From f62a81797a731595353a2d48499dec9457e37946 Mon Sep 17 00:00:00 2001
From: Tom <git@thomastrapp.com>
Date: Fri, 17 Jul 2020 23:37:33 +0200
Subject: [PATCH] AtomicCondition: add wait*_value helpers

---
 include/sgnl/AtomicCondition.h | 36 +++++++++++++++++++++
 test/test.cpp                  | 59 ++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/include/sgnl/AtomicCondition.h b/include/sgnl/AtomicCondition.h
index 07fd8e3..2d2a7f1 100644
--- a/include/sgnl/AtomicCondition.h
+++ b/include/sgnl/AtomicCondition.h
@@ -65,6 +65,18 @@ public:
     return this->condvar_.wait(lock, std::forward<Args>(args)...);
   }
 
+  template<typename... Args>
+  auto wait_value(ValueType value, Args&&... args) const
+  {
+    std::unique_lock lock(this->mutex_);
+    return this->condvar_.wait(
+        lock,
+        std::forward<Args>(args)...,
+        [this, &value](){
+          return this->value_.load() == value;
+        });
+  }
+
   template<typename... Args>
   auto wait_for(Args&&... args) const
   {
@@ -72,6 +84,18 @@ public:
     return this->condvar_.wait_for(lock, std::forward<Args>(args)...);
   }
 
+  template<typename... Args>
+  auto wait_for_value(ValueType value, Args&&... args) const
+  {
+    std::unique_lock lock(this->mutex_);
+    return this->condvar_.wait_for(
+        lock,
+        std::forward<Args>(args)...,
+        [this, &value](){
+          return this->value_.load() == value;
+        });
+  }
+
   template<typename... Args>
   auto wait_until(Args&&... args) const
   {
@@ -79,6 +103,18 @@ public:
     return this->condvar_.wait_until(lock, std::forward<Args>(args)...);
   }
 
+  template<typename... Args>
+  auto wait_until_value(ValueType value, Args&&... args) const
+  {
+    std::unique_lock lock(this->mutex_);
+    return this->condvar_.wait_until(
+        lock,
+        std::forward<Args>(args)...,
+        [this, &value](){
+          return this->value_.load() == value;
+        });
+  }
+
 private:
   std::atomic<ValueType> value_;
   mutable std::mutex mutex_;
diff --git a/test/test.cpp b/test/test.cpp
index f0d3d10..d7ab3ed 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -85,6 +85,23 @@ TEST_CASE("wait-pred")
   REQUIRE( future.get() == true );
 }
 
+TEST_CASE("wait-value")
+{
+  sgnl::AtomicCondition condition(0);
+  std::future<int> future =
+    std::async(
+        std::launch::async,
+        [&condition](){ condition.wait_value(23); return condition.get(); });
+
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  std::this_thread::yield();
+
+  condition.notify_all();
+  condition.set_and_notify_one(23);
+
+  REQUIRE( future.get() == 23 );
+}
+
 TEST_CASE("wait-for-predicate")
 {
   sgnl::AtomicCondition condition(23);
@@ -105,6 +122,24 @@ TEST_CASE("wait-for-predicate")
   REQUIRE( condition.get() == 42 );
 }
 
+TEST_CASE("wait-for-value")
+{
+  sgnl::AtomicCondition condition(23);
+  std::future<void> future =
+    std::async(
+        std::launch::async,
+        [&condition](){
+          condition.wait_for_value(42, std::chrono::hours(1000)); });
+
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  std::this_thread::yield();
+
+  condition.set_and_notify_all(42);
+  future.wait();
+
+  REQUIRE( condition.get() == 42 );
+}
+
 TEST_CASE("wait-for-predicate-simple")
 {
   sgnl::AtomicCondition condition(23);
@@ -146,6 +181,30 @@ TEST_CASE("wait-until-predicate")
   REQUIRE( condition.get() == 42 );
 }
 
+TEST_CASE("wait-until-value")
+{
+  sgnl::AtomicCondition condition(23);
+  std::future<int> future =
+    std::async(
+        std::launch::async,
+        [&condition](){
+          condition.wait_until_value(
+              42,
+              std::chrono::system_clock::now() + std::chrono::hours(1));
+          return condition.get();
+        });
+
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  std::this_thread::yield();
+
+  condition.notify_all();
+  condition.set(42);
+  condition.notify_all();
+
+  REQUIRE( future.get() == 42 );
+  REQUIRE( condition.get() == 42 );
+}
+
 TEST_CASE("sigwait")
 {
   sgnl::SignalHandler signal_handler({SIGUSR1});