Template NoteI2c Singleton make_ function

Author: zfields

src/NoteI2c.hpp

@@ -7,12 +7,6 @@
 class NoteI2c
 {
 public:
-    /**************************************************************************/
-    /*!
-        @brief  Type used to abstract specific hardware implementation types.
-    */
-    /**************************************************************************/
-    typedef void * param_t;
 
     virtual ~NoteI2c(void) {}
 
@@ -94,8 +88,7 @@ class NoteI2c
                the platform specific I2C implementation.
 */
 /******************************************************************************/
-NoteI2c * make_note_i2c (
-    NoteI2c::param_t i2c_parameters
-);
+template <typename T> NoteI2c * make_note_i2c (T & i2c_parameters);
+NoteI2c * make_note_i2c (nullptr_t);
 
 #endif // NOTE_I2C_HPP

src/NoteI2c_Arduino.cpp

@@ -4,20 +4,37 @@
 static const char *i2cerr = "i2c {io}";
 #endif
 
+// Singleton instance of the NoteI2c_Arduino class
+namespace instance {
+    inline NoteI2c* & note_i2c (void) {
+        static NoteI2c* note_i2c = nullptr;
+        return note_i2c;
+    }
+};
+
 NoteI2c *
 make_note_i2c (
-    NoteI2c::param_t i2c_parameters_
+    nullptr_t
+) {
+    NoteI2c* & note_i2c = instance::note_i2c();
+    if (note_i2c) {
+        delete note_i2c;
+        note_i2c = nullptr;
+    }
+    return note_i2c;
+}
+
+template <typename T>
+NoteI2c *
+make_note_i2c (
+    T & i2c_parameters_
 )
 {
-    static NoteI2c * note_i2c = nullptr;
-    if (!i2c_parameters_) {
-        if (note_i2c) {
-            delete note_i2c;
-            note_i2c = nullptr;
-        }
-    } else if (!note_i2c) {
-        note_i2c = new NoteI2c_Arduino(*reinterpret_cast<TwoWire *>(i2c_parameters_));
+    NoteI2c* & note_i2c = instance::note_i2c();
+    if (!note_i2c) {
+        note_i2c = new NoteI2c_Arduino(i2c_parameters_);
     }
+
     return note_i2c;
 }
 
@@ -182,3 +199,6 @@ NoteI2c_Arduino::transmit (
 
     return result;
 }
+
+// Explicitly instantiate the template function for the supported types
+template NoteI2c * make_note_i2c<TwoWire>(TwoWire &);

src/Notecard.h

@@ -63,7 +63,7 @@ class Notecard
     inline void begin(uint32_t i2cAddress = NOTE_I2C_ADDR_DEFAULT,
                       uint32_t i2cMax = NOTE_I2C_MAX_DEFAULT,
                       TwoWire &wirePort = Wire) {
-        begin(make_note_i2c(&wirePort), i2cAddress, i2cMax);
+        begin(make_note_i2c(wirePort), i2cAddress, i2cMax);
     }
     inline void begin(HardwareSerial &serial, uint32_t speed = 9600) {
         MakeNoteSerial_ArduinoParameters<HardwareSerial> arduino_parameters(serial, speed);

test/NoteI2c_Arduino.test.cpp

@@ -16,7 +16,7 @@ int test_make_note_i2c_instantiates_notei2c_object()
   NoteI2c * notei2c = nullptr;
 
   // Action
-  notei2c = make_note_i2c(reinterpret_cast<NoteI2c::param_t>(&Wire));
+  notei2c = make_note_i2c(Wire);
 
   // Assert
   if (nullptr != notei2c)
@@ -42,10 +42,10 @@ int test_make_note_i2c_enforces_singleton_by_returning_same_notei2c_object_for_a
   int result;
 
   // Arrange
-  NoteI2c * const notei2c_1 = make_note_i2c(reinterpret_cast<NoteI2c::param_t>(&Wire));
+  NoteI2c * const notei2c_1 = make_note_i2c(Wire);
 
