fix(nft): switch nft traits to not require moving underlying struct

near-contract-standards/src/non_fungible_token/core/core_impl.rs

@@ -329,11 +329,12 @@ impl NonFungibleTokenCore for NonFungibleToken {
         .into()
     }
 
-    fn nft_token(self, token_id: TokenId) -> Option<Token> {
+    fn nft_token(&self, token_id: TokenId) -> Option<Token> {
         let owner_id = self.owner_by_id.get(&token_id)?;
-        let metadata = self.token_metadata_by_id.and_then(|by_id| by_id.get(&token_id));
+        let metadata = self.token_metadata_by_id.as_ref().and_then(|by_id| by_id.get(&token_id));
         let approved_account_ids = self
             .approvals_by_id
+            .as_ref()
             .and_then(|by_id| by_id.get(&token_id).or_else(|| Some(HashMap::new())));
         Some(Token { token_id, owner_id, metadata, approved_account_ids })
     }

near-contract-standards/src/non_fungible_token/core/mod.rs

@@ -94,7 +94,7 @@ pub trait NonFungibleTokenCore {
     ) -> PromiseOrValue<bool>;
 
     /// Returns the token with the given `token_id` or `null` if no such token.
-    fn nft_token(self, token_id: TokenId) -> Option<Token>;
+    fn nft_token(&self, token_id: TokenId) -> Option<Token>;
 
     /// Mint a new token. Not part of official standard, but needed in most situations.
     /// Consuming contract expected to wrap this with an `nft_mint` function.

near-contract-standards/src/non_fungible_token/enumeration/enumeration_impl.rs

@@ -19,7 +19,7 @@ impl NonFungibleToken {
 }
 
 impl NonFungibleTokenEnumeration for NonFungibleToken {
-    fn nft_total_supply(self) -> U128 {
+    fn nft_total_supply(&self) -> U128 {
         // An unfortunate cast from the max of TreeMap to the spec
         (self.owner_by_id.len() as u128).into()
     }
@@ -43,8 +43,8 @@ impl NonFungibleTokenEnumeration for NonFungibleToken {
             .collect()
     }
 
-    fn nft_supply_for_owner(self, account_id: AccountId) -> U128 {
-        let tokens_per_owner = self.tokens_per_owner.expect(
+    fn nft_supply_for_owner(&self, account_id: AccountId) -> U128 {
+        let tokens_per_owner = self.tokens_per_owner.as_ref().expect(
             "Could not find tokens_per_owner when calling a method on the enumeration standard.",
         );
         tokens_per_owner

near-contract-standards/src/non_fungible_token/enumeration/mod.rs

@@ -8,7 +8,7 @@ use near_sdk::AccountId;
 pub trait NonFungibleTokenEnumeration {
     /// Returns the total supply of non-fungible tokens as a string representing an
     /// unsigned 128-bit integer to avoid JSON number limit of 2^53.
-    fn nft_total_supply(self) -> U128;
+    fn nft_total_supply(&self) -> U128;
 
     /// Get a list of all tokens
     ///
@@ -32,7 +32,7 @@ pub trait NonFungibleTokenEnumeration {
     /// Returns the number of non-fungible tokens owned by given `account_id` as
     /// a string representing the value as an unsigned 128-bit integer to avoid JSON
     /// number limit of 2^53.
-    fn nft_supply_for_owner(self, account_id: AccountId) -> U128;
+    fn nft_supply_for_owner(&self, account_id: AccountId) -> U128;
 
     /// Get list of all tokens owned by a given account
     ///

near-contract-standards/src/non_fungible_token/macros.rs

@@ -32,7 +32,7 @@ macro_rules! impl_non_fungible_token_core {
                 self.$token.nft_transfer_call(receiver_id, token_id, approval_id, memo, msg)
             }
 
-            fn nft_token(self, token_id: TokenId) -> Option<Token> {
+            fn nft_token(&self, token_id: TokenId) -> Option<Token> {
                 self.$token.nft_token(token_id)
             }
 
@@ -118,15 +118,15 @@ macro_rules! impl_non_fungible_token_enumeration {
 
         #[near_bindgen]
         impl NonFungibleTokenEnumeration for $contract {
-            fn nft_total_supply(self) -> U128 {
+            fn nft_total_supply(&self) -> U128 {
                 self.$token.nft_total_supply()
             }
 
             fn nft_tokens(&self, from_index: Option<U128>, limit: Option<u64>) -> Vec<Token> {
                 self.$token.nft_tokens(from_index, limit)
             }
 
-            fn nft_supply_for_owner(self, account_id: AccountId) -> U128 {
+            fn nft_supply_for_owner(&self, account_id: AccountId) -> U128 {
                 self.$token.nft_supply_for_owner(account_id)
             }