spec v0.6.1: attestation processing/verif

eth2/state_processing/src/common/convert_to_indexed.rs

@@ -0,0 +1,29 @@
+use super::get_attesting_indices;
+use itertools::{Either, Itertools};
+use types::*;
+
+/// Convert `attestation` to (almost) indexed-verifiable form.
+///
+/// Spec v0.6.1
+pub fn convert_to_indexed<T: EthSpec>(
+    state: &BeaconState<T>,
+    attestation: &Attestation,
+) -> Result<IndexedAttestation, BeaconStateError> {
+    let attesting_indices =
+        get_attesting_indices(state, &attestation.data, &attestation.aggregation_bitfield)?;
+
+    let (custody_bit_0_indices, custody_bit_1_indices) =
+        attesting_indices.into_iter().enumerate().partition_map(
+            |(committee_idx, validator_idx)| match attestation.custody_bitfield.get(committee_idx) {
+                Ok(true) => Either::Right(validator_idx as u64),
+                _ => Either::Left(validator_idx as u64),
+            },
+        );
+
+    Ok(IndexedAttestation {
+        custody_bit_0_indices,
+        custody_bit_1_indices,
+        data: attestation.data.clone(),
+        signature: attestation.signature.clone(),
+    })
+}

eth2/state_processing/src/common/mod.rs

@@ -1,8 +1,10 @@
+mod convert_to_indexed;
 mod exit;
 mod get_attesting_indices;
 mod slash_validator;
 mod verify_bitfield;
 
+pub use convert_to_indexed::convert_to_indexed;
 pub use exit::initiate_validator_exit;
 pub use get_attesting_indices::{get_attesting_indices, get_attesting_indices_unsorted};
 pub use slash_validator::slash_validator;