regulators: Create FFDCFile class
Create C++ class for a file that contains FFDC (first failure data
capture) data.
This class is used to store FFDC data in an error log. The FFDC data is
passed to the error logging system using a file descriptor.
The constructor creates the file and opens it for both reading and
writing. The getFileDescriptor() method returns the file descriptor for
reading/writing the file. The destructor closes and deletes the file.
Also moved the test utility functions makeFileUnRemovable() and
makeFileRemovable() to test_utils.hpp so they can be used by multiple
testcases.
Change-Id: Iddef488a28e83a0df7e7f6955c3217ecb3ec2d51
diff --git a/phosphor-regulators/src/ffdc_file.hpp b/phosphor-regulators/src/ffdc_file.hpp
new file mode 100644
index 0000000..923f09e
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+++ b/phosphor-regulators/src/ffdc_file.hpp
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+/**
+ * Copyright © 2020 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.
+ */
+#pragma once
+
+#include "file_descriptor.hpp"
+#include "temporary_file.hpp"
+#include "xyz/openbmc_project/Logging/Create/server.hpp"
+
+#include <cstdint>
+#include <filesystem>
+
+namespace phosphor::power::regulators
+{
+
+namespace fs = std::filesystem;
+using FFDCFormat =
+ sdbusplus::xyz::openbmc_project::Logging::server::Create::FFDCFormat;
+using FileDescriptor = phosphor::power::util::FileDescriptor;
+
+/**
+ * @class FFDCFile
+ *
+ * File that contains FFDC (first failure data capture) data.
+ *
+ * This class is used to store FFDC data in an error log. The FFDC data is
+ * passed to the error logging system using a file descriptor.
+ *
+ * The constructor creates the file and opens it for both reading and writing.
+ *
+ * Use getFileDescriptor() to obtain the file descriptor needed to read or write
+ * data to the file.
+ *
+ * Use remove() to delete the file. Otherwise the file will be deleted by the
+ * destructor.
+ *
+ * FFDCFile objects cannot be copied, but they can be moved. This enables them
+ * to be stored in containers like std::vector.
+ */
+class FFDCFile
+{
+ public:
+ // Specify which compiler-generated methods we want
+ FFDCFile() = delete;
+ FFDCFile(const FFDCFile&) = delete;
+ FFDCFile(FFDCFile&&) = default;
+ FFDCFile& operator=(const FFDCFile&) = delete;
+ FFDCFile& operator=(FFDCFile&&) = default;
+ ~FFDCFile() = default;
+
+ /**
+ * Constructor.
+ *
+ * Creates the file and opens it for both reading and writing.
+ *
+ * Throws an exception if an error occurs.
+ *
+ * @param format format type of the contained data
+ * @param subType format subtype; used for the 'Custom' type
+ * @param version version of the data format; used for the 'Custom' type
+ */
+ explicit FFDCFile(FFDCFormat format, uint8_t subType = 0,
+ uint8_t version = 0);
+
+ /**
+ * Returns the file descriptor for the file.
+ *
+ * The file is open for both reading and writing.
+ *
+ * @return file descriptor
+ */
+ int getFileDescriptor()
+ {
+ // Return the integer file descriptor within the FileDescriptor object
+ return descriptor();
+ }
+
+ /**
+ * Returns the format type of the contained data.
+ *
+ * @return format type
+ */
+ FFDCFormat getFormat() const
+ {
+ return format;
+ }
+
+ /**
+ * Returns the absolute path to the file.
+ *
+ * @return absolute path
+ */
+ const fs::path& getPath() const
+ {
+ return tempFile.getPath();
+ }
+
+ /**
+ * Returns the format subtype.
+ *
+ * @return subtype
+ */
+ uint8_t getSubType() const
+ {
+ return subType;
+ }
+
+ /**
+ * Returns the version of the data format.
+ *
+ * @return version
+ */
+ uint8_t getVersion() const
+ {
+ return version;
+ }
+
+ /**
+ * Closes and deletes the file.
+ *
+ * Does nothing if the file has already been removed.
+ *
+ * Throws an exception if an error occurs.
+ */
+ void remove();
+
+ private:
+ /**
+ * Format type of the contained data.
+ */
+ FFDCFormat format{FFDCFormat::Text};
+
+ /**
+ * Format subtype; used for the 'Custom' type.
+ */
+ uint8_t subType{0};
+
+ /**
+ * Version of the data format; used for the 'Custom' type.
+ */
+ uint8_t version{0};
+
+ /**
+ * Temporary file where FFDC data is stored.
+ *
+ * The TemporaryFile destructor will automatically delete the file if it was
+ * not explicitly deleted using remove().
+ */
+ TemporaryFile tempFile{};
+
+ /**
+ * File descriptor for reading from/writing to the file.
+ *
+ * The FileDescriptor destructor will automatically close the file if it was
+ * not explicitly closed using remove().
+ */
+ FileDescriptor descriptor{};
+};
+
+} // namespace phosphor::power::regulators