diff options
Diffstat (limited to 'src/encoding/gob/encode.go')
| -rw-r--r-- | src/encoding/gob/encode.go | 73 |
1 files changed, 49 insertions, 24 deletions
diff --git a/src/encoding/gob/encode.go b/src/encoding/gob/encode.go index 3da848c851..f66279f141 100644 --- a/src/encoding/gob/encode.go +++ b/src/encoding/gob/encode.go @@ -7,7 +7,6 @@ package gob import ( - "bytes" "encoding" "math" "reflect" @@ -23,14 +22,46 @@ type encHelper func(state *encoderState, v reflect.Value) bool // 0 terminates the structure. type encoderState struct { enc *Encoder - b *bytes.Buffer + b *encBuffer sendZero bool // encoding an array element or map key/value pair; send zero values fieldnum int // the last field number written. buf [1 + uint64Size]byte // buffer used by the encoder; here to avoid allocation. next *encoderState // for free list } -func (enc *Encoder) newEncoderState(b *bytes.Buffer) *encoderState { +// encBuffer is an extremely simple, fast implementation of a write-only byte buffer. +// It never returns a non-nil error, but Write returns an error value so it matches io.Writer. +type encBuffer struct { + data []byte + scratch [64]byte +} + +func (e *encBuffer) WriteByte(c byte) { + e.data = append(e.data, c) +} + +func (e *encBuffer) Write(p []byte) (int, error) { + e.data = append(e.data, p...) + return len(p), nil +} + +func (e *encBuffer) WriteString(s string) { + e.data = append(e.data, s...) +} + +func (e *encBuffer) Len() int { + return len(e.data) +} + +func (e *encBuffer) Bytes() []byte { + return e.data +} + +func (e *encBuffer) Reset() { + e.data = e.data[0:0] +} + +func (enc *Encoder) newEncoderState(b *encBuffer) *encoderState { e := enc.freeList if e == nil { e = new(encoderState) @@ -41,6 +72,9 @@ func (enc *Encoder) newEncoderState(b *bytes.Buffer) *encoderState { e.sendZero = false e.fieldnum = 0 e.b = b + if len(b.data) == 0 { + b.data = b.scratch[0:0] + } return e } @@ -57,10 +91,7 @@ func (enc *Encoder) freeEncoderState(e *encoderState) { // encodeUint writes an encoded unsigned integer to state.b. func (state *encoderState) encodeUint(x uint64) { if x <= 0x7F { - err := state.b.WriteByte(uint8(x)) - if err != nil { - error_(err) - } + state.b.WriteByte(uint8(x)) return } i := uint64Size @@ -70,10 +101,7 @@ func (state *encoderState) encodeUint(x uint64) { i-- } state.buf[i] = uint8(i - uint64Size) // = loop count, negated - _, err := state.b.Write(state.buf[i : uint64Size+1]) - if err != nil { - error_(err) - } + state.b.Write(state.buf[i : uint64Size+1]) } // encodeInt writes an encoded signed integer to state.w. @@ -251,7 +279,7 @@ func valid(v reflect.Value) bool { } // encodeSingle encodes a single top-level non-struct value. -func (enc *Encoder) encodeSingle(b *bytes.Buffer, engine *encEngine, value reflect.Value) { +func (enc *Encoder) encodeSingle(b *encBuffer, engine *encEngine, value reflect.Value) { state := enc.newEncoderState(b) defer enc.freeEncoderState(state) state.fieldnum = singletonField @@ -268,7 +296,7 @@ func (enc *Encoder) encodeSingle(b *bytes.Buffer, engine *encEngine, value refle } // encodeStruct encodes a single struct value. -func (enc *Encoder) encodeStruct(b *bytes.Buffer, engine *encEngine, value reflect.Value) { +func (enc *Encoder) encodeStruct(b *encBuffer, engine *encEngine, value reflect.Value) { if !valid(value) { return } @@ -295,7 +323,7 @@ func (enc *Encoder) encodeStruct(b *bytes.Buffer, engine *encEngine, value refle } // encodeArray encodes an array. -func (enc *Encoder) encodeArray(b *bytes.Buffer, value reflect.Value, op encOp, elemIndir int, length int, helper encHelper) { +func (enc *Encoder) encodeArray(b *encBuffer, value reflect.Value, op encOp, elemIndir int, length int, helper encHelper) { state := enc.newEncoderState(b) defer enc.freeEncoderState(state) state.fieldnum = -1 @@ -329,7 +357,7 @@ func encodeReflectValue(state *encoderState, v reflect.Value, op encOp, indir in } // encodeMap encodes a map as unsigned count followed by key:value pairs. -func (enc *Encoder) encodeMap(b *bytes.Buffer, mv reflect.Value, keyOp, elemOp encOp, keyIndir, elemIndir int) { +func (enc *Encoder) encodeMap(b *encBuffer, mv reflect.Value, keyOp, elemOp encOp, keyIndir, elemIndir int) { state := enc.newEncoderState(b) state.fieldnum = -1 state.sendZero = true @@ -347,7 +375,7 @@ func (enc *Encoder) encodeMap(b *bytes.Buffer, mv reflect.Value, keyOp, elemOp e // by the type identifier (which might require defining that type right now), followed // by the concrete value. A nil value gets sent as the empty string for the name, // followed by no value. -func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) { +func (enc *Encoder) encodeInterface(b *encBuffer, iv reflect.Value) { // Gobs can encode nil interface values but not typed interface // values holding nil pointers, since nil pointers point to no value. elem := iv.Elem() @@ -371,10 +399,7 @@ func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) { } // Send the name. state.encodeUint(uint64(len(name))) - _, err := state.b.WriteString(name) - if err != nil { - error_(err) - } + state.b.WriteString(name) // Define the type id if necessary. enc.sendTypeDescriptor(enc.writer(), state, ut) // Send the type id. @@ -382,7 +407,7 @@ func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) { // Encode the value into a new buffer. Any nested type definitions // should be written to b, before the encoded value. enc.pushWriter(b) - data := new(bytes.Buffer) + data := new(encBuffer) data.Write(spaceForLength) enc.encode(data, elem, ut) if enc.err != nil { @@ -391,7 +416,7 @@ func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) { enc.popWriter() enc.writeMessage(b, data) if enc.err != nil { - error_(err) + error_(enc.err) } enc.freeEncoderState(state) } @@ -433,7 +458,7 @@ func isZero(val reflect.Value) bool { // encGobEncoder encodes a value that implements the GobEncoder interface. // The data is sent as a byte array. -func (enc *Encoder) encodeGobEncoder(b *bytes.Buffer, ut *userTypeInfo, v reflect.Value) { +func (enc *Encoder) encodeGobEncoder(b *encBuffer, ut *userTypeInfo, v reflect.Value) { // TODO: should we catch panics from the called method? var data []byte @@ -653,7 +678,7 @@ func buildEncEngine(info *typeInfo, ut *userTypeInfo, building map[*typeInfo]boo return enc } -func (enc *Encoder) encode(b *bytes.Buffer, value reflect.Value, ut *userTypeInfo) { +func (enc *Encoder) encode(b *encBuffer, value reflect.Value, ut *userTypeInfo) { defer catchError(&enc.err) engine := getEncEngine(ut, nil) indir := ut.indir |