurate path for each token to allow upper layers to filter/modify
*/

import (
	"bytes"
	"fmt"
	"io"
	"strings"
	"testing"

	"github.com/sailfishdell/jsonstream"
)

// nolint: gochecknoglobals
var tests = []struct {
	json   string
	tokens []string
}{
	{json: `"a"`, tokens: []string{`"a"`}},
	{json: `1`, tokens: []string{`1`}},
	{json: `{}`, tokens: []string{``}},
	{json: `[]`, tokens: []string{``}},
	{json: `[[[[[[{"true":true}]]]]]]`, tokens: []string{`true`, ``, ``, ``, ``, ``, ``, ``}},
	{json: `[{},{}]`, tokens: []string{``, ``, ``}},
	{json: `{"a":0}`, tokens: []string{`0`, ``}},
	{json: `{"a":[]}`, tokens: []string{``, ``}},
	{json: `{"a":{},"b":{}}`, tokens: []string{``, ``, ``}},
	{json: `[10]`, tokens: []string{`10`, ``}},
	{json: `""`, tokens: []string{`""`}},
	{json: `[{}]`, tokens: []string{``, ``}},
	{json: `[{"a":[{}]}]`, tokens: []string{``, ``, ``, ``}},
	{json: `[{"a":1,"b":123.456,"c":null,"d":[1,-2,"three",true,false,""]}]`,
		tokens: []string{
			`1`,
			`123.456`,
			`null`,
			`1`, `-2`, `"three"`, `true`, `false`, `""`,
			``,
			``,
			``,
		},
	},
}

type token struct {
	path  jsonstream.JSONPath
	token []byte
}

func simpleParse(filters []jsonstream.Filter, input, expected string, expectedTokens []token) func(*testing.T) {
	return func(t *testing.T) {
		t.Logf("INPUT: %s", input)

		out := &strings.Builder{}
		enc := jsonstream.NewEncoder(out)
		var dec jsonstream.TokenIterator

		dec = jsonstream.NewDecoder(io.NopCloser(strings.NewReader(input)))
		defer dec.Close()
		for _, f := range filters {
			dec = f(dec)
		}

		failure := ""

		var decErr error
		for n, want := range expectedTokens {
			var pth jsonstream.JSONPath
			var got []byte
			pth, got, decErr = dec.NextToken()
			t.Logf("path: %#v, token: %q", pth, got)
			encErr := enc.EncodeOne(pth, got)
			if encErr != nil {
				failure += fmt.Sprintf("unexpected encoding error: %s", encErr.Error())
				break
			}

			if !bytes.Equal(got, want.token) {
				failure += fmt.Sprintf("%v: expected: %#v, got: %#v, %v\n", n+1, want, got, decErr)
			}

			if decErr != nil {
				break
			}
		}
		if out.String() != expected {
			failure += fmt.Sprintf("expected: %q  got: %q  err %v", expected, out.String(), decErr)
		}

		if failure != "" {
			t.Fatal(failure)
		}
	}
}

func TestNewJSONPathProp(t *testing.T) {
	ret := jsonstream.NewJSONPathProp("test")
	if !bytes.Equal(ret, []byte(`"test"`)) {
		t.Errorf("Expected \"test\" got %s", ret)
	}
	ret = jsonstream.NewJSONPathProp("")
	if !bytes.Equal(ret, []byte(`""`)) {
		t.Errorf("Expected \"\" got %s", ret)
	}
}

func TestNewJSONPathElem(t *testing.T) {
	ret := jsonstream.NewJSONPathElem(1)
	if ret != 1 {
		t.Errorf("Expected 1 got %d", ret)
	}
	ret = jsonstream.NewJSONPathElem([]byte(`"test"`))
	retBytes, ok := ret.([]byte)
	if !ok {
		t.Fatalf("Expected []byte got %T", ret)
	}
	if !bytes.Equal(retBytes, []byte(`"test"`)) {
		t.Errorf("Expected \"test\" got %s", ret)
	}
	ret = jsonstream.NewJSONPathElem("123")
	retBytes, ok = ret.([]byte)
	if !ok {
		t.Fatalf("Expected []byte got %T", ret)
	}
	if !bytes.Equal(retBytes, []byte(`"123"`)) {
		t.Errorf("Expected \"123\" got %s", ret)
	}
}

func TestNewJSONPathElemNegative(t *testing.T) {
	defer func() {
		if r := recover(); r == nil {
			t.Errorf("Expected panic")
		}
	}()
	jsonstream.NewJSONPathElem(0.1)
}

func TestJSONPathLen(t *testing.T) {
	path := jsonstream.NewJSONPath()
	if path.Len() != 0 {
		t.Errorf("Expected 0 got %d", path.Len())
	}
	path = jsonstream.NewJSONPath("test")
	if path.Len() != 1 {
		t.Errorf("Expected 1 got %d", path.Len())
	}
	path = jsonstream.NewJSONPath("test", "123", 3)
	if path.Len() != 3 {
		t.Errorf("Expected 3 got %d", path.Len())
	}
}

