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-rw-r--r--libgo/go/gob/decode.go1020
1 files changed, 1020 insertions, 0 deletions
diff --git a/libgo/go/gob/decode.go b/libgo/go/gob/decode.go
new file mode 100644
index 000000000..2db75215c
--- /dev/null
+++ b/libgo/go/gob/decode.go
@@ -0,0 +1,1020 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+// TODO(rsc): When garbage collector changes, revisit
+// the allocations in this file that use unsafe.Pointer.
+
+import (
+ "bytes"
+ "io"
+ "math"
+ "os"
+ "reflect"
+ "unicode"
+ "unsafe"
+ "utf8"
+)
+
+var (
+ errBadUint = os.ErrorString("gob: encoded unsigned integer out of range")
+ errBadType = os.ErrorString("gob: unknown type id or corrupted data")
+ errRange = os.ErrorString("gob: internal error: field numbers out of bounds")
+)
+
+// The execution state of an instance of the decoder. A new state
+// is created for nested objects.
+type decodeState struct {
+ dec *Decoder
+ // The buffer is stored with an extra indirection because it may be replaced
+ // if we load a type during decode (when reading an interface value).
+ b **bytes.Buffer
+ fieldnum int // the last field number read.
+ buf []byte
+}
+
+func newDecodeState(dec *Decoder, b **bytes.Buffer) *decodeState {
+ d := new(decodeState)
+ d.dec = dec
+ d.b = b
+ d.buf = make([]byte, uint64Size)
+ return d
+}
+
+func overflow(name string) os.ErrorString {
+ return os.ErrorString(`value for "` + name + `" out of range`)
+}
+
+// decodeUintReader reads an encoded unsigned integer from an io.Reader.
+// Used only by the Decoder to read the message length.
+func decodeUintReader(r io.Reader, buf []byte) (x uint64, err os.Error) {
+ _, err = r.Read(buf[0:1])
+ if err != nil {
+ return
+ }
+ b := buf[0]
+ if b <= 0x7f {
+ return uint64(b), nil
+ }
+ nb := -int(int8(b))
+ if nb > uint64Size {
+ err = errBadUint
+ return
+ }
+ var n int
+ n, err = io.ReadFull(r, buf[0:nb])
+ if err != nil {
+ if err == os.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return
+ }
+ // Could check that the high byte is zero but it's not worth it.
+ for i := 0; i < n; i++ {
+ x <<= 8
+ x |= uint64(buf[i])
+ }
+ return
+}
+
+// decodeUint reads an encoded unsigned integer from state.r.
+// Does not check for overflow.
+func (state *decodeState) decodeUint() (x uint64) {
+ b, err := state.b.ReadByte()
+ if err != nil {
+ error(err)
+ }
+ if b <= 0x7f {
+ return uint64(b)
+ }
+ nb := -int(int8(b))
+ if nb > uint64Size {
+ error(errBadUint)
+ }
+ n, err := state.b.Read(state.buf[0:nb])
+ if err != nil {
+ error(err)
+ }
+ // Don't need to check error; it's safe to loop regardless.
+ // Could check that the high byte is zero but it's not worth it.
+ for i := 0; i < n; i++ {
+ x <<= 8
+ x |= uint64(state.buf[i])
+ }
+ return x
+}
+
+// decodeInt reads an encoded signed integer from state.r.
+// Does not check for overflow.
+func (state *decodeState) decodeInt() int64 {
+ x := state.decodeUint()
+ if x&1 != 0 {
+ return ^int64(x >> 1)
+ }
+ return int64(x >> 1)
+}
+
+type decOp func(i *decInstr, state *decodeState, p unsafe.Pointer)
+
+// The 'instructions' of the decoding machine
+type decInstr struct {
+ op decOp
+ field int // field number of the wire type
+ indir int // how many pointer indirections to reach the value in the struct
+ offset uintptr // offset in the structure of the field to encode
+ ovfl os.ErrorString // error message for overflow/underflow (for arrays, of the elements)
+}
+
+// Since the encoder writes no zeros, if we arrive at a decoder we have
+// a value to extract and store. The field number has already been read
+// (it's how we knew to call this decoder).
+// Each decoder is responsible for handling any indirections associated
+// with the data structure. If any pointer so reached is nil, allocation must
+// be done.
