add resp3 protocol part 1(add data type and implement some simple) (#77)

internal/protcl/errors.go

@@ -101,3 +101,31 @@ func (e *ErrUnknownCommand) Error() string {
 func (ErrUnknownCommand) Recoverable() bool {
 	return true
 }
+
+// ErrProtocolType is for protocol type error
+type ErrProtocolType struct {
+	Type byte
+}
+
+// Recoverable whether error is recoverable or not
+func (e *ErrProtocolType) Recoverable() bool {
+	return true
+}
+
+func (e *ErrProtocolType) Error() string {
+	return fmt.Sprintf("unknown protocol type: %s", string(e.Type))
+}
+
+// ErrUnexpectString is for unexpect string error
+type ErrUnexpectString struct {
+	Str string
+}
+
+// Recoverable whether error is recoverable or not
+func (e *ErrUnexpectString) Recoverable() bool {
+	return true
+}
+
+func (e *ErrUnexpectString) Error() string {
+	return fmt.Sprintf("unexpect string: %s", e.Str)
+}

internal/protcl/resp3.go

@@ -0,0 +1,179 @@
+package protcl
+
+import (
+	"bufio"
+	"fmt"
+	"strconv"
+)
+
+// resp3 protocol type
+const (
+	Resp3SimpleString   = '+' // +<string>\n
+	Resp3BlobString     = '$' // $<length>\n<bytes>\n
+	Resp3VerbatimString = '=' // =<length>\n<format(3 bytes)>\n<bytes>\n
+	Resp3SimpleError    = '-' // -<string>\n
+	Resp3BolbError      = '!' // !<length>\n<bytes>\n
+	Resp3Number         = ':' // :<number>\n
+	Resp3Double         = ',' // ,<floating-point-number>\n
+	Resp3BigNumber      = '(' // (<big number>\n
+	Resp3Null           = '_' // _\n
+	Resp3Boolean        = '#' // #t\n or #f\n
+	Resp3Array          = '*' // *<elements number>\n... numelements other types ...
+	Resp3Map            = '%' // %<elements number>\n... numelements other types ...
+	Resp3Set            = '~' // ~<elements number>\n... numelements other types ...
+)
+
+// LF is \n
+const LF = '\n'
+
+// Resp3 the response of resp3 protocol
+type Resp3 struct {
+	Type    byte
+	Str     string
+	Integer int
+	Boolean bool
+}
+
+func (r *Resp3) String() string {
+	switch r.Type {
+	case RepSimpleString, Resp3BlobString:
+		return fmt.Sprintf("%q", r.Str)
+	case Resp3SimpleError, Resp3BolbError:
+		return "(error) " + r.Str
+	case Resp3Number:
+		return "(integer) " + strconv.Itoa(r.Integer)
+	case Resp3Null:
+		return "(null)"
+	case Resp3Boolean:
+		if r.Boolean {
+			return "(boolean) true"
+		}
+		return "(boolean) false"
+	}
+
+	return "(error) unknown protocol type: " + string(r.Type)
+}
+
+// Resp3Parser is for parser resp3 protocol
+type Resp3Parser struct {
+	reader *bufio.Reader
+}
+
+// NewResp3Parser return a Resp3Parser
+func NewResp3Parser(r *bufio.Reader) *Resp3Parser {
+	return &Resp3Parser{reader: r}
+}
+
+// Parse return Resp3
+func (r *Resp3Parser) Parse() (*Resp3, error) {
+	b, err := r.reader.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	switch b {
+	case Resp3SimpleString, Resp3SimpleError:
+		str, err := r.stringBeforeLF()
+		if err != nil {
+			return nil, err
+		}
+		return &Resp3{Type: b, Str: str}, nil
+	case Resp3BlobString, Resp3BolbError:
+		length, err := r.intBeforeLF()
+		if err != nil {
+			return nil, err
+		}
+
+		bs, err := r.readLengthBytesWithLF(length)
+		if err != nil {
+			return nil, err
+		}
+
+		return &Resp3{Type: b, Str: string(bs)}, nil
+	case Resp3Number:
+		integer, err := r.intBeforeLF()
+		if err != nil {
+			return nil, err
+		}
+		return &Resp3{Type: b, Integer: integer}, nil
+	case Resp3Null:
+		if _, err := r.readLengthBytesWithLF(0); err != nil {
+			return nil, err
+		}
+		return &Resp3{Type: b}, nil
+	case Resp3Boolean:
+		buf, err := r.readLengthBytesWithLF(1)
+		if err != nil {
+			return nil, err
+		}
+
+		switch buf[0] {
+		case 't':
+			return &Resp3{Type: b, Boolean: true}, nil
+		case 'f':
+			return &Resp3{Type: b, Boolean: false}, nil
+		}
+		return nil, &ErrUnexpectString{Str: "t/f"}
+	}
+
+	return nil, &ErrProtocolType{Type: b}
+}
+
+func (r *Resp3Parser) stringBeforeLF() (string, error) {
+	buf, err := r.reader.ReadBytes(LF)
+	if err != nil {
+		return "", err
+	}
+	bs, err := trimLastLF(buf)
+	if err != nil {
+		return "", err
+	}
+	return string(bs), nil
+}
+
+func (r *Resp3Parser) intBeforeLF() (int, error) {
+	buf, err := r.reader.ReadBytes(LF)
+	if err != nil {
+		return 0, err
+	}
+	bs, err := trimLastLF(buf)
+	if err != nil {
+		return 0, err
+	}
+	s := string(bs)
+	i, err := strconv.Atoi(s)
+	if err != nil {
+		return 0, &ErrCastFailedToInt{Val: s}
+	}
+	return i, nil
+}
+
+func (r *Resp3Parser) readLengthBytesWithLF(length int) ([]byte, error) {
+	if length == 0 {
+		if b, err := r.reader.ReadByte(); err != nil {
+			return nil, err
+		} else if b != LF {
+			return nil, &ErrUnexpectString{Str: "<LF>"}
+		}
+		return nil, nil
+	}
+
+	buf := make([]byte, length+1)
+	n, err := r.reader.Read(buf)
+	if err != nil {
+		return nil, err
+	} else if n < length+1 {
+		return nil, &ErrUnexpectedLineEnd{}
+	}
+
+	return trimLastLF(buf)
+}
+
+func trimLastLF(buf []byte) ([]byte, error) {
+	bufLen := len(buf)
+	if len(buf) == 0 || buf[bufLen-1] != LF {
+		return nil, &ErrUnexpectedLineEnd{}
+	}
+
+	return buf[:bufLen-1], nil
+}

