Refactor a bit.

helper/serialize.go

Index: helper/serialize.go
diff --git a/helper/serialize.go b/helper/serialize.go
deleted file mode 100644
index 41175257af361868c3e969d760d1fc353164be23..0000000000000000000000000000000000000000
--- a/helper/serialize.go
+++ /dev/null
@@ -1,343 +0,0 @@
-// Copyright 2015 The Chromium 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 helper
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"sort"
-	"time"
-
-	"github.com/luci/gae"
-	"github.com/luci/luci-go/common/cmpbin"
-)
-
-// WriteDSPropertyMapDeterministic allows tests to make WriteDSPropertyMap
-// deterministic.
-var WriteDSPropertyMapDeterministic = false
-
-// ReadDSPropertyMapReasonableLimit sets a limit on the number of rows and
-// number of properties per row which can be read by ReadDSPropertyMap. The
-// total number of Property objects readable by this method is this number
-// squared (e.g. Limit rows * Limit properties)
-const ReadDSPropertyMapReasonableLimit uint64 = 30000
-
-// ReadKeyNumToksReasonableLimit is the maximum number of DSKey tokens that
-// ReadDSKey is willing to read for a single key.
-const ReadKeyNumToksReasonableLimit uint64 = 50
-
-// DSKeyContext controls whether the various Write and Read serializtion
-// routines should encode the context of DSKeys (read: the appid and namespace).
-// Frequently the appid and namespace of keys are known in advance and so there's
-// no reason to redundantly encode them.
-type DSKeyContext bool
-
-// With- and WithoutContext indicate if the serialization method should include
-// context for DSKeys. See DSKeyContext for more information.
-const (
-	WithContext    DSKeyContext = true
-	WithoutContext              = false
-)
-
-// WriteDSKey encodes a key to the buffer. If context is WithContext, then this
-// encoded value will include the appid and namespace of the key.
-func WriteDSKey(buf *bytes.Buffer, context DSKeyContext, k gae.DSKey) {
-	// [appid ++ namespace]? ++ #tokens ++ tokens*
-	appid, namespace, toks := DSKeySplit(k)
-	if context == WithContext {
-		buf.WriteByte(1)
-		cmpbin.WriteString(buf, appid)
-		cmpbin.WriteString(buf, namespace)
-	} else {
-		buf.WriteByte(0)
-	}
-	cmpbin.WriteUint(buf, uint64(len(toks)))
-	for _, tok := range toks {
-		WriteDSKeyTok(buf, tok)
-	}
-}
-
-// ReadDSKey deserializes a key from the buffer. The value of context must match
-// the value of context that was passed to WriteDSKey when the key was encoded.
-// If context == WithoutContext, then the appid and namespace parameters are
-// used in the decoded DSKey. Otherwise they're ignored.
-func ReadDSKey(buf *bytes.Buffer, context DSKeyContext, appid, namespace string) (ret gae.DSKey, err error) {
-	actualCtx, err := buf.ReadByte()
-	if err != nil {
-		return
-	}
-
-	actualAid, actualNS := "", ""
-	if actualCtx == 1 {
-		if actualAid, _, err = cmpbin.ReadString(buf); err != nil {
-			return
-		}
-		if actualNS, _, err = cmpbin.ReadString(buf); err != nil {
-			return
-		}
-	} else if actualCtx != 0 {
-		err = fmt.Errorf("helper: expected actualCtx to be 0 or 1, got %d", actualCtx)
-		return
-	}
-
-	if context == WithoutContext {
-		// overrwrite with the supplied ones
-		actualAid = appid
-		actualNS = namespace
-	}
-
-	numToks := uint64(0)
-	if numToks, _, err = cmpbin.ReadUint(buf); err != nil {
-		return
-	}
-	if numToks > ReadKeyNumToksReasonableLimit {
-		err = fmt.Errorf("helper: tried to decode huge key of length %d", numToks)
-		return
-	}
-
-	toks := make([]gae.DSKeyTok, numToks)
-	for i := uint64(0); i < numToks; i++ {
-		if toks[i], err = ReadDSKeyTok(buf); err != nil {
-			return
-		}
-	}
-
-	return NewDSKeyToks(actualAid, actualNS, toks), nil
-}
-
-// WriteDSKeyTok writes a DSKeyTok to the buffer. You usually want WriteDSKey
-// instead of this.
-func WriteDSKeyTok(buf *bytes.Buffer, tok gae.DSKeyTok) {
-	// tok.kind ++ typ ++ [tok.stringID || tok.intID]
-	cmpbin.WriteString(buf, tok.Kind)
-	if tok.StringID != "" {
-		buf.WriteByte(byte(gae.DSPTString))
-		cmpbin.WriteString(buf, tok.StringID)
-	} else {
-		buf.WriteByte(byte(gae.DSPTInt))
-		cmpbin.WriteInt(buf, tok.IntID)
-	}
-}
-
-// ReadDSKeyTok reads a DSKeyTok from the buffer. You usually want ReadDSKey
-// instead of this.
