From 97a124a51be7976fbf967304437c7f81c83f2fc1 Mon Sep 17 00:00:00 2001
From: Linwei Shang <linwei.shang@dfinity.org>
Date: Fri, 27 Oct 2023 16:31:04 -0400
Subject: [PATCH] stateful

---
 Cargo.lock            |  8 ++++++++
 Cargo.toml            |  2 +-
 build_script/build.rs |  2 +-
 dfx.json              |  7 +++++++
 stateful/Cargo.toml   | 12 +++++++++++
 stateful/src/lib.rs   | 46 +++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 stateful/Cargo.toml
 create mode 100644 stateful/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index faf9832..4602e17 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -456,6 +456,14 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "stateful"
+version = "0.1.0"
+dependencies = [
+ "ic-cdk",
+ "once_cell",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
diff --git a/Cargo.toml b/Cargo.toml
index 1cd99fe..1911c72 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [workspace]
-members = ["unit_struct", "build_script"]
+members = ["unit_struct", "build_script", "stateful"]
 resolver = "2"
 
 [workspace.dependencies]
diff --git a/build_script/build.rs b/build_script/build.rs
index c9253fc..f273376 100644
--- a/build_script/build.rs
+++ b/build_script/build.rs
@@ -31,5 +31,5 @@ fn main() {
     // 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();
+    std::fs::write(path, BINDING).unwrap();
 }
diff --git a/dfx.json b/dfx.json
index 45ab1dd..b4f814d 100644
--- a/dfx.json
+++ b/dfx.json
@@ -13,6 +13,13 @@
             "candid": "counter.did",
             "wasm": "target/wasm32-unknown-unknown/release/build_script.wasm",
             "shrink": true
+        },
+        "stateful": {
+            "type": "custom",
+            "build": "sh build.sh stateful",
+            "candid": "counter.did",
+            "wasm": "target/wasm32-unknown-unknown/release/stateful.wasm",
+            "shrink": true
         }
     }
 }
\ No newline at end of file
diff --git a/stateful/Cargo.toml b/stateful/Cargo.toml
new file mode 100644
index 0000000..5a8bfb8
--- /dev/null
+++ b/stateful/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "stateful"
+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
+once_cell  = "1"
+[lib]
+crate-type = ["cdylib"]
diff --git a/stateful/src/lib.rs b/stateful/src/lib.rs
new file mode 100644
index 0000000..5149014
--- /dev/null
+++ b/stateful/src/lib.rs
@@ -0,0 +1,46 @@
+// ic_cdk::generate!({path: "../../counter.did", service : Canister, trait: Counter});
+
+// Expand Start
+trait Counter {
+    fn inc(&mut self);
+    fn read(&self) -> u64;
+}
+
+#[export_name = "canister_update inc"]
+fn __canister_method_inc() {
+    ic_cdk::setup();
+    ic_cdk::spawn(async {
+        let _result = CANISTER.lock().unwrap().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.lock().unwrap().read();
+        ic_cdk::api::call::reply((result,))
+    });
+}
+
+use once_cell::sync::Lazy;
+use std::sync::Mutex;
+static CANISTER: Lazy<Mutex<Canister>> = Lazy::new(|| Mutex::new(Default::default()));
+
+// Expand End
+
+#[derive(Default)]
+struct Canister {
+    counter: u64,
+}
+
+impl Counter for Canister {
+    fn inc(&mut self) {
+        self.counter += 1;
+    }
+
+    fn read(&self) -> u64 {
+        self.counter
+    }
+}