WIP: Template Singleton make_ functions (#132)

* Template NoteTxn Singleton `make_` function
* Template NoteLog Singleton `make_` function
* 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/NoteLog.hpp

@@ -6,12 +6,6 @@
 class NoteLog
 {
 public:
-    /**************************************************************************/
-    /*!
-        @brief  Type used to abstract specific hardware implementation types.
-    */
-    /**************************************************************************/
-    typedef void * param_t;
 
     virtual ~NoteLog(void) {}
 
@@ -36,8 +30,7 @@ class NoteLog
                the platform specific log output implementation.
 */
 /******************************************************************************/
-NoteLog * make_note_log (
-    NoteLog::param_t log_parameters
-);
+template <typename T> NoteLog * make_note_log (T & log_parameters);
+NoteLog * make_note_log (nullptr_t);
 
 #endif // NOTE_LOG_HPP

src/NoteLog_Arduino.cpp

@@ -1,19 +1,35 @@
 #include "NoteLog_Arduino.hpp"
 
+// Singleton instance of the NoteLog_Arduino class
+namespace instance {
+    inline NoteLog* & note_log (void) {
+        static NoteLog* note_log = nullptr;
+        return note_log;
+    }
+};
+
 NoteLog *
 make_note_log (
-    NoteLog::param_t log_parameters_
-)
-{
-    static NoteLog * note_log = nullptr;
-    if (!log_parameters_) {
-        if (note_log) {
-            delete note_log;
-            note_log = nullptr;
-        }
-    } else if (!note_log) {
-        note_log = new NoteLog_Arduino(reinterpret_cast<Stream *>(log_parameters_));
+    nullptr_t
+) {
+    NoteLog* & note_log = instance::note_log();
+    if (note_log) {
+        delete note_log;
+        note_log = nullptr;
+    }
+    return note_log;
+}
+
+template <typename T>
+NoteLog *
+make_note_log (
+    T & log_parameters_
+) {
+    NoteLog* & note_log = instance::note_log();
+    if (!note_log) {
+        note_log = new NoteLog_Arduino(reinterpret_cast<T *>(&log_parameters_));
     }
+
     return note_log;
 }
 
@@ -35,3 +51,6 @@ NoteLog_Arduino::print (
 
     return result;
 }
+
+// Explicitly instantiate the template function for the supported types
+template NoteLog * make_note_log<Stream>(Stream &);

src/NoteTxn.hpp

@@ -7,12 +7,6 @@
 class NoteTxn
 {
 public:
-    /**************************************************************************/
-    /*!
-        @brief  Type used to abstract specific hardware implementation types.
-    */
-    /**************************************************************************/
-    typedef void * param_t;
 
     virtual ~NoteTxn(void) {}
 
@@ -44,8 +38,7 @@ class NoteTxn
                the platform specific transaction implementation.
 */
 /******************************************************************************/
-NoteTxn * make_note_txn (
-    NoteTxn::param_t txn_parameters
-);
+template<typename T> NoteTxn * make_note_txn (T & txn_parameters);
+NoteTxn * make_note_txn (nullptr_t);
 
 #endif // NOTE_TXN_HPP

src/NoteTxn_Arduino.cpp

@@ -7,21 +7,43 @@
   #include "mock/mock-parameters.hpp"
 #endif
 
+// Singleton instance of the NoteTxn_Arduino class
+namespace instance {
+    inline NoteTxn* & note_txn (void) {
+        static NoteTxn* note_txn = nullptr;
+        return note_txn;
+    }
+};
+
 NoteTxn *
 make_note_txn (
-    NoteTxn::param_t txn_parameters_
-)
-{
-    static NoteTxn * note_txn = nullptr;
-    if (!txn_parameters_) {
+    nullptr_t
+) {
+    NoteTxn* & note_txn = instance::note_txn();
+    if (note_txn) {
+        delete note_txn;
+        note_txn = nullptr;
+    }
+    return note_txn;
+}
+
+template <typename T>
+NoteTxn *
+make_note_txn (
+    T & txn_pins_
+) {
+    NoteTxn* & note_txn = instance::note_txn();
+
+    if (txn_pins_[0] == txn_pins_[1]) {
+        // Invalid tuple invokes deletion
         if (note_txn) {
             delete note_txn;
             note_txn = nullptr;
         }
     } else if (!note_txn) {
-        const uint8_t * txn_pins = reinterpret_cast<uint8_t *>(txn_parameters_);
-        note_txn = new NoteTxn_Arduino(txn_pins[0], txn_pins[1]);
+        note_txn = new NoteTxn_Arduino(txn_pins_[0], txn_pins_[1]);
     }
+
     return note_txn;
 }
 
@@ -80,3 +102,7 @@ NoteTxn_Arduino::stop (
     // Float RTX pin
     ::pinMode(_rtx_pin, INPUT);
 }
+
+// Explicitly instantiate the template function for array types
+template NoteTxn * make_note_txn<uint8_t[2]>(uint8_t(&)[2]);
+template NoteTxn * make_note_txn<const uint8_t[2]>(const uint8_t(&)[2]);

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);
@@ -76,7 +76,7 @@ class Notecard
     }
 #endif
     inline void setDebugOutputStream(Stream &dbgserial) {
-        setDebugOutputStream(make_note_log(&dbgserial));
+        setDebugOutputStream(make_note_log(dbgserial));
     }
     inline void setTransactionPins(uint8_t ctx_pin, uint8_t rtx_pin) {
         uint8_t txn_pins[2] = {ctx_pin, rtx_pin};

