feat(cw721): Extend Cw721Contract with more token management functions

contracts/cw721-base/src/state.rs

@@ -3,7 +3,7 @@ use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use std::marker::PhantomData;
 
-use cosmwasm_std::{Addr, BlockInfo, CustomMsg, StdResult, Storage};
+use cosmwasm_std::{Addr, BlockInfo, CustomMsg, StdError, StdResult, Storage};
 
 use cw721::{ContractInfoResponse, Cw721, Expiration};
 use cw_storage_plus::{Index, IndexList, IndexedMap, Item, Map, MultiIndex};
@@ -98,6 +98,80 @@ where
         self.token_count.save(storage, &val)?;
         Ok(val)
     }
+
+    // Adds an approval for a token, ensuring not to duplicate or exceed a max number of approvals.
+    pub fn add_approval(
+        &self,
+        storage: &mut dyn Storage,
+        token_id: &'a str,
+        approval: Approval,
+    ) -> StdResult<()> {
+        self.tokens.update(
+            storage,
+            token_id,
+            |token_info_option| match token_info_option {
+                Some(mut token_info) => {
+                    // Ensure the approval does not already exist
+                    if !token_info
+                        .approvals
+                        .iter()
+                        .any(|a| a.spender == approval.spender)
+                    {
+                        token_info.approvals.push(approval);
+                    }
+                    Ok(token_info)
+                }
+                None => Err(StdError::not_found("TokenInfo")),
+            },
+        )?;
+        Ok(())
+    }
+
+    // Revokes an approval for a token.
+    pub fn revoke_approval(
+        &self,
+        storage: &mut dyn Storage,
+        token_id: &'a str,
+        spender: &Addr,
+    ) -> StdResult<()> {
+        self.tokens.update(
+            storage,
+            token_id,
+            |token_info_option| match token_info_option {
+                Some(mut token_info) => {
+                    token_info.approvals.retain(|a| a.spender != spender);
+                    Ok(token_info)
+                }
+                None => Err(StdError::not_found("TokenInfo")),
+            },
+        )?;
+        Ok(())
+    }
+
+    // Queries all current approvals for a token, excluding expired ones.
+    pub fn query_approvals(
+        &self,
+        storage: &dyn Storage,
+        token_id: &'a str,
+        block_info: &BlockInfo,
+    ) -> StdResult<Vec<Approval>> {
+        // Attempt to load the token info. If it does not exist, return an empty vector.
+        match self.tokens.load(storage, token_id) {
+            Ok(token_info) => {
+                // Filter out expired approvals
+                let current_approvals = token_info
+                    .approvals
+                    .into_iter()
+                    .filter(|a| !a.is_expired(block_info))
+                    .collect();
+                Ok(current_approvals)
+            }
+            Err(_) => {
+                // If there's no token info, return an empty list of approvals
+                Ok(vec![])
+            }
+        }
+    }
 }
 
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]