Implement PSU Power Sensor

Implement Power Supply Input Power Sensor.

Tested By:
With the related change in entity-manager, after run psusensor in
BMC console, xyz.openbmc_project.PSUSensor has been created and
PSU pin dbus interface has been created with correct Thresholds
and value. Ipmitool sensor list can show PSU pin sensor.

Change-Id: Ib057a9ecca7bf317eb8d98af1ddb8be39841a54f
Signed-off-by: Cheng C Yang <cheng.c.yang@linux.intel.com>
diff --git a/src/PSUSensor.cpp b/src/PSUSensor.cpp
new file mode 100644
index 0000000..c71b84d
--- /dev/null
+++ b/src/PSUSensor.cpp
@@ -0,0 +1,147 @@
+/*
+// Copyright (c) 2019 Intel 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 <unistd.h>
+
+#include <PSUSensor.hpp>
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/algorithm/string/replace.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include <iostream>
+#include <limits>
+#include <sdbusplus/asio/connection.hpp>
+#include <sdbusplus/asio/object_server.hpp>
+#include <string>
+
+PSUSensor::PSUSensor(const std::string& path, const std::string& objectType,
+                     sdbusplus::asio::object_server& objectServer,
+                     std::shared_ptr<sdbusplus::asio::connection>& conn,
+                     boost::asio::io_service& io, const std::string& sensorName,
+                     std::vector<thresholds::Threshold>&& _thresholds,
+                     const std::string& sensorConfiguration,
+                     std::string& sensorTypeName, unsigned int factor,
+                     double max, double min) :
+    Sensor(boost::replace_all_copy(sensorName, " ", "_"), path,
+           std::move(_thresholds), sensorConfiguration, objectType, max, min),
+    objServer(objectServer), inputDev(io, open(path.c_str(), O_RDONLY)),
+    waitTimer(io), errCount(0), sensorFactor(factor)
+{
+    sensorInterface = objectServer.add_interface(
+        "/xyz/openbmc_project/sensors/" + sensorTypeName + name,
+        "xyz.openbmc_project.Sensor.Value");
+
+    if (thresholds::hasWarningInterface(thresholds))
+    {
+        thresholdInterfaceWarning = objectServer.add_interface(
+            "/xyz/openbmc_project/sensors/" + sensorTypeName + name,
+            "xyz.openbmc_project.Sensor.Threshold.Warning");
+    }
+    if (thresholds::hasCriticalInterface(thresholds))
+    {
+        thresholdInterfaceCritical = objectServer.add_interface(
+            "/xyz/openbmc_project/sensors/" + sensorTypeName + name,
+            "xyz.openbmc_project.Sensor.Threshold.Critical");
+    }
+    setInitialProperties(conn);
+    setupRead();
+}
+
+PSUSensor::~PSUSensor()
+{
+    inputDev.close();
+    waitTimer.cancel();
+    objServer.remove_interface(sensorInterface);
+    objServer.remove_interface(thresholdInterfaceWarning);
+    objServer.remove_interface(thresholdInterfaceCritical);
+}
+
+void PSUSensor::setupRead(void)
+{
+    boost::asio::async_read_until(
+        inputDev, readBuf, '\n',
+        [&](const boost::system::error_code& ec,
+            std::size_t /*bytes_transfered*/) { handleResponse(ec); });
+}
+
+void PSUSensor::handleResponse(const boost::system::error_code& err)
+{
+    if (err == boost::system::errc::bad_file_descriptor)
+    {
+        return;
+    }
+    std::istream responseStream(&readBuf);
+    if (!err)
+    {
+        std::string response;
+        try
+        {
+            std::getline(responseStream, response);
+            float nvalue = std::stof(response);
+            responseStream.clear();
+            nvalue /= sensorFactor;
+            if (overridenState)
+            {
+                nvalue = overriddenValue;
+            }
+            if (nvalue != value)
+            {
+                updateValue(nvalue);
+            }
+            errCount = 0;
+        }
+        catch (const std::invalid_argument&)
+        {
+            errCount++;
+        }
+    }
+    else
+    {
+        errCount++;
+    }
+
+    if (errCount >= warnAfterErrorCount)
+    {
+        if (errCount == warnAfterErrorCount)
+        {
+            std::cerr << "Failure to read sensor " << name << " at " << path
+                      << "\n";
+        }
+        updateValue(0);
+        errCount++;
+    }
+
+    responseStream.clear();
+    inputDev.close();
+    int fd = open(path.c_str(), O_RDONLY);
+    if (fd <= 0)
+    {
+        return;
+    }
+    inputDev.assign(fd);
+    waitTimer.expires_from_now(boost::posix_time::milliseconds(sensorPollMs));
+    waitTimer.async_wait([&](const boost::system::error_code& ec) {
+        if (ec == boost::asio::error::operation_aborted)
+        {
+            return;
+        }
+        setupRead();
+    });
+}
+
+void PSUSensor::checkThresholds(void)
+{
+    thresholds::checkThresholds(this);
+}