[json] Add forward definition header (#5676)

apriltag/src/main/native/include/frc/apriltag/AprilTag.h

@@ -5,13 +5,10 @@
 #pragma once
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Pose3d.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 struct WPILIB_DLLEXPORT AprilTag {

apriltag/src/main/native/include/frc/apriltag/AprilTagFieldLayout.h

@@ -11,14 +11,11 @@
 
 #include <units/length.h>
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/apriltag/AprilTag.h"
 #include "frc/geometry/Pose3d.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 /**
  * Class for representing a layout of AprilTags on a field and reading them from

cscore/src/main/native/cpp/PropertyContainer.h

@@ -14,6 +14,7 @@
 #include <vector>
 
 #include <wpi/StringMap.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 
 #include "PropertyImpl.h"
@@ -23,7 +24,6 @@ namespace wpi {
 class Logger;
 template <typename T>
 class SmallVectorImpl;
-class json;
 }  // namespace wpi
 
 namespace cs {

cscore/src/main/native/cpp/SinkImpl.h

@@ -10,14 +10,11 @@
 #include <string_view>
 
 #include <wpi/Logger.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 
 #include "SourceImpl.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace cs {
 
 class Frame;

cscore/src/main/native/cpp/SourceImpl.h

@@ -14,6 +14,7 @@
 
 #include <wpi/Logger.h>
 #include <wpi/condition_variable.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 
 #include "Frame.h"
@@ -22,10 +23,6 @@
 #include "PropertyContainer.h"
 #include "cscore_cpp.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace cs {
 
 class Notifier;

cscore/src/main/native/include/cscore_cpp.h

@@ -14,6 +14,7 @@
 #include <vector>
 
 #include <wpi/SmallVector.h>
+#include <wpi/json_fwd.h>
 
 #include "cscore_c.h"
 
@@ -23,10 +24,6 @@
 #pragma warning(disable : 26495)
 #endif
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 /** CameraServer (cscore) namespace */
 namespace cs {
 

glass/src/lib/native/include/glass/Storage.h

@@ -16,10 +16,7 @@
 
 #include <wpi/StringMap.h>
 #include <wpi/iterator_range.h>
-
-namespace wpi {
-class json;
-}  // namespace wpi
+#include <wpi/json_fwd.h>
 
 namespace glass {
 

ntcore/src/generate/include/networktables/Topic.h.jinja

@@ -11,12 +11,13 @@
 #include <string_view>
 #include <vector>
 
+#include <wpi/json_fwd.h>
+
 #include "networktables/Topic.h"
 
 namespace wpi {
 template <typename T>
 class SmallVectorImpl;
-class json;
 }  // namespace wpi
 
 namespace nt {

ntcore/src/main/native/cpp/net/NetworkInterface.h

@@ -8,11 +8,9 @@
 #include <string>
 #include <string_view>
 
-#include "ntcore_cpp.h"
+#include <wpi/json_fwd.h>
 
-namespace wpi {
-class json;
-}  // namespace wpi
+#include "ntcore_cpp.h"
 
 namespace nt {
 class PubSubOptionsImpl;

ntcore/src/main/native/cpp/net/WireDecoder.h

@@ -11,9 +11,10 @@
 #include <string>
 #include <string_view>
 
+#include <wpi/json_fwd.h>
+
 namespace wpi {
 class Logger;
-class json;
 }  // namespace wpi
 
 namespace nt {

ntcore/src/main/native/cpp/net/WireEncoder.h

@@ -9,8 +9,9 @@
 #include <string>
 #include <string_view>
 
+#include <wpi/json_fwd.h>
+
 namespace wpi {
-class json;
 class raw_ostream;
 }  // namespace wpi
 

ntcore/src/main/native/include/networktables/Topic.h

@@ -11,14 +11,12 @@
 #include <utility>
 #include <vector>
 
+#include <wpi/json_fwd.h>
+
 #include "networktables/NetworkTableType.h"
 #include "ntcore_c.h"
 #include "ntcore_cpp.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace nt {
 
 class GenericEntry;

ntcore/src/main/native/include/networktables/UnitTopic.h

@@ -10,13 +10,11 @@
 #include <string_view>
 #include <vector>
 
+#include <wpi/json_fwd.h>
+
 #include "networktables/Topic.h"
 #include "ntcore_cpp.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace nt {
 
 template <typename T>

ntcore/src/main/native/include/ntcore_cpp.h

@@ -17,6 +17,8 @@
 #include <variant>
 #include <vector>
 
+#include <wpi/json_fwd.h>
+
 #include "networktables/NetworkTableValue.h"
 #include "ntcore_c.h"
 #include "ntcore_cpp_types.h"
@@ -24,7 +26,6 @@
 namespace wpi {
 template <typename T>
 class SmallVectorImpl;
-class json;
 }  // namespace wpi
 
 namespace wpi::log {

simulation/halsim_ws_client/src/main/native/include/HALSimWS.h

@@ -12,15 +12,12 @@
 #include <WSProviderContainer.h>
 #include <WSProvider_SimDevice.h>
 #include <wpi/StringMap.h>
+#include <wpi/json_fwd.h>
 #include <wpinet/uv/Async.h>
 #include <wpinet/uv/Loop.h>
 #include <wpinet/uv/Tcp.h>
 #include <wpinet/uv/Timer.h>
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace wpilibws {
 
 class HALSimWSClientConnection;

simulation/halsim_ws_client/src/main/native/include/HALSimWSClientConnection.h

@@ -8,6 +8,7 @@
 #include <utility>
 
 #include <HALSimBaseWebSocketConnection.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 #include <wpinet/WebSocket.h>
 #include <wpinet/uv/Buffer.h>
@@ -15,10 +16,6 @@
 