+
+// Walk the pointer hierarchy, allocating if we find a nil. Stop one before the end.
+func decIndirect(p unsafe.Pointer, indir int) unsafe.Pointer {
+ for ; indir > 1; indir-- {
+ if *(*unsafe.Pointer)(p) == nil {
+ // Allocation required
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(unsafe.Pointer))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ return p
+}
+
+func ignoreUint(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.decodeUint()
+}
+
+func ignoreTwoUints(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.decodeUint()
+ state.decodeUint()
+}
+
+func decBool(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(bool))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ *(*bool)(p) = state.decodeInt() != 0
+}
+
+func decInt8(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(int8))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeInt()
+ if v < math.MinInt8 || math.MaxInt8 < v {
+ error(i.ovfl)
+ } else {
+ *(*int8)(p) = int8(v)
+ }
+}
+
+func decUint8(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint8))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeUint()
+ if math.MaxUint8 < v {
+ error(i.ovfl)
+ } else {
+ *(*uint8)(p) = uint8(v)
+ }
+}
+
+func decInt16(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(int16))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeInt()
+ if v < math.MinInt16 || math.MaxInt16 < v {
+ error(i.ovfl)
+ } else {
+ *(*int16)(p) = int16(v)
+ }
+}
+
+func decUint16(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint16))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeUint()
+ if math.MaxUint16 < v {
+ error(i.ovfl)
+ } else {
+ *(*uint16)(p) = uint16(v)
+ }
+}
+
+func decInt32(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(int32))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeInt()
+ if v < math.MinInt32 || math.MaxInt32 < v {
+ error(i.ovfl)
+ } else {
+ *(*int32)(p) = int32(v)
+ }
+}
+
+func decUint32(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint32))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ v := state.decodeUint()
+ if math.MaxUint32 < v {
+ error(i.ovfl)
+ } else {
+ *(*uint32)(p) = uint32(v)
+ }
+}
+
+func decInt64(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(int64))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ *(*int64)(p) = int64(state.decodeInt())
+}
+
+func decUint64(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint64))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ *(*uint64)(p) = uint64(state.decodeUint())
+}
+
+// Floating-point numbers are transmitted as uint64s holding the bits
+// of the underlying representation. They are sent byte-reversed, with
+// the exponent end coming out first, so integer floating point numbers
+// (for example) transmit more compactly. This routine does the
+// unswizzling.
+func floatFromBits(u uint64) float64 {
+ var v uint64
+ for i := 0; i < 8; i++ {
+ v <<= 8
+ v |= u & 0xFF
+ u >>= 8
+ }
+ return math.Float64frombits(v)
+}
+
+func storeFloat32(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ v := floatFromBits(state.decodeUint())
+ av := v
+ if av < 0 {
+ av = -av
+ }
+ // +Inf is OK in both 32- and 64-bit floats. Underflow is always OK.
+ if math.MaxFloat32 < av && av <= math.MaxFloat64 {
+ error(i.ovfl)
+ } else {
+ *(*float32)(p) = float32(v)
+ }
+}
+
+func decFloat32(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(float32))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ storeFloat32(i, state, p)
+}
+
+func decFloat64(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(float64))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ *(*float64)(p) = floatFromBits(uint64(state.decodeUint()))
+}
+
+// Complex numbers are just a pair of floating-point numbers, real part first.
+func decComplex64(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(complex64))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ storeFloat32(i, state, p)
+ storeFloat32(i, state, unsafe.Pointer(uintptr(p)+uintptr(unsafe.Sizeof(float32(0)))))
+}
+
+func decComplex128(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new(complex128))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ real := floatFromBits(uint64(state.decodeUint()))
+ imag := floatFromBits(uint64(state.decodeUint()))
+ *(*complex128)(p) = complex(real, imag)
+}
+
+// uint8 arrays are encoded as an unsigned count followed by the raw bytes.
+func decUint8Array(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new([]uint8))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ b := make([]uint8, state.decodeUint())
+ state.b.Read(b)
+ *(*[]uint8)(p) = b
+}
+
+// Strings are encoded as an unsigned count followed by the raw bytes.
