Add a method that calls the reducer and updates circulating

FungibleToken.test.ts

@@ -177,6 +177,27 @@ describe("token integration", () => {
       )
     })
 
+    it("calling the reducer should not change the reported circulating supply", async () => {
+      const initialCirculating = (await tokenAContract.getCirculating()).toBigInt()
+
+      const tx = await Mina.transaction({
+        sender: sender,
+        fee: 1e8,
+      }, async () => {
+        await tokenAContract.updateCirculating()
+      })
+
+      tx.sign([sender.key])
+      await tx.prove()
+      await tx.send()
+
+      localChain.incrementGlobalSlot(1)
+      equal(
+        (await tokenAContract.getCirculating()).toBigInt(),
+        initialCirculating,
+      )
+    })
+
     it("should burn tokens for the sender account", async () => {
       const initialBalance = (await tokenAContract.getBalanceOf(sender))
         .toBigInt()

FungibleToken.ts

@@ -4,6 +4,7 @@ import {
   DeployArgs,
   Field,
   Int64,
+  MerkleList,
   method,
   PublicKey,
   Reducer,
@@ -115,12 +116,11 @@ export class FungibleToken extends TokenContract implements FungibleTokenLike {
     return balance
   }
 
-  @method.returns(UInt64)
-  async getCirculating(): Promise<UInt64> {
-    let oldCirculating = this.circulating.getAndRequireEquals()
-    let actionState = this.actionState.getAndRequireEquals()
-    let pendingActions = this.reducer.getActions({ fromActionState: actionState })
-
+  /** This function is used to fold the actions from minting/burning */
+  private calculateCirculating(
+    oldCirculating: UInt64,
+    pendingActions: MerkleList<MerkleList<Int64>>,
+  ): UInt64 {
     let newCirculating: Int64 = this.reducer.reduce(
       pendingActions,
       Int64,
@@ -134,6 +134,32 @@ export class FungibleToken extends TokenContract implements FungibleTokenLike {
     return newCirculating.magnitude
   }
 
+  /** Reports the current circulating supply
+   * This does take into account currently unreduced actions.
+   */
+  @method.returns(UInt64)
+  async getCirculating(): Promise<UInt64> {
+    let oldCirculating = this.circulating.getAndRequireEquals()
+    let actionState = this.actionState.getAndRequireEquals()
+    let pendingActions = this.reducer.getActions({ fromActionState: actionState })
+
+    let newCirculating = this.calculateCirculating(oldCirculating, pendingActions)
+    return newCirculating
+  }
+
+  /** Aggregate actions from minting and burning to update the circulating supply */
+  @method
+  async updateCirculating() {
+    let oldCirculating = this.circulating.getAndRequireEquals()
+    let actionState = this.actionState.getAndRequireEquals()
+    let pendingActions = this.reducer.getActions({ fromActionState: actionState })
+
+    let newCirculating = this.calculateCirculating(oldCirculating, pendingActions)
+
+    this.circulating.set(newCirculating)
+    this.actionState.set(pendingActions.hash)
+  }
+
   @method.returns(UInt64)
   async getDecimals() {
     return this.decimals