build_script

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["unit_struct"]
+members = ["unit_struct", "build_script"]
 resolver = "2"
 
 [workspace.dependencies]

build_script/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "build_script"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ic-cdk.workspace = true
+
+[lib]
+crate-type = ["cdylib"]

build_script/build.rs

@@ -0,0 +1,35 @@
+use std::path::Path;
+
+static BINDING: &str = "trait Counter {
+    fn inc();
+    fn read() -> u64;
+}
+
+#[export_name = \"canister_update inc\"]
+fn __canister_method_inc() {
+    ic_cdk::setup();
+    ic_cdk::spawn(async {
+        let _result = Canister::inc();
+        ic_cdk::api::call::reply(())
+    });
+}
+
+#[export_name = \"canister_query read\"]
+fn __canister_method_read() {
+    ic_cdk::setup();
+    ic_cdk::spawn(async {
+        let result = Canister::read();
+        ic_cdk::api::call::reply((result,))
+    });
+}";
+
+fn main() {
+    println!("cargo:rerun-if-changed=../counter.did");
+    println!("cargo:rerun-if-changed=build.rs");
+    // ic_cdk_bindgen::generate_provider("../counter.did").unwrap()
+    // We can also introduce Config similar to
+    // https://docs.rs/prost-build/latest/prost_build/struct.Config.html#method.compile_protos
+    let out_dir = std::env::var("OUT_DIR").unwrap();
+    let path = Path::new(&out_dir).join("counter.rs");
+    std::fs::write(&path, BINDING).unwrap();
+}

build_script/src/lib.rs

@@ -0,0 +1,19 @@
+include!(concat!(env!("OUT_DIR"), "/counter.rs"));
+
+use std::cell::Cell;
+
+thread_local! {
+    static COUNTER: Cell<u64> = Cell::new(0);
+}
+
+struct Canister;
+
+impl Counter for Canister {
+    fn inc() {
+        COUNTER.set(COUNTER.get() + 1);
+    }
+
+    fn read() -> u64 {
+        COUNTER.get()
+    }
+}

dfx.json

@@ -5,17 +5,14 @@
             "build": "sh build.sh unit_struct",
             "candid": "counter.did",
             "wasm": "target/wasm32-unknown-unknown/release/unit_struct.wasm",
-            "shrink": true,
-            "metadata": [
-                {
-                    "name": "candid:service",
-                    "visibility": "public"
-                },
-                {
-                    "name": "candid:args",
-                    "visibility": "public"
-                }
-            ]
+            "shrink": true
+        },
+        "build_script": {
+            "type": "custom",
+            "build": "sh build.sh build_script",
+            "candid": "counter.did",
+            "wasm": "target/wasm32-unknown-unknown/release/build_script.wasm",
+            "shrink": true
         }
     }
 }