Sensor Objects

This includes all the sensor objects including a few
implementations, including dbus and sysfs sensors.

Change-Id: I9897c79f9fd463f00f0e02aeb6c32ffa89635dbe
Signed-off-by: Patrick Venture <venture@google.com>

6 files changed, 228 insertions, 0 deletions

diff --git a/sysfs/sysfsread.cpp b/sysfs/sysfsread.cpp
new file mode 100644
index 0000000..284aa55
--- /dev/null
+++ b/sysfs/sysfsread.cpp
@@ -0,0 +1,39 @@
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * 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 <chrono>
+#include <fstream>
+#include <iostream>
+
+#include "sysfs/sysfsread.hpp"
+
+
+ReadReturn SysFsRead::read(void)
+{
+    int64_t value;
+    std::ifstream ifs;
+
+    ifs.open(_path);
+    ifs >> value;
+    ifs.close();
+
+    struct ReadReturn r = {
+        static_cast<double>(value),
+        std::chrono::high_resolution_clock::now()
+    };
+
+    return r;
+}
diff --git a/sysfs/sysfsread.hpp b/sysfs/sysfsread.hpp
new file mode 100644
index 0000000..0dbc71b
--- /dev/null
+++ b/sysfs/sysfsread.hpp
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <string>
+
+#include "interfaces.hpp"
+#include "sysfs/util.hpp"
+
+
+/*
+ * A ReadInterface that is expecting a path that's sysfs, but really could be
+ * any filesystem path.
+ */
+class SysFsRead : public ReadInterface
+{
+    public:
+        SysFsRead(const std::string& path)
+            : ReadInterface(),
+              _path(FixupPath(path))
+        { }
+
+        ReadReturn read(void) override;
+
+    private:
+        const std::string _path;
+};
diff --git a/sysfs/sysfswrite.cpp b/sysfs/sysfswrite.cpp
new file mode 100644
index 0000000..c3e1b03
--- /dev/null
+++ b/sysfs/sysfswrite.cpp
@@ -0,0 +1,48 @@
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * 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 <fstream>
+#include <iostream>
+
+#include "sysfswrite.hpp"
+
+
+void SysFsWritePercent::write(double value)
+{
+    float minimum = getMin();
+    float maximum = getMax();
+
+    float range = maximum - minimum;
+    float offset = range * value;
+    float ovalue = offset + minimum;
+
+    std::ofstream ofs;
+    ofs.open(_writepath);
+    ofs << static_cast<int64_t>(ovalue);
+    ofs.close();
+
+    return;
+}
+
+void SysFsWrite::write(double value)
+{
+    std::ofstream ofs;
+    ofs.open(_writepath);
+    ofs << static_cast<int64_t>(value);
+    ofs.close();
+
+    return;
+}
diff --git a/sysfs/sysfswrite.hpp b/sysfs/sysfswrite.hpp
new file mode 100644
index 0000000..9f7083c
--- /dev/null
+++ b/sysfs/sysfswrite.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <string>
+
+#include "interfaces.hpp"
+#include "sysfs/util.hpp"
+
+
+/*
+ * A WriteInterface that is expecting a path that's sysfs, but really could be
+ * any filesystem path.
+ */
+class SysFsWritePercent : public WriteInterface
+{
+    public:
+        SysFsWritePercent(std::string& writepath, int64_t min, int64_t max)
+            : WriteInterface(min, max),
+              _writepath(FixupPath(writepath))
+        { }
+
+        void write(double value) override;
+
+    private:
+        std::string _writepath;
+};
+
+class SysFsWrite : public WriteInterface
+{
+    public:
+        SysFsWrite(std::string& writepath, int64_t min, int64_t max)
+            : WriteInterface(min, max),
+              _writepath(FixupPath(writepath))
+        { }
+
+        void write(double value) override;
+
+    private:
+        std::string _writepath;
+};
diff --git a/sysfs/util.cpp b/sysfs/util.cpp
new file mode 100644
index 0000000..c297412
--- /dev/null
+++ b/sysfs/util.cpp
@@ -0,0 +1,71 @@
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * 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 <experimental/filesystem>
+#include <iostream>
+#include <string>
+
+
+#include "sysfs/util.hpp"
+
+/*
+ * There are two basic paths I want to support:
+ * 1. /sys/class/hwmon/hwmon0/pwm1
+ * 2. /sys/devices/platform/ahb/1e786000.pwm-tacho-controller/hwmon/<asterisk asterisk>/pwm1
+ *
+ * In this latter case, I want to fill in that gap.  Assuming because it's this
+ * path that it'll only have one directory there.
+ */
+
+static constexpr auto platform = "/sys/devices/platform/";
+namespace fs = std::experimental::filesystem;
+
+
+std::string FixupPath(std::string original)
+{
+    std::string::size_type n, x;
+
+    /* TODO: Consider the merits of using regex for this. */
+    n = original.find("**");
+    x = original.find(platform);
+
+    if ((n != std::string::npos) && (x != std::string::npos))
+    {
+        /* This path has some missing pieces and we support it. */
+        std::string base = original.substr(0, n);
+        std::string fldr;
+        std::string f = original.substr(n + 2, original.size() - (n + 2));
+
+        /* Equivalent to glob and grab 0th entry. */
+        for (const auto& folder : fs::directory_iterator(base))
+        {
+            fldr = folder.path();
+            break;
+        }
+
+        if (!fldr.length())
+        {
+            return original;
+        }
+
+        return fldr + f;
+    }
+    else
+    {
+        /* It'll throw an exception when we use it if it's still bad. */
+        return original;
+    }
+}
diff --git a/sysfs/util.hpp b/sysfs/util.hpp
new file mode 100644
index 0000000..2d4c274
--- /dev/null
+++ b/sysfs/util.hpp
@@ -0,0 +1,6 @@
+#include <string>
+
+/*
+ * Given a path that optionally has a glob portion, fill it out.
+ */
+std::string FixupPath(std::string original);