chore: more boiler plate code for merge rollup (#3182)

---------

Co-authored-by: sirasistant <[email protected]>

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/abis/append_only_tree_snapshot.nr

@@ -1,4 +1,10 @@
 struct AppendOnlyTreeSnapshot {
     root : Field,
     next_available_leaf_index : u32
+}
+
+impl AppendOnlyTreeSnapshot{
+    pub fn eq(self, other : AppendOnlyTreeSnapshot) -> bool {
+        (self.root == other.root) & (self.next_available_leaf_index == other.next_available_leaf_index)
+    }
 }

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/abis/base_or_merge_rollup_public_inputs.nr

@@ -31,6 +31,10 @@ struct BaseOrMergeRollupPublicInputs {
 
     start_public_data_tree_root : Field,
     end_public_data_tree_root : Field,
-//     // We hash public inputs to make them constant-sized (to then be unpacked on-chain)
+
+    // We hash public inputs to make them constant-sized (to then be unpacked on-chain)
+    // TODO(Kev): Want to make this a U128, but Re-export bug 3384
+
+    // We hash public inputs to make them constant-sized (to then be unpacked on-chain)
     calldata_hash : [Field; 2],
 }

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/abis/constant_rollup_data.nr

@@ -12,4 +12,15 @@ struct ConstantRollupData {
     merge_rollup_vk_hash : Field,
 
     global_variables : GlobalVariables,
+}
+
+impl ConstantRollupData {
+    pub fn eq(self, other : ConstantRollupData) -> bool {
+        self.start_historic_blocks_tree_roots_snapshot.eq(other.start_historic_blocks_tree_roots_snapshot) &
+        self.global_variables.eq(other.global_variables) &
+        (self.private_kernel_vk_tree_root == other.private_kernel_vk_tree_root) &
+        (self.public_kernel_vk_tree_root == other.public_kernel_vk_tree_root) &
+        (self.base_rollup_vk_hash == other.base_rollup_vk_hash) &
+        (self.merge_rollup_vk_hash == other.merge_rollup_vk_hash)
+    }
 }

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/abis/global_variables.nr

@@ -20,4 +20,10 @@ impl GlobalVariables {
             )
     }
 
+    pub fn eq(self, other : GlobalVariables) -> bool {
+        (self.chain_id == other.chain_id) &
+        (self.version == other.version) &
+        (self.block_number == other.block_number) &
+        (self.timestamp == other.timestamp)
+    }
 }

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/components.nr

@@ -0,0 +1,68 @@
+use crate::abis::base_or_merge_rollup_public_inputs::{BaseOrMergeRollupPublicInputs, AggregationObject};
+use dep::private_kernel_lib::hash::accumulate_sha256;
+use dep::private_kernel_lib::utils::uint128::U128;
+use dep::aztec::constants_gen::NUM_FIELDS_PER_SHA256;
+use crate::abis::previous_rollup_data::PreviousRollupData;
+
+/**
+ * Create an aggregation object for the proofs that are provided
+ *          - We add points P0 for each of our proofs
+ *          - We add points P1 for each of our proofs
+ *          - We concat our public inputs
+ * TODO(Kev): This seems similar to the aggregate_proof method in the private-kernel-lib
+ */
+pub fn aggregate_proofs(left : BaseOrMergeRollupPublicInputs, right : BaseOrMergeRollupPublicInputs) -> AggregationObject {
+    // TODO: Similar to cpp code this does not do anything.
+    left.end_aggregation_object
+}
+
+/**
+ * Asserts that the rollup types are the same. 
+ * Either both merge or both base
+ */
+pub fn assert_both_input_proofs_of_same_rollup_type(left : BaseOrMergeRollupPublicInputs, right : BaseOrMergeRollupPublicInputs)
+{
+    assert(left.rollup_type == right.rollup_type, "input proofs are of different rollup types");
+}
+
+/**
+ * Asserts that the rollup subtree heights are the same and returns the height
+ * Returns the height of the rollup subtrees
+ */
+pub fn assert_both_input_proofs_of_same_height_and_return(left : BaseOrMergeRollupPublicInputs, right : BaseOrMergeRollupPublicInputs) -> Field{
+    assert(left.rollup_subtree_height == right.rollup_subtree_height, "input proofs are of different rollup heights");
+    left.rollup_subtree_height
+}
+
+/**
+ * Asserts that the constants used in the left and right child are identical
+ *
+ */
+pub fn assert_equal_constants(left : BaseOrMergeRollupPublicInputs, right : BaseOrMergeRollupPublicInputs) {
+    assert(left.constants.eq(right.constants), "input proofs have different constants");
+}
+
+// asserts that the end snapshot of previous_rollup 0 equals the start snapshot of previous_rollup 1 (i.e. ensure they
+// follow on from one-another). Ensures that right uses the tres that was updated by left.
+pub fn assert_prev_rollups_follow_on_from_each_other(left : BaseOrMergeRollupPublicInputs, right : BaseOrMergeRollupPublicInputs)
+{
+    assert(left.end_note_hash_tree_snapshot.eq(right.start_note_hash_tree_snapshot), "input proofs have different note hash tree snapshots");
+    assert(left.end_nullifier_tree_snapshot.eq(right.start_nullifier_tree_snapshot),"input proofs have different nullifier tree snapshots");
+    assert(left.end_contract_tree_snapshot.eq(right.start_contract_tree_snapshot), "input proofs have different contract tree snapshots");
+    assert(left.end_public_data_tree_root == right.start_public_data_tree_root, "input proofs have different public data tree snapshots");
+}
+
+/**
+ * @brief From two previous rollup data, compute a single calldata hash
+ *
+ * @param previous_rollup_data
+ * @return calldata hash stored in 2 fields
+ */
+pub fn compute_calldata_hash(previous_rollup_data : [PreviousRollupData ; 2]) -> [Field; NUM_FIELDS_PER_SHA256]{
+    accumulate_sha256([
+        U128::from_field(previous_rollup_data[0].base_or_merge_rollup_public_inputs.calldata_hash[0]),
+        U128::from_field(previous_rollup_data[0].base_or_merge_rollup_public_inputs.calldata_hash[1]),
+        U128::from_field(previous_rollup_data[1].base_or_merge_rollup_public_inputs.calldata_hash[0]),
+        U128::from_field(previous_rollup_data[1].base_or_merge_rollup_public_inputs.calldata_hash[1])
+    ])
+}

