Split Sendable into NT and non-NT portions (#3432)

The non-NT portion has been moved to wpiutil.
The NT portion has been moved to ntcore (as NTSendable).

SendableBuilder similarly split and moved.

SendableRegistry moved to wpiutil.

In C++, SendableHelper also moved to wpiutil.

This enables use of Sendable from wpimath and also enables
moving several classes from wpilib to wpimath.

wpiutil/src/main/native/include/wpi/sendable/SendableBuilder.h

@@ -0,0 +1,217 @@
+// 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 <functional>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "wpi/SmallVector.h"
+#include "wpi/span.h"
+
+namespace wpi {
+
+class SendableBuilder {
+ public:
+  /**
+   * The backend kinds used for the sendable builder.
+   */
+  enum BackendKind { kUnknown, kNetworkTables };
+
+  virtual ~SendableBuilder() = default;
+
+  /**
+   * Set the string representation of the named data type that will be used
+   * by the smart dashboard for this sendable.
+   *
+   * @param type    data type
+   */
+  virtual void SetSmartDashboardType(std::string_view type) = 0;
+
+  /**
+   * Set a flag indicating if this sendable should be treated as an actuator.
+   * By default this flag is false.
+   *
+   * @param value   true if actuator, false if not
+   */
+  virtual void SetActuator(bool value) = 0;
+
+  /**
+   * Set the function that should be called to set the Sendable into a safe
+   * state.  This is called when entering and exiting Live Window mode.
+   *
+   * @param func    function
+   */
+  virtual void SetSafeState(std::function<void()> func) = 0;
+
+  /**
+   * Add a boolean property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddBooleanProperty(std::string_view key,
+                                  std::function<bool()> getter,
+                                  std::function<void(bool)> setter) = 0;
+
+  /**
+   * Add a double property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddDoubleProperty(std::string_view key,
+                                 std::function<double()> getter,
+                                 std::function<void(double)> setter) = 0;
+
+  /**
+   * Add a string property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddStringProperty(
+      std::string_view key, std::function<std::string()> getter,
+      std::function<void(std::string_view)> setter) = 0;
+
+  /**
+   * Add a boolean array property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddBooleanArrayProperty(
+      std::string_view key, std::function<std::vector<int>()> getter,
+      std::function<void(wpi::span<const int>)> setter) = 0;
+
+  /**
+   * Add a double array property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddDoubleArrayProperty(
+      std::string_view key, std::function<std::vector<double>()> getter,
+      std::function<void(wpi::span<const double>)> setter) = 0;
+
+  /**
+   * Add a string array property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddStringArrayProperty(
+      std::string_view key, std::function<std::vector<std::string>()> getter,
+      std::function<void(wpi::span<const std::string>)> setter) = 0;
+
+  /**
+   * Add a raw property.
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddRawProperty(std::string_view key,
+                              std::function<std::string()> getter,
+                              std::function<void(std::string_view)> setter) = 0;
+
+  /**
+   * Add a string property (SmallString form).
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddSmallStringProperty(
+      std::string_view key,
+      std::function<std::string_view(wpi::SmallVectorImpl<char>& buf)> getter,
+      std::function<void(std::string_view)> setter) = 0;
+
+  /**
+   * Add a boolean array property (SmallVector form).
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddSmallBooleanArrayProperty(
+      std::string_view key,
+      std::function<wpi::span<const int>(wpi::SmallVectorImpl<int>& buf)>
+          getter,
+      std::function<void(wpi::span<const int>)> setter) = 0;
+
+  /**
+   * Add a double array property (SmallVector form).
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddSmallDoubleArrayProperty(
+      std::string_view key,
+      std::function<wpi::span<const double>(wpi::SmallVectorImpl<double>& buf)>
+          getter,
+      std::function<void(wpi::span<const double>)> setter) = 0;
+
+  /**
+   * Add a string array property (SmallVector form).
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddSmallStringArrayProperty(
+      std::string_view key,
+      std::function<
+          wpi::span<const std::string>(wpi::SmallVectorImpl<std::string>& buf)>
+          getter,
+      std::function<void(wpi::span<const std::string>)> setter) = 0;
+
+  /**
+   * Add a raw property (SmallVector form).
+   *
+   * @param key     property name
+   * @param getter  getter function (returns current value)
+   * @param setter  setter function (sets new value)
+   */
+  virtual void AddSmallRawProperty(
+      std::string_view key,
+      std::function<std::string_view(wpi::SmallVectorImpl<char>& buf)> getter,
+      std::function<void(std::string_view)> setter) = 0;
+
+  /**
+   * Gets the kind of backend being used.
+   *
+   * @return Backend kind
+   */
+  virtual BackendKind GetBackendKind() const = 0;
+
+  /**
+   * Return whether this sendable has been published.
+   *
+   * @return True if it has been published, false if not.
+   */
+  virtual bool IsPublished() const = 0;
+
+  /**
+   * Update the published values by calling the getters for all properties.
+   */
+  virtual void Update() = 0;
+
+  /**
+   * Clear properties.
+   */
+  virtual void ClearProperties() = 0;
+};
+
+}  // namespace wpi