internal/protcl/resp3_test.go

@@ -0,0 +1,62 @@
+package protcl
+
+import (
+	"bufio"
+	"strings"
+	"testing"
+
+	testifyAssert "github.com/stretchr/testify/assert"
+)
+
+func testResp3Parser(t *testing.T, input, expect string) {
+	assert := testifyAssert.New(t)
+
+	parser := NewResp3Parser(bufio.NewReader(strings.NewReader(input)))
+	result, err := parser.Parse()
+	assert.Nil(err)
+	assert.Equal(expect, result.String())
+}
+
+func testResp3Error(t *testing.T, input, e string) {
+	assert := testifyAssert.New(t)
+
+	parser := NewResp3Parser(bufio.NewReader(strings.NewReader(input)))
+	result, err := parser.Parse()
+	assert.NotNil(err)
+	assert.Nil(result)
+	assert.Equal(e, err.Error())
+}
+
+func TestResp3Parser(t *testing.T) {
+	// simple string
+	testResp3Error(t, "+string", `EOF`)
+	testResp3Parser(t, "+string\n", `"string"`)
+
+	// blob string
+	testResp3Parser(t, "$0\n\n", `""`)
+	testResp3Error(t, "$1\n\n", `unexpected line end`)
+	testResp3Error(t, "$1\naa\n", `unexpected line end`)
+	testResp3Parser(t, "$10\n1234567890\n", `"1234567890"`)
+
+	// simple error
+	testResp3Parser(t, "-error\n", `(error) error`)
+	testResp3Parser(t, "-Err error\n", `(error) Err error`)
+
+	// blob error
+	testResp3Parser(t, "!3\nerr\n", `(error) err`)
+	testResp3Parser(t, "!17\nErr this is error\n", `(error) Err this is error`)
+
+	// number
+	testResp3Parser(t, ":-1\n", `(integer) -1`)
+	testResp3Parser(t, ":0\n", `(integer) 0`)
+	testResp3Parser(t, ":100\n", `(integer) 100`)
+
+	// null
+	testResp3Parser(t, "_\n", "(null)")
+
+	// boolean
+	testResp3Parser(t, "#t\n", `(boolean) true`)
+	testResp3Parser(t, "#f\n", `(boolean) false`)
+	testResp3Error(t, "#x\n", `unexpect string: t/f`)
+	testResp3Error(t, "#\n", `unexpected line end`)
+}