From 80f1d792187be73e6747d356982201d1ea58ce2f Mon Sep 17 00:00:00 2001
From: Peter Johnson <johnson.peter@gmail.com>
Date: Sun, 23 May 2021 20:46:25 -0700
Subject: [PATCH] [wpiutil] Split function_ref to a separate header

---
 .../lib/native/cpp/hardware/LEDDisplay.cpp    |  2 +
 .../include/glass/hardware/AnalogGyro.h       |  2 +-
 .../include/glass/hardware/AnalogInput.h      |  2 +-
 .../include/glass/hardware/AnalogOutput.h     |  2 +-
 .../lib/native/include/glass/hardware/DIO.h   |  2 +-
 .../native/include/glass/hardware/Encoder.h   |  2 +-
 .../include/glass/hardware/LEDDisplay.h       |  2 +-
 .../lib/native/include/glass/hardware/PCM.h   |  2 +-
 .../lib/native/include/glass/hardware/PDP.h   |  2 +-
 .../lib/native/include/glass/hardware/PWM.h   |  2 +-
 .../lib/native/include/glass/hardware/Relay.h |  2 +-
 .../lib/native/include/glass/other/Field2D.h  |  2 +-
 .../native/include/glass/other/Mechanism2D.h  |  2 +-
 .../glass/networktables/NTDifferentialDrive.h |  1 -
 .../glass/networktables/NTMecanumDrive.h      |  1 -
 .../glass/networktables/NetworkTables.h       |  1 -
 .../frc/smartdashboard/SendableRegistry.h     |  2 +-
 .../src/main/native/include/wpi/STLExtras.h   | 39 +----------
 .../main/native/include/wpi/function_ref.h    | 65 +++++++++++++++++++
 19 files changed, 81 insertions(+), 54 deletions(-)
 create mode 100644 wpiutil/src/main/native/include/wpi/function_ref.h

diff --git a/glass/src/lib/native/cpp/hardware/LEDDisplay.cpp b/glass/src/lib/native/cpp/hardware/LEDDisplay.cpp
index c32e3df1a3..c1ece3a142 100644
--- a/glass/src/lib/native/cpp/hardware/LEDDisplay.cpp
+++ b/glass/src/lib/native/cpp/hardware/LEDDisplay.cpp
@@ -4,6 +4,8 @@
 
 #include "glass/hardware/LEDDisplay.h"
 
+#include <wpi/SmallVector.h>
+
 #include "glass/Context.h"
 #include "glass/support/ExtraGuiWidgets.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/AnalogGyro.h b/glass/src/lib/native/include/glass/hardware/AnalogGyro.h
index b0ae397706..fdfcf4f798 100644
--- a/glass/src/lib/native/include/glass/hardware/AnalogGyro.h
+++ b/glass/src/lib/native/include/glass/hardware/AnalogGyro.h
@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/AnalogInput.h b/glass/src/lib/native/include/glass/hardware/AnalogInput.h
index 10f4b40b79..2e49b9ccce 100644
--- a/glass/src/lib/native/include/glass/hardware/AnalogInput.h
+++ b/glass/src/lib/native/include/glass/hardware/AnalogInput.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/AnalogOutput.h b/glass/src/lib/native/include/glass/hardware/AnalogOutput.h
index 16f95a3e05..7ba8be6dd1 100644
--- a/glass/src/lib/native/include/glass/hardware/AnalogOutput.h
+++ b/glass/src/lib/native/include/glass/hardware/AnalogOutput.h
@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/DIO.h b/glass/src/lib/native/include/glass/hardware/DIO.h
index a8236f3487..5593ba69da 100644
--- a/glass/src/lib/native/include/glass/hardware/DIO.h
+++ b/glass/src/lib/native/include/glass/hardware/DIO.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/Encoder.h b/glass/src/lib/native/include/glass/hardware/Encoder.h
index d553ef10fa..41d781aa9a 100644
--- a/glass/src/lib/native/include/glass/hardware/Encoder.h
+++ b/glass/src/lib/native/include/glass/hardware/Encoder.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/LEDDisplay.h b/glass/src/lib/native/include/glass/hardware/LEDDisplay.h
index c7af045897..ddd3c27ca0 100644
--- a/glass/src/lib/native/include/glass/hardware/LEDDisplay.h
+++ b/glass/src/lib/native/include/glass/hardware/LEDDisplay.h
@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 #include <wpi/span.h>
 