-func ReadDSKeyTok(buf *bytes.Buffer) (ret gae.DSKeyTok, err error) {
-	if ret.Kind, _, err = cmpbin.ReadString(buf); err != nil {
-		return
-	}
-	typ, err := buf.ReadByte()
-	if err != nil {
-		return
-	}
-	switch gae.DSPropertyType(typ) {
-	case gae.DSPTString:
-		ret.StringID, _, err = cmpbin.ReadString(buf)
-	case gae.DSPTInt:
-		ret.IntID, _, err = cmpbin.ReadInt(buf)
-		if err == nil && ret.IntID <= 0 {
-			err = errors.New("helper: decoded key with empty stringID and zero/negative intID")
-		}
-	default:
-		err = fmt.Errorf("helper: invalid type %s", gae.DSPropertyType(typ))
-	}
-	return
-}
-
-// WriteDSGeoPoint writes a DSGeoPoint to the buffer.
-func WriteDSGeoPoint(buf *bytes.Buffer, gp gae.DSGeoPoint) {
-	cmpbin.WriteFloat64(buf, gp.Lat)
-	cmpbin.WriteFloat64(buf, gp.Lng)
-}
-
-// ReadDSGeoPoint reads a DSGeoPoint from the buffer.
-func ReadDSGeoPoint(buf *bytes.Buffer) (gp gae.DSGeoPoint, err error) {
-	if gp.Lat, _, err = cmpbin.ReadFloat64(buf); err != nil {
-		return
-	}
-	gp.Lng, _, err = cmpbin.ReadFloat64(buf)
-	if err == nil && !gp.Valid() {
-		err = fmt.Errorf("helper: decoded invalid DSGeoPoint: %v", gp)
-	}
-	return
-}
-
-// WriteTime writes a time.Time in a byte-sortable way.
-//
-// This method truncates the time to microseconds and drops the timezone,
-// because that's the (undocumented) way that the appengine SDK does it.
-func WriteTime(buf *bytes.Buffer, t time.Time) {
-	name, off := t.Zone()
-	if name != "UTC" || off != 0 {
-		panic(fmt.Errorf("helper: UTC OR DEATH: %s", t))
-	}
-	cmpbin.WriteUint(buf, uint64(t.Unix())*1e6+uint64(t.Nanosecond()/1e3))
-}
-
-// ReadTime reads a time.Time from the buffer.
-func ReadTime(buf *bytes.Buffer) (time.Time, error) {
-	v, _, err := cmpbin.ReadUint(buf)
-	if err != nil {
-		return time.Time{}, err
-	}
-	return time.Unix(int64(v/1e6), int64((v%1e6)*1e3)).UTC(), nil
-}
-
-// WriteDSProperty writes a DSProperty to the buffer. `context` behaves the same
-// way that it does for WriteDSKey, but only has an effect if `p` contains a
-// DSKey as its Value.
-func WriteDSProperty(buf *bytes.Buffer, p gae.DSProperty, context DSKeyContext) {
-	typb := byte(p.Type())
-	if p.IndexSetting() == gae.NoIndex {
-		typb |= 0x80
-	}
-	buf.WriteByte(typb)
-	switch p.Type() {
-	case gae.DSPTNull, gae.DSPTBoolTrue, gae.DSPTBoolFalse:
-	case gae.DSPTInt:
-		cmpbin.WriteInt(buf, p.Value().(int64))
-	case gae.DSPTFloat:
-		cmpbin.WriteFloat64(buf, p.Value().(float64))
-	case gae.DSPTString:
-		cmpbin.WriteString(buf, p.Value().(string))
-	case gae.DSPTBytes:
-		if p.IndexSetting() == gae.NoIndex {
-			cmpbin.WriteBytes(buf, p.Value().([]byte))
-		} else {
-			cmpbin.WriteBytes(buf, p.Value().(gae.DSByteString))
-		}
-	case gae.DSPTTime:
-		WriteTime(buf, p.Value().(time.Time))
-	case gae.DSPTGeoPoint:
-		WriteDSGeoPoint(buf, p.Value().(gae.DSGeoPoint))
-	case gae.DSPTKey:
-		WriteDSKey(buf, context, p.Value().(gae.DSKey))
-	case gae.DSPTBlobKey:
-		cmpbin.WriteString(buf, string(p.Value().(gae.BSKey)))
-	}
-}
-
-// ReadDSProperty reads a DSProperty from the buffer. `context`, `appid`, and
-// `namespace` behave the same way they do for ReadDSKey, but only have an
-// effect if the decoded property has a DSKey value.
