Make consistent set of get and getTry methods on SemiFuture.

[folly.git] / folly / futures / Future.h

diff --git a/folly/futures/Future.h b/folly/futures/Future.h
index 5eda2c34b4d9c8d263815bfe3f1ea9b1b269440f..5b2dc82f7b44b6c8f9a4a910f1f17fdb0c6c1204 100644 (file)
--- a/folly/futures/Future.h
+++ b/folly/futures/Future.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Facebook, Inc.
+ * Copyright 2017-present Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 #pragma once
 
 #include <algorithm>
@@ -97,6 +96,13 @@ class FutureBase {
   T&& value() &&;
   T const&& value() const&&;
 
+  /// Returns a reference to the try of the result. Throws as for value if
+  /// future is not valid.
+  Try<T>& result() &;
+  Try<T> const& result() const&;
+  Try<T>&& result() &&;
+  Try<T> const&& result() const&&;
+
   /** True when the result (or exception) is ready. */
   bool isReady() const;
 
@@ -106,9 +112,6 @@ class FutureBase {
   /// sugar for getTry().hasException()
   bool hasException();
 
-  /** A reference to the Try of the value */
-  Try<T>& getTry();
-
   /// If the promise has been fulfilled, return an Optional with the Try<T>.
   /// Otherwise return an empty Optional.
   /// Note that this moves the Try<T> out.
@@ -233,7 +236,6 @@ class SemiFuture : private futures::detail::FutureBase<T> {
   /* implicit */ SemiFuture(Future<T>&&) noexcept;
 
   using Base::cancel;
-  using Base::getTry;
   using Base::hasException;
   using Base::hasValue;
   using Base::isActive;
@@ -242,6 +244,7 @@ class SemiFuture : private futures::detail::FutureBase<T> {
   using Base::raise;
   using Base::setCallback_;
   using Base::value;
+  using Base::result;
 
   SemiFuture& operator=(SemiFuture const&) = delete;
   SemiFuture& operator=(SemiFuture&&) noexcept;
@@ -256,6 +259,24 @@ class SemiFuture : private futures::detail::FutureBase<T> {
   /// exception).
   T get(Duration dur) &&;
 
+  /// Block until the future is fulfilled, or until timed out. Returns the
+  /// Try of the value (moved out).
+  Try<T> getTry() &&;
+
+  /// Block until the future is fulfilled, or until timed out. Returns the
+  /// Try of the value (moved out) or may throw a TimedOut exception.
+  Try<T> getTry(Duration dur) &&;
+
+  /// Call e->drive() repeatedly until the future is fulfilled. Examples
+  /// of DrivableExecutor include EventBase and ManualExecutor. Returns the
+  /// value (moved out), or throws the exception.
+  T getVia(DrivableExecutor* e) &&;
+
+  /// Call e->drive() repeatedly until the future is fulfilled. Examples
+  /// of DrivableExecutor include EventBase and ManualExecutor. Returns the
+  /// Try of the value (moved out).
+  Try<T> getTryVia(DrivableExecutor* e) &&;
+
   /// Block until this Future is complete. Returns a reference to this Future.
   SemiFuture<T>& wait() &;
 
@@ -269,6 +290,15 @@ class SemiFuture : private futures::detail::FutureBase<T> {
   /// Overload of wait(Duration) for rvalue Futures
   SemiFuture<T>&& wait(Duration) &&;
 
+  /// Call e->drive() repeatedly until the future is fulfilled. Examples
+  /// of DrivableExecutor include EventBase and ManualExecutor. Returns a
+  /// reference to this SemiFuture so that you can chain calls if desired.
+  /// value (moved out), or throws the exception.
+  SemiFuture<T>& waitVia(DrivableExecutor* e) &;
+
+  /// Overload of waitVia() for rvalue Futures
+  SemiFuture<T>&& waitVia(DrivableExecutor* e) &&;
+
   /// Returns an inactive Future which will call back on the other side of
   /// executor (when it is activated).
   ///
@@ -312,6 +342,7 @@ class SemiFuture : private futures::detail::FutureBase<T> {
   void boost_();
 
  private:
+  friend class Promise<T>;
   template <class>
   friend class futures::detail::FutureBase;
   template <class>
@@ -391,7 +422,6 @@ class Future : private futures::detail::FutureBase<T> {
   Future& operator=(Future<T2>&&);
 
   using Base::cancel;
-  using Base::getTry;
   using Base::hasException;
   using Base::hasValue;
   using Base::isActive;
@@ -400,6 +430,7 @@ class Future : private futures::detail::FutureBase<T> {
   using Base::raise;
   using Base::setCallback_;
   using Base::value;
+  using Base::result;
 
   static Future<T> makeEmpty(); // equivalent to moved-from
 
@@ -409,16 +440,16 @@ class Future : private futures::detail::FutureBase<T> {
   // movable
   Future& operator=(Future&&) noexcept;
 
-  /// Call e->drive() repeatedly until the future is fulfilled. Examples
-  /// of DrivableExecutor include EventBase and ManualExecutor. Returns a
-  /// reference to the Try of the value.
-  Try<T>& getTryVia(DrivableExecutor* e);
-
   /// Call e->drive() repeatedly until the future is fulfilled. Examples
   /// of DrivableExecutor include EventBase and ManualExecutor. Returns the
   /// value (moved out), or throws the exception.
   T getVia(DrivableExecutor* e);
 
+  /// Call e->drive() repeatedly until the future is fulfilled. Examples
+  /// of DrivableExecutor include EventBase and ManualExecutor. Returns a
+  /// reference to the Try of the value.
+  Try<T>& getTryVia(DrivableExecutor* e);
+
   /// Unwraps the case of a Future<Future<T>> instance, and returns a simple
   /// Future<T> instance.
   template <class F = T>
@@ -645,6 +676,9 @@ class Future : private futures::detail::FutureBase<T> {
   /// exception).
   T get(Duration dur);
 
+  /** A reference to the Try of the value */
+  Try<T>& getTry();
+
   /// Block until this Future is complete. Returns a reference to this Future.
   Future<T>& wait() &;