manager/json-parser.hpp

#include "config.h"

#include "json-config.hpp"
#include "ledlayout.hpp"

#include <nlohmann/json.hpp>
#include <phosphor-logging/lg2.hpp>
#include <sdbusplus/bus.hpp>
#include <sdeventplus/event.hpp>

#include <filesystem>
#include <fstream>
#include <iostream>

namespace fs = std::filesystem;

using Json = nlohmann::json;

// Priority for a particular LED needs to stay SAME across all groups
// phosphor::led::Layout::Action can only be one of `Blink` and `On`
using PriorityMap =
    std::unordered_map<std::string, phosphor::led::Layout::Action>;

static constexpr auto ledGroups = "/xyz/openbmc_project/led/groups";

/** @brief Parse LED JSON file and output Json object
 *
 *  @param[in] path - path of LED JSON file
 *
 *  @return const Json - Json object
 */
Json readJson(const fs::path& path)
{
    if (!fs::exists(path) || fs::is_empty(path))
    {
        lg2::error("Incorrect File Path or empty file, FILE_PATH = {PATH}",
                   "PATH", path);
        throw std::runtime_error("Incorrect File Path or empty file");
    }

    try
    {
        std::ifstream jsonFile(path);
        return Json::parse(jsonFile);
    }
    catch (const std::exception& e)
    {
        lg2::error(
            "Failed to parse config file, ERROR = {ERROR}, FILE_PATH = {PATH}",
            "ERROR", e, "PATH", path);
        throw std::runtime_error("Failed to parse config file");
    }
}

/** @brief Returns action enum based on string
 *
 *  @param[in] action - action string
 *
 *  @return Action - action enum (On/Blink)
 */
phosphor::led::Layout::Action getAction(const std::string& action)
{
    assert(action == "On" || action == "Blink");

    return action == "Blink" ? phosphor::led::Layout::Action::Blink
                             : phosphor::led::Layout::Action::On;
}

/** @brief Validate the Priority of an LED is same across ALL groups
 *
 *  @param[in] name - led name member of each group
 *  @param[in] priority - member priority of each group
 *  @param[out] priorityMap - std::unordered_map, key:name, value:priority
 *
 *  @return
 */
void validatePriority(const std::string& name,
                      const phosphor::led::Layout::Action& priority,
                      PriorityMap& priorityMap)
{
    auto iter = priorityMap.find(name);
    if (iter == priorityMap.end())
    {
        priorityMap.emplace(name, priority);
        return;
    }

    if (iter->second != priority)
    {
        lg2::error(
            "Priority of LED is not same across all, Name = {NAME}, Old Priority = {OLD_PRIO}, New Priority = {NEW_PRIO}",
            "NAME", name, "OLD_PRIO", int(iter->second), "NEW_PRIO",
            int(priority));

        throw std::runtime_error(
            "Priority of at least one LED is not same across groups");
    }
}

/** @brief Load JSON config and return led map (JSON version 1)
 *
 *  @return phosphor::led::GroupMap
 */
const phosphor::led::GroupMap loadJsonConfigV1(const Json& json)
{
    phosphor::led::GroupMap ledMap{};
    PriorityMap priorityMap{};

    // define the default JSON as empty
    const Json empty{};
    auto leds = json.value("leds", empty);

    for (const auto& entry : leds)
    {
        fs::path tmpPath(std::string{ledGroups});
        tmpPath /= entry.value("group", "");
        auto objpath = tmpPath.string();
        auto members = entry.value("members", empty);

        phosphor::led::ActionSet ledActions{};
        for (const auto& member : members)
        {
            auto name = member.value("Name", "");
            auto action = getAction(member.value("Action", ""));
            uint8_t dutyOn = member.value("DutyOn", 50);
            uint16_t period = member.value("Period", 0);

            // Since only have Blink/On and default priority is Blink
            auto priority = getAction(member.value("Priority", "Blink"));

            // Same LEDs can be part of multiple groups. However, their
            // priorities across groups need to match.
            validatePriority(name, priority, priorityMap);

            phosphor::led::Layout::LedAction ledAction{name, action, dutyOn,
                                                       period, priority};
            ledActions.emplace(ledAction);
        }

        // Generated an std::unordered_map of LedGroupNames to std::set of LEDs
        // containing the name and properties.
        ledMap.emplace(objpath, ledActions);
    }

    return ledMap;
}

/** @brief Load JSON config and return led map
 *
 *  @return phosphor::led::GroupMap
 */
const phosphor::led::GroupMap loadJsonConfig(const fs::path& path)
{
    auto json = readJson(path);

    auto version = json.value("version", 1);
    switch (version)
    {
        case 1:
            return loadJsonConfigV1(json);

        default:
            lg2::error("Unsupported JSON Version: {VERSION}", "VERSION",
                       version);
            throw std::runtime_error("Unsupported version");
    }

    return phosphor::led::GroupMap{};
}

/** @brief Get led map from LED groups JSON config
 *
 *  @param[in] config - Path to the JSON config.
 *  @return phosphor::led::GroupMap
 *
 *  @note if config is an empty string, daemon will interrogate dbus for
 *        compatible strings.
 */
const phosphor::led::GroupMap getSystemLedMap(fs::path config)
{
    if (config.empty())
    {
        config = phosphor::led::getJsonConfig();
    }

    return loadJsonConfig(config);
}