Patch internal change 111557819.

Defer calls to mutable_unknown_fields() until it is actually required to
save memory for C++ lite runtime.

Change-Id: Ica9c1fd276cdb164942d1e7b6e098c83ee3ffdc5

1 files changed, 83 insertions, 0 deletions

diff --git a/src/google/protobuf/stubs/callback.h b/src/google/protobuf/stubs/callback.h
index 6da530d3..1ba6ea7a 100644
--- a/src/google/protobuf/stubs/callback.h
+++ b/src/google/protobuf/stubs/callback.h
@@ -78,6 +78,18 @@ class LIBPROTOBUF_EXPORT Closure {
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Closure);
 };
 
+template<typename R>
+class LIBPROTOBUF_EXPORT ResultCallback {
+ public:
+  ResultCallback() {}
+  virtual ~ResultCallback() {}
+
+  virtual R Run() = 0;
+
+ private:
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ResultCallback);
+};
+
 template<typename R, typename A1>
 class LIBPROTOBUF_EXPORT ResultCallback1 {
  public:
@@ -240,6 +252,50 @@ class MethodClosure2 : public Closure {
   Arg2 arg2_;
 };
 
+template<typename R>
+class FunctionResultCallback_0_0 : public ResultCallback<R> {
+ public:
+  typedef R (*FunctionType)();
+
+  FunctionResultCallback_0_0(FunctionType function, bool self_deleting)
+      : function_(function), self_deleting_(self_deleting) {}
+  ~FunctionResultCallback_0_0() {}
+
+  R Run() {
+    bool needs_delete = self_deleting_;  // read in case callback deletes
+    R result = function_();
+    if (needs_delete) delete this;
+    return result;
+  }
+
+ private:
+  FunctionType function_;
+  bool self_deleting_;
+};
+
+template<typename R, typename P1>
+class FunctionResultCallback_1_0 : public ResultCallback<R> {
+ public:
+  typedef R (*FunctionType)(P1);
+
+  FunctionResultCallback_1_0(FunctionType function, bool self_deleting,
+                             P1 p1)
+      : function_(function), self_deleting_(self_deleting), p1_(p1) {}
+  ~FunctionResultCallback_1_0() {}
+
+  R Run() {
+    bool needs_delete = self_deleting_;  // read in case callback deletes
+    R result = function_(p1_);
+    if (needs_delete) delete this;
+    return result;
+  }
+
+ private:
+  FunctionType function_;
+  bool self_deleting_;
+  P1 p1_;
+};
+
 template<typename R, typename Arg1>
 class FunctionResultCallback_0_1 : public ResultCallback1<R, Arg1> {
  public:
@@ -408,6 +464,33 @@ inline Closure* NewPermanentCallback(
     object, method, false, arg1, arg2);
 }
 
+// See ResultCallback
+template<typename R>
+inline ResultCallback<R>* NewCallback(R (*function)()) {
+  return new internal::FunctionResultCallback_0_0<R>(function, true);
+}
+
+// See ResultCallback
+template<typename R>
+inline ResultCallback<R>* NewPermanentCallback(R (*function)()) {
+  return new internal::FunctionResultCallback_0_0<R>(function, false);
+}
+
+// See ResultCallback
+template<typename R, typename P1>
+inline ResultCallback<R>* NewCallback(R (*function)(P1), P1 p1) {
+  return new internal::FunctionResultCallback_1_0<R, P1>(
+      function, true, p1);
+}
+
+// See ResultCallback
+template<typename R, typename P1>
+inline ResultCallback<R>* NewPermanentCallback(
+    R (*function)(P1), P1 p1) {
+  return new internal::FunctionResultCallback_1_0<R, P1>(
+      function, false, p1);
+}
+
 // See ResultCallback1
 template<typename R, typename A1>
 inline ResultCallback1<R, A1>* NewCallback(R (*function)(A1)) {