 #include "glass/Model.h"
diff --git a/glass/src/lib/native/include/glass/hardware/PCM.h b/glass/src/lib/native/include/glass/hardware/PCM.h
index af8bde892e..107a2a84fc 100644
--- a/glass/src/lib/native/include/glass/hardware/PCM.h
+++ b/glass/src/lib/native/include/glass/hardware/PCM.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/PDP.h b/glass/src/lib/native/include/glass/hardware/PDP.h
index c0d5c3f487..8417ea35d6 100644
--- a/glass/src/lib/native/include/glass/hardware/PDP.h
+++ b/glass/src/lib/native/include/glass/hardware/PDP.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/PWM.h b/glass/src/lib/native/include/glass/hardware/PWM.h
index d8a6a4ed47..74c7461c8a 100644
--- a/glass/src/lib/native/include/glass/hardware/PWM.h
+++ b/glass/src/lib/native/include/glass/hardware/PWM.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/hardware/Relay.h b/glass/src/lib/native/include/glass/hardware/Relay.h
index 287c42b71b..b025119b6b 100644
--- a/glass/src/lib/native/include/glass/hardware/Relay.h
+++ b/glass/src/lib/native/include/glass/hardware/Relay.h
@@ -6,7 +6,7 @@
 
 #include <string_view>
 
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 
diff --git a/glass/src/lib/native/include/glass/other/Field2D.h b/glass/src/lib/native/include/glass/other/Field2D.h
index 8c86acd702..9399876ac5 100644
--- a/glass/src/lib/native/include/glass/other/Field2D.h
+++ b/glass/src/lib/native/include/glass/other/Field2D.h
@@ -10,7 +10,7 @@
 #include <frc/geometry/Rotation2d.h>
 #include <frc/geometry/Translation2d.h>
 #include <imgui.h>
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 #include <wpi/span.h>
 
 #include "glass/Model.h"
diff --git a/glass/src/lib/native/include/glass/other/Mechanism2D.h b/glass/src/lib/native/include/glass/other/Mechanism2D.h
index 58af961143..7617e6f3ca 100644
--- a/glass/src/lib/native/include/glass/other/Mechanism2D.h
+++ b/glass/src/lib/native/include/glass/other/Mechanism2D.h
@@ -7,7 +7,7 @@
 #include <frc/geometry/Rotation2d.h>
 #include <frc/geometry/Translation2d.h>
 #include <imgui.h>
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 #include "glass/Model.h"
 #include "glass/View.h"
diff --git a/glass/src/libnt/native/include/glass/networktables/NTDifferentialDrive.h b/glass/src/libnt/native/include/glass/networktables/NTDifferentialDrive.h
index 3dcf72106d..49b3eb0518 100644
--- a/glass/src/libnt/native/include/glass/networktables/NTDifferentialDrive.h
+++ b/glass/src/libnt/native/include/glass/networktables/NTDifferentialDrive.h
@@ -9,7 +9,6 @@
 #include <vector>
 
 #include <ntcore_cpp.h>
-#include <wpi/STLExtras.h>
 
 #include "glass/DataSource.h"
 #include "glass/networktables/NetworkTablesHelper.h"
diff --git a/glass/src/libnt/native/include/glass/networktables/NTMecanumDrive.h b/glass/src/libnt/native/include/glass/networktables/NTMecanumDrive.h
index 3d4718a207..ce7d2342df 100644
--- a/glass/src/libnt/native/include/glass/networktables/NTMecanumDrive.h
+++ b/glass/src/libnt/native/include/glass/networktables/NTMecanumDrive.h
@@ -9,7 +9,6 @@
 #include <vector>
 
 #include <ntcore_cpp.h>
-#include <wpi/STLExtras.h>
 
 #include "glass/DataSource.h"
 #include "glass/networktables/NetworkTablesHelper.h"
diff --git a/glass/src/libnt/native/include/glass/networktables/NetworkTables.h b/glass/src/libnt/native/include/glass/networktables/NetworkTables.h
index e16ac3ad14..8538eaa4d6 100644
--- a/glass/src/libnt/native/include/glass/networktables/NetworkTables.h
+++ b/glass/src/libnt/native/include/glass/networktables/NetworkTables.h
@@ -11,7 +11,6 @@
 
 #include <ntcore_cpp.h>
 #include <wpi/DenseMap.h>
-#include <wpi/STLExtras.h>
 
 #include "glass/Model.h"
 #include "glass/View.h"
diff --git a/wpilibc/src/main/native/include/frc/smartdashboard/SendableRegistry.h b/wpilibc/src/main/native/include/frc/smartdashboard/SendableRegistry.h
index e93d77a613..2109ec245f 100644
--- a/wpilibc/src/main/native/include/frc/smartdashboard/SendableRegistry.h
+++ b/wpilibc/src/main/native/include/frc/smartdashboard/SendableRegistry.h
@@ -9,7 +9,7 @@
 #include <string_view>
 
