Change RawDatastore to do less reflection.

go/src/infra/gae/libs/gae/helper/datastore.go

Index: go/src/infra/gae/libs/gae/helper/datastore.go
diff --git a/go/src/infra/gae/libs/gae/helper/datastore.go b/go/src/infra/gae/libs/gae/helper/datastore.go
index 32622b4c3910dd66d98d96e2d740092e27deef26..425063f5a379fec4b6409abf846dce9fdabfbf33 100644
--- a/go/src/infra/gae/libs/gae/helper/datastore.go
+++ b/go/src/infra/gae/libs/gae/helper/datastore.go
@@ -7,15 +7,14 @@
 package helper
 
 import (
-	"fmt"
 	"reflect"
 
 	"infra/gae/libs/gae"
 )
 
-// GetStructPLS resolves o into a gae.DSStructPLS. o must be a pointer to a
+// GetPLS resolves o into a gae.DSStructPLS. o must be a pointer to a
 // struct of some sort.
-func GetStructPLS(o interface{}) gae.DSStructPLS {
+func GetPLS(o interface{}) gae.DSPropertyLoadSaver {

[iannucci, 2015/07/14 18:15:43]

To simplify things, I've merged the 'DSStructPLS' interface into
DSPropertyLoadSaver itself. This means that DSPropertyLoadSaver can represent
both data (key -> values) and metadata ($key -> value).

This was done to allow a data blob to communicate with various filters in the
stack (for example: cache control), without needing the RawDatastore interface
to grow new warts.

It also ends up simplifying a lot of stuff since there's now only one interface
to care about.

 	v := reflect.ValueOf(o)
 	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
 		return &structPLS{c: &structCodec{problem: gae.ErrDSInvalidEntityType}}
@@ -34,44 +33,3 @@ func GetStructPLS(o interface{}) gae.DSStructPLS {
 	defer structCodecsMutex.Unlock()
 	return &structPLS{v, getStructCodecLocked(t)}
 }
-
-// GetPLS resolves o into a gae.DSPropertyLoadSaver. If o implements the
-// gae.DSPropertyLoadSaver interface already, it's returned unchanged. Otherwise
-// this calls GetStructPLS and returns the result.
-func GetPLS(o interface{}) (gae.DSPropertyLoadSaver, error) {
-	if pls, ok := o.(gae.DSPropertyLoadSaver); ok {
-		return pls, nil
-	}
-	pls := GetStructPLS(o)
-	if err := pls.Problem(); err != nil {
-		return nil, err
-	}
-	return pls, nil
-}
-
-// MultiGetPLS resolves os to a []gae.DSPropertyLoadSaver. os must be a slice of
-// something. If os is already a []gae.DSPropertyLoadSaver, it's returned
-// unchanged. Otherwise this calls GetPLS on each item, and composes the
-// resulting slice that way.
-func MultiGetPLS(os interface{}) ([]gae.DSPropertyLoadSaver, error) {
-	if plss, ok := os.([]gae.DSPropertyLoadSaver); ok {
-		return plss, nil
-	}
-
-	v := reflect.ValueOf(os)
-	if v.Kind() != reflect.Slice {
-		return nil, fmt.Errorf("gae/helper: bad type in MultiObjToPLS: %T", os)
-	}
-
-	// TODO(riannucci): define a higher-level type DSMultiPropertyLoadSaver
-	// to avoid this slice?
-	ret := make([]gae.DSPropertyLoadSaver, v.Len())
-	for i := 0; i < v.Len(); i++ {
-		pls, err := GetPLS(v.Index(i).Interface())
-		if err != nil {
-			return nil, err
-		}
-		ret[i] = pls
-	}
-	return ret, nil
-}