Add a default timeout parameter to HHWheelTimer.

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

diff --git a/folly/io/async/HHWheelTimer.h b/folly/io/async/HHWheelTimer.h
index 7c6db8a0b428073e0e30ef4ad9a449758d380a01..0424ac59793b769fa95006a5b5e00c4265c4cfb3 100644 (file)
--- a/folly/io/async/HHWheelTimer.h
+++ b/folly/io/async/HHWheelTimer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2015 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -76,6 +76,13 @@ class HHWheelTimer : private folly::AsyncTimeout,
      */
     virtual void timeoutExpired() noexcept = 0;
 
+    /// This callback was canceled. The default implementation is to just
+    /// proxy to `timeoutExpired` but if you care about the difference between
+    /// the timeout finishing or being canceled you can override this.
+    virtual void callbackCanceled() noexcept {
+      timeoutExpired();
+    }
+
     /**
      * Cancel the timeout, if it is running.
      *
@@ -141,21 +148,39 @@ class HHWheelTimer : private folly::AsyncTimeout,
   };
 
   /**
-   * Create a new HHWheelTimer with the specified interval.
+   * Create a new HHWheelTimer with the specified interval and the
+   * default timeout value set.
+   *
+   * Objects created using this version of constructor can be used
+   * to schedule both variable interval timeouts using
+   * scheduleTimeout(callback, timeout) method, and default
+   * interval timeouts using scheduleTimeout(callback) method.
    */
   static int DEFAULT_TICK_INTERVAL;
   explicit HHWheelTimer(folly::EventBase* eventBase,
                         std::chrono::milliseconds intervalMS =
-                        std::chrono::milliseconds(DEFAULT_TICK_INTERVAL));
+                        std::chrono::milliseconds(DEFAULT_TICK_INTERVAL),
+                        AsyncTimeout::InternalEnum internal =
+                        AsyncTimeout::InternalEnum::NORMAL,
+                        std::chrono::milliseconds defaultTimeoutMS =
+                        std::chrono::milliseconds(-1));
 
   /**
    * Destroy the HHWheelTimer.
    *
    * A HHWheelTimer should only be destroyed when there are no more
-   * callbacks pending in the set.
+   * callbacks pending in the set. (If it helps you may use cancelAll() to
+   * cancel all pending timeouts explicitly before calling this.)
    */
   virtual void destroy();
 
+  /**
+   * Cancel all outstanding timeouts
+   *
+   * @returns the number of timeouts that were cancelled.
+   */
+  size_t cancelAll();
+
   /**
    * Get the tick interval for this HHWheelTimer.
    *
@@ -165,6 +190,15 @@ class HHWheelTimer : private folly::AsyncTimeout,
     return interval_;
   }
 
+  /**
+   * Get the default timeout interval for this HHWheelTimer.
+   *
+   * Returns the timeout interval in milliseconds.
+   */
+  std::chrono::milliseconds getDefaultTimeout() const {
+    return defaultTimeout_;
+  }
+
   /**
    * Schedule the specified Callback to be invoked after the
    * specified timeout interval.
@@ -177,6 +211,18 @@ class HHWheelTimer : private folly::AsyncTimeout,
   void scheduleTimeoutImpl(Callback* callback,
                        std::chrono::milliseconds timeout);
 
+  /**
+   * Schedule the specified Callback to be invoked after the
+   * fefault timeout interval.
+   *
+   * If the callback is already scheduled, this cancels the existing timeout
+   * before scheduling the new timeout.
+   *
+   * This method uses CHECK() to make sure that the default timeout was
+   * specified on the object initialization.
+   */
+  void scheduleTimeout(Callback* callback);
+
   template <class F>
   void scheduleTimeoutFn(F fn, std::chrono::milliseconds timeout) {
     struct Wrapper : Callback {
@@ -245,6 +291,7 @@ class HHWheelTimer : private folly::AsyncTimeout,
   virtual void timeoutExpired() noexcept;
 
   std::chrono::milliseconds interval_;
+  std::chrono::milliseconds defaultTimeout_;
 
   static constexpr int WHEEL_BUCKETS = 4;
   static constexpr int WHEEL_BITS = 8;