rename frontends to frontend

frontend/http/bencode/bencode.go

@@ -0,0 +1,33 @@
+// Copyright 2016 Jimmy Zelinskie
+//
+// 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 bencode implements bencoding of data as defined in BEP 3 using
+// type assertion over reflection for performance.
+package bencode
+
+// Dict represents a bencode dictionary.
+type Dict map[string]interface{}
+
+// NewDict allocates the memory for a Dict.
+func NewDict() Dict {
+	return make(Dict)
+}
+
+// List represents a bencode list.
+type List []interface{}
+
+// NewList allocates the memory for a List.
+func NewList() List {
+	return make(List, 0)
+}

frontend/http/bencode/decoder.go

@@ -0,0 +1,145 @@
+// Copyright 2016 Jimmy Zelinskie
+//
+// 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 bencode
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"io"
+	"strconv"
+)
+
+// A Decoder reads bencoded objects from an input stream.
+type Decoder struct {
+	r *bufio.Reader
+}
+
+// NewDecoder returns a new decoder that reads from r.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{r: bufio.NewReader(r)}
+}
+
+// Decode unmarshals the next bencoded value in the stream.
+func (dec *Decoder) Decode() (interface{}, error) {
+	return unmarshal(dec.r)
+}
+
+// Unmarshal deserializes and returns the bencoded value in buf.
+func Unmarshal(buf []byte) (interface{}, error) {
+	r := bufio.NewReader(bytes.NewBuffer(buf))
+	return unmarshal(r)
+}
+
+// unmarshal reads bencoded values from a bufio.Reader
+func unmarshal(r *bufio.Reader) (interface{}, error) {
+	tok, err := r.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	switch tok {
+	case 'i':
+		return readTerminatedInt(r, 'e')
+
+	case 'l':
+		list := NewList()
+		for {
+			ok, err := readTerminator(r, 'e')
+			if err != nil {
+				return nil, err
+			} else if ok {
+				break
+			}
+
+			v, err := unmarshal(r)
+			if err != nil {
+				return nil, err
+			}
+			list = append(list, v)
+		}
+		return list, nil
+
+	case 'd':
+		dict := NewDict()
+		for {
+			ok, err := readTerminator(r, 'e')
+			if err != nil {
+				return nil, err
+			} else if ok {
+				break
+			}
+
+			v, err := unmarshal(r)
+			if err != nil {
+				return nil, err
+			}
+
+			key, ok := v.(string)
+			if !ok {
+				return nil, errors.New("bencode: non-string map key")
+			}
+
+			dict[key], err = unmarshal(r)
+			if err != nil {
+				return nil, err
+			}
+		}
+		return dict, nil
+
+	default:
+		err = r.UnreadByte()
+		if err != nil {
+			return nil, err
+		}
+
+		length, err := readTerminatedInt(r, ':')
+		if err != nil {
+			return nil, errors.New("bencode: unknown input sequence")
+		}
+
+		buf := make([]byte, length)
+		n, err := r.Read(buf)
+
+		if err != nil {
+			return nil, err
+		} else if int64(n) != length {
+			return nil, errors.New("bencode: short read")
+		}
+
+		return string(buf), nil
+	}
+}
+
+func readTerminator(r io.ByteScanner, term byte) (bool, error) {
+	tok, err := r.ReadByte()
+	if err != nil {
+		return false, err
+	} else if tok == term {
+		return true, nil
+	}
+	return false, r.UnreadByte()
+}
+
+func readTerminatedInt(r *bufio.Reader, term byte) (int64, error) {
+	buf, err := r.ReadSlice(term)
+	if err != nil {
+		return 0, err
+	} else if len(buf) <= 1 {
+		return 0, errors.New("bencode: empty integer field")
+	}
+
+	return strconv.ParseInt(string(buf[:len(buf)-1]), 10, 64)
+}

