presence: Add any of redundancy policy

Add a bitwise logical or redundancy policy implementation
(fan is present if any sensor indicates as such).

Change-Id: I1d161478a4a6fe9d5690a385703e41c6fff9c81c
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/presence/anyof.cpp b/presence/anyof.cpp
new file mode 100644
index 0000000..4dbf356
--- /dev/null
+++ b/presence/anyof.cpp
@@ -0,0 +1,78 @@
+/**
+ * Copyright © 2017 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <algorithm>
+#include <phosphor-logging/log.hpp>
+#include "anyof.hpp"
+#include "fan.hpp"
+#include "psensor.hpp"
+
+namespace phosphor
+{
+namespace fan
+{
+namespace presence
+{
+AnyOf::AnyOf(
+        const Fan& fan,
+        const std::vector<std::reference_wrapper<PresenceSensor>>& s)
+        : RedundancyPolicy(fan),
+        state()
+{
+    for (auto& sensor: s)
+    {
+        state.emplace_back(sensor, false);
+    }
+}
+
+void AnyOf::stateChanged(bool present, PresenceSensor& sensor)
+{
+    // Find the sensor that changed state.
+    auto sit = std::find_if(
+            state.begin(),
+            state.end(),
+            [&sensor](const auto& s){ return std::get<0>(s).get() == sensor; });
+    if (sit != state.end())
+    {
+        // Update our cache of the sensors state and re-evaluate.
+        std::get<bool>(*sit) = present;
+        auto newState = std::any_of(
+                state.begin(),
+                state.end(),
+                [](const auto& s){ return std::get<bool>(s); });
+        setPresence(fan, newState);
+    }
+}
+
+void AnyOf::monitor()
+{
+    // Start all sensors in the anyof redundancy set.
+
+    for (auto& s: state)
+    {
+        auto &sensor = std::get<0>(s);
+        std::get<bool>(s) = sensor.get().start();
+    }
+
+    auto present = std::any_of(
+            state.begin(),
+            state.end(),
+            [](const auto& s){ return std::get<bool>(s); });
+    setPresence(fan, present);
+}
+
+} // namespace presence
+} // namespace fan
+} // namespace phosphor