func TestJSONPathClone(t *testing.T) {
	inputArgs := [][]interface{}{
		{},
		{"test"},
		{"test", "123", 3},
		{"test", []byte(nil)},
	}
	expectedStrings := []string{
		"",
		"/test",
		"/test/123/3",
		"/test/<nil>",
	}
	for i, input := range inputArgs {
		path := jsonstream.NewJSONPath(input...)
		path2 := path.Clone()
		if &path == &path2 {
			t.Errorf("Expected different pointers")
		}
		if path.Len() != path2.Len() {
			t.Errorf("Expected same length got %d and %d", path.Len(), path2.Len())
		}
		if path.String() != expectedStrings[i] {
			t.Errorf("Expected %s got %s", expectedStrings[i], path.String())
		}
	}
}

func TestJSONPathFromPropEnd(t *testing.T) {
	path := jsonstream.NewJSONPath()
	ret, ok := path.PathPropFromEnd(0)
	if ok {
		t.Errorf("Expected false got true for empty path")
	}
	if ret != nil {
		t.Errorf("Expected nil got %s for empty path", ret)
	}
	path = jsonstream.NewJSONPath("test", "123", 3)
	ret, ok = path.PathPropFromEnd(0)
	if ok {
		t.Errorf("Expected false got true for array element")
	}
	if ret != nil {
		t.Errorf("Expected nil got %#v for array element", ret)
	}
	ret, ok = path.PathPropFromEnd(1)
	if !ok {
		t.Errorf("Expected true got false for object element")
	}
	if !bytes.Equal(ret, []byte(`123`)) {
		t.Errorf("Expected 123 got %s for object element", ret)
	}
}

// nolint:funlen
func TestPathPropFromEnd(t *testing.T) {
	type testCase struct {
		testName    string
		path        jsonstream.JSONPath
		elemIdx     int
		expectedRet []byte
		expectedIdx int
		expectedOk  bool
	}
	testCases := []testCase{
		{
			testName:    "Out of bounds",
			path:        jsonstream.NewJSONPath("one", "two", "three"),
			elemIdx:     500,
			expectedRet: nil,
			expectedIdx: -1,
			expectedOk:  false,
		},
		{
			testName:    "Invalid []byte property",
			path:        jsonstream.NewJSONPath("one", "two", []byte("a")),
			elemIdx:     0,
			expectedRet: []byte("a"),
			expectedIdx: -1,
			expectedOk:  false,
		},
		{
			testName:    "Valid []byte property",
			path:        jsonstream.NewJSONPath("one", "two", "three"),
			elemIdx:     0,
			expectedRet: []byte("three"),
			expectedIdx: -1,
			expectedOk:  true,
		},
		{
			testName:    "Invalid index",
			path:        jsonstream.NewJSONPath("one", "two", -5),
			elemIdx:     0,
			expectedRet: nil,
			expectedIdx: -5,
			expectedOk:  false,
		},
		{
			testName:    "Valid index",
			path:        jsonstream.NewJSONPath("one", "two", 2),
			elemIdx:     0,
			expectedRet: nil,
			expectedIdx: 2,
			expectedOk:  true,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.testName, func(t *testing.T) {
			ret, idx, ok := tc.path.PathPropOrIndexFromEnd(tc.elemIdx)
			if !bytes.Equal(ret, tc.expectedRet) {
				t.Errorf("pathPropFromEnd() ret=%v, expected %v", string(ret), string(tc.expectedRet))
			}
			if idx != tc.expectedIdx {
				t.Errorf("pathPropFromEnd() idx=%d, expected %d", idx, tc.expectedIdx)
			}
			if ok != tc.expectedOk {
				t.Errorf("pathPropFromEnd() ok=%t, expected %t", ok, tc.expectedOk)
			}
		})
	}
}

func TestJSONPathArr(t *testing.T) {
	path := jsonstream.NewJSONPath()
	ret, ok := path.PathArr(0)
	if ok {
		t.Errorf("Expected false got true for empty path")
	}
	if ret != 0 {
		t.Errorf("Expected 0 got %d for empty path", ret)
	}
	path = jsonstream.NewJSONPath("test", "123", 3)
	ret, ok = path.PathArr(2)
	if !ok {
		t.Errorf("Expected true got false for array element")
	}
	if ret != 3 {
		t.Errorf("Expected 3 got %#v for array element", ret)
	}
	ret, ok = path.PathArr(1)
	if ok {
		t.Errorf("Expected false got true for object element")
	}
	if ret != 0 {
		t.Errorf("Expected 0 got %d for object element", ret)
	}
}

func TestNewTokenFromString(t *testing.T) {
	ret := jsonstream.NewTokenFromString("test")
	if !bytes.Equal(ret, []byte(`"test"`)) {
		t.Errorf("Expected \"test\" got %s", ret)
	}
}

type nextTokenOutput struct {
	Path  jsonstream.JSONPath
	Token []byte
	Error error
}

type decodingTestCase struct {
	Name            string
	Input           []byte
	ExpectedOutputs []nextTokenOutput
}

