example/smart-contract: Cleanup

example/smart-contract/.gitignore

@@ -1,3 +1,3 @@
 target/*
-Cargo.lock
-smart_contract.wasm
+proof/*.bin
+contract.wasm

example/smart-contract/Cargo.toml

@@ -1,6 +1,8 @@
 [package]
 name = "smart-contract"
 version = "0.3.0"
+authors = ["darkfi <dev@dark.fi>"]
+license = "AGPL-3.0-only"
 edition = "2021"
 
 [workspace]
@@ -8,19 +10,15 @@ edition = "2021"
 [lib]
 crate-type = ["cdylib", "rlib"]
 
-[dependencies]
-darkfi-sdk = { path = "../../src/sdk" }
-darkfi = { path = "../../", features = ["serial"]}
-pasta_curves = "0.4.0"
-
-[dev-dependencies]
-darkfi = { path = "../../", features = ["wasm-runtime"] }
-incrementalmerkletree = "0.3.0"
-lazy-init = "0.5.1"
-simplelog = "0.12.0"
-sled = "0.34.7"
-
 [profile.release]
 lto = true
 codegen-units = 1
 overflow-checks = true
+
+[dependencies]
+darkfi-sdk = { path = "../../src/sdk" }
+darkfi = { path = "../../", features = ["serial"] }
+
+[dev-dependencies]
+darkfi = { path = "../../", features = ["wasm-runtime"] }
+simplelog = "0.12.0"

example/smart-contract/Makefile

@@ -1,22 +1,39 @@
 .POSIX:
 
-SRC = $(shell find src -type f)
+WASM_SRC = $(shell find src -type f)
+PROOF_SRC = $(shell find proof -type f -name '*.zk')
 
 # Cargo binary
 CARGO = cargo
 
-BIN = smart_contract.wasm
+# zkas binary
+ZKAS = ../../zkas
 
-all: $(BIN)
+# wasm-strip binary (Part of https://github.com/WebAssembly/wabt)
+WASM_STRIP = wasm-strip
 
-smart_contract.wasm: $(SRC)
+# Contract WASM binary
+WASM_BIN = contract.wasm
+
+# ZK circuit binaries
+PROOF_BIN = $(PROOF_SRC:=.bin)
+
+all: $(PROOF_BIN) $(WASM_BIN)
+
+strip: $(WASM_BIN)
+	$(WASM_STRIP) $<
+
+$(WASM_BIN): $(WASM_SRC)
 	$(CARGO) build --release --lib --target wasm32-unknown-unknown
-	cp -f target/wasm32-unknown-unknown/release/$@ $@
+	cp -f target/wasm32-unknown-unknown/release/*.wasm $@
+
+$(PROOF_BIN): $(PROOF_SRC)
+	$(ZKAS) $(basename $@) -o $@
 
 test: all
 	$(CARGO) test --release -- --nocapture
 
 clean:
-	rm -f $(BIN)
+	rm -f $(PROOF_BIN) $(WASM_BIN)
 
 .PHONY: all test clean

example/smart-contract/README.md

@@ -0,0 +1,6 @@
+Smart contract demo and template
+================================
+
+This crate is a reference DarkFI smart contract implementation. All
+repositories implementing contracts should follow the same layout, as
+this will allow easy deployments using the commandline utilities.

example/smart-contract/proof/contract.zk

@@ -0,0 +1,13 @@
+# Currently just a dummy contract
+
+constant "SmartContract" {
+	EcFixedPointBase NULLIFIER_K,
+}
+
+contract "SmartContract" {
+	Base something,
+}
+
+circuit "SmartContract" {
+	constrain_instance(something);
+}

example/smart-contract/src/lib.rs

@@ -4,31 +4,38 @@ use darkfi_sdk::{
     entrypoint,
     error::{ContractError, ContractResult},
     msg,
+    pasta::pallas,
     state::nullifier_exists,
 };
-use pasta_curves::pallas;
 
+// An example of deserializing the payload into a struct
 #[derive(SerialEncodable, SerialDecodable)]
 pub struct Args {
     pub a: u64,
     pub b: u64,
 }
 
+// This is the main entrypoint function where the payload is fed.
+// Through here, you can branch out into different functions inside
+// this library.
 entrypoint!(process_instruction);
 fn process_instruction(ix: &[u8]) -> ContractResult {
+    // Deserialize the payload into `Args`.
     let args: Args = deserialize(ix)?;
 
     if args.a < args.b {
+        // Returning custom errors
         return Err(ContractError::Custom(69))
     }
 
     let sum = args.a + args.b;
-
+    // Publicly logged messages
     msg!("Hello from the VM runtime!");
     msg!("Sum: {:?}", sum);
 
