apply clang-tidy modernize-use-override

[folly.git] / folly / io / async / DelayedDestruction.h

diff --git a/folly/io/async/DelayedDestruction.h b/folly/io/async/DelayedDestruction.h
index bda26f7e325faa5e4026ad6d68f5895bb5eb39aa..c46b8ff0d701b48e529d904caab0323ee1a556e2 100644 (file)
--- a/folly/io/async/DelayedDestruction.h
+++ b/folly/io/async/DelayedDestruction.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,9 @@
 
 #pragma once
 
-#include <boost/noncopyable.hpp>
-#include <inttypes.h>
-#include <assert.h>
+#include <folly/io/async/DelayedDestructionBase.h>
+
+#include <glog/logging.h>
 
 namespace folly {
 
@@ -39,23 +39,8 @@ namespace folly {
  * DelayedDestruction does not perform any locking.  It is intended to be used
  * only from a single thread.
  */
-class DelayedDestruction : private boost::noncopyable {
+class DelayedDestruction : public DelayedDestructionBase {
  public:
-  /**
-   * Helper class to allow DelayedDestruction classes to be used with
-   * std::shared_ptr.
-   *
-   * This class can be specified as the destructor argument when creating the
-   * shared_ptr, and it will destroy the guarded class properly when all
-   * shared_ptr references are released.
-   */
-  class Destructor {
-   public:
-    void operator()(DelayedDestruction* dd) const {
-      dd->destroy();
-    }
-  };
-
   /**
    * destroy() requests destruction of the object.
    *
@@ -66,67 +51,33 @@ class DelayedDestruction : private boost::noncopyable {
   virtual void destroy() {
     // If guardCount_ is not 0, just set destroyPending_ to delay
     // actual destruction.
-    if (guardCount_ != 0) {
+    if (getDestructorGuardCount() != 0) {
       destroyPending_ = true;
     } else {
-      destroyNow(false);
+      onDelayedDestroy(false);
     }
   }
 
   /**
-   * Classes should create a DestructorGuard object on the stack in any
-   * function that may invoke callback functions.
+   * Helper class to allow DelayedDestruction classes to be used with
+   * std::shared_ptr.
    *
-   * The DestructorGuard prevents the guarded class from being destroyed while
-   * it exists.  Without this, the callback function could delete the guarded
-   * object, causing problems when the callback function returns and the
-   * guarded object's method resumes execution.
+   * This class can be specified as the destructor argument when creating the
+   * shared_ptr, and it will destroy the guarded class properly when all
+   * shared_ptr references are released.
    */
-  class DestructorGuard {
+  class Destructor {
    public:
-
-    explicit DestructorGuard(DelayedDestruction* dd) : dd_(dd) {
-      ++dd_->guardCount_;
-      assert(dd_->guardCount_ > 0); // check for wrapping
-    }
-
-    DestructorGuard(const DestructorGuard& dg) : dd_(dg.dd_) {
-      ++dd_->guardCount_;
-      assert(dd_->guardCount_ > 0); // check for wrapping
-    }
-
-    ~DestructorGuard() {
-      assert(dd_->guardCount_ > 0);
-      --dd_->guardCount_;
-      if (dd_->guardCount_ == 0 && dd_->destroyPending_) {
-        dd_->destroyPending_ = false;
-        dd_->destroyNow(true);
-      }
+    void operator()(DelayedDestruction* dd) const {
+      dd->destroy();
     }
-
-   private:
-    DelayedDestruction* dd_;
   };
 
- protected:
-  /**
-   * destroyNow() is invoked to actually destroy the object, after destroy()
-   * has been called and no more DestructorGuard objects exist.  By default it
-   * calls "delete this", but subclasses may override this behavior.
-   *
-   * @param delayed  This parameter is true if destruction was delayed because
-   *                 of a DestructorGuard object, or false if destroyNow() is
-   *                 being called directly from destroy().
-   */
-  virtual void destroyNow(bool delayed) {
-    delete this;
-    (void)delayed; // prevent unused variable warnings
+  bool getDestroyPending() const {
+    return destroyPending_;
   }
 
-  DelayedDestruction()
-    : guardCount_(0)
-    , destroyPending_(false) {}
-
+ protected:
   /**
    * Protected destructor.
    *
@@ -143,37 +94,29 @@ class DelayedDestruction : private boost::noncopyable {
    * shared_ptr using a DelayedDestruction::Destructor as the second argument
    * to the shared_ptr constructor.
    */
-  virtual ~DelayedDestruction() = default;
+  ~DelayedDestruction() override = default;
 
-  /**
-   * Get the number of DestructorGuards currently protecting this object.
-   *
-   * This is primarily intended for debugging purposes, such as asserting
-   * that an object has at least 1 guard.
-   */
-  uint32_t getDestructorGuardCount() const {
-    return guardCount_;
+  DelayedDestruction()
+    : destroyPending_(false) {
   }
 
  private:
-  /**
-   * guardCount_ is incremented by DestructorGuard, to indicate that one of
-   * the DelayedDestruction object's methods is currently running.
-   *
-   * If destroy() is called while guardCount_ is non-zero, destruction will
-   * be delayed until guardCount_ drops to 0.  This allows DelayedDestruction
-   * objects to invoke callbacks without having to worry about being deleted
-   * before the callback returns.
-   */
-  uint32_t guardCount_;
-
   /**
    * destroyPending_ is set to true if destoy() is called while guardCount_ is
-   * non-zero.
+   * non-zero. It is set to false before the object is deleted.
    *
    * If destroyPending_ is true, the object will be destroyed the next time
    * guardCount_ drops to 0.
    */
   bool destroyPending_;
+
+  void onDelayedDestroy(bool delayed) override {
+    // check if it is ok to destroy now
+    if (delayed && !destroyPending_) {
+      return;
+    }
+    destroyPending_ = false;
+    delete this;
+  }
 };
 } // folly