   // Action
-  NoteI2c * const notei2c_2 = make_note_i2c(reinterpret_cast<NoteI2c::param_t>(&Wire));
+  NoteI2c * const notei2c_2 = make_note_i2c(Wire);
 
   // Assert
   if (notei2c_1 == notei2c_2)
@@ -72,7 +72,7 @@ int test_make_note_i2c_deletes_singleton_when_nullptr_is_passed_as_parameter()
   int result;
 
   // Arrange
-  NoteI2c * notei2c = make_note_i2c(reinterpret_cast<NoteI2c::param_t>(&Wire));
+  NoteI2c * notei2c = make_note_i2c(Wire);
   assert(notei2c);
 
   // Action

test/Notecard.test.cpp

@@ -1706,7 +1706,7 @@ int test_notecard_end_provides_nullptr_to_make_note_i2c_to_free_associated_memor
   Notecard notecard;
   NoteI2c_Mock mockI2c;  // Instantiate NoteI2c (mocked)
   make_note_i2c_Parameters.reset();
-  make_note_i2c_Parameters.i2c_parameters = &mockI2c;
+  make_note_i2c_Parameters.i2c_parameters = &Wire;
   notecard.begin(&mockI2c);
 
    // Action

test/mock/NoteI2c_Mock.cpp

@@ -1,15 +1,29 @@
 #include "mock/NoteI2c_Mock.hpp"
 
-MakeNoteI2c_Parameters make_note_i2c_Parameters;
+MakeNoteI2c_Parameters<TwoWire> make_note_i2c_Parameters;
 NoteI2cReceive_Parameters noteI2cReceive_Parameters;
 NoteI2cReset_Parameters noteI2cReset_Parameters;
 NoteI2cTransmit_Parameters noteI2cTransmit_Parameters;
 
 NoteI2c *
 make_note_i2c (
-    NoteI2c::param_t i2c_parameters_
-)
-{
+    nullptr_t
+) {
+    // Record invocation(s)
+    ++make_note_i2c_Parameters.invoked;
+
+    // Stash parameter(s)
+    make_note_i2c_Parameters.i2c_parameters = nullptr;
+
+    // Return user-supplied result
+    return make_note_i2c_Parameters.result;
+}
+
+template <typename T>
+NoteI2c *
+make_note_i2c (
+    T & i2c_parameters_
+) {
     // Record invocation(s)
     ++make_note_i2c_Parameters.invoked;
 

test/mock/NoteI2c_Mock.hpp

@@ -7,6 +7,7 @@
 #include <string>
 
 #include "NoteI2c.hpp"
+#include "mock/mock-arduino.hpp"
 
 class NoteI2c_Mock final : public NoteI2c
 {
@@ -16,6 +17,7 @@ class NoteI2c_Mock final : public NoteI2c
     const char * transmit(uint16_t device_address, uint8_t * buffer, uint16_t size) override;
 };
 
+template <typename T>
 struct MakeNoteI2c_Parameters {
     MakeNoteI2c_Parameters(
         void
@@ -32,7 +34,7 @@ struct MakeNoteI2c_Parameters {
         result = nullptr;
     }
     size_t invoked;
-    NoteI2c::param_t i2c_parameters;
+    T * i2c_parameters;
     NoteI2c * result;
 };
 
@@ -115,7 +117,7 @@ struct NoteI2cTransmit_Parameters {
     const char * result;
 };
 
-extern MakeNoteI2c_Parameters make_note_i2c_Parameters;
+extern MakeNoteI2c_Parameters<TwoWire> make_note_i2c_Parameters;
 extern NoteI2cReceive_Parameters noteI2cReceive_Parameters;
 extern NoteI2cReset_Parameters noteI2cReset_Parameters;
 extern NoteI2cTransmit_Parameters noteI2cTransmit_Parameters;