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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package lowmemjson_test
import (
"bytes"
"errors"
"fmt"
"io"
"strings"
"testing"
"github.com/stretchr/testify/assert"
"git.lukeshu.com/go/lowmemjson"
)
type ShortSum string
func (s ShortSum) EncodeJSON(w io.Writer) error {
// Test that it's OK to call lowmemjson.Encoder.Encode for the top-level value in a method.
return lowmemjson.NewEncoder(w).Encode(string(s))
}
type SumRun struct {
ChecksumSize int `json:",omitempty"`
Addr int64 `json:",omitempty"`
Sums ShortSum
}
type SumRunWithGaps struct {
Addr int64
Size int64
Runs []SumRun
}
func (sg SumRunWithGaps) EncodeJSON(w io.Writer) error {
if _, err := fmt.Fprintf(w, `{"Addr":%d,"Size":%d,"Runs":[`, sg.Addr, sg.Size); err != nil {
return err
}
cur := sg.Addr
for i, run := range sg.Runs {
if i > 0 {
if _, err := w.Write([]byte{','}); err != nil {
return err
}
}
if run.Addr > cur {
if _, err := fmt.Fprintf(w, `{"Gap":%d},`, run.Addr-cur); err != nil {
return err
}
}
if err := lowmemjson.NewEncoder(w).Encode(run); err != nil {
return err
}
}
end := sg.Addr + sg.Size
switch {
case end < cur:
return fmt.Errorf("invalid %T: addr went backwards: %v < %v", sg, end, cur)
case end > cur:
if _, err := fmt.Fprintf(w, `,{"Gap":%d}`, end-cur); err != nil {
return err
}
}
if _, err := w.Write([]byte("]}")); err != nil {
return err
}
return nil
}
func (sg *SumRunWithGaps) DecodeJSON(r io.RuneScanner) error {
*sg = SumRunWithGaps{}
var name string
return lowmemjson.DecodeObject(r,
func(r io.RuneScanner) error {
return lowmemjson.NewDecoder(r).Decode(&name)
},
func(r io.RuneScanner) error {
switch name {
case "Addr":
return lowmemjson.NewDecoder(r).Decode(&sg.Addr)
case "Size":
return lowmemjson.NewDecoder(r).Decode(&sg.Size)
case "Runs":
return lowmemjson.DecodeArray(r, func(r io.RuneScanner) error {
var run SumRun
if err := lowmemjson.NewDecoder(r).Decode(&run); err != nil {
return err
}
if run.ChecksumSize > 0 {
sg.Runs = append(sg.Runs, run)
}
return nil
})
default:
return fmt.Errorf("unknown key %q", name)
}
})
}
func TestMethods(t *testing.T) {
t.Parallel()
in := SumRunWithGaps{
Addr: 13631488,
Size: 416033783808,
Runs: []SumRun{
{
ChecksumSize: 4,
Addr: 1095761920,
Sums: "c160817cb5c72bbbe",
},
},
}
var buf bytes.Buffer
assert.NoError(t, lowmemjson.NewEncoder(&buf).Encode(in))
assert.Equal(t,
`{"Addr":13631488,"Size":416033783808,"Runs":[{"Gap":1082130432},{"ChecksumSize":4,"Addr":1095761920,"Sums":"c160817cb5c72bbbe"},{"Gap":416033783808}]}`,
buf.String())
var out SumRunWithGaps
assert.NoError(t, lowmemjson.NewDecoder(&buf).Decode(&out))
assert.Equal(t, in, out)
}
type strEncoder string
func (s strEncoder) EncodeJSON(w io.Writer) error {
_, err := io.WriteString(w, string(s))
return err
}
type strMarshaler string
func (s strMarshaler) MarshalJSON() ([]byte, error) {
return []byte(s), nil
}
type strTextMarshaler struct {
str string
err string
}
func (m strTextMarshaler) MarshalText() (txt []byte, err error) {
if len(m.str) > 0 {
txt = []byte(m.str)
}
if len(m.err) > 0 {
err = errors.New(m.err)
}
return
}
func TestMethodsEncode(t *testing.T) {
t.Parallel()
type testcase struct {
In string
ExpectedErr string
}
testcases := map[string]testcase{
"basic": {In: `{}`},
"empty": {In: ``, ExpectedErr: `syntax error at input byte 0: EOF`},
"short": {In: `{`, ExpectedErr: `syntax error at input byte 1: unexpected EOF`},
"long": {In: `{}{}`, ExpectedErr: `syntax error at input byte 2: invalid character '{' after top-level value`},
}
t.Run("encodable", func(t *testing.T) {
t.Parallel()
for tcName, tc := range testcases {
tc := tc
t.Run(tcName, func(t *testing.T) {
t.Parallel()
var buf strings.Builder
err := lowmemjson.NewEncoder(&buf).Encode([]any{strEncoder(tc.In)})
if tc.ExpectedErr == "" {
assert.NoError(t, err)
assert.Equal(t, "["+tc.In+"]", buf.String())
} else {
assert.EqualError(t, err,
`json: error calling EncodeJSON for type lowmemjson_test.strEncoder: `+
tc.ExpectedErr)
}
})
}
})
t.Run("marshaler", func(t *testing.T) {
t.Parallel()
for tcName, tc := range testcases {
tc := tc
t.Run(tcName, func(t *testing.T) {
t.Parallel()
var buf strings.Builder
err := lowmemjson.NewEncoder(&buf).Encode([]any{strMarshaler(tc.In)})
if tc.ExpectedErr == "" {
assert.NoError(t, err)
assert.Equal(t, "["+tc.In+"]", buf.String())
} else {
assert.EqualError(t, err,
`json: error calling MarshalJSON for type lowmemjson_test.strMarshaler: `+
tc.ExpectedErr)
}
})
}
})
t.Run("text", func(t *testing.T) {
t.Parallel()
type testcase struct {
Str string
Err string
}
testcases := map[string]testcase{
"basic": {Str: `a`},
"err": {Err: `xxx`},
"both": {Str: `a`, Err: `xxx`},
}
for tcName, tc := range testcases {
tc := tc
t.Run(tcName, func(t *testing.T) {
t.Parallel()
var buf strings.Builder
err := lowmemjson.NewEncoder(&buf).Encode([]any{strTextMarshaler{str: tc.Str, err: tc.Err}})
if tc.Err == "" {
assert.NoError(t, err)
assert.Equal(t, `["`+tc.Str+`"]`, buf.String())
} else {
assert.EqualError(t, err,
`json: error calling MarshalText for type lowmemjson_test.strTextMarshaler: `+
tc.Err)
assert.Equal(t, "[", buf.String())
}
})
}
})
}
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