pseq: Create standalone config file parser
Create a standalone JSON configuration file parser for the
phosphor-power-sequencer application. Support the new config file
properties in the parser.
Separating the config file parser from the rest of the code makes it
easier to implement and test.
Create automated test cases to verify the parser functions.
Change-Id: Ia753ffadf395359899964a612e479b00377ad495
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/config_file_parser.cpp b/phosphor-power-sequencer/src/config_file_parser.cpp
new file mode 100644
index 0000000..db055d1
--- /dev/null
+++ b/phosphor-power-sequencer/src/config_file_parser.cpp
@@ -0,0 +1,173 @@
+/**
+ * Copyright © 2024 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 "config_file_parser.hpp"
+
+#include "config_file_parser_error.hpp"
+
+#include <exception>
+#include <fstream>
+#include <optional>
+
+using json = nlohmann::json;
+
+namespace phosphor::power::sequencer::config_file_parser
+{
+
+std::vector<std::unique_ptr<Rail>> parse(const std::filesystem::path& pathName)
+{
+ try
+ {
+ // Use standard JSON parser to create tree of JSON elements
+ std::ifstream file{pathName};
+ json rootElement = json::parse(file);
+
+ // Parse tree of JSON elements and return corresponding C++ objects
+ return internal::parseRoot(rootElement);
+ }
+ catch (const std::exception& e)
+ {
+ throw ConfigFileParserError{pathName, e.what()};
+ }
+}
+
+namespace internal
+{
+
+GPIO parseGPIO(const json& element)
+{
+ verifyIsObject(element);
+ unsigned int propertyCount{0};
+
+ // Required line property
+ const json& lineElement = getRequiredProperty(element, "line");
+ unsigned int line = parseUnsignedInteger(lineElement);
+ ++propertyCount;
+
+ // Optional active_low property
+ bool activeLow{false};
+ auto activeLowIt = element.find("active_low");
+ if (activeLowIt != element.end())
+ {
+ activeLow = parseBoolean(*activeLowIt);
+ ++propertyCount;
+ }
+
+ // Verify no invalid properties exist
+ verifyPropertyCount(element, propertyCount);
+
+ return GPIO(line, activeLow);
+}
+
+std::unique_ptr<Rail> parseRail(const json& element)
+{
+ verifyIsObject(element);
+ unsigned int propertyCount{0};
+
+ // Required name property
+ const json& nameElement = getRequiredProperty(element, "name");
+ std::string name = parseString(nameElement);
+ ++propertyCount;
+
+ // Optional presence property
+ std::optional<std::string> presence{};
+ auto presenceIt = element.find("presence");
+ if (presenceIt != element.end())
+ {
+ presence = parseString(*presenceIt);
+ ++propertyCount;
+ }
+
+ // Optional page property
+ std::optional<uint8_t> page{};
+ auto pageIt = element.find("page");
+ if (pageIt != element.end())
+ {
+ page = parseUint8(*pageIt);
+ ++propertyCount;
+ }
+
+ // Optional check_status_vout property
+ bool checkStatusVout{false};
+ auto checkStatusVoutIt = element.find("check_status_vout");
+ if (checkStatusVoutIt != element.end())
+ {
+ checkStatusVout = parseBoolean(*checkStatusVoutIt);
+ ++propertyCount;
+ }
+
+ // Optional compare_voltage_to_limits property
+ bool compareVoltageToLimits{false};
+ auto compareVoltageToLimitsIt = element.find("compare_voltage_to_limits");
+ if (compareVoltageToLimitsIt != element.end())
+ {
+ compareVoltageToLimits = parseBoolean(*compareVoltageToLimitsIt);
+ ++propertyCount;
+ }
+
+ // Optional gpio property
+ std::optional<GPIO> gpio{};
+ auto gpioIt = element.find("gpio");
+ if (gpioIt != element.end())
+ {
+ gpio = parseGPIO(*gpioIt);
+ ++propertyCount;
+ }
+
+ // If check_status_vout or compare_voltage_to_limits property is true,
+ // the page property is required; verify page was specified
+ if ((checkStatusVout || compareVoltageToLimits) && !page.has_value())
+ {
+ throw std::invalid_argument{"Required property missing: page"};
+ }
+
+ // Verify no invalid properties exist
+ verifyPropertyCount(element, propertyCount);
+
+ return std::make_unique<Rail>(name, presence, page, checkStatusVout,
+ compareVoltageToLimits, gpio);
+}
+
+std::vector<std::unique_ptr<Rail>> parseRailArray(const json& element)
+{
+ verifyIsArray(element);
+ std::vector<std::unique_ptr<Rail>> rails;
+ for (auto& railElement : element)
+ {
+ rails.emplace_back(parseRail(railElement));
+ }
+ return rails;
+}
+
+std::vector<std::unique_ptr<Rail>> parseRoot(const json& element)
+{
+ verifyIsObject(element);
+ unsigned int propertyCount{0};
+
+ // Required rails property
+ const json& railsElement = getRequiredProperty(element, "rails");
+ std::vector<std::unique_ptr<Rail>> rails = parseRailArray(railsElement);
+ ++propertyCount;
+
+ // Verify no invalid properties exist
+ verifyPropertyCount(element, propertyCount);
+
+ return rails;
+}
+
+} // namespace internal
+
+} // namespace phosphor::power::sequencer::config_file_parser