-func ReadDSProperty(buf *bytes.Buffer, context DSKeyContext, appid, namespace string) (p gae.DSProperty, err error) {
-	val := interface{}(nil)
-	typb, err := buf.ReadByte()
-	if err != nil {
-		return
-	}
-	is := gae.ShouldIndex
-	if (typb & 0x80) != 0 {
-		is = gae.NoIndex
-	}
-	switch gae.DSPropertyType(typb & 0x7f) {
-	case gae.DSPTNull:
-	case gae.DSPTBoolTrue:
-		val = true
-	case gae.DSPTBoolFalse:
-		val = false
-	case gae.DSPTInt:
-		val, _, err = cmpbin.ReadInt(buf)
-	case gae.DSPTFloat:
-		val, _, err = cmpbin.ReadFloat64(buf)
-	case gae.DSPTString:
-		val, _, err = cmpbin.ReadString(buf)
-	case gae.DSPTBytes:
-		b := []byte(nil)
-		if b, _, err = cmpbin.ReadBytes(buf); err != nil {
-			break
-		}
-		if is == gae.NoIndex {
-			val = b
-		} else {
-			val = gae.DSByteString(b)
-		}
-	case gae.DSPTTime:
-		val, err = ReadTime(buf)
-	case gae.DSPTGeoPoint:
-		val, err = ReadDSGeoPoint(buf)
-	case gae.DSPTKey:
-		val, err = ReadDSKey(buf, context, appid, namespace)
-	case gae.DSPTBlobKey:
-		s := ""
-		if s, _, err = cmpbin.ReadString(buf); err != nil {
-			break
-		}
-		val = gae.BSKey(s)
-	default:
-		err = fmt.Errorf("read: unknown type! %v", typb)
-	}
-	if err == nil {
-		err = p.SetValue(val, is)
-	}
-	return
-}
-
-// WriteDSPropertyMap writes an entire DSPropertyMap to the buffer. `context`
-// behaves the same way that it does for WriteDSKey. If
-// WriteDSPropertyMapDeterministic is true, then the rows will be sorted by
-// property name before they're serialized to buf (mostly useful for testing,
-// but also potentially useful if you need to make a hash of the property data).
-func WriteDSPropertyMap(buf *bytes.Buffer, propMap gae.DSPropertyMap, context DSKeyContext) {
-	rows := make(sort.StringSlice, 0, len(propMap))
-	tmpBuf := &bytes.Buffer{}
-	for name, vals := range propMap {
-		tmpBuf.Reset()
-		cmpbin.WriteString(tmpBuf, name)
-		cmpbin.WriteUint(tmpBuf, uint64(len(vals)))
-		for _, p := range vals {
-			WriteDSProperty(tmpBuf, p, context)
-		}
-		rows = append(rows, tmpBuf.String())
-	}
-
-	if WriteDSPropertyMapDeterministic {
-		rows.Sort()
-	}
-
-	cmpbin.WriteUint(buf, uint64(len(propMap)))
-	for _, r := range rows {
-		buf.WriteString(r)
-	}
-}
-
-// ReadDSPropertyMap reads a DSPropertyMap from the buffer. `context` and
-// friends behave the same way that they do for ReadDSKey.
-func ReadDSPropertyMap(buf *bytes.Buffer, context DSKeyContext, appid, namespace string) (propMap gae.DSPropertyMap, err error) {
-	numRows := uint64(0)
-	if numRows, _, err = cmpbin.ReadUint(buf); err != nil {
-		return
-	}
-	if numRows > ReadDSPropertyMapReasonableLimit {
-		err = fmt.Errorf("helper: tried to decode map with huge number of rows %d", numRows)
-		return
-	}
-
-	name, prop := "", gae.DSProperty{}
-	propMap = make(gae.DSPropertyMap, numRows)
-	for i := uint64(0); i < numRows; i++ {
-		if name, _, err = cmpbin.ReadString(buf); err != nil {
-			return
-		}
-
-		numProps := uint64(0)
-		if numProps, _, err = cmpbin.ReadUint(buf); err != nil {
-			return
-		}
-		if numProps > ReadDSPropertyMapReasonableLimit {
-			err = fmt.Errorf("helper: tried to decode map with huge number of properties %d", numProps)
-			return
-		}
-		props := make([]gae.DSProperty, 0, numProps)
-		for j := uint64(0); j < numProps; j++ {
-			if prop, err = ReadDSProperty(buf, context, appid, namespace); err != nil {
-				return
-			}
-			props = append(props, prop)
-		}
-		propMap[name] = props
-	}
-	return
-}