Reland: Refactor current GAE abstraction library to be free of the SDK*

go/src/infra/gae/libs/gae/brokenfeatures.go

Index: go/src/infra/gae/libs/gae/brokenfeatures.go
diff --git a/go/src/infra/gae/libs/wrapper/brokenfeatures.go b/go/src/infra/gae/libs/gae/brokenfeatures.go
similarity index 75%
rename from go/src/infra/gae/libs/wrapper/brokenfeatures.go
rename to go/src/infra/gae/libs/gae/brokenfeatures.go
index 4e4524b203bf57efc8e3af5150761512ce4b1282..65bf231c38bfa3af21f523812b2784d1cc561b0a 100644
--- a/go/src/infra/gae/libs/wrapper/brokenfeatures.go
+++ b/go/src/infra/gae/libs/gae/brokenfeatures.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package wrapper
+package gae
 
 import (
 	"errors"
@@ -34,8 +34,8 @@ type FeatureBreaker interface {
 	UnbreakFeatures(feature ...string)
 }
 
-// ErrBrokenFeaturesBroken is returned from IsBroken when BrokenFeatures itself
-// isn't working correctly.
+// ErrBrokenFeaturesBroken is returned from RunIfNotBroken when BrokenFeatures
+// itself isn't working correctly.
 var ErrBrokenFeaturesBroken = errors.New("brokenFeatures: Unable to retrieve caller information")
 
 // BrokenFeatures implements the FeatureBreaker interface, and is suitable for
@@ -81,14 +81,14 @@ func (b *BrokenFeatures) UnbreakFeatures(feature ...string) {
 	}
 }
 
-// IsBroken is to be called internally by the fake service on every
-// publically-facing method. If it returns an error, the fake should return
-// the error.
+// RunIfNotBroken is to be called internally by the fake service on every
+// publically-facing method. If it returns an error, the fake should return the
+// error.
 //
 // Example:
 //   type MyService struct { BrokenFeatures }
 //   func (ms *MyService) Thingy() error {
-//     if err := ms.IsBroken(); err != nil {
+//     if err := ms.RunIfNotBroken(); err != nil {
 //       return err
 //     }
 //		 ...
@@ -97,23 +97,25 @@ func (b *BrokenFeatures) UnbreakFeatures(feature ...string) {
 //  You can now do ms.SetBrokenFeatures("Thingy"), and Thingy will return an
 //  error.
 //
-//  Note that IsBroken will keep walking the stack until it finds the first
-//  publically-exported method, which will allow you to put the IsBroken call
-//  in an internal helper method of your service implementation.
+//  Note that RunIfNotBroken will keep walking the stack until it finds the
+//  first publically-exported method, which will allow you to put the
+//  RunIfNotBroken call in an internal helper method of your service
+//  implementation.
 //
-//  Additionaly, IsBroken allows a very primitive form of overriding; it walks
-//  the stack until it finds the first method which is not called "IsBroken".
-//  This allows the embedding struct to call into BrokenFeatures.IsBroken from
-//  another IsBroken function, and still have it behave correctly.
-func (b *BrokenFeatures) IsBroken() error {
+//  Additionaly, RunIfNotBroken allows a very primitive form of overriding; it
+//  walks the stack until it finds the first method which is not called
+//  "RunIfNotBroken".  This allows the embedding struct to call into
+//  BrokenFeatures.RunIfNotBroken from another RunIfNotBroken function, and
+//  still have it behave correctly.
+func (b *BrokenFeatures) RunIfNotBroken(f func() error) error {
 	if b.noBrokenFeatures() {
-		return nil
+		return f()
 	}
 
 	var name string
 	for off := 1; ; off++ { // offset of 1 skips ourselves by default
 		// TODO(riannucci): Profile this to see if it's having an adverse
-		// performance impact ont tests.
+		// performance impact on tests.
 		fn, _, _, ok := runtime.Caller(off)
 		if !ok {
 			return ErrBrokenFeaturesBroken
@@ -127,17 +129,19 @@ func (b *BrokenFeatures) IsBroken() error {
 			// !IsLower, and afaik, in unicode-land they're not direct opposites.
 			continue
 		}
-		if name == "IsBroken" {
-			// Allow users to override IsBroken, keep walking until we see a function
-			// which is named differently than IsBroken.
+		if name == "RunIfNotBroken" {
+			// Allow users to override RunIfNotBroken, keep walking until we see
+			// a function which is named differently than RunIfNotBroken.
 			continue
 		}
 		break
 	}
 
 	b.lock.Lock()
+	err, ok := b.broken[name]
 	defer b.lock.Unlock()
-	if err, ok := b.broken[name]; ok {
+
+	if ok {
 		if err != nil {
 			return err
 		}
@@ -147,7 +151,7 @@ func (b *BrokenFeatures) IsBroken() error {
 		return fmt.Errorf("feature %q is broken", name)
 	}
 
-	return nil
+	return f()
 }
 
 func (b *BrokenFeatures) noBrokenFeatures() bool {