From 6f1592b8758c7524373e989f2a58b05dbf31ee6a Mon Sep 17 00:00:00 2001
From: Ignacio Duart <iduartgomez@gmail.com>
Date: Mon, 9 Mar 2026 13:46:13 +0100
Subject: [PATCH 1/2] feat: add create_delegate host function for
 delegate-spawned delegates

Adds the stdlib side of issue freenet/freenet-core#2833, enabling
delegates to create child delegates at runtime via a new V2 host
function.

Changes:
- New error codes: ERR_DEPTH_EXCEEDED, ERR_CREATIONS_EXCEEDED,
  ERR_INVALID_WASM, ERR_STORE_FAILED
- New extern block (freenet_delegate_management) with
  __frnt__delegate__create_delegate
- DelegateCtx::create_delegate() ergonomic wrapper
---
 rust/src/delegate_host.rs | 86 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/rust/src/delegate_host.rs b/rust/src/delegate_host.rs
index 166f539..1390bc8 100644
--- a/rust/src/delegate_host.rs
+++ b/rust/src/delegate_host.rs
@@ -98,6 +98,14 @@ pub mod error_codes {
     pub const ERR_MEMORY_BOUNDS: i32 = -9;
     /// Contract code not registered in the index.
     pub const ERR_CONTRACT_CODE_NOT_REGISTERED: i32 = -10;
+    /// Delegate creation depth limit exceeded.
+    pub const ERR_DEPTH_EXCEEDED: i32 = -20;
+    /// Per-call delegate creation limit exceeded.
+    pub const ERR_CREATIONS_EXCEEDED: i32 = -21;
+    /// Invalid WASM module (failed to construct DelegateContainer).
+    pub const ERR_INVALID_WASM: i32 = -23;
+    /// Failed to register delegate in secret/delegate store.
+    pub const ERR_STORE_FAILED: i32 = -24;
 }
 
 // ============================================================================
@@ -160,6 +168,24 @@ extern "C" {
     fn __frnt__delegate__subscribe_contract(id_ptr: i64, id_len: i32) -> i64;
 }
 
+#[cfg(target_family = "wasm")]
+#[link(wasm_import_module = "freenet_delegate_management")]
+extern "C" {
+    /// Create a new delegate from WASM code + parameters.
+    /// Returns 0 on success, negative error code on failure.
+    /// On success, writes 32 bytes to out_key_ptr and 32 bytes to out_hash_ptr.
+    fn __frnt__delegate__create_delegate(
+        wasm_ptr: i64,
+        wasm_len: i64,
+        params_ptr: i64,
+        params_len: i32,
+        cipher_ptr: i64,
+        nonce_ptr: i64,
+        out_key_ptr: i64,
+        out_hash_ptr: i64,
+    ) -> i32;
+}
+
 // ============================================================================
 // DelegateCtx - Unified handle to context, secrets, and contracts
 // ============================================================================
@@ -183,6 +209,9 @@ extern "C" {
 ///   [`put_contract_state`](Self::put_contract_state),
 ///   [`update_contract_state`](Self::update_contract_state),
 ///   [`subscribe_contract`](Self::subscribe_contract)
+///
+/// # Delegate Management Methods (V2)
+/// - [`create_delegate`](Self::create_delegate)
 #[derive(Default)]
 #[repr(transparent)]
 pub struct DelegateCtx {
@@ -526,6 +555,63 @@ impl DelegateCtx {
             false
         }
     }
+
+    /// Create a new child delegate from WASM bytecode and parameters.
+    ///
+    /// This V2 host function allows a delegate to spawn new delegates at runtime.
+    /// The child delegate is registered in the node's delegate store and secret store
+    /// with the provided cipher and nonce.
+    ///
+    /// Returns `Ok((key_hash, code_hash))` where both are 32-byte arrays identifying
+    /// the newly created delegate. Returns `Err(error_code)` on failure.
+    ///
+    /// # Resource Limits
+    /// - Maximum creation depth: 4 (prevents fork bombs)
+    /// - Maximum creations per process() call: 8
+    ///
+    /// # Error Codes
+    /// - `-1`: Called outside process() context
+    /// - `-4`: Invalid parameter
+    /// - `-9`: WASM memory bounds violation
+    /// - `-20`: Depth limit exceeded
+    /// - `-21`: Per-call creation limit exceeded
+    /// - `-23`: Invalid WASM module
+    /// - `-24`: Store registration failed
+    pub fn create_delegate(
+        &mut self,
+        wasm_code: &[u8],
+        params: &[u8],
+        cipher: &[u8; 32],
+        nonce: &[u8; 24],
+    ) -> Result<([u8; 32], [u8; 32]), i32> {
+        #[cfg(target_family = "wasm")]
+        {
+            let mut key_buf = [0u8; 32];
+            let mut hash_buf = [0u8; 32];
+            let result = unsafe {
+                __frnt__delegate__create_delegate(
+                    wasm_code.as_ptr() as i64,
+                    wasm_code.len() as i64,
+                    params.as_ptr() as i64,
+                    params.len() as i32,
+                    cipher.as_ptr() as i64,
+                    nonce.as_ptr() as i64,
+                    key_buf.as_mut_ptr() as i64,
+                    hash_buf.as_mut_ptr() as i64,
+                )
+            };
+            if result == 0 {
+                Ok((key_buf, hash_buf))
+            } else {
+                Err(result)
+            }
+        }
+        #[cfg(not(target_family = "wasm"))]
+        {
+            let _ = (wasm_code, params, cipher, nonce);
+            Err(error_codes::ERR_NOT_IN_PROCESS)
+        }
+    }
 }
 
 impl std::fmt::Debug for DelegateCtx {

From e9a452e6a0a2d53f9a6a9f61d656470bac92ba33 Mon Sep 17 00:00:00 2001
From: Ignacio Duart <iduartgomez@gmail.com>
Date: Mon, 9 Mar 2026 14:37:48 +0100
Subject: [PATCH 2/2] build: bump version to 0.2.1

---
 rust/Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 0f6081f..bddfff6 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "freenet-stdlib"
-version = "0.2.0"
+version = "0.2.1"
 edition = "2021"
 rust-version = "1.80"
 publish = true