Merge pull request #43 from mempool/junderw/sigops

Feature: Count sigops on electrs side

src/chain.rs

@@ -1,15 +1,19 @@
 #[cfg(not(feature = "liquid"))] // use regular Bitcoin data structures
 pub use bitcoin::{
-    blockdata::script, consensus::deserialize, util::address, Block, BlockHash, BlockHeader,
-    OutPoint, Script, Transaction, TxIn, TxOut, Txid,
+    blockdata::{opcodes, script, witness::Witness},
+    consensus::deserialize,
+    hashes,
+    util::address,
+    Block, BlockHash, BlockHeader, OutPoint, Script, Transaction, TxIn, TxOut, Txid,
 };
 
 #[cfg(feature = "liquid")]
 pub use {
     crate::elements::asset,
     elements::{
-        address, confidential, encode::deserialize, script, Address, AssetId, Block, BlockHash,
-        BlockHeader, OutPoint, Script, Transaction, TxIn, TxOut, Txid,
+        address, confidential, encode::deserialize, hashes, opcodes, script, Address, AssetId,
+        Block, BlockHash, BlockHeader, OutPoint, Script, Transaction, TxIn, TxInWitness as Witness,
+        TxOut, Txid,
     },
 };
 

src/rest.rs

@@ -4,8 +4,8 @@ use crate::errors;
 use crate::new_index::{compute_script_hash, Query, SpendingInput, Utxo};
 use crate::util::{
     create_socket, electrum_merkle, extract_tx_prevouts, full_hash, get_innerscripts, get_tx_fee,
-    has_prevout, is_coinbase, BlockHeaderMeta, BlockId, FullHash, ScriptToAddr, ScriptToAsm,
-    TransactionStatus,
+    has_prevout, is_coinbase, transaction_sigop_count, BlockHeaderMeta, BlockId, FullHash,
+    ScriptToAddr, ScriptToAsm, TransactionStatus,
 };
 
 #[cfg(not(feature = "liquid"))]
@@ -144,6 +144,7 @@ struct TransactionValue {
     vout: Vec<TxOutValue>,
     size: u32,
     weight: u32,
+    sigops: u32,
     fee: u64,
     #[serde(skip_serializing_if = "Option::is_none")]
     status: Option<TransactionStatus>,
@@ -157,6 +158,8 @@ impl TransactionValue {
         config: &Config,
     ) -> Result<Self, errors::Error> {
         let prevouts = extract_tx_prevouts(&tx, txos)?;
+        let sigops = transaction_sigop_count(&tx, &prevouts)
+            .map_err(|_| errors::Error::from("Couldn't count sigops"))? as u32;
 
         let vins: Vec<TxInValue> = tx
             .input
@@ -183,6 +186,7 @@ impl TransactionValue {
             vout: vouts,
             size: tx.size() as u32,
             weight: tx.weight() as u32,
+            sigops,
             fee,
             status: Some(TransactionStatus::from(blockid)),
         })

src/util/block.rs

@@ -146,7 +146,7 @@ impl HeaderList {
                 + 1
         };
         (new_height..)
-            .zip(hashed_headers.into_iter())
+            .zip(hashed_headers)
             .map(|(height, hashed_header)| HeaderEntry {
                 height,
                 hash: hashed_header.blockhash,

src/util/mod.rs

@@ -11,7 +11,7 @@ pub use self::fees::get_tx_fee;
 pub use self::script::{get_innerscripts, ScriptToAddr, ScriptToAsm};
 pub use self::transaction::{
     extract_tx_prevouts, has_prevout, is_coinbase, is_spendable, serialize_outpoint,
-    TransactionStatus, TxInput,
+    sigops::transaction_sigop_count, TransactionStatus, TxInput,
 };
 
 use std::collections::HashMap;