 #include <networktables/NetworkTable.h>
-#include <wpi/STLExtras.h>
+#include <wpi/function_ref.h>
 
 namespace frc {
 
diff --git a/wpiutil/src/main/native/include/wpi/STLExtras.h b/wpiutil/src/main/native/include/wpi/STLExtras.h
index d7ddd9286d..7f4d6d9250 100644
--- a/wpiutil/src/main/native/include/wpi/STLExtras.h
+++ b/wpiutil/src/main/native/include/wpi/STLExtras.h
@@ -18,6 +18,7 @@
 #define WPIUTIL_WPI_STLEXTRAS_H
 
 #include "wpi/SmallVector.h"
+#include "wpi/function_ref.h"
 #include "wpi/iterator.h"
 #include "wpi/iterator_range.h"
 #include "wpi/ErrorHandling.h"
@@ -94,44 +95,6 @@ template <class Ty> struct greater_ptr {
   }
 };
 
-/// An efficient, type-erasing, non-owning reference to a callable. This is
-/// intended for use as the type of a function parameter that is not used
-/// after the function in question returns.
-///
-/// This class does not own the callable, so it is not in general safe to store
-/// a function_ref.
-template<typename Fn> class function_ref;
-
-template<typename Ret, typename ...Params>
-class function_ref<Ret(Params...)> {
-  Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
-  intptr_t callable;
-
-  template<typename Callable>
-  static Ret callback_fn(intptr_t callable, Params ...params) {
-    return (*reinterpret_cast<Callable*>(callable))(
-        std::forward<Params>(params)...);
-  }
-
-public:
-  function_ref() = default;
-  function_ref(std::nullptr_t) {}
-
-  template <typename Callable>
-  function_ref(Callable &&callable,
-               typename std::enable_if<
-                   !std::is_same<typename std::remove_reference<Callable>::type,
-                                 function_ref>::value>::type * = nullptr)
-      : callback(callback_fn<typename std::remove_reference<Callable>::type>),
-        callable(reinterpret_cast<intptr_t>(&callable)) {}
-
-  Ret operator()(Params ...params) const {
-    return callback(callable, std::forward<Params>(params)...);
-  }
-
-  explicit operator bool() const { return callback; }
-};
-
 // deleter - Very very very simple method that is used to invoke operator
 // delete on something.  It is used like this:
 //
diff --git a/wpiutil/src/main/native/include/wpi/function_ref.h b/wpiutil/src/main/native/include/wpi/function_ref.h
new file mode 100644
index 0000000000..05654153d1
--- /dev/null
+++ b/wpiutil/src/main/native/include/wpi/function_ref.h
@@ -0,0 +1,65 @@
+// 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.
+
+//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef WPIUTIL_WPI_FUNCTION_REF_H_
+#define WPIUTIL_WPI_FUNCTION_REF_H_
+
+#include <stdint.h>
+
+#include <type_traits>
+#include <utility>
+
+namespace wpi {
+
+/// An efficient, type-erasing, non-owning reference to a callable. This is
+/// intended for use as the type of a function parameter that is not used
+/// after the function in question returns.
+///
+/// This class does not own the callable, so it is not in general safe to store
+/// a function_ref.
+template <typename Fn>
+class function_ref;
+
+template <typename Ret, typename... Params>
+class function_ref<Ret(Params...)> {
+  Ret (*callback)(intptr_t callable, Params... params) = nullptr;
+  intptr_t callable;
+
+  template <typename Callable>
+  static Ret callback_fn(intptr_t callable, Params... params) {
+    return (*reinterpret_cast<Callable*>(callable))(
+        std::forward<Params>(params)...);
+  }
+
+ public:
+  function_ref() = default;
+  function_ref(std::nullptr_t) {}
+
+  template <typename Callable>
+  function_ref(Callable&& callable,
+               typename std::enable_if<
+                   !std::is_same<typename std::remove_reference<Callable>::type,
+                                 function_ref>::value>::type* = nullptr)
+      : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+        callable(reinterpret_cast<intptr_t>(&callable)) {}
+
+  Ret operator()(Params... params) const {
+    return callback(callable, std::forward<Params>(params)...);
+  }
+
+  explicit operator bool() const { return callback; }
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_WPI_FUNCTION_REF_H_