artf4154: Get rid of raw pointers in C++.

This deals with the majority of the user-facing code
in wpilibC++Devices and a substantial portion of it in
wpilibC++. wpilibC++Sim and wpilibC++IntegrationTests
are untouched except where it is necessary to make them
work with the rest of the libraries.

There is still a lot to do in the following areas:
-The HAL (which we may not want to touch at all).
-The I2C, Serial, and SPI interfaces in wpilibC++Devices,
  which I haven't gotten around to doing yet.
-Most wpilibC++Devices classes have void* pointers
  for interacting with the HAL.
-InterruptableSensorBase passes a void *params for
  the interrupt handler.
-I haven't converted all the const char* to std::strings.
-There are plenty of other cases of raw pointers still
  existing.
-This doesn't fall directly under raw pointer stuff,
  but move syntax and rvalue references could be introduced
  in many places.
-I haven't touched vision code.
-The Resource classes conflict (one is in the hal, the other
  in wpilibC++). Someone should figure out a more
  permanent fix (eg, just renaming them), then doing
  what I did (making a new namespace for one of them,
  essentially the same as renaming it).

A few other things:
-I created a NullDeleter class which is marked as deprecated.
  What this does is it can be passed as the deleter to a
  std::shared_ptr so that when you are converting raw pointers
  to shared_ptrs the shared_ptr doesn't do any deletion if
  someone else owns the raw pointer. This should only be
  used in making old raw pointer UIs.
-I had to alter the build.gradle so that it did not
  emit errors when deprecated functions called deprecated
  functions. Unfortunately, gradle doesn't appear to be
  actually printing out gcc warnigns for some reason.
  The best way I have found to fix this is to patch
  the toolchains (https://bitbucket.org/byteit101/toolchain-builder/pull-request/5/make-gcc-not-throw-warnings-for-nested/diff)
  so that a deprecated function calling a deprecated
  function is fine but a non-deprecated function calling
  a deprecated function will throw a warning (which we
  then elevate with -Werror). I believe that clang
  deals with this properly, although I have not
  tried it myself.

Change-Id: Ib8090c66893576fe73654f4e9d268f9d37be06a2

wpilibc/wpilibC++Devices/include/Encoder.h

@@ -13,6 +13,8 @@
 #include "PIDSource.h"
 #include "LiveWindow/LiveWindowSendable.h"
 
+#include <memory>
+
 class DigitalSource;
 
 /**
@@ -47,8 +49,19 @@ class Encoder : public SensorBase,
 
   Encoder(uint32_t aChannel, uint32_t bChannel, bool reverseDirection = false,
           EncodingType encodingType = k4X);
+  Encoder(::std::shared_ptr<DigitalSource> aSource,
+          ::std::shared_ptr<DigitalSource> bSource,
+          bool reverseDirection = false, EncodingType encodingType = k4X);
+  [[deprecated(
+      "Raw pointers are deprecated; if you wish to construct your own copy of "
+      "the DigitalSource and pass it to the constructor, use an "
+      "std::shared_ptr instead.")]]
   Encoder(DigitalSource *aSource, DigitalSource *bSource,
           bool reverseDirection = false, EncodingType encodingType = k4X);
+  [[deprecated(
+      "References are deprecated; if you wish to construct your own copy of "
+      "the DigitalSource and pass it to the constructor, use an "
+      "std::shared_ptr instead.")]]
   Encoder(DigitalSource &aSource, DigitalSource &bSource,
           bool reverseDirection = false, EncodingType encodingType = k4X);
   virtual ~Encoder();
@@ -74,17 +87,18 @@ class Encoder : public SensorBase,
   double PIDGet() const override;
 
   void SetIndexSource(uint32_t channel, IndexingType type = kResetOnRisingEdge);
+  [[deprecated("Raw pointers are deprecated; use references instead.")]]
   void SetIndexSource(DigitalSource *source,
                       IndexingType type = kResetOnRisingEdge);
-  void SetIndexSource(DigitalSource &source,
+  void SetIndexSource(const DigitalSource &source,
                       IndexingType type = kResetOnRisingEdge);
 
   void UpdateTable() override;
   void StartLiveWindowMode() override;
   void StopLiveWindowMode() override;
   std::string GetSmartDashboardType() const override;
-  void InitTable(ITable *subTable) override;
-  ITable *GetTable() const override;
+  void InitTable(::std::shared_ptr<ITable> subTable) override;
+  ::std::shared_ptr<ITable> GetTable() const override;
 
   int32_t GetFPGAIndex() const { return m_index; }
 
@@ -92,18 +106,17 @@ class Encoder : public SensorBase,
   void InitEncoder(bool _reverseDirection, EncodingType encodingType);
   double DecodingScaleFactor() const;
 
-  DigitalSource *m_aSource;  // the A phase of the quad encoder
-  DigitalSource *m_bSource;  // the B phase of the quad encoder
-  bool m_allocatedASource;   // was the A source allocated locally?
-  bool m_allocatedBSource;   // was the B source allocated locally?
+  ::std::shared_ptr<DigitalSource> m_aSource; // the A phase of the quad encoder
+  ::std::shared_ptr<DigitalSource> m_bSource; // the B phase of the quad encoder
   void *m_encoder = nullptr;
   int32_t m_index = 0;             // The encoder's FPGA index.
   double m_distancePerPulse = 1.0; // distance of travel for each encoder tick
-  Counter *m_counter = nullptr;    // Counter object for 1x and 2x encoding
+  ::std::unique_ptr<Counter> m_counter =
+      nullptr;                     // Counter object for 1x and 2x encoding
   EncodingType m_encodingType;     // Encoding type
   int32_t m_encodingScale;         // 1x, 2x, or 4x, per the encodingType
   PIDSourceParameter
       m_pidSource = kDistance; // Encoder parameter that sources a PID controller
 
-  ITable *m_table = nullptr;
+  ::std::shared_ptr<ITable> m_table = nullptr;
 };