diff --git a/android/singleton.go b/android/singleton.go
new file mode 100644
index 0000000..f2f575f
--- /dev/null
+++ b/android/singleton.go
@@ -0,0 +1,162 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/pathtools"
+)
+
+// SingletonContext
+type SingletonContext interface {
+	// TODO(ccross): make this return an android.Config
+	Config() interface{}
+
+	ModuleName(module blueprint.Module) string
+	ModuleDir(module blueprint.Module) string
+	ModuleSubDir(module blueprint.Module) string
+	ModuleType(module blueprint.Module) string
+	BlueprintFile(module blueprint.Module) string
+
+	ModuleErrorf(module blueprint.Module, format string, args ...interface{})
+	Errorf(format string, args ...interface{})
+	Failed() bool
+
+	Variable(pctx PackageContext, name, value string)
+	Rule(pctx PackageContext, name string, params RuleParams, argNames ...string) blueprint.Rule
+	Build(pctx PackageContext, params BuildParams)
+	RequireNinjaVersion(major, minor, micro int)
+
+	// SetNinjaBuildDir sets the value of the top-level "builddir" Ninja variable
+	// that controls where Ninja stores its build log files.  This value can be
+	// set at most one time for a single build, later calls are ignored.
+	SetNinjaBuildDir(pctx PackageContext, value string)
+
+	// Eval takes a string with embedded ninja variables, and returns a string
+	// with all of the variables recursively expanded. Any variables references
+	// are expanded in the scope of the PackageContext.
+	Eval(pctx PackageContext, ninjaStr string) (string, error)
+
+	VisitAllModules(visit func(Module))
+	VisitAllModulesIf(pred func(Module) bool, visit func(Module))
+	VisitDepsDepthFirst(module Module, visit func(Module))
+	VisitDepsDepthFirstIf(module Module, pred func(Module) bool,
+		visit func(Module))
+
+	VisitAllModuleVariants(module Module, visit func(Module))
+
+	PrimaryModule(module Module) Module
+	FinalModule(module Module) Module
+
+	AddNinjaFileDeps(deps ...string)
+
+	// GlobWithDeps returns a list of files that match the specified pattern but do not match any
+	// of the patterns in excludes.  It also adds efficient dependencies to rerun the primary
+	// builder whenever a file matching the pattern as added or removed, without rerunning if a
+	// file that does not match the pattern is added to a searched directory.
+	GlobWithDeps(pattern string, excludes []string) ([]string, error)
+
+	Fs() pathtools.FileSystem
+}
+
+type singletonAdaptor struct {
+	Singleton
+}
+
+func (s singletonAdaptor) GenerateBuildActions(ctx blueprint.SingletonContext) {
+	s.Singleton.GenerateBuildActions(singletonContextAdaptor{ctx})
+}
+
+type Singleton interface {
+	GenerateBuildActions(SingletonContext)
+}
+
+type singletonContextAdaptor struct {
+	blueprint.SingletonContext
+}
+
+func (s singletonContextAdaptor) Variable(pctx PackageContext, name, value string) {
+	s.SingletonContext.Variable(pctx.PackageContext, name, value)
+}
+
+func (s singletonContextAdaptor) Rule(pctx PackageContext, name string, params RuleParams, argNames ...string) blueprint.Rule {
+	return s.SingletonContext.Rule(pctx.PackageContext, name, params.RuleParams, argNames...)
+}
+
+func (s singletonContextAdaptor) Build(pctx PackageContext, params BuildParams) {
+	bparams := convertBuildParams(params)
+	s.SingletonContext.Build(pctx.PackageContext, bparams)
+
+}
+
+func (s singletonContextAdaptor) SetNinjaBuildDir(pctx PackageContext, value string) {
+	s.SingletonContext.SetNinjaBuildDir(pctx.PackageContext, value)
+}
+
+func (s singletonContextAdaptor) Eval(pctx PackageContext, ninjaStr string) (string, error) {
+	return s.SingletonContext.Eval(pctx.PackageContext, ninjaStr)
+}
+
+// visitAdaptor wraps a visit function that takes an android.Module parameter into
+// a function that takes an blueprint.Module parameter and only calls the visit function if the
+// blueprint.Module is an android.Module.
+func visitAdaptor(visit func(Module)) func(blueprint.Module) {
+	return func(module blueprint.Module) {
+		if aModule, ok := module.(Module); ok {
+			visit(aModule)
+		}
+	}
+}
+
+// predAdaptor wraps a pred function that takes an android.Module parameter
+// into a function that takes an blueprint.Module parameter and only calls the visit function if the
+// blueprint.Module is an android.Module, otherwise returns false.
+func predAdaptor(pred func(Module) bool) func(blueprint.Module) bool {
+	return func(module blueprint.Module) bool {
+		if aModule, ok := module.(Module); ok {
+			return pred(aModule)
+		} else {
+			return false
+		}
+	}
+}
+
+func (s singletonContextAdaptor) VisitAllModules(visit func(Module)) {
+	s.SingletonContext.VisitAllModules(visitAdaptor(visit))
+}
+
+func (s singletonContextAdaptor) VisitAllModulesIf(pred func(Module) bool, visit func(Module)) {
+	s.SingletonContext.VisitAllModulesIf(predAdaptor(pred), visitAdaptor(visit))
+}
+
+func (s singletonContextAdaptor) VisitDepsDepthFirst(module Module, visit func(Module)) {
+	s.SingletonContext.VisitDepsDepthFirst(module, visitAdaptor(visit))
+}
+
+func (s singletonContextAdaptor) VisitDepsDepthFirstIf(module Module, pred func(Module) bool, visit func(Module)) {
+	s.SingletonContext.VisitDepsDepthFirstIf(module, predAdaptor(pred), visitAdaptor(visit))
+}
+
+func (s singletonContextAdaptor) VisitAllModuleVariants(module Module, visit func(Module)) {
+	s.SingletonContext.VisitAllModuleVariants(module, visitAdaptor(visit))
+}
+
+func (s singletonContextAdaptor) PrimaryModule(module Module) Module {
+	return s.SingletonContext.PrimaryModule(module).(Module)
+}
+
+func (s singletonContextAdaptor) FinalModule(module Module) Module {
+	return s.SingletonContext.FinalModule(module).(Module)
+}