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/NoteLog_Arduino.test.cpp

@@ -14,9 +14,10 @@ int test_make_note_log_instantiates_notelog_object()
 
     // Arrange
     NoteLog * notelog = nullptr;
+    Stream & serial_stream = Serial;
 
     // Action
-    notelog = make_note_log(reinterpret_cast<NoteLog::param_t>(&Serial));
+    notelog = make_note_log(serial_stream);
 
     // Assert
     if (nullptr != notelog)
@@ -42,10 +43,11 @@ int test_make_note_log_enforces_singleton_by_returning_same_notelog_object_for_a
     int result;
 
     // Arrange
-    NoteLog * const notelog_1 = make_note_log(reinterpret_cast<NoteLog::param_t>(&Serial));
+    Stream & serial_stream = Serial;
+    NoteLog * const notelog_1 = make_note_log(serial_stream);
 
     // Action
-    NoteLog * const notelog_2 = make_note_log(reinterpret_cast<NoteLog::param_t>(&Serial));
+    NoteLog * const notelog_2 = make_note_log(serial_stream);
 
     // Assert
     if (notelog_1 == notelog_2)
@@ -72,7 +74,8 @@ int test_make_note_log_deletes_singleton_when_nullptr_is_passed_as_parameter()
     int result;
 
     // Arrange
-    NoteLog * notelog = make_note_log(reinterpret_cast<NoteLog::param_t>(&Serial));
+    Stream & serial_stream = Serial;
+    NoteLog * notelog = make_note_log(serial_stream);
     assert(notelog);
 
     // Action

test/NoteTxn_Arduino.test.cpp

@@ -16,7 +16,7 @@ int test_make_note_txn_instantiates_notetxn_object()
   uint8_t txn_pins[2] = {19, 79};
 
   // Action
-  notetxn = make_note_txn(reinterpret_cast<NoteTxn::param_t>(txn_pins));
+  notetxn = make_note_txn(txn_pins);
 
   // Assert
   if (nullptr != notetxn)
@@ -32,7 +32,8 @@ int test_make_note_txn_instantiates_notetxn_object()
   }
 
   // Clean-up
-  make_note_txn(nullptr);
+  uint8_t invalid_pins[2] = {0};
+  make_note_txn(invalid_pins);
 
   return result;
 }
@@ -43,11 +44,11 @@ int test_make_note_txn_enforces_singleton_by_returning_same_notetxn_object_for_a
 
   // Arrange
   uint8_t txn_pins_1[2] = {19, 79};
-  NoteTxn * const notetxn_1 = make_note_txn(reinterpret_cast<NoteTxn::param_t>(txn_pins_1));
+  NoteTxn * const notetxn_1 = make_note_txn(txn_pins_1);
 
   // Action
   uint8_t txn_pins_2[2] = {9, 17};
-  NoteTxn * const notetxn_2 = make_note_txn(reinterpret_cast<NoteTxn::param_t>(txn_pins_2));
+  NoteTxn * const notetxn_2 = make_note_txn(txn_pins_2);
 
   // Assert
   if (notetxn_1 == notetxn_2)
@@ -63,23 +64,25 @@ int test_make_note_txn_enforces_singleton_by_returning_same_notetxn_object_for_a
   }
 
   // Clean-up
-  make_note_txn(nullptr);
+  uint8_t invalid_pins[2] = {0};
+  make_note_txn(invalid_pins);
 
   return result;
 }
 
-//int test_make_note_txn_returns_nullptr_when_nullptr_is_passed_as_parameter()
-int test_make_note_txn_deletes_singleton_when_nullptr_is_passed_as_parameter()
+//int test_make_note_txn_returns_nullptr_when_same_pins_are_passed_as_parameter()
+int test_make_note_txn_deletes_singleton_when_same_pins_are_passed_as_parameter()
 {
   int result;
 
   // Arrange
   uint8_t txn_pins[2] = {19, 79};
-  NoteTxn * notetxn = make_note_txn(reinterpret_cast<NoteTxn::param_t>(txn_pins));
+  NoteTxn * notetxn = make_note_txn(txn_pins);
   assert(notetxn);
 
   // Action
-  notetxn = make_note_txn(nullptr);
+  uint8_t invalid_pins[2] = {0};
+  notetxn = make_note_txn(invalid_pins);
 
   // Assert
   if (nullptr == notetxn)
@@ -605,7 +608,7 @@ int main(void)
   TestFunction tests[] = {
       {test_make_note_txn_instantiates_notetxn_object, "test_make_note_txn_instantiates_notetxn_object"},
       {test_make_note_txn_enforces_singleton_by_returning_same_notetxn_object_for_all_calls, "test_make_note_txn_enforces_singleton_by_returning_same_notetxn_object_for_all_calls"},
-      {test_make_note_txn_deletes_singleton_when_nullptr_is_passed_as_parameter, "test_make_note_txn_deletes_singleton_when_nullptr_is_passed_as_parameter"},
+      {test_make_note_txn_deletes_singleton_when_same_pins_are_passed_as_parameter, "test_make_note_txn_deletes_singleton_when_same_pins_are_passed_as_parameter"},
       {test_notetxn_arduino_constructor_floats_ctx_pin, "test_notetxn_arduino_constructor_floats_ctx_pin"},
       {test_notetxn_arduino_constructor_floats_rtx_pin, "test_notetxn_arduino_constructor_floats_rtx_pin"},
       {test_notetxn_arduino_start_initially_configures_ctx_pin_as_input_pullup, "test_notetxn_arduino_start_initially_configures_ctx_pin_as_input_pullup"},