//nolint:funlen // This is just a list of test cases
func getNegativeDecodingTestCases() []decodingTestCase {
	return []decodingTestCase{
		{
			Name:            "Empty input",
			Input:           []byte{},
			ExpectedOutputs: []nextTokenOutput{{Error: io.ErrUnexpectedEOF}},
		},
		{
			Name:            "just a string",
			Input:           []byte(`test`),
			ExpectedOutputs: []nextTokenOutput{{Error: io.ErrUnexpectedEOF}},
		},
		{
			Name:  "empty object",
			Input: []byte(`{}`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(nil)), Token: []byte(``), Error: nil},
				{Error: io.EOF},
			},
		},
		{
			Name:  "unterminated object",
			Input: []byte(`{`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(nil)), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "object key only",
			Input: []byte(`{"test"}`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Token: []byte(`}`), Error: jsonstream.ErrObjectNoColon},
			},
		},
		{
			Name:  "object key only unterminated",
			Input: []byte(`{"test"`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "object key and colon",
			Input: []byte(`{"test":}`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Token: []byte(`}`)},
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "object key colon unterminated",
			Input: []byte(`{"test":`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "object non-string key",
			Input: []byte(`{1:"abc"}`),
			ExpectedOutputs: []nextTokenOutput{
				{Error: jsonstream.ErrMissingKey},
			},
		},
		{
			Name:  "object key value unterminated",
			Input: []byte(`{"test":"123"`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Token: []byte(`"123"`), Error: nil},
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "object key value no comma",
			Input: []byte(`{"test":"123""foo":"bar"}`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Token: []byte(`"123"`), Error: nil},
				{Path: jsonstream.NewJSONPath([]byte(`"test"`)), Token: []byte(`"foo"`), Error: jsonstream.ErrExpectingComma},
			},
		},
		{
			Name:  "unterminated array",
			Input: []byte(`[`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath(0), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "comma array",
			Input: []byte(`[,]`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath(0), Error: jsonstream.ErrUnexpectedComma},
			},
		},
		{
			Name:  "unterminated array first element",
			Input: []byte(`[1`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath(0), Token: []byte(`1`)},
				{Path: jsonstream.NewJSONPath(0), Error: io.ErrUnexpectedEOF},
			},
		},
		{
			Name:  "array not comma separated",
			Input: []byte(`[1"test"]`),
			ExpectedOutputs: []nextTokenOutput{
				{Path: jsonstream.NewJSONPath(0), Token: []byte(`1`)},
				{Path: jsonstream.NewJSONPath(0), Error: fmt.Errorf("stateArrayComma: expected comma, [false]")},
			},
		},
		{
			Name:  "just comma",
			Input: []byte(`,`),
			ExpectedOutputs: []nextTokenOutput{
				{Error: jsonstream.ErrValueUnexpectedComma},
			},
		},
	}
}

func TestNegativeDecoding(t *testing.T) {
	testCases := getNegativeDecodingTestCases()
	for _, tc := range testCases {
		t.Run(tc.Name, func(t *testing.T) {
			dec := jsonstream.NewDecoder(io.NopCloser(bytes.NewReader(tc.Input)))
			i := 0
			for {
				path, token, err := dec.NextToken()
				if len(tc.ExpectedOutputs) <= i {
					t.Errorf("got unexpected extra output %s %s %v", path, token, err)
					i++
					if err != nil {
						break
					}
					continue
				}
				if path.String() != tc.ExpectedOutputs[i].Path.String() {
					t.Errorf("%d: expected path: \"%s\", got: \"%s\"", i, tc.ExpectedOutputs[i].Path, path)
				}
				if !bytes.Equal(token, tc.ExpectedOutputs[i].Token) {
					t.Errorf("%d: expected token: %s, got: %s", i, tc.ExpectedOutputs[i].Token, token)
				}
				CompareErrors(t, tc.ExpectedOutputs[i].Error, err)
				i++
				if err != nil {
					break
				}
			}
		})
	}
}

func CompareErrors(t testing.TB, expected, actual error) {
	t.Helper()
	if actual != expected && (actual == nil || expected == nil || actual.Error() != expected.Error()) {
		err1 := "<nil>"
		if actual != nil {
			err1 = actual.Error()
		}
		err2 := "<nil>"
		if expected != nil {
			err2 = expected.Error()
		}
		t.Errorf("expected error %s, got %s", err2, err1)
	}
}