C/Cpp: Add main.cpp example, doxygen config

cpp/src/main.cpp

@@ -0,0 +1,152 @@
+/**
+ * @file      main.cpp
+ * @brief     Main event loop
+ *
+ * Here typically goes a more extensive explanation of what the header defines.
+ *
+ * @author    Name <email@example.com>
+ * @copyright (c) Company Name/ Author, YEAR
+ * @copyright Licensed under the Apache License, Version 2.0 <http://www.apache.org/licenses/LICENSE-2.0>
+ * @copyright Licensed under the GNU GPLv3 License <http://www.gnu.org/licenses/gpl-3.0.txt>
+ */
+
+#include <algorithm>
+#include <iostream>
+#include <thread>
+#include <vector>
+
+#include "version.h"
+
+// static configuration
+#define LOGFILE_PATH      "ctestapp.log"
+#define MAINLOOP_SLEEP_US 1
+
+// other default values
+#define LOG_VERBOSE 1
+#define LOG_DEBUG   2
+#define LOG_MAX     9
+
+/**
+ * @brief Helper class to parse CLI arguments
+ *
+ * CLI arguments can be specified with an equals sign between the parameter name and the
+ * value, so for `-o=foobar.txt` the option would be `-o`.
+ */
+struct AppOptions {
+  int         verbosity;
+  std::string configstring{};
+
+  AppOptions(int argc, char* argv[] /* NOLINT(modernize-avoid-c-arrays,cppcoreguidelines-avoid-c-arrays) */)
+      : verbosity{0}, applicationName{argv[0]} {
+    auto cliArgs = std::vector<std::string>{};
+    for (int i = 1; i < argc; i++) {
+      cliArgs.emplace_back(argv[i]);
+    }
+
+    while (!cliArgs.empty()) {
+      auto arg = *cliArgs.begin();
+
+      // find flags (but only at the beginning)
+      if (0 == arg.find("-h")) {
+        printUsage();
+        exit(EXIT_SUCCESS);
+        break;
+      }
+      if (0 == arg.find("-v")) {
+        this->verbosity = static_cast<int>(std::count(arg.begin(), arg.end(), 'v'));
+
+      } else if (0 == arg.find("-d=")) {
+        this->configstring = arg.substr(arg.find('=') + 1);
+
+      } else {
+        printUsageShort();
+        std::cerr << "error: unrecognized arguments: " << arg << "\n";
+        exit(EXIT_FAILURE);
+        break;
+      }
+
+      // remove the parsed argument from the vector
+      cliArgs.erase(cliArgs.begin());
+    }
+  }
+
+  void printUsageShort() {
+    std::cout << "usage: " << this->applicationName << " ";
+    std::cout << "[-h] ";
+    std::cout << "[-v] ";
+    std::cout << "[-d=SOME_CONFIG]\n";
+  }
+
+  void printUsage() {
+    printUsageShort();
+    std::cout << "\n";
+    std::cout << "optional arguments:\n";
+    std::cout << "  -h,          show this help message and exit\n";
+    std::cout << "  -v,          increase output verbosity (-vv for VERBOSE)\n";
+    std::cout << "  -d=SOME_CONFIG, TODO config parameter\n";
+  }
+
+private:
+  std::string applicationName;
+};
+
+int main(int argc, char* argv[]) {
+  printf("Template C++ App: " GIT_VERSION_TAG "\n\n");
+
+  // parse CLI options
+  AppOptions options(argc, argv);
+
+  // start logging
+  loguru::g_preamble_date    = false;  // The date field
+  loguru::g_preamble_time    = false;  // The time of the current day
+  loguru::g_preamble_uptime  = true;   // The time since init call
+  loguru::g_preamble_thread  = false;  // The logging thread
+  loguru::g_preamble_file    = true;   // The file from which the log originates from
+  loguru::g_preamble_verbose = true;   // The verbosity field
+  loguru::g_preamble_pipe    = true;   // The pipe symbol right before the message
+
+  loguru::add_file(LOGFILE_PATH, loguru::Truncate, loguru::Verbosity_8);
+  LOG_F(INFO, "Version " GIT_VERSION_TAG "");
+
+  // set stdout verbosity level (0 -> WARNING, 1 -> INFO, 2 -> 1, 3 -> 2, 4 -> MAX)
+  switch (options.verbosity) {
+  case 0:                                                    // NOLINT(bugprone-branch-clone)
+    loguru::g_stderr_verbosity = loguru::Verbosity_WARNING;  // custom default
+    break;
+  case 1:                                                 // NOLINT(bugprone-branch-clone)
+    loguru::g_stderr_verbosity = loguru::Verbosity_INFO;  // INFO with -v
+    break;
+  case 2:                                      // NOLINT(bugprone-branch-clone)
+    loguru::g_stderr_verbosity = LOG_VERBOSE;  // "verbose" with -vv
+    break;
+  case 3:                                    // NOLINT(bugprone-branch-clone)
+    loguru::g_stderr_verbosity = LOG_DEBUG;  // "debug" with -vvv
+    break;
+  case 4:                                                // NOLINT(bugprone-branch-clone)
+    loguru::g_stderr_verbosity = loguru::Verbosity_MAX;  // everything with -vvvv
+    break;
+
+  default:
+    LOG_F(WARNING, "Unrecognised verbosity level %i!", options.verbosity);
+    break;
+  }
+
+  //
+  // SETUP
+  //
+
+  // TODO: do some setup here
+
+  //
+  // MAIN LOOP
+  //
+  while (true) {
+
+    // TODO: do some work here
+
+    // very simple ratelimit
+    std::this_thread::sleep_for(std::chrono::milliseconds(MAINLOOP_SLEEP_US));
+  }
+
+  return EXIT_SUCCESS;
+}