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Commit b77035b8 authored by Luis Hector Chavez's avatar Luis Hector Chavez
Browse files

Allow android::base::ScopeGuard in STL containers 

This change lets android::base::ScopeGuard be useful in STL containers
(e.g. std::vector<android::base::ScopeGuard<std::function<void()>>>). It
also provides perfect forwarding for android::base::make_scope_guard.

Bug: 34764308
Test: libbase_test

Change-Id: I7d1e5494b0f0695763cff0700efdb9ec18ae85c8
parent e8d1b75c

base/include/android-base/scopeguard.h

+15 −5
Original line number Diff line number Diff line
@@ -17,20 +17,27 @@ 
#ifndef ANDROID_BASE_SCOPEGUARD_H

#define ANDROID_BASE_SCOPEGUARD_H



#include <utility>  // for std::move

#include <utility>  // for std::move, std::forward



namespace android {

namespace base {



// ScopeGuard ensures that the specified functor is executed no matter how the

// current scope exits.

template <typename F>

class ScopeGuard {

 public:

  ScopeGuard(F f) : f_(f), active_(true) {}

  ScopeGuard(F&& f) : f_(std::forward<F>(f)), active_(true) {}



  ScopeGuard(ScopeGuard&& that) : f_(std::move(that.f_)), active_(that.active_) {

    that.active_ = false;

  }



  template <typename Functor>

  ScopeGuard(ScopeGuard<Functor>&& that) : f_(std::move(that.f_)), active_(that.active_) {

    that.active_ = false;

  }



  ~ScopeGuard() {

    if (active_) f_();

  }
@@ -45,13 +52,16 @@ class ScopeGuard { 
  bool active() const { return active_; }



 private:

  template <typename Functor>

  friend class ScopeGuard;



  F f_;

  bool active_;

};



template <typename T>

ScopeGuard<T> make_scope_guard(T f) {

  return ScopeGuard<T>(f);

template <typename F>

ScopeGuard<F> make_scope_guard(F&& f) {

  return ScopeGuard<F>(std::forward<F>(f));

}



}  // namespace base

base/scopeguard_test.cpp

+13 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include "android-base/scopeguard.h"



#include <utility>

#include <vector>



#include <gtest/gtest.h>
@@ -44,3 +45,15 @@ TEST(scopeguard, moved) { 
  EXPECT_FALSE(scopeguard.active());

  ASSERT_FALSE(guarded_var);

}



TEST(scopeguard, vector) {

  int guarded_var = 0;

  {

    std::vector<android::base::ScopeGuard<std::function<void()>>> scopeguards;

    scopeguards.emplace_back(android::base::make_scope_guard(

        std::bind([](int& guarded_var) { guarded_var++; }, std::ref(guarded_var))));

    scopeguards.emplace_back(android::base::make_scope_guard(

        std::bind([](int& guarded_var) { guarded_var++; }, std::ref(guarded_var))));

  }

  ASSERT_EQ(guarded_var, 2);

}