Improve plugin interface file

src/eth_plugin_interface.h

@@ -1,3 +1,5 @@
+// clang-format off
+
 #ifndef _ETH_PLUGIN_INTERFACE_H_
 #define _ETH_PLUGIN_INTERFACE_H_
 
@@ -7,7 +9,14 @@
 #include "tokens.h"
 #include "shared_context.h"
 
-// Interface version. To be updated everytime we introduce breaking changes to the plugin interface.
+/*************************************************************************************************
+ * Comments provided in this file are quick reminders on the usage of the plugin interface       *
+ * Reading the real plugin documentation is GREATLY recommended.                                 *
+ * You can find the latest version here:                                                         *
+ * https://github.com/LedgerHQ/app-ethereum/blob/develop/doc/ethapp_plugins.adoc                 *
+ *************************************************************************************************/
+
+// Interface version. Will be updated every time a breaking change in the interface is introduced.
 typedef enum eth_plugin_interface_version_e {
     ETH_PLUGIN_INTERFACE_VERSION_1 = 1,
     ETH_PLUGIN_INTERFACE_VERSION_2 = 2,
@@ -17,20 +26,26 @@ typedef enum eth_plugin_interface_version_e {
     ETH_PLUGIN_INTERFACE_VERSION_LATEST = 6,
 } eth_plugin_interface_version_t;
 
-typedef enum eth_plugin_msg_e {
 
+// Codes for the different requests Ethereum can send to the plugin
+// The dispatch is handled by the SDK itself, the plugin code does not have to handle it
+typedef enum eth_plugin_msg_e {
+    // Codes for actions the Ethereum app can ask the plugin to perform
     ETH_PLUGIN_INIT_CONTRACT = 0x0101,
     ETH_PLUGIN_PROVIDE_PARAMETER = 0x0102,
     ETH_PLUGIN_FINALIZE = 0x0103,
     ETH_PLUGIN_PROVIDE_INFO = 0x0104,
     ETH_PLUGIN_QUERY_CONTRACT_ID = 0x0105,
     ETH_PLUGIN_QUERY_CONTRACT_UI = 0x0106,
-    ETH_PLUGIN_CHECK_PRESENCE = 0x01FF,
 
+    // Special request: the Ethereum app is checking if we are installed on the device
+    ETH_PLUGIN_CHECK_PRESENCE = 0x01FF,
 } eth_plugin_msg_t;
 
+
+// Reply codes when responding to the Ethereum application
 typedef enum eth_plugin_result_e {
-    // Unsuccesful return values
+    // Unsuccessful return values
     ETH_PLUGIN_RESULT_ERROR = 0x00,
     ETH_PLUGIN_RESULT_UNAVAILABLE = 0x01,
     ETH_PLUGIN_RESULT_UNSUCCESSFUL = 0x02,  // Used for comparison
@@ -40,37 +55,57 @@ typedef enum eth_plugin_result_e {
     ETH_PLUGIN_RESULT_OK = 0x04,
     ETH_PLUGIN_RESULT_OK_ALIAS = 0x05,
     ETH_PLUGIN_RESULT_FALLBACK = 0x06,
-
 } eth_plugin_result_t;
 
-typedef enum eth_ui_type_e {
 
+// Format of UI the Ethereum application has to use for this plugin
+typedef enum eth_ui_type_e {
+    // If uiType is UI_AMOUNT_ADDRESS, Ethereum will use the amount/address UI
+    // the amount and address provided by the plugin will be used
+    // If tokenLookup1 is set, the amount is provided for this token
     ETH_UI_TYPE_AMOUNT_ADDRESS = 0x01,
-    ETH_UI_TYPE_GENERIC = 0x02,
 
+    // If uiType is UI_TYPE_GENERIC, Ethereum will use the dedicated ETH plugin UI
+    // the ETH application provides tokens if requested then prompts for each UI field
+    // The first field is forced by the ETH app to be the name + version of the plugin handling the
+    // request. The last field is the fee amount
+    ETH_UI_TYPE_GENERIC = 0x02,
 } eth_ui_type_t;
 
-typedef void (*PluginCall)(int, void *);
-
-// Shared objects, read-write
 
+// Scratch objects and utilities available to the plugin READ-WRITE
 typedef struct ethPluginSharedRW_s {
     cx_sha3_t *sha3;
-
 } ethPluginSharedRW_t;
 
-// Shared objects, read-only
 
+// Transaction data available to the plugin READ-ONLY
 typedef struct ethPluginSharedRO_s {
     txContent_t *txContent;
-
 } ethPluginSharedRO_t;
 
+
+// Plugin-only memory allocated by the Ethereum application and used by the plugin.
+#define PLUGIN_CONTEXT_SIZE (5 * INT256_LENGTH)
+// It is recommended to cast the raw uin8_t array to a structure meaningfull for your plugin
+// Helper to check that the actual plugin context structure is not bigger than the allocated memory
+#define ASSERT_SIZEOF_PLUGIN_CONTEXT(s) \
+    _Static_assert(sizeof(s) <= PLUGIN_CONTEXT_SIZE, "Plugin context structure is too big.")
+
+
+/*
+ * HANDLERS AND PARAMETERS
+ * Parameters associated with the requests the Ethereum application can ask the plugin to perform
+ * The plugin SDK will automatically call the relevant handler for the received code, so the plugin
+ * has to define each of the handler functions declared below.
+ */
+
+
 // Init Contract
 
 typedef struct ethPluginInitContract_s {
-    uint8_t interfaceVersion;
-    uint8_t result;
+    eth_plugin_interface_version_t interfaceVersion;
+    eth_plugin_result_t result;
 
