feat: add simple call (#91)

Author: skosito

programs/gateway/src/lib.rs

@@ -666,6 +666,28 @@ pub mod gateway {
         Ok(())
     }
 
+    /// Calls a contract on ZetaChain zEVM.
+    ///
+    /// # Arguments
+    /// * `ctx` - The instruction context.
+    /// * `receiver` - The Ethereum address of the receiver on ZetaChain zEVM.
+    /// * `message` - The message passed to the contract.
+    pub fn call(_ctx: Context<Call>, receiver: [u8; 20], message: Vec<u8>) -> Result<()> {
+        require!(receiver != [0u8; 20], Errors::EmptyReceiver);
+        require!(
+            message.len() <= MAX_DEPOSIT_PAYLOAD_SIZE,
+            Errors::MemoLengthExceeded
+        );
+
+        msg!(
+            "Call executed: receiver = {:?}, message = {:?}",
+            receiver,
+            message
+        );
+
+        Ok(())
+    }
+
     /// Withdraws SOL. Caller is TSS.
     ///
     /// # Arguments
@@ -1058,6 +1080,14 @@ pub struct DepositSplToken<'info> {
     pub system_program: Program<'info, System>,
 }
 
+/// Instruction context for call operation.
+#[derive(Accounts)]
+pub struct Call<'info> {
+    /// The account of the signer making the call.
+    #[account(mut)]
+    pub signer: Signer<'info>,
+}
+
 /// Instruction context for SOL withdrawal operations.
 #[derive(Accounts)]
 pub struct Withdraw<'info> {

tests/gateway.ts

@@ -1888,6 +1888,43 @@ describe("Gateway", () => {
     }
   });
 
+  it("Call with empty address receiver should fail", async () => {
+    try {
+      await gatewayProgram.methods
+        .call(Array(20).fill(0), Buffer.from("hello", "utf-8"))
+        .rpc();
+      throw new Error("Expected error not thrown");
+    } catch (err) {
+      expect(err).to.be.instanceof(anchor.AnchorError);
+      expect(err.message).to.include("EmptyReceiver");
+    }
+  });
+
+  it("Call with above max payload size should fail", async () => {
+    try {
+      await gatewayProgram.methods
+        .call(
+          Array.from(address),
+          Buffer.from(Array(maxPayloadSize + 1).fill(1))
+        )
+        .rpc();
+      throw new Error("Expected error not thrown");
+    } catch (err) {
+      expect(err).to.be.instanceof(anchor.AnchorError);
+      expect(err.message).to.include("MemoLengthExceeded");
+    }
+  });
+
+  it("Call with max payload size", async () => {
+    const txsig = await gatewayProgram.methods
+      .call(Array.from(address), Buffer.from(Array(maxPayloadSize).fill(1)))
+      .preInstructions([
+        ComputeBudgetProgram.setComputeUnitLimit({ units: 400000 }),
+      ])
+      .rpc({ commitment: "processed" });
+    await conn.getParsedTransaction(txsig, "confirmed");
+  });
+
   it("Deposit and call with max payload size", async () => {
     const bal1 = await conn.getBalance(pdaAccount);
     const txsig = await gatewayProgram.methods