withdrawals, consolidations: return fee instead of excess requests from read operation

src/consolidations/main.eas

@@ -1,7 +1,7 @@
-;; ▗▄▄▄▖▄▄▄▄ ▄▄▄▄ ▄ ▗▞▀▜▌ ▄▄▄  
-;;    ▐▌   █ █    █ ▝▚▄▟▌▀▄▄  ▄▄▄▄          
-;;    ▐▌█▀▀▀ ▀▀▀█ █      ▄▄▄▀ █ █ █         
-;;    ▐▌█▄▄▄ ▄▄▄█ █           █   █              
+;; ▗▄▄▄▖▄▄▄▄ ▄▄▄▄ ▄ ▗▞▀▜▌ ▄▄▄
+;;    ▐▌   █ █    █ ▝▚▄▟▌▀▄▄  ▄▄▄▄
+;;    ▐▌█▀▀▀ ▀▀▀█ █      ▄▄▄▀ █ █ █
+;;    ▐▌█▄▄▄ ▄▄▄█ █           █   █
 
 ;; This is an implementation of EIP-7251 style contract handling EL triggerred
 ;; consolidations. It leverages on the fee mechanism and the queue design of the
@@ -50,29 +50,6 @@
   ;; --------------------------------------------------------------------------
   ;; USER SUBROUTINE ----------------------------------------------------------
   ;; --------------------------------------------------------------------------
-  ;;
-  ;; Record new request ~~
-  ;; This is the default code path. It will attempt to record a user's request
-  ;; so long as they pay the required fee.
-
-  ;; If calldatasize == 0, return the current excess requests.
-  calldatasize          ;; [calldatasize]
-  iszero                ;; [calldatasize == 0]
-  jumpi @read_excess
-
-  ;; Input data has the following layout:
-  ;;
-  ;;  +--------+--------+
-  ;;  | source | target |
-  ;;  +--------+--------+
-  ;;      48       48
-
-  ;; Verify the input is exactly INPUT_SIZE bytes.
-  calldatasize          ;; [calldatasize]
-  push INPUT_SIZE       ;; [INPUT_SIZE, calldatasize]
-  eq                    ;; [INPUT_SIZE == calldatasize]
-  iszero                ;; [INPUT_SIZE != calldatasize]
-  jumpi @revert         ;; []
 
   ;; Compute the fee using fake expo and the current excess requests.
   push FEE_UPDATE_FRACTION
@@ -88,6 +65,37 @@
   push MIN_FEE          ;; [min_fee, excess, update_fraction]
   #include "../common/fake_expo.eas"
 
+  ;; If calldatasize matches the expected input size, go to adding the request.
+  calldatasize          ;; [calldatasize, req_fee]
+  push INPUT_SIZE       ;; [INPUT_SIZE, calldatasize, req_fee]
+  eq                    ;; [INPUT_SIZE == calldatasize, req_fee]
+  jumpi @handle_input   ;; [req_fee]
+
+  ;; Otherwise calldatasize must be zero.
+  calldatasize          ;; [calldatasize, req_fee]
+  jumpi @revert         ;; [req_fee]
+
+  ;; This is the read path, where we return the current excess.
+  ;; Reject any callvalue here to prevent lost funds.
+  callvalue             ;; [value, req_fee]
+  jumpi @revert         ;; [req_fee]
+
+  ;; Return req_fee.
+  push 0                ;; [0, req_fee]
+  mstore                ;; []
+  push 32               ;; [32]
+  push 0                ;; [0, 32]
+  return                ;; []
+
+handle_input:
+  ;; This is the write path. We expect the computed fee on the stack.
+  ;; Input data has the following layout:
+  ;;
+  ;;  +--------+--------+
+  ;;  | source | target |
+  ;;  +--------+--------+
+  ;;      48       48
+
   ;; Determine if the fee provided is enough to cover the request fee.
   callvalue             ;; [callvalue, req_fee]
   lt                    ;; [callvalue < req_fee]
@@ -167,23 +175,6 @@
 
   stop
 
-read_excess:
-  ;; This is the read path, where we return the current excess.
-  ;; Reject any callvalue here to prevent lost funds.
-  callvalue             ;; [value]
-  iszero                ;; [value == 0]
-  iszero                ;; [value != 0]
-  jumpi @revert
-
-  ;; Load excess requests and return the value.
-  push SLOT_EXCESS      ;; [excess_reqs_slot]
-  sload                 ;; [excess_reqs]
-  push 0                ;; [0, excess_reqs]
-  mstore                ;; []
-  push 32               ;; [32]
-  push 0                ;; [0, 32]
-  return                ;; []
-
 ;; ----------------------------------------------------------------------------
 ;; SYSTEM SUBROUTINE ----------------------------------------------------------
 ;; ----------------------------------------------------------------------------