frontend/http/bencode/decoder_test.go

@@ -0,0 +1,96 @@
+// Copyright 2016 Jimmy Zelinskie
+//
+// 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 bencode
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var unmarshalTests = []struct {
+	input    string
+	expected interface{}
+}{
+	{"i42e", int64(42)},
+	{"i-42e", int64(-42)},
+
+	{"7:example", "example"},
+
+	{"l3:one3:twoe", List{"one", "two"}},
+	{"le", List{}},
+
+	{"d3:one2:aa3:two2:bbe", Dict{"one": "aa", "two": "bb"}},
+	{"de", Dict{}},
+}
+
+func TestUnmarshal(t *testing.T) {
+	for _, tt := range unmarshalTests {
+		got, err := Unmarshal([]byte(tt.input))
+		assert.Nil(t, err, "unmarshal should not fail")
+		assert.Equal(t, got, tt.expected, "unmarshalled values should match the expected results")
+	}
+}
+
+type bufferLoop struct {
+	val string
+}
+
+func (r *bufferLoop) Read(b []byte) (int, error) {
+	n := copy(b, r.val)
+	return n, nil
+}
+
+func BenchmarkUnmarshalScalar(b *testing.B) {
+	d1 := NewDecoder(&bufferLoop{"7:example"})
+	d2 := NewDecoder(&bufferLoop{"i42e"})
+
+	for i := 0; i < b.N; i++ {
+		d1.Decode()
+		d2.Decode()
+	}
+}
+
+func TestUnmarshalLarge(t *testing.T) {
+	data := Dict{
+		"k1": List{"a", "b", "c"},
+		"k2": int64(42),
+		"k3": "val",
+		"k4": int64(-42),
+	}
+
+	buf, _ := Marshal(data)
+	dec := NewDecoder(&bufferLoop{string(buf)})
+
+	got, err := dec.Decode()
+	assert.Nil(t, err, "decode should not fail")
+	assert.Equal(t, got, data, "encoding and decoding should equal the original value")
+}
+
+func BenchmarkUnmarshalLarge(b *testing.B) {
+	data := map[string]interface{}{
+		"k1": []string{"a", "b", "c"},
+		"k2": 42,
+		"k3": "val",
+		"k4": uint(42),
+	}
+
+	buf, _ := Marshal(data)
+	dec := NewDecoder(&bufferLoop{string(buf)})
+
+	for i := 0; i < b.N; i++ {
+		dec.Decode()
+	}
+}

frontend/http/bencode/encoder.go

@@ -0,0 +1,173 @@
+// Copyright 2016 Jimmy Zelinskie
+//
+// 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 bencode
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"time"
+)
+
+// An Encoder writes bencoded objects to an output stream.
+type Encoder struct {
+	w io.Writer
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{w: w}
+}
+
+// Encode writes the bencoding of v to the stream.
+func (enc *Encoder) Encode(v interface{}) error {
+	return marshal(enc.w, v)
+}
+
+// Marshal returns the bencoding of v.
+func Marshal(v interface{}) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	err := marshal(buf, v)
+	return buf.Bytes(), err
+}
+
+// Marshaler is the interface implemented by objects that can marshal
+// themselves.
+type Marshaler interface {
+	MarshalBencode() ([]byte, error)
+}
+
+// marshal writes types bencoded to an io.Writer
+func marshal(w io.Writer, data interface{}) error {
+	switch v := data.(type) {
+	case Marshaler:
+		bencoded, err := v.MarshalBencode()
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(bencoded)
+		if err != nil {
+			return err
+		}
+
+	case string:
+		marshalString(w, v)
+
+	case int:
+		marshalInt(w, int64(v))
+
+	case uint:
+		marshalUint(w, uint64(v))
+
+	case int16:
+		marshalInt(w, int64(v))
+
+	case uint16:
+		marshalUint(w, uint64(v))
+
+	case int32:
+		marshalInt(w, int64(v))
+
+	case uint32:
+		marshalUint(w, uint64(v))
+
+	case int64:
+		marshalInt(w, v)
+
+	case uint64:
+		marshalUint(w, v)
+
+	case []byte:
+		marshalBytes(w, v)
+
+	case time.Duration: // Assume seconds
+		marshalInt(w, int64(v/time.Second))
+
+	case Dict:
+		marshal(w, map[string]interface{}(v))
+
+	case []Dict:
+		w.Write([]byte{'l'})
+		for _, val := range v {
+			err := marshal(w, val)
+			if err != nil {
+				return err
+			}
+		}
+		w.Write([]byte{'e'})
+
+	case map[string]interface{}:
+		w.Write([]byte{'d'})
+		for key, val := range v {
+			marshalString(w, key)
+			err := marshal(w, val)
+			if err != nil {
+				return err
+			}
+		}
+		w.Write([]byte{'e'})
+
+	case []string:
+		w.Write([]byte{'l'})
+		for _, val := range v {
+			err := marshal(w, val)
+			if err != nil {
+				return err
+			}
+		}
+		w.Write([]byte{'e'})
+
+	case List:
+		marshal(w, []interface{}(v))
+
+	case []interface{}:
+		w.Write([]byte{'l'})
+		for _, val := range v {
+			err := marshal(w, val)
+			if err != nil {
+				return err
+			}
+		}
+		w.Write([]byte{'e'})
+
+	default:
+		return fmt.Errorf("attempted to marshal unsupported type:\n%t", v)
+	}
+
+	return nil
+}
+
+func marshalInt(w io.Writer, v int64) {
+	w.Write([]byte{'i'})
+	w.Write([]byte(strconv.FormatInt(v, 10)))
+	w.Write([]byte{'e'})
+}
+
+func marshalUint(w io.Writer, v uint64) {
+	w.Write([]byte{'i'})
+	w.Write([]byte(strconv.FormatUint(v, 10)))
+	w.Write([]byte{'e'})
+}
+
+func marshalBytes(w io.Writer, v []byte) {
+	w.Write([]byte(strconv.Itoa(len(v))))
+	w.Write([]byte{':'})
+	w.Write(v)
+}
+
+func marshalString(w io.Writer, v string) {
+	marshalBytes(w, []byte(v))
+}