+func decString(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ if i.indir > 0 {
+ if *(*unsafe.Pointer)(p) == nil {
+ *(*unsafe.Pointer)(p) = unsafe.Pointer(new([]byte))
+ }
+ p = *(*unsafe.Pointer)(p)
+ }
+ b := make([]byte, state.decodeUint())
+ state.b.Read(b)
+ *(*string)(p) = string(b)
+}
+
+func ignoreUint8Array(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ b := make([]byte, state.decodeUint())
+ state.b.Read(b)
+}
+
+// Execution engine
+
+// The encoder engine is an array of instructions indexed by field number of the incoming
+// decoder. It is executed with random access according to field number.
+type decEngine struct {
+ instr []decInstr
+ numInstr int // the number of active instructions
+}
+
+// allocate makes sure storage is available for an object of underlying type rtyp
+// that is indir levels of indirection through p.
+func allocate(rtyp reflect.Type, p uintptr, indir int) uintptr {
+ if indir == 0 {
+ return p
+ }
+ up := unsafe.Pointer(p)
+ if indir > 1 {
+ up = decIndirect(up, indir)
+ }
+ if *(*unsafe.Pointer)(up) == nil {
+ // Allocate object.
+ *(*unsafe.Pointer)(up) = unsafe.New(rtyp)
+ }
+ return *(*uintptr)(up)
+}
+
+func (dec *Decoder) decodeSingle(engine *decEngine, rtyp reflect.Type, b **bytes.Buffer, p uintptr, indir int) (err os.Error) {
+ defer catchError(&err)
+ p = allocate(rtyp, p, indir)
+ state := newDecodeState(dec, b)
+ state.fieldnum = singletonField
+ basep := p
+ delta := int(state.decodeUint())
+ if delta != 0 {
+ errorf("gob decode: corrupted data: non-zero delta for singleton")
+ }
+ instr := &engine.instr[singletonField]
+ ptr := unsafe.Pointer(basep) // offset will be zero
+ if instr.indir > 1 {
+ ptr = decIndirect(ptr, instr.indir)
+ }
+ instr.op(instr, state, ptr)
+ return nil
+}
+
+func (dec *Decoder) decodeStruct(engine *decEngine, rtyp *reflect.StructType, b **bytes.Buffer, p uintptr, indir int) (err os.Error) {
+ defer catchError(&err)
+ p = allocate(rtyp, p, indir)
+ state := newDecodeState(dec, b)
+ state.fieldnum = -1
+ basep := p
+ for state.b.Len() > 0 {
+ delta := int(state.decodeUint())
+ if delta < 0 {
+ errorf("gob decode: corrupted data: negative delta")
+ }
+ if delta == 0 { // struct terminator is zero delta fieldnum
+ break
+ }
+ fieldnum := state.fieldnum + delta
+ if fieldnum >= len(engine.instr) {
+ error(errRange)
+ break
+ }
+ instr := &engine.instr[fieldnum]
+ p := unsafe.Pointer(basep + instr.offset)
+ if instr.indir > 1 {
+ p = decIndirect(p, instr.indir)
+ }
+ instr.op(instr, state, p)
+ state.fieldnum = fieldnum
+ }
+ return nil
+}
+
+func (dec *Decoder) ignoreStruct(engine *decEngine, b **bytes.Buffer) (err os.Error) {
+ defer catchError(&err)
+ state := newDecodeState(dec, b)
+ state.fieldnum = -1
+ for state.b.Len() > 0 {
+ delta := int(state.decodeUint())
+ if delta < 0 {
+ errorf("gob ignore decode: corrupted data: negative delta")
+ }
+ if delta == 0 { // struct terminator is zero delta fieldnum
+ break
+ }
+ fieldnum := state.fieldnum + delta
+ if fieldnum >= len(engine.instr) {
+ error(errRange)
+ }
+ instr := &engine.instr[fieldnum]
+ instr.op(instr, state, unsafe.Pointer(nil))
+ state.fieldnum = fieldnum
+ }
+ return nil
+}
+
+func (dec *Decoder) decodeArrayHelper(state *decodeState, p uintptr, elemOp decOp, elemWid uintptr, length, elemIndir int, ovfl os.ErrorString) {
