Allow widgets to be added by passing value suppliers (#1690)

wpilibc/src/main/native/include/frc/shuffleboard/ShuffleboardContainer.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -24,6 +25,7 @@
 #include "frc/shuffleboard/LayoutType.h"
 #include "frc/shuffleboard/ShuffleboardComponentBase.h"
 #include "frc/shuffleboard/ShuffleboardValue.h"
+#include "frc/shuffleboard/SuppliedValueWidget.h"
 
 namespace cs {
 class VideoSource;
@@ -262,6 +264,98 @@ class ShuffleboardContainer : public virtual ShuffleboardValue,
   SimpleWidget& Add(const wpi::Twine& title,
                     wpi::ArrayRef<std::string> defaultValue);
 
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::string>& AddString(
+      const wpi::Twine& title, std::function<std::string()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<double>& AddNumber(const wpi::Twine& title,
+                                         std::function<double()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<bool>& AddBoolean(const wpi::Twine& title,
+                                        std::function<bool()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<std::string>>& AddStringArray(
+      const wpi::Twine& title,
+      std::function<std::vector<std::string>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<double>>& AddNumberArray(
+      const wpi::Twine& title, std::function<std::vector<double>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<int>>& AddBooleanArray(
+      const wpi::Twine& title, std::function<std::vector<int>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<wpi::StringRef>& AddRaw(
+      const wpi::Twine& title, std::function<wpi::StringRef()> supplier);
+
   /**
    * Adds a widget to this container to display a simple piece of data.
    *

wpilibc/src/main/native/include/frc/shuffleboard/SuppliedValueWidget.h

@@ -0,0 +1,48 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <functional>
+#include <memory>
+
+#include <networktables/NetworkTable.h>
+#include <networktables/NetworkTableEntry.h>
+#include <wpi/Twine.h>
+
+#include "frc/shuffleboard/ShuffleboardComponent.h"
+#include "frc/shuffleboard/ShuffleboardComponent.inc"
+#include "frc/shuffleboard/ShuffleboardComponentBase.h"
+#include "frc/shuffleboard/ShuffleboardContainer.h"
+#include "frc/shuffleboard/ShuffleboardWidget.h"
+
+namespace frc {
+template <typename T>
+class SuppliedValueWidget : public ShuffleboardWidget<SuppliedValueWidget<T> > {
+ public:
+  SuppliedValueWidget(ShuffleboardContainer& parent, const wpi::Twine& title,
+                      std::function<T()> supplier,
+                      std::function<void(nt::NetworkTableEntry, T)> setter)
+      : ShuffleboardValue(title),
+        ShuffleboardWidget<SuppliedValueWidget<T> >(parent, title),
+        m_supplier(supplier),
+        m_setter(setter) {}
+
+  void BuildInto(std::shared_ptr<nt::NetworkTable> parentTable,
+                 std::shared_ptr<nt::NetworkTable> metaTable) override {
+    this->BuildMetadata(metaTable);
+    metaTable->GetEntry("Controllable").SetBoolean(false);
+
+    auto entry = parentTable->GetEntry(this->GetTitle());
+    m_setter(entry, m_supplier());
+  }
+
+ private:
+  std::function<T()> m_supplier;
+  std::function<void(nt::NetworkTableEntry, T)> m_setter;
+};
+}  // namespace frc