[wpilib] Add DataLogManager

This creates a default log file that captures NT changes and
automatically renames the log file based on time and match info.

DriverStation joystick logging will be implemented by the DriverStation
class instead.

wpilibc/src/main/native/include/frc/DataLogManager.h

@@ -0,0 +1,85 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+namespace wpi::log {
+class DataLog;
+}  // namespace wpi::log
+
+namespace frc {
+
+/**
+ * Centralized data log that provides automatic data log file management. It
+ * automatically cleans up old files when disk space is low and renames the file
+ * based either on current date/time or (if available) competition match number.
+ * The deta file will be saved to a USB flash drive if one is attached, or to
+ * /home/lvuser otherwise.
+ *
+ * Log files are initially named "FRC_TBD_{random}.wpilog" until the DS
+ * connects. After the DS connects, the log file is renamed to
+ * "FRC_yyyyMMdd_HHmmss.wpilog" (where the date/time is UTC). If the FMS is
+ * connected and provides a match number, the log file is renamed to
+ * "FRC_yyyyMMdd_HHmmss_{event}_{match}.wpilog".
+ *
+ * On startup, all existing FRC_TBD log files are deleted. If there is less than
+ * 50 MB of free space on the target storage, FRC_ log files are deleted (oldest
+ * to newest) until there is 50 MB free OR there are 10 files remaining.
+ *
+ * By default, all NetworkTables value changes are stored to the data log.
+ */
+class DataLogManager final {
+ public:
+  DataLogManager() = delete;
+
+  /**
+   * Start data log manager. The parameters have no effect if the data log
+   * manager was already started (e.g. by calling another static function).
+   *
+   * @param dir if not empty, directory to use for data log storage
+   * @param filename filename to use; if none provided, the filename is
+   *     automatically generated
+   * @param period time between automatic flushes to disk, in seconds;
+   *               this is a time/storage tradeoff
+   */
+  static void Start(std::string_view dir = "", std::string_view filename = "",
+                    double period = 0.25);
+
+  /**
+   * Log a message to the "messages" entry. The message is also printed to
+   * standard output (followed by a newline).
+   *
+   * @param message message
+   */
+  static void Log(std::string_view message);
+
+  /**
+   * Get the managed data log (for custom logging). Starts the data log manager
+   * if not already started.
+   *
+   * @return data log
+   */
+  static wpi::log::DataLog& GetLog();
+
+  /**
+   * Get the log directory.
+   *
+   * @return log directory
+   */
+  static std::string GetLogDir();
+
+  /**
+   * Enable or disable logging of NetworkTables data. Note that unlike the
+   * network interface for NetworkTables, this will capture every value change.
+   * Defaults to enabled.
+   *
+   * @param enabled true to enable, false to disable
+   */
+  static void LogNetworkTables(bool enabled);
+};
+
+}  // namespace frc