+ instr := &decInstr{elemOp, 0, elemIndir, 0, ovfl}
+ for i := 0; i < length; i++ {
+ up := unsafe.Pointer(p)
+ if elemIndir > 1 {
+ up = decIndirect(up, elemIndir)
+ }
+ elemOp(instr, state, up)
+ p += uintptr(elemWid)
+ }
+}
+
+func (dec *Decoder) decodeArray(atyp *reflect.ArrayType, state *decodeState, p uintptr, elemOp decOp, elemWid uintptr, length, indir, elemIndir int, ovfl os.ErrorString) {
+ if indir > 0 {
+ p = allocate(atyp, p, 1) // All but the last level has been allocated by dec.Indirect
+ }
+ if n := state.decodeUint(); n != uint64(length) {
+ errorf("gob: length mismatch in decodeArray")
+ }
+ dec.decodeArrayHelper(state, p, elemOp, elemWid, length, elemIndir, ovfl)
+}
+
+func decodeIntoValue(state *decodeState, op decOp, indir int, v reflect.Value, ovfl os.ErrorString) reflect.Value {
+ instr := &decInstr{op, 0, indir, 0, ovfl}
+ up := unsafe.Pointer(v.Addr())
+ if indir > 1 {
+ up = decIndirect(up, indir)
+ }
+ op(instr, state, up)
+ return v
+}
+
+func (dec *Decoder) decodeMap(mtyp *reflect.MapType, state *decodeState, p uintptr, keyOp, elemOp decOp, indir, keyIndir, elemIndir int, ovfl os.ErrorString) {
+ if indir > 0 {
+ p = allocate(mtyp, p, 1) // All but the last level has been allocated by dec.Indirect
+ }
+ up := unsafe.Pointer(p)
+ if *(*unsafe.Pointer)(up) == nil { // maps are represented as a pointer in the runtime
+ // Allocate map.
+ *(*unsafe.Pointer)(up) = unsafe.Pointer(reflect.MakeMap(mtyp).Get())
+ }
+ // Maps cannot be accessed by moving addresses around the way
+ // that slices etc. can. We must recover a full reflection value for
+ // the iteration.
+ v := reflect.NewValue(unsafe.Unreflect(mtyp, unsafe.Pointer((p)))).(*reflect.MapValue)
+ n := int(state.decodeUint())
+ for i := 0; i < n; i++ {
+ key := decodeIntoValue(state, keyOp, keyIndir, reflect.MakeZero(mtyp.Key()), ovfl)
+ elem := decodeIntoValue(state, elemOp, elemIndir, reflect.MakeZero(mtyp.Elem()), ovfl)
+ v.SetElem(key, elem)
+ }
+}
+
+func (dec *Decoder) ignoreArrayHelper(state *decodeState, elemOp decOp, length int) {
+ instr := &decInstr{elemOp, 0, 0, 0, os.ErrorString("no error")}
+ for i := 0; i < length; i++ {
+ elemOp(instr, state, nil)
+ }
+}
+
+func (dec *Decoder) ignoreArray(state *decodeState, elemOp decOp, length int) {
+ if n := state.decodeUint(); n != uint64(length) {
+ errorf("gob: length mismatch in ignoreArray")
+ }
+ dec.ignoreArrayHelper(state, elemOp, length)
+}
+
+func (dec *Decoder) ignoreMap(state *decodeState, keyOp, elemOp decOp) {
+ n := int(state.decodeUint())
+ keyInstr := &decInstr{keyOp, 0, 0, 0, os.ErrorString("no error")}
+ elemInstr := &decInstr{elemOp, 0, 0, 0, os.ErrorString("no error")}
+ for i := 0; i < n; i++ {
+ keyOp(keyInstr, state, nil)
+ elemOp(elemInstr, state, nil)
+ }
+}
+
+func (dec *Decoder) decodeSlice(atyp *reflect.SliceType, state *decodeState, p uintptr, elemOp decOp, elemWid uintptr, indir, elemIndir int, ovfl os.ErrorString) {
+ n := int(uintptr(state.decodeUint()))
+ if indir > 0 {
+ up := unsafe.Pointer(p)
+ if *(*unsafe.Pointer)(up) == nil {
+ // Allocate the slice header.
+ *(*unsafe.Pointer)(up) = unsafe.Pointer(new([]unsafe.Pointer))
+ }
+ p = *(*uintptr)(up)
+ }
+ // Allocate storage for the slice elements, that is, the underlying array.
+ // Always write a header at p.
