Merge pull request #103 from LedgerHQ/fbe/xmacro

Use Xmacro to centralize selectors definition

src/contract.c → src/boilerplate_plugin.c

@@ -18,15 +18,6 @@
 #include <stdint.h>
 #include "boilerplate_plugin.h"
 
-// List of selectors supported by this plugin.
-// EDIT THIS: Adapt the variable names and change the `0x` values to match your selectors.
-static const uint32_t SWAP_EXACT_ETH_FOR_TOKENS_SELECTOR = 0x7ff36ab5;
-static const uint32_t BOILERPLATE_DUMMY_SELECTOR_2 = 0x13374242;
-
-// Array of all the different boilerplate selectors. Make sure this follows the same order as the
-// enum defined in `boilerplate_plugin.h`
-// EDIT THIS: Use the names of the array declared above.
-const uint32_t BOILERPLATE_SELECTORS[NUM_SELECTORS] = {
-    SWAP_EXACT_ETH_FOR_TOKENS_SELECTOR,
-    BOILERPLATE_DUMMY_SELECTOR_2,
-};
+// This array will be automatically expanded to map all selector_t names with the correct value.
+// Do not modify !
+const uint32_t SELECTORS[SELECTOR_COUNT] = {SELECTORS_LIST(TO_VALUE)};

src/boilerplate_plugin.h

@@ -1,25 +1,55 @@
+/*******************************************************************************
+ *   Plugin Boilerplate
+ *   (c) 2023 Ledger
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ ********************************************************************************/
+
 #pragma once
 
+#include <string.h>
 #include "eth_internals.h"
 #include "eth_plugin_interface.h"
-#include <string.h>
-
-// Number of selectors defined in this plugin. Should match the enum `selector_t`.
-// EDIT THIS: Put in the number of selectors your plugin is going to support.
-#define NUM_SELECTORS 2
 
 // Name of the plugin.
 // EDIT THIS: Replace with your plugin name.
 #define PLUGIN_NAME "PluginBoilerplate"
 
-// Enumeration of the different selectors possible.
-// Should follow the exact same order as the array declared in main.c
-// EDIT THIS: Change the naming (`selector_t`), and add your selector names.
-typedef enum {
-    SWAP_EXACT_ETH_FOR_TOKENS = 0,
-    BOILERPLATE_DUMMY_2,
+// All possible selectors of your plugin.
+// EDIT THIS: Enter your selectors here, in the format X(NAME, value)
+// A Xmacro below will create for you:
+//     - an enum named selector_t with every NAME
+//     - a map named SELECTORS associating each NAME with it's value
+#define SELECTORS_LIST(X)                    \
+    X(SWAP_EXACT_ETH_FOR_TOKENS, 0x7ff36ab5) \
+    X(BOILERPLATE_DUMMY_2, 0x13374242)
+
+// Xmacro helpers to define the enum and map
+// Do not modify !
+#define TO_ENUM(selector_name, selector_id)  selector_name,
+#define TO_VALUE(selector_name, selector_id) selector_id,
+
+// This enum will be automatically expanded to hold all selector names.
+// The value SELECTOR_COUNT can be used to get the number of defined selectors
+// Do not modify !
+typedef enum selector_e {
+    SELECTORS_LIST(TO_ENUM) SELECTOR_COUNT,
 } selector_t;
 
+// This array will be automatically expanded to map all selector_t names with the correct value.
+// Do not modify !
+extern const uint32_t SELECTORS[SELECTOR_COUNT];
+
 // Enumeration used to parse the smart contract data.
 // EDIT THIS: Adapt the parameter names here.
 typedef enum {
@@ -31,9 +61,6 @@ typedef enum {
     UNEXPECTED_PARAMETER,
 } parameter;
 
-// EDIT THIS: Rename `BOILERPLATE` to be the same as the one initialized in `main.c`.
-extern const uint32_t BOILERPLATE_SELECTORS[NUM_SELECTORS];
-
 // Shared global memory with Ethereum app. Must be at most 5 * 32 bytes.
 // EDIT THIS: This struct is used by your plugin to save the parameters you parse. You
 // will need to adapt this struct to your plugin.

src/handle_init_contract.c

@@ -24,7 +24,7 @@ void handle_init_contract(ethPluginInitContract_t *msg) {
     memset(context, 0, sizeof(*context));
 
     size_t index;
-    if (!find_selector(U4BE(msg->selector, 0), BOILERPLATE_SELECTORS, NUM_SELECTORS, &index)) {
+    if (!find_selector(U4BE(msg->selector, 0), SELECTORS, SELECTOR_COUNT, &index)) {
         PRINTF("Error: selector not found!\n");
         msg->result = ETH_PLUGIN_RESULT_UNAVAILABLE;
         return;