[Feature]: ERC721Wrapper extension

contracts/src/token/erc721/extensions/mod.rs

@@ -4,6 +4,7 @@ pub mod consecutive;
 pub mod enumerable;
 pub mod metadata;
 pub mod uri_storage;
+pub mod wrapper;
 
 pub use burnable::IErc721Burnable;
 pub use enumerable::{Erc721Enumerable, IErc721Enumerable};

contracts/src/token/erc721/extensions/wrapper.rs

@@ -0,0 +1,85 @@
+//! Extension of the ERC-721 token contract to support token wrapping.
+//!
+//! Users can deposit and withdraw an "underlying token" and receive a "wrapped
+//! token" with a matching tokenId. This is useful in conjunction with other
+//! modules.
+use alloc::{vec, vec::Vec};
+
+use alloy_primitives::{Address, U256};
+use stylus_sdk::{contract, prelude::storage, stylus_proc::SolidityError};
+
+use crate::token::{
+    erc721,
+    erc721::{ERC721IncorrectOwner, Erc721, IErc721},
+};
+
+/// State of an [`Erc721Wrapper`] token.
+#[storage]
+pub struct Erc721Wrapper {
+    /// Erc721 contract storage.
+    pub _underlying: Erc721,
+    /// The ERC-721 token.
+    pub erc721: Erc721,
+}
+
+pub use sol::*;
+#[cfg_attr(coverage_nightly, coverage(off))]
+mod sol {
+    use alloy_sol_macro::sol;
+
+    sol! {
+        /// The received ERC-721 token couldn't be wrapped.
+        #[derive(Debug)]
+        #[allow(missing_docs)]
+        error ERC721UnsupportedToken(uint256 token_id);
+    }
+}
+
+/// An [`Erc721Wrapper`] error.
+#[derive(SolidityError, Debug)]
+pub enum Error {
+    /// Error type from [`Erc721`] contract [`erc721::Error`].
+    Erc721(erc721::Error),
+    /// The received ERC-721 token couldn't be wrapped.
+    ERC721UnsupportedToken(ERC721UnsupportedToken),
+}
+
+impl Erc721Wrapper {
+    /// Wraps an ERC-721 token.
+    pub fn deposit_for(
+        &mut self,
+        account: Address,
+        token_ids: Vec<U256>,
+    ) -> bool {
+        let length = token_ids.len();
+
+        true
+    }
+
+    /// Returns the underlying token.
+    pub fn underlying(&self) -> &Erc721 {
+        &self._underlying
+    }
+}
+
+// ************** ERC-721 Internal **************
+
+impl Erc721Wrapper {
+    fn _recover(
+        &mut self,
+        account: Address,
+        token_id: U256,
+    ) -> Result<U256, Error> {
+        let owner = self.underlying().owner_of(token_id)?;
+        if owner != contract::address() {
+            return Err(erc721::Error::IncorrectOwner(ERC721IncorrectOwner {
+                sender: contract::address(),
+                token_id,
+                owner,
+            })
+            .into());
+        }
+        self.erc721._safe_mint(account, token_id, &vec![].into())?;
+        Ok(token_id)
+    }
+}