+ hdrp := (*reflect.SliceHeader)(unsafe.Pointer(p))
+ hdrp.Data = uintptr(unsafe.NewArray(atyp.Elem(), n))
+ hdrp.Len = n
+ hdrp.Cap = n
+ dec.decodeArrayHelper(state, hdrp.Data, elemOp, elemWid, n, elemIndir, ovfl)
+}
+
+func (dec *Decoder) ignoreSlice(state *decodeState, elemOp decOp) {
+ dec.ignoreArrayHelper(state, elemOp, int(state.decodeUint()))
+}
+
+// setInterfaceValue sets an interface value to a concrete value through
+// reflection. If the concrete value does not implement the interface, the
+// setting will panic. This routine turns the panic into an error return.
+// This dance avoids manually checking that the value satisfies the
+// interface.
+// TODO(rsc): avoid panic+recover after fixing issue 327.
+func setInterfaceValue(ivalue *reflect.InterfaceValue, value reflect.Value) {
+ defer func() {
+ if e := recover(); e != nil {
+ error(e.(os.Error))
+ }
+ }()
+ ivalue.Set(value)
+}
+
+// decodeInterface receives the name of a concrete type followed by its value.
+// If the name is empty, the value is nil and no value is sent.
+func (dec *Decoder) decodeInterface(ityp *reflect.InterfaceType, state *decodeState, p uintptr, indir int) {
+ // Create an interface reflect.Value. We need one even for the nil case.
+ ivalue := reflect.MakeZero(ityp).(*reflect.InterfaceValue)
+ // Read the name of the concrete type.
+ b := make([]byte, state.decodeUint())
+ state.b.Read(b)
+ name := string(b)
+ if name == "" {
+ // Copy the representation of the nil interface value to the target.
+ // This is horribly unsafe and special.
+ *(*[2]uintptr)(unsafe.Pointer(p)) = ivalue.Get()
+ return
+ }
+ // The concrete type must be registered.
+ typ, ok := nameToConcreteType[name]
+ if !ok {
+ errorf("gob: name not registered for interface: %q", name)
+ }
+ // Read the concrete value.
+ value := reflect.MakeZero(typ)
+ dec.decodeValueFromBuffer(value, false, true)
+ if dec.err != nil {
+ error(dec.err)
+ }
+ // Allocate the destination interface value.
+ if indir > 0 {
+ p = allocate(ityp, p, 1) // All but the last level has been allocated by dec.Indirect
+ }
+ // Assign the concrete value to the interface.
+ // Tread carefully; it might not satisfy the interface.
+ setInterfaceValue(ivalue, value)
+ // Copy the representation of the interface value to the target.
+ // This is horribly unsafe and special.
+ *(*[2]uintptr)(unsafe.Pointer(p)) = ivalue.Get()
+}
+
+func (dec *Decoder) ignoreInterface(state *decodeState) {
+ // Read the name of the concrete type.
+ b := make([]byte, state.decodeUint())
+ _, err := state.b.Read(b)
+ if err != nil {
+ error(err)
+ }
+ dec.decodeValueFromBuffer(nil, true, true)
+ if dec.err != nil {
+ error(err)
+ }
+}
+
+// Index by Go types.
+var decOpMap = []decOp{
+ reflect.Bool: decBool,
+ reflect.Int8: decInt8,
+ reflect.Int16: decInt16,
+ reflect.Int32: decInt32,
+ reflect.Int64: decInt64,
+ reflect.Uint8: decUint8,
+ reflect.Uint16: decUint16,
+ reflect.Uint32: decUint32,
+ reflect.Uint64: decUint64,
+ reflect.Float32: decFloat32,
+ reflect.Float64: decFloat64,
+ reflect.Complex64: decComplex64,
+ reflect.Complex128: decComplex128,
+ reflect.String: decString,
+}
+
+// Indexed by gob types. tComplex will be added during type.init().
+var decIgnoreOpMap = map[typeId]decOp{
+ tBool: ignoreUint,
+ tInt: ignoreUint,
+ tUint: ignoreUint,
+ tFloat: ignoreUint,
+ tBytes: ignoreUint8Array,
+ tString: ignoreUint8Array,
+ tComplex: ignoreTwoUints,
+}
+
+// Return the decoding op for the base type under rt and
+// the indirection count to reach it.
