From 3207f6413c15edc91e46c9cd154a84c93c78bbc8 Mon Sep 17 00:00:00 2001
From: Xuehan Xu <xxhdx1985126@gmail.com>
Date: Wed, 1 Sep 2021 15:33:02 +0800
Subject: [PATCH] crimson/common: a new condition variable

Signed-off-by: Xuehan Xu <xxhdx1985126@gmail.com>
---
 src/crimson/common/condition_variable.h | 43 +++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 src/crimson/common/condition_variable.h

diff --git a/src/crimson/common/condition_variable.h b/src/crimson/common/condition_variable.h
new file mode 100644
index 0000000000000..19267f38abeaf
--- /dev/null
+++ b/src/crimson/common/condition_variable.h
@@ -0,0 +1,43 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <seastar/core/future.hh>
+#include <seastar/core/condition-variable.hh>
+#include <seastar/core/loop.hh>
+
+#include "crimson/common/interruptible_future.h"
+
+namespace crimson {
+
+class condition_variable : public seastar::condition_variable {
+public:
+  template <typename Pred, typename Func>
+  auto wait(
+    Pred&& pred,
+    Func&& action) noexcept {
+    using func_result_t = std::invoke_result_t<Func>;
+    using intr_errorator_t = typename func_result_t::interrupt_errorator_type;
+    using intr_cond_t = typename func_result_t::interrupt_cond_type;
+    using interruptor = crimson::interruptible::interruptor<intr_cond_t>;
+    return interruptor::repeat(
+      [this, pred=std::forward<Pred>(pred),
+      action=std::forward<Func>(action)]()
+      -> typename intr_errorator_t::template future<seastar::stop_iteration> {
+      if (!pred()) {
+	return seastar::condition_variable::wait().then([] {
+	  return seastar::make_ready_future<
+	    seastar::stop_iteration>(seastar::stop_iteration::no);
+	});
+      } else {
+	return action().si_then([] {
+	  return seastar::make_ready_future<
+	    seastar::stop_iteration>(seastar::stop_iteration::yes);
+	});
+      }
+    });
+  }
+};
+
+} // namespace crimson
-- 
2.39.5