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/lib.nr

@@ -7,4 +7,6 @@ mod base;
 mod merge;
 
 // Root rollup
-mod root;
+mod root;
+
+mod components;

yarn-project/noir-protocol-circuits/src/crates/rollup-lib/src/merge/merge_rollup_inputs.nr

@@ -1,5 +1,6 @@
 use crate::abis::previous_rollup_data::PreviousRollupData;
-use crate::abis::base_or_merge_rollup_public_inputs::BaseOrMergeRollupPublicInputs;
+use crate::abis::base_or_merge_rollup_public_inputs::{BaseOrMergeRollupPublicInputs, MERGE_ROLLUP_TYPE};
+use crate::components;
 
 struct MergeRollupInputs{
     // TODO(Kev): Why is this 2?
@@ -8,7 +9,41 @@ struct MergeRollupInputs{
 
 impl MergeRollupInputs {
     pub fn merge_rollup_circuit(self) -> BaseOrMergeRollupPublicInputs {
-        let zeroed = dep::std::unsafe::zeroed();
-        zeroed
+
+        // TODO(Lasse): Verify the previous rollup proofs
+        // TODO(Lasse): Check both previous rollup vks (in previous_rollup_data) against the permitted set of kernel vks.
+        // we don't have a set of permitted kernel vks yet.
+
+        let left = self.previous_rollup_data[0].base_or_merge_rollup_public_inputs;
+        let right = self.previous_rollup_data[1].base_or_merge_rollup_public_inputs;
+
+        // check that both input proofs are either both "BASE" or "MERGE" and not a mix!
+        // this prevents having wonky commitment, nullifier and contract subtrees.
+        let aggregation_object = components::aggregate_proofs(left, right);
+        components::assert_both_input_proofs_of_same_rollup_type(left, right);
+        let current_height = components::assert_both_input_proofs_of_same_height_and_return(left, right);
+        components::assert_equal_constants(left, right);
+        components::assert_prev_rollups_follow_on_from_each_other(left, right);
+
+        // compute calldata hash:
+        let new_calldata_hash = components::compute_calldata_hash(self.previous_rollup_data);
+
+        let public_inputs = BaseOrMergeRollupPublicInputs {
+            rollup_type : MERGE_ROLLUP_TYPE,
+            rollup_subtree_height : current_height + 1,
+            end_aggregation_object : aggregation_object,
+            constants : left.constants,
+            start_note_hash_tree_snapshot : left.start_note_hash_tree_snapshot,
+            end_note_hash_tree_snapshot : right.end_note_hash_tree_snapshot,
+            start_nullifier_tree_snapshot : left.start_nullifier_tree_snapshot,
+            end_nullifier_tree_snapshot : right.end_nullifier_tree_snapshot,
+            start_contract_tree_snapshot : left.start_contract_tree_snapshot,
+            end_contract_tree_snapshot : right.end_contract_tree_snapshot,
+            start_public_data_tree_root : left.start_public_data_tree_root,
+            end_public_data_tree_root : right.end_public_data_tree_root,
+            calldata_hash : new_calldata_hash,
+        };
+
+        public_inputs
     }
 }