+func (dec *Decoder) decOpFor(wireId typeId, rt reflect.Type, name string) (decOp, int) {
+ typ, indir := indirect(rt)
+ var op decOp
+ k := typ.Kind()
+ if int(k) < len(decOpMap) {
+ op = decOpMap[k]
+ }
+ if op == nil {
+ // Special cases
+ switch t := typ.(type) {
+ case *reflect.ArrayType:
+ name = "element of " + name
+ elemId := dec.wireType[wireId].ArrayT.Elem
+ elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name)
+ ovfl := overflow(name)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.dec.decodeArray(t, state, uintptr(p), elemOp, t.Elem().Size(), t.Len(), i.indir, elemIndir, ovfl)
+ }
+
+ case *reflect.MapType:
+ name = "element of " + name
+ keyId := dec.wireType[wireId].MapT.Key
+ elemId := dec.wireType[wireId].MapT.Elem
+ keyOp, keyIndir := dec.decOpFor(keyId, t.Key(), name)
+ elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name)
+ ovfl := overflow(name)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ up := unsafe.Pointer(p)
+ state.dec.decodeMap(t, state, uintptr(up), keyOp, elemOp, i.indir, keyIndir, elemIndir, ovfl)
+ }
+
+ case *reflect.SliceType:
+ name = "element of " + name
+ if t.Elem().Kind() == reflect.Uint8 {
+ op = decUint8Array
+ break
+ }
+ var elemId typeId
+ if tt, ok := builtinIdToType[wireId]; ok {
+ elemId = tt.(*sliceType).Elem
+ } else {
+ elemId = dec.wireType[wireId].SliceT.Elem
+ }
+ elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name)
+ ovfl := overflow(name)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.dec.decodeSlice(t, state, uintptr(p), elemOp, t.Elem().Size(), i.indir, elemIndir, ovfl)
+ }
+
+ case *reflect.StructType:
+ // Generate a closure that calls out to the engine for the nested type.
+ enginePtr, err := dec.getDecEnginePtr(wireId, typ)
+ if err != nil {
+ error(err)
+ }
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ // indirect through enginePtr to delay evaluation for recursive structs
+ err = dec.decodeStruct(*enginePtr, t, state.b, uintptr(p), i.indir)
+ if err != nil {
+ error(err)
+ }
+ }
+ case *reflect.InterfaceType:
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ dec.decodeInterface(t, state, uintptr(p), i.indir)
+ }
+ }
+ }
+ if op == nil {
+ errorf("gob: decode can't handle type %s", rt.String())
+ }
+ return op, indir
+}
+
+// Return the decoding op for a field that has no destination.
+func (dec *Decoder) decIgnoreOpFor(wireId typeId) decOp {
+ op, ok := decIgnoreOpMap[wireId]
+ if !ok {
+ if wireId == tInterface {
+ // Special case because it's a method: the ignored item might
+ // define types and we need to record their state in the decoder.
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ dec.ignoreInterface(state)
+ }
+ return op
+ }
+ // Special cases
+ wire := dec.wireType[wireId]
+ switch {
+ case wire == nil:
+ panic("internal error: can't find ignore op for type " + wireId.string())
+ case wire.ArrayT != nil:
+ elemId := wire.ArrayT.Elem
+ elemOp := dec.decIgnoreOpFor(elemId)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.dec.ignoreArray(state, elemOp, wire.ArrayT.Len)
+ }
+
+ case wire.MapT != nil:
+ keyId := dec.wireType[wireId].MapT.Key
+ elemId := dec.wireType[wireId].MapT.Elem
+ keyOp := dec.decIgnoreOpFor(keyId)
+ elemOp := dec.decIgnoreOpFor(elemId)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.dec.ignoreMap(state, keyOp, elemOp)
+ }
+
+ case wire.SliceT != nil:
+ elemId := wire.SliceT.Elem
+ elemOp := dec.decIgnoreOpFor(elemId)
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ state.dec.ignoreSlice(state, elemOp)
+ }
+
+ case wire.StructT != nil:
+ // Generate a closure that calls out to the engine for the nested type.
+ enginePtr, err := dec.getIgnoreEnginePtr(wireId)
+ if err != nil {
+ error(err)
+ }
+ op = func(i *decInstr, state *decodeState, p unsafe.Pointer) {
+ // indirect through enginePtr to delay evaluation for recursive structs
+ state.dec.ignoreStruct(*enginePtr, state.b)
+ }
+ }
+ }
+ if op == nil {
+ errorf("ignore can't handle type %s", wireId.string())
+ }
+ return op
+}
+
+// Are these two gob Types compatible?