 #include "HALSimWS.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace wpilibws {
 
 class HALSimWS;

simulation/halsim_ws_core/src/main/native/include/HALSimBaseWebSocketConnection.h

@@ -6,7 +6,7 @@
 
 #include <memory>
 
-#include <wpi/json.h>
+#include <wpi/json_fwd.h>
 
 namespace wpilibws {
 

simulation/halsim_ws_core/src/main/native/include/WSHalProviders.h

@@ -10,7 +10,7 @@
 #include <string_view>
 
 #include <hal/simulation/NotifyListener.h>
-#include <wpi/json.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 
 #include "WSBaseProvider.h"

simulation/halsim_ws_server/src/main/native/include/HALSimHttpConnection.h

@@ -10,6 +10,7 @@
 #include <utility>
 
 #include <HALSimBaseWebSocketConnection.h>
+#include <wpi/json_fwd.h>
 #include <wpi/mutex.h>
 #include <wpinet/HttpWebSocketServerConnection.h>
 #include <wpinet/uv/AsyncFunction.h>
@@ -17,10 +18,6 @@
 
 #include "HALSimWeb.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace wpilibws {
 
 class HALSimHttpConnection

simulation/halsim_ws_server/src/main/native/include/HALSimWeb.h

@@ -13,14 +13,11 @@
 #include <WSProviderContainer.h>
 #include <WSProvider_SimDevice.h>
 #include <wpi/StringMap.h>
+#include <wpi/json_fwd.h>
 #include <wpinet/uv/Async.h>
 #include <wpinet/uv/Loop.h>
 #include <wpinet/uv/Tcp.h>
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace wpilibws {
 
 class HALSimWeb : public std::enable_shared_from_this<HALSimWeb> {

simulation/halsim_xrp/src/main/native/cpp/XRP.cpp

@@ -7,6 +7,7 @@
 #include <fmt/format.h>
 #include <wpi/Endian.h>
 #include <wpi/MathExtras.h>
+#include <wpi/json.h>
 
 using namespace wpilibxrp;
 

simulation/halsim_xrp/src/main/native/include/HALSimXRP.h

@@ -12,6 +12,7 @@
 #include <HALSimBaseWebSocketConnection.h>
 #include <WSProviderContainer.h>
 #include <WSProvider_SimDevice.h>
+#include <wpi/json_fwd.h>
 #include <wpinet/uv/Async.h>
 #include <wpinet/uv/Buffer.h>
 #include <wpinet/uv/Loop.h>
@@ -20,10 +21,6 @@
 
 #include "XRP.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace wpilibxrp {
 
 // This masquerades as a "WebSocket" so that we can reuse the

simulation/halsim_xrp/src/main/native/include/XRP.h

@@ -9,7 +9,7 @@
 #include <span>
 #include <string>
 
-#include <wpi/json.h>
+#include <wpi/json_fwd.h>
 #include <wpinet/raw_uv_ostream.h>
 
 #define XRP_TAG_MOTOR 0x12

wpimath/src/main/native/include/frc/geometry/Pose2d.h

@@ -8,15 +8,12 @@
 #include <span>
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Transform2d.h"
 #include "frc/geometry/Translation2d.h"
 #include "frc/geometry/Twist2d.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/geometry/Pose3d.h

@@ -5,16 +5,13 @@
 #pragma once
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Pose2d.h"
 #include "frc/geometry/Transform3d.h"
 #include "frc/geometry/Translation3d.h"
 #include "frc/geometry/Twist3d.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/geometry/Quaternion.h

@@ -6,10 +6,7 @@
 
 #include <Eigen/Core>
 #include <wpi/SymbolExports.h>
-
-namespace wpi {
-class json;
-}  // namespace wpi
+#include <wpi/json_fwd.h>
 
 namespace frc {
 

wpimath/src/main/native/include/frc/geometry/Rotation2d.h

@@ -5,13 +5,10 @@
 #pragma once
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "units/angle.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/geometry/Rotation3d.h

@@ -6,15 +6,12 @@
 
 #include <Eigen/Core>
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Quaternion.h"
 #include "frc/geometry/Rotation2d.h"
 #include "units/angle.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/geometry/Translation2d.h

@@ -8,14 +8,11 @@
 #include <span>
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Rotation2d.h"
 #include "units/length.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/geometry/Translation3d.h

@@ -5,15 +5,12 @@
 #pragma once
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Rotation3d.h"
 #include "frc/geometry/Translation2d.h"
 #include "units/length.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 
 /**

wpimath/src/main/native/include/frc/trajectory/Trajectory.h

@@ -7,6 +7,7 @@
 #include <vector>
 
 #include <wpi/SymbolExports.h>
+#include <wpi/json_fwd.h>
 
 #include "frc/geometry/Pose2d.h"
 #include "frc/geometry/Transform2d.h"
@@ -15,10 +16,6 @@
 #include "units/time.h"
 #include "units/velocity.h"
 
-namespace wpi {
-class json;
-}  // namespace wpi
-
 namespace frc {
 /**
  * Represents a time-parameterized trajectory. The trajectory contains of

wpiutil/src/main/native/thirdparty/json/include/wpi/json_fwd.h

@@ -0,0 +1,9 @@
+// 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
+
+namespace wpi {
+class json;
+}  // namespace wpi