src/withdrawals/main.eas

@@ -55,29 +55,6 @@
   ;; --------------------------------------------------------------------------
   ;; USER SUBROUTINE ----------------------------------------------------------
   ;; --------------------------------------------------------------------------
-  ;;
-  ;; Record new withdrawal request ~~
-  ;; This is the default code path. It will attempt to record a user's request
-  ;; so long as they pay the required fee.
-
-  ;; If calldatasize == 0, return the current excess requests.
-  calldatasize          ;; [calldatasize]
-  iszero                ;; [calldatasize == 0]
-  jumpi @read_excess
-
-  ;; Input data has the following layout:
-  ;;
-  ;;  +--------+--------+
-  ;;  | pubkey | amount |
-  ;;  +--------+--------+
-  ;;      48       8
-
-  ;; Verify the input is exactly 56 bytes.
-  calldatasize          ;; [calldatasize]
-  push INPUT_SIZE       ;; [INPUT_SIZE, calldatasize]
-  eq                    ;; [INPUT_SIZE == calldatasize]
-  iszero                ;; [INPUT_SIZE != calldatasize]
-  jumpi @revert         ;; []
 
   ;; Compute the fee using fake expo and the current excess withdrawal requests.
   push FEE_UPDATE_FRACTION
@@ -93,6 +70,37 @@
   push MIN_FEE          ;; [min_fee, excess, update_fraction]
   #include "../common/fake_expo.eas"
 
+  ;; If calldatasize matches the expected input size, go to adding the request.
+  calldatasize          ;; [calldatasize, req_fee]
+  push INPUT_SIZE       ;; [INPUT_SIZE, calldatasize, req_fee]
+  eq                    ;; [INPUT_SIZE == calldatasize, req_fee]
+  jumpi @handle_input
+
+  ;; Otherwise calldatasize must be zero.
+  calldatasize          ;; [calldatasize, req_fee]
+  jumpi @revert         ;; [req_fee]
+
+  ;; This is the read path, where we return the current fee.
+  ;; Reject any callvalue here to prevent lost funds.
+  callvalue             ;; [value, req_fee]
+  jumpi @revert
+
+  ;; Return req_fee.
+  push 0                ;; [0, req_fee]
+  mstore                ;; []
+  push 32               ;; [32]
+  push 0                ;; [0, 32]
+  return                ;; []
+
+handle_input:
+  ;; This is the write path. We expect the computed fee on the stack.
+  ;; Input data has the following layout:
+  ;;
+  ;;  +--------+--------+
+  ;;  | pubkey | amount |
+  ;;  +--------+--------+
+  ;;      48       8
+
   ;; Determine if the fee provided is enough to cover the withdrawal request fee.
   callvalue             ;; [callvalue, req_fee]
   lt                    ;; [callvalue < req_fee]
@@ -162,23 +170,6 @@
 
   stop
 
-read_excess:
-  ;; This is the read path, where we return the current excess.
-  ;; Reject any callvalue here to prevent lost funds.
-  callvalue             ;; [value]
-  iszero                ;; [value == 0]
-  iszero                ;; [value != 0]
-  jumpi @revert
-
-  ;; Load excess withdrawal requests and return the value.
-  push SLOT_EXCESS      ;; [excess_reqs_slot]
-  sload                 ;; [excess_reqs]
-  push 0                ;; [0, excess_reqs]
-  mstore                ;; []
-  push 32               ;; [32]
-  push 0                ;; [0, 32]
-  return                ;; []
-
 ;; ----------------------------------------------------------------------------
 ;; SYSTEM SUBROUTINE ----------------------------------------------------------
 ;; ----------------------------------------------------------------------------

test/Test.sol

@@ -50,8 +50,9 @@ abstract contract Test is StdTest {
   // system contract matches count.
   function assertExcess(uint256 count) internal {
     assertStorage(excess_slot, count, "unexpected excess requests");
+    uint256 expectedFee = computeFee(count);
     (, bytes memory data) = addr.call("");
-    assertEq(toFixed(data, 0, 32), count, "unexpected excess requests");
+    assertEq(uint256(bytes32(data)), expectedFee, "unexpected fee returned");
   }
 }