     // in
     ethPluginSharedRW_t *pluginSharedRW;
@@ -84,25 +119,31 @@ typedef struct ethPluginInitContract_s {
 
 } ethPluginInitContract_t;
 
+void handle_init_contract(ethPluginInitContract_t *parameters);
+
+
 // Provide parameter
 
 typedef struct ethPluginProvideParameter_s {
     ethPluginSharedRW_t *pluginSharedRW;
     ethPluginSharedRO_t *pluginSharedRO;
-    uint8_t *pluginContext;
+    uint8_t *pluginContext; // PLUGIN_CONTEXT_SIZE
     const uint8_t *parameter;  // 32 bytes parameter
     uint32_t parameterOffset;
 
-    uint8_t result;
+    eth_plugin_result_t result;
 
 } ethPluginProvideParameter_t;
 
+void handle_provide_parameter(ethPluginProvideParameter_t *parameters);
+
+
 // Finalize
 
 typedef struct ethPluginFinalize_s {
     ethPluginSharedRW_t *pluginSharedRW;
     ethPluginSharedRO_t *pluginSharedRO;
-    uint8_t *pluginContext;
+    uint8_t *pluginContext; // PLUGIN_CONTEXT_SIZE
 
     uint8_t *tokenLookup1;  // set by the plugin if a token should be looked up
     uint8_t *tokenLookup2;
@@ -111,55 +152,56 @@ typedef struct ethPluginFinalize_s {
     const uint8_t *address;  // set to the destination address if uiType is UI_AMOUNT_ADDRESS. Set
                              // to the user's address if uiType is UI_TYPE_GENERIC
 
-    uint8_t uiType;
+    eth_ui_type_t uiType;
     uint8_t numScreens;  // ignored if uiType is UI_AMOUNT_ADDRESS
-    uint8_t result;
+    eth_plugin_result_t result;
 
 } ethPluginFinalize_t;
 
-// If uiType is UI_AMOUNT_ADDRESS, the amount and address provided by the plugin will be used
-// If tokenLookup1 is set, the amount is provided for this token
+void handle_finalize(ethPluginFinalize_t *parameters);
 
-// if uiType is UI_TYPE_GENERIC, the ETH application provides tokens if requested then prompts
-// for each UI field
-// The first field is forced by the ETH app to be the name + version of the plugin handling the
-// request The last field is the fee amount
 
 // Provide token
 
 typedef struct ethPluginProvideInfo_s {
     ethPluginSharedRW_t *pluginSharedRW;
     ethPluginSharedRO_t *pluginSharedRO;
-    uint8_t *pluginContext;
+    uint8_t *pluginContext; // PLUGIN_CONTEXT_SIZE
 
     union extraInfo_t *item1;  // set by the ETH application, to be saved by the plugin
     union extraInfo_t *item2;
 
     uint8_t additionalScreens;  // Used by the plugin if it needs to display additional screens
                                 // based on the information received from the token definitions.
 
-    uint8_t result;
+    eth_plugin_result_t result;
 
 } ethPluginProvideInfo_t;
 
+void handle_provide_token(ethPluginProvideInfo_t *parameters);
+
+
 // Query Contract name and version
 
 // This is always called on the non aliased contract
 
 typedef struct ethQueryContractID_s {
     ethPluginSharedRW_t *pluginSharedRW;
     ethPluginSharedRO_t *pluginSharedRO;
-    uint8_t *pluginContext;
+    uint8_t *pluginContext; // PLUGIN_CONTEXT_SIZE
 
     char *name;
     size_t nameLength;
     char *version;
     size_t versionLength;
 
-    uint8_t result;
+    eth_plugin_result_t result;
 
 } ethQueryContractID_t;
 
+void handle_query_contract_id(ethQueryContractID_t *parameters);
+
+
 // Query Contract UI
 
 typedef struct ethQueryContractUI_s {
@@ -168,21 +210,20 @@ typedef struct ethQueryContractUI_s {
     union extraInfo_t *item1;
     union extraInfo_t *item2;
     char network_ticker[MAX_TICKER_LEN];
-    uint8_t *pluginContext;
+    uint8_t *pluginContext; // PLUGIN_CONTEXT_SIZE
     uint8_t screenIndex;
 
     char *title;
     size_t titleLength;
     char *msg;
     size_t msgLength;
 
-    uint8_t result;
+    eth_plugin_result_t result;
 
 } ethQueryContractUI_t;
 
-// Helper to check that the plugin context structure is not bigger than 5 * 32
-#define PLUGIN_CONTEXT_SIZE (5 * INT256_LENGTH)
-#define ASSERT_SIZEOF_PLUGIN_CONTEXT(s) \
-    _Static_assert(sizeof(s) <= PLUGIN_CONTEXT_SIZE, "Plugin context structure is too big.")
+void handle_query_contract_ui(ethQueryContractUI_t *parameters);
 
 #endif  // _ETH_PLUGIN_INTERFACE_H_
+
+// clang-format on

src/eth_plugin_internal.h

@@ -21,6 +21,7 @@ bool U2BE_from_parameter(const uint8_t* parameter, uint16_t* value);
 bool U4BE_from_parameter(const uint8_t* parameter, uint32_t* value);
 
 typedef bool (*PluginAvailableCheck)(void);
+typedef void (*PluginCall)(int, void *);
 
 typedef struct internalEthPlugin_t {
     PluginAvailableCheck availableCheck;