+// Answers the question for basic types, arrays, and slices.
+// Structs are considered ok; fields will be checked later.
+func (dec *Decoder) compatibleType(fr reflect.Type, fw typeId) bool {
+ fr, _ = indirect(fr)
+ switch t := fr.(type) {
+ default:
+ // map, chan, etc: cannot handle.
+ return false
+ case *reflect.BoolType:
+ return fw == tBool
+ case *reflect.IntType:
+ return fw == tInt
+ case *reflect.UintType:
+ return fw == tUint
+ case *reflect.FloatType:
+ return fw == tFloat
+ case *reflect.ComplexType:
+ return fw == tComplex
+ case *reflect.StringType:
+ return fw == tString
+ case *reflect.InterfaceType:
+ return fw == tInterface
+ case *reflect.ArrayType:
+ wire, ok := dec.wireType[fw]
+ if !ok || wire.ArrayT == nil {
+ return false
+ }
+ array := wire.ArrayT
+ return t.Len() == array.Len && dec.compatibleType(t.Elem(), array.Elem)
+ case *reflect.MapType:
+ wire, ok := dec.wireType[fw]
+ if !ok || wire.MapT == nil {
+ return false
+ }
+ MapType := wire.MapT
+ return dec.compatibleType(t.Key(), MapType.Key) && dec.compatibleType(t.Elem(), MapType.Elem)
+ case *reflect.SliceType:
+ // Is it an array of bytes?
+ if t.Elem().Kind() == reflect.Uint8 {
+ return fw == tBytes
+ }
+ // Extract and compare element types.
+ var sw *sliceType
+ if tt, ok := builtinIdToType[fw]; ok {
+ sw = tt.(*sliceType)
+ } else {
+ sw = dec.wireType[fw].SliceT
+ }
+ elem, _ := indirect(t.Elem())
+ return sw != nil && dec.compatibleType(elem, sw.Elem)
+ case *reflect.StructType:
+ return true
+ }
+ return true
+}
+
+// typeString returns a human-readable description of the type identified by remoteId.
+func (dec *Decoder) typeString(remoteId typeId) string {
+ if t := idToType[remoteId]; t != nil {
+ // globally known type.
+ return t.string()
+ }
+ return dec.wireType[remoteId].string()
+}
+
+
+func (dec *Decoder) compileSingle(remoteId typeId, rt reflect.Type) (engine *decEngine, err os.Error) {
+ engine = new(decEngine)
+ engine.instr = make([]decInstr, 1) // one item
+ name := rt.String() // best we can do
+ if !dec.compatibleType(rt, remoteId) {
+ return nil, os.ErrorString("gob: wrong type received for local value " + name + ": " + dec.typeString(remoteId))
+ }
+ op, indir := dec.decOpFor(remoteId, rt, name)
+ ovfl := os.ErrorString(`value for "` + name + `" out of range`)
+ engine.instr[singletonField] = decInstr{op, singletonField, indir, 0, ovfl}
+ engine.numInstr = 1
+ return
+}
+
+// Is this an exported - upper case - name?
+func isExported(name string) bool {
+ rune, _ := utf8.DecodeRuneInString(name)
+ return unicode.IsUpper(rune)
+}
+
+func (dec *Decoder) compileDec(remoteId typeId, rt reflect.Type) (engine *decEngine, err os.Error) {
+ defer catchError(&err)
+ srt, ok := rt.(*reflect.StructType)
+ if !ok {
+ return dec.compileSingle(remoteId, rt)
+ }
+ var wireStruct *structType
+ // Builtin types can come from global pool; the rest must be defined by the decoder.
+ // Also we know we're decoding a struct now, so the client must have sent one.
+ if t, ok := builtinIdToType[remoteId]; ok {
+ wireStruct, _ = t.(*structType)
+ } else {
+ wireStruct = dec.wireType[remoteId].StructT
+ }
+ if wireStruct == nil {
+ errorf("gob: type mismatch in decoder: want struct type %s; got non-struct", rt.String())
+ }
+ engine = new(decEngine)
+ engine.instr = make([]decInstr, len(wireStruct.Field))
+ // Loop over the fields of the wire type.
