Update based on few tweaks to the API

Author: Donatien Garnier

docs/design-documents/nfc/nfc_design.md

@@ -160,6 +160,12 @@ The `NFCController` class is the entrypoint into NFC for the user.
 
 When NCI integration is complete (phase 2), this class will be able to drive a `NCIDriver` instance. For now, the one controller we support is the PN512, which implements the `NFCControllerDriver` class. This class is specific to the current MicroNFC release.
 
+```cpp
+NFCController(NFCControllerDriver *driver, events::EventQueue *queue, const Span<uint8_t> &ndef_buffer);
+```
+
+The user instantiates the `NFCController` class using a driver, an event queue used for asynchronous operations and a scratch buffer used for NDEF processing.
+
 It offers the following methods:
 
 ```cpp
@@ -314,8 +320,6 @@ The class is constructed using a scratch buffer which is used to encode and/or d
 
 ```cpp
 bool is_ndef_supported() const;
-
-void set_ndef_delegate(Delegate* delegate);
 ```
 
 API used by descendant classes:
@@ -326,18 +330,23 @@ void build_ndef_message(ac_buffer_builder_t& buffer_builder);
 ndef_msg_t* ndef_message();
 ```
 
+API implemented by descendant classes:
+```cpp
+virtual NFCNDEFCapable::Delegate* ndef_capable_delegate();
+```
+
 **Delegate**
 
 The instance receives requests to encode and decode NDEF messages, and the user can choose how to handle them using the relevant builders and parsers.
 
 ```cpp
-void parse_ndef_message(const uint8_t* buffer, size_t size);
+void parse_ndef_message(const Span<const uint8_t> &buffer);
 ```
 
 The user receives the encoded NDEF message for processing.
 
 ```cpp
-size_t build_ndef_message(uint8_t* buffer, size_t capacity);
+size_t build_ndef_message(const Span<uint8_t> &buffer);
 ```
 
 The user can encode a NDEF message in the buffer provided and return its size (or 0).
@@ -363,11 +372,11 @@ nfc_tag_type_t nfc_tag_type();
 
 Additionally, the user can recover the type of NFC tag (1 to 5) being emulated. Type 4 is implemented on either one of two technologies; therefore, this enum both includes type 4a and type 4b to identify the underlying technology.
 
-*Note: This is initially out of scope for the initial release*
+*Note: ISO7816 is only used internally for the initial release*
 
 ```cpp
 bool is_iso7816_supported();
-void add_iso7816_application(ISO7816App* app);
+void add_iso7816_application(nfc_tech_iso7816_app_t *application);
 ```
 
 If the underlying technology supports it (ISO-DEP), the user can emulate a contactless smartcard and register ISO7816-4 applications using this API.
@@ -409,7 +418,7 @@ The `NFCEEPROM` class derives from `NFCTarget` and shares the same API. The user
 
 #### NFC remote target
 
-*Note: This is initially out of scope for the initial release*
+*Note: This is out of scope for the initial release*
 
 The `NFCRemoteTarget` class derives from `NFCTarget` and additionally from `NFCRemoteEndpoint`.
 
@@ -593,7 +602,7 @@ The `set_size()` command is called to change the size of the NDEF buffer (within
 ```cpp
 void reset();
 size_t get_max_size();
-void start_session();
+void start_session(bool force = true);
 void end_session();
 void read_bytes(uint32_t address, size_t count);
 void write_bytes(uint32_t address, const uint8_t* bytes, size_t count);

docs/design-documents/nfc/uml_diagram_endpoints.png

@@ -2,16 +2,16 @@
 
 abstract class NFCNDEFCapable {
   +{abstract} bool is_ndef_supported() const
-  +void set_ndef_delegate(Delegate* parser)
 
   #void parse_ndef_message(const ac_buffer_t& buffer)
   #void build_ndef_message(ac_buffer_builder_t& buffer_builder)
   #ndef_msg_t* ndef_message()
+  #{abstract} NFCNDEFCapable::Delegate* ndef_capable_delegate()
 }
 
 abstract class NFCNDEFCapable::Delegate {
-  +{abstract} void parse_ndef_message(const uint8_t* buffer, size_t size)
-  +{abstract} size_t build_ndef_message(uint8_t* buffer, size_t capacity)
+  +{abstract} void parse_ndef_message(const Span<const uint8_t> &buffer)
+  +{abstract} size_t build_ndef_message(const Span<uint8_t> &buffer)
 }
 
 abstract class NFCRemoteEndpoint {
@@ -39,6 +39,9 @@ abstract class NFCTarget::Delegate {
   +{abstract} void on_ndef_message_read(nfc_err_t result)
 }
 
+NFCNDEFCapable <-- NFCTarget
+NFCNDEFCapable::Delegate <-- NFCTarget::Delegate
+
 class NFCEEPROM {
   +nfc_err_t initialize()
   +void set_delegate(NFCEEPROM::Delegate* delegate)
@@ -54,14 +57,14 @@ abstract class NFCEEPROMDriver {
 
   +{abstract} void reset()
   +{abstract} size_t get_max_size()
-  +{abstract} void start_session()
+  +{abstract} void start_session(bool force = true)
   +{abstract} void end_session()
   +{abstract} void read_bytes(uint32_t address, size_t count)
   +{abstract} void write_bytes(uint32_t address, const uint8_t* bytes, size_t count)
   +{abstract} void write_size(size_t count)
   +{abstract} void read_size()
   +{abstract} void erase_bytes(uint32_t address, size_t size)
-  #Delegate *delegate()
+  #NFCEEPROMDriver::Delegate *delegate()
   #events::EventQueue *event_queue()
 }
 
@@ -75,7 +78,6 @@ abstract class NFCEEPROMDriver::Delegate {
   +{abstract} void on_bytes_erased(size_t count)
 }
 
-NFCNDEFCapable <-- NFCTarget
 NFCTarget <-- NFCEEPROM
 NFCTarget::Delegate <-- NFCEEPROM::Delegate
 NFCEEPROM o-- NFCEEPROM::Delegate
@@ -84,10 +86,10 @@ NFCEEPROMDriver o-- NFCEEPROMDriver::Delegate
 NFCEEPROMDriver::Delegate <-- NFCEEPROM
 
 class NFCRemoteInitiator {
-  +void set_remote_initiator_delegate(NFCRemoteInitiator::Delegate* delegate)
+  +void set_delegate(NFCRemoteInitiator::Delegate* delegate)
 
   +{abstract}bool is_iso7816_supported() const
-  +{abstract}void add_iso7816_application(ISO7816App* app)
+  +{abstract}void add_iso7816_application(nfc_tech_iso7816_app_t *application)
 
   +{abstract} nfc_tag_type_t nfc_tag_type()
   +{abstract} bool is_ndef_supported()