+    // Querying of ledger state available from the VM host
     let nf = Nullifier::from(pallas::Base::from(0x10));
-    msg!("Contract nf: {:?}", nf);
+    msg!("Contract Nullifier: {:?}", nf);
 
     if nullifier_exists(&nf)? {
         msg!("Nullifier exists");

example/smart-contract/tests/runtime.rs

@@ -1,47 +1,43 @@
-use incrementalmerkletree::bridgetree::BridgeTree;
-use lazy_init::Lazy;
-use pasta_curves::pallas;
-
 use darkfi::{
-    blockchain::Blockchain,
-    consensus::{TESTNET_GENESIS_HASH_BYTES, TESTNET_GENESIS_TIMESTAMP},
-    crypto::{merkle_node::MerkleNode, nullifier::Nullifier},
+    crypto::nullifier::Nullifier,
     node::{MemoryState, State},
     runtime::{util::serialize_payload, vm_runtime::Runtime},
     serial::serialize,
     Result,
 };
+use darkfi_sdk::pasta::pallas;
 
 use smart_contract::Args;
 
 #[test]
 fn run_contract() -> Result<()> {
-    let mut logcfg = simplelog::ConfigBuilder::new();
-    logcfg.add_filter_ignore("sled".to_string());
+    // Debug log configuration
+    let mut cfg = simplelog::ConfigBuilder::new();
+    cfg.add_filter_ignore("sled".to_string());
     simplelog::TermLogger::init(
         simplelog::LevelFilter::Debug,
-        logcfg.build(),
+        cfg.build(),
         simplelog::TerminalMode::Mixed,
         simplelog::ColorChoice::Auto,
     )?;
 
-    // ============================================================
+    // =============================================================
     // Build a ledger state so the runtime has something to work on
-    // ============================================================
-    let state_machine = MemoryState::new(State::dummy())?;
+    // =============================================================
+    let state_machine = State::dummy()?;
 
-    // We check if this nullifier is in the set from the contract
+    // Add a nullifier to the nullifier set. (This is checked by the contract)
     state_machine.nullifiers.insert(&[Nullifier::from(pallas::Base::from(0x10))])?;
 
     // ================================================================
     // Load the wasm binary into memory and create an execution runtime
     // ================================================================
-    let wasm_bytes = std::fs::read("smart_contract.wasm")?;
+    let wasm_bytes = std::fs::read("contract.wasm")?;
     let mut runtime = Runtime::new(&wasm_bytes, MemoryState::new(state_machine))?;
 
-    // ===========================================================
-    // Build some kind of payload for the wasm entrypoint function
-    // ===========================================================
+    // =============================================
+    // Build some kind of payload to show an example
+    // =============================================
     let args = Args { a: 777, b: 666 };
     let payload = serialize(&args);
 

src/sdk/src/error.rs

@@ -19,6 +19,9 @@ pub enum ContractError {
 
     #[error("Error checking if nullifier exists")]
     NullifierExistCheck,
+
+    #[error("Error checking merkle root validity")]
+    ValidMerkleCheck,
 }
 
 /// Builtin return values occupy the upper 32 bits
@@ -33,6 +36,7 @@ pub const CUSTOM_ZERO: u64 = to_builtin!(1);
 pub const INTERNAL_ERROR: u64 = to_builtin!(2);
 pub const IO_ERROR: u64 = to_builtin!(3);
 pub const NULLIFIER_EXIST_CHECK: u64 = to_builtin!(4);
+pub const VALID_MERKLE_CHECK: u64 = to_builtin!(5);
 
 impl From<ContractError> for u64 {
     fn from(err: ContractError) -> Self {
@@ -40,6 +44,7 @@ impl From<ContractError> for u64 {
             ContractError::Internal => INTERNAL_ERROR,
             ContractError::IoError(_) => IO_ERROR,
             ContractError::NullifierExistCheck => NULLIFIER_EXIST_CHECK,
+            ContractError::ValidMerkleCheck => VALID_MERKLE_CHECK,
             ContractError::Custom(error) => {
                 if error == 0 {
                     CUSTOM_ZERO
@@ -58,6 +63,7 @@ impl From<u64> for ContractError {
             INTERNAL_ERROR => Self::Internal,
             IO_ERROR => Self::IoError("Unknown".to_string()),
             NULLIFIER_EXIST_CHECK => Self::NullifierExistCheck,
+            VALID_MERKLE_CHECK => Self::ValidMerkleCheck,
             _ => Self::Custom(error as u32),
         }
     }

src/sdk/src/lib.rs

@@ -1,3 +1,5 @@
+pub use pasta_curves as pasta;
+
 /// Entrypoint used for the wasm binaries
 pub mod entrypoint;