frontend/http/bencode/encoder_test.go

@@ -0,0 +1,81 @@
+// Copyright 2016 Jimmy Zelinskie
+//
+// 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 bencode
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var marshalTests = []struct {
+	input    interface{}
+	expected []string
+}{
+	{int(42), []string{"i42e"}},
+	{int(-42), []string{"i-42e"}},
+	{uint(43), []string{"i43e"}},
+	{int64(44), []string{"i44e"}},
+	{uint64(45), []string{"i45e"}},
+	{int16(44), []string{"i44e"}},
+	{uint16(45), []string{"i45e"}},
+
+	{"example", []string{"7:example"}},
+	{[]byte("example"), []string{"7:example"}},
+	{30 * time.Minute, []string{"i1800e"}},
+
+	{[]string{"one", "two"}, []string{"l3:one3:twoe", "l3:two3:onee"}},
+	{[]interface{}{"one", "two"}, []string{"l3:one3:twoe", "l3:two3:onee"}},
+	{[]string{}, []string{"le"}},
+
+	{map[string]interface{}{"one": "aa", "two": "bb"}, []string{"d3:one2:aa3:two2:bbe", "d3:two2:bb3:one2:aae"}},
+	{map[string]interface{}{}, []string{"de"}},
+}
+
+func TestMarshal(t *testing.T) {
+	for _, test := range marshalTests {
+		got, err := Marshal(test.input)
+		assert.Nil(t, err, "marshal should not fail")
+		assert.Contains(t, test.expected, string(got), "the marshaled result should be one of the expected permutations")
+	}
+}
+
+func BenchmarkMarshalScalar(b *testing.B) {
+	buf := &bytes.Buffer{}
+	encoder := NewEncoder(buf)
+
+	for i := 0; i < b.N; i++ {
+		encoder.Encode("test")
+		encoder.Encode(123)
+	}
+}
+
+func BenchmarkMarshalLarge(b *testing.B) {
+	data := map[string]interface{}{
+		"k1": []string{"a", "b", "c"},
+		"k2": 42,
+		"k3": "val",
+		"k4": uint(42),
+	}
+
+	buf := &bytes.Buffer{}
+	encoder := NewEncoder(buf)
+
+	for i := 0; i < b.N; i++ {
+		encoder.Encode(data)
+	}
+}