+ for fieldnum := 0; fieldnum < len(wireStruct.Field); fieldnum++ {
+ wireField := wireStruct.Field[fieldnum]
+ if wireField.Name == "" {
+ errorf("gob: empty name for remote field of type %s", wireStruct.Name)
+ }
+ ovfl := overflow(wireField.Name)
+ // Find the field of the local type with the same name.
+ localField, present := srt.FieldByName(wireField.Name)
+ // TODO(r): anonymous names
+ if !present || !isExported(wireField.Name) {
+ op := dec.decIgnoreOpFor(wireField.Id)
+ engine.instr[fieldnum] = decInstr{op, fieldnum, 0, 0, ovfl}
+ continue
+ }
+ if !dec.compatibleType(localField.Type, wireField.Id) {
+ errorf("gob: wrong type (%s) for received field %s.%s", localField.Type, wireStruct.Name, wireField.Name)
+ }
+ op, indir := dec.decOpFor(wireField.Id, localField.Type, localField.Name)
+ engine.instr[fieldnum] = decInstr{op, fieldnum, indir, uintptr(localField.Offset), ovfl}
+ engine.numInstr++
+ }
+ return
+}
+
+func (dec *Decoder) getDecEnginePtr(remoteId typeId, rt reflect.Type) (enginePtr **decEngine, err os.Error) {
+ decoderMap, ok := dec.decoderCache[rt]
+ if !ok {
+ decoderMap = make(map[typeId]**decEngine)
+ dec.decoderCache[rt] = decoderMap
+ }
+ if enginePtr, ok = decoderMap[remoteId]; !ok {
+ // To handle recursive types, mark this engine as underway before compiling.
+ enginePtr = new(*decEngine)
+ decoderMap[remoteId] = enginePtr
+ *enginePtr, err = dec.compileDec(remoteId, rt)
+ if err != nil {
+ decoderMap[remoteId] = nil, false
+ }
+ }
+ return
+}
+
+// When ignoring struct data, in effect we compile it into this type
+type emptyStruct struct{}
+
+var emptyStructType = reflect.Typeof(emptyStruct{})
+
+func (dec *Decoder) getIgnoreEnginePtr(wireId typeId) (enginePtr **decEngine, err os.Error) {
+ var ok bool
+ if enginePtr, ok = dec.ignorerCache[wireId]; !ok {
+ // To handle recursive types, mark this engine as underway before compiling.
+ enginePtr = new(*decEngine)
+ dec.ignorerCache[wireId] = enginePtr
+ *enginePtr, err = dec.compileDec(wireId, emptyStructType)
+ if err != nil {
+ dec.ignorerCache[wireId] = nil, false
+ }
+ }
+ return
+}
+
+func (dec *Decoder) decode(wireId typeId, val reflect.Value) os.Error {
+ // Dereference down to the underlying struct type.
+ rt, indir := indirect(val.Type())
+ enginePtr, err := dec.getDecEnginePtr(wireId, rt)
+ if err != nil {
+ return err
+ }
+ engine := *enginePtr
+ if st, ok := rt.(*reflect.StructType); ok {
+ if engine.numInstr == 0 && st.NumField() > 0 && len(dec.wireType[wireId].StructT.Field) > 0 {
+ name := rt.Name()
+ return os.ErrorString("gob: type mismatch: no fields matched compiling decoder for " + name)
+ }
+ return dec.decodeStruct(engine, st, dec.state.b, uintptr(val.Addr()), indir)
+ }
+ return dec.decodeSingle(engine, rt, dec.state.b, uintptr(val.Addr()), indir)
+}
+
+func init() {
+ var iop, uop decOp
+ switch reflect.Typeof(int(0)).Bits() {
+ case 32:
+ iop = decInt32
+ uop = decUint32
+ case 64:
+ iop = decInt64
+ uop = decUint64
+ default:
+ panic("gob: unknown size of int/uint")
+ }
+ decOpMap[reflect.Int] = iop
+ decOpMap[reflect.Uint] = uop
+
+ // Finally uintptr
+ switch reflect.Typeof(uintptr(0)).Bits() {
+ case 32:
+ uop = decUint32
+ case 64:
+ uop = decUint64
+ default:
+ panic("gob: unknown size of uintptr")
+ }
+ decOpMap[reflect.Uintptr] = uop
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-10 05:38:17 +0000