src/util/transaction.rs

@@ -114,3 +114,245 @@ where
     s.serialize_field("vout", &outpoint.vout)?;
     s.end()
 }
+
+pub(super) mod sigops {
+    use crate::chain::{
+        hashes::hex::FromHex,
+        opcodes::{
+            all::{OP_CHECKMULTISIG, OP_CHECKMULTISIGVERIFY, OP_CHECKSIG, OP_CHECKSIGVERIFY},
+            All,
+        },
+        script::{self, Instruction},
+        Transaction, TxOut, Witness,
+    };
+    use std::collections::HashMap;
+
+    /// Get sigop count for transaction. prevout_map must have all the prevouts.
+    pub fn transaction_sigop_count(
+        tx: &Transaction,
+        prevout_map: &HashMap<u32, &TxOut>,
+    ) -> Result<usize, script::Error> {
+        let input_count = tx.input.len();
+        let mut prevouts = Vec::with_capacity(input_count);
+
+        #[cfg(not(feature = "liquid"))]
+        let is_coinbase = tx.is_coin_base();
+        #[cfg(feature = "liquid")]
+        let is_coinbase = tx.is_coinbase();
+
+        if !is_coinbase {
+            for idx in 0..input_count {
+                prevouts.push(
+                    *prevout_map
+                        .get(&(idx as u32))
+                        .ok_or(script::Error::EarlyEndOfScript)?,
+                );
+            }
+        }
+
+        // coinbase tx won't use prevouts so it can be empty.
+        get_sigop_cost(tx, &prevouts, true, true)
+    }
+
+    fn decode_pushnum(op: &All) -> Option<u8> {
+        // 81 = OP_1, 96 = OP_16
+        // 81 -> 1, so... 81 - 80 -> 1
+        let self_u8 = op.into_u8();
+        match self_u8 {
+            81..=96 => Some(self_u8 - 80),
+            _ => None,
+        }
+    }
+
+    fn count_sigops(script: &script::Script, accurate: bool) -> usize {
+        let mut n = 0;
+        let mut pushnum_cache = None;
+        for inst in script.instructions() {
+            match inst {
+                Ok(Instruction::Op(opcode)) => {
+                    match opcode {
+                        OP_CHECKSIG | OP_CHECKSIGVERIFY => {
+                            n += 1;
+                        }
+                        OP_CHECKMULTISIG | OP_CHECKMULTISIGVERIFY => {
+                            match (accurate, pushnum_cache) {
+                                (true, Some(pushnum)) => {
+                                    // Add the number of pubkeys in the multisig as sigop count
+                                    n += usize::from(pushnum);
+                                }
+                                _ => {
+                                    // MAX_PUBKEYS_PER_MULTISIG from Bitcoin Core
+                                    // https://github.com/bitcoin/bitcoin/blob/v25.0/src/script/script.h#L29-L30
+                                    n += 20;
+                                }
+                            }
+                        }
+                        _ => {
+                            pushnum_cache = decode_pushnum(&opcode);
+                        }
+                    }
+                }
+                // We ignore errors as well as pushdatas
+                _ => {
+                    pushnum_cache = None;
+                }
+            }
+        }
+
+        n
+    }
+
+    /// Get the sigop count for legacy transactions
+    fn get_legacy_sigop_count(tx: &Transaction) -> usize {
+        let mut n = 0;
+        for input in &tx.input {
+            n += count_sigops(&input.script_sig, false);
+        }
+        for output in &tx.output {
+            n += count_sigops(&output.script_pubkey, false);
+        }
+        n
+    }
+
+    fn get_p2sh_sigop_count(tx: &Transaction, previous_outputs: &[&TxOut]) -> usize {
+        #[cfg(not(feature = "liquid"))]
+        if tx.is_coin_base() {
+            return 0;
+        }
+        #[cfg(feature = "liquid")]
+        if tx.is_coinbase() {
+            return 0;
+        }
+        let mut n = 0;
+        for (input, prevout) in tx.input.iter().zip(previous_outputs.iter()) {
+            if prevout.script_pubkey.is_p2sh() {
+                if let Some(Ok(script::Instruction::PushBytes(redeem))) =
+                    input.script_sig.instructions().last()
+                {
+                    let script =
+                        script::Script::from_byte_iter(redeem.iter().map(|v| Ok(*v))).unwrap(); // I only return Ok, so it won't error
+                    n += count_sigops(&script, true);
+                }
+            }
+        }
+        n
+    }
+
+    fn get_witness_sigop_count(tx: &Transaction, previous_outputs: &[&TxOut]) -> usize {
+        let mut n = 0;
+
+        #[inline]
+        fn is_push_only(script: &script::Script) -> bool {
+            for inst in script.instructions() {
+                match inst {
+                    Err(_) => return false,
+                    Ok(Instruction::Op(_)) => return false,
+                    Ok(Instruction::PushBytes(_)) => {}
+                }
+            }
+            true
+        }
+
+        #[inline]
+        fn last_pushdata(script: &script::Script) -> Option<&[u8]> {
+            match script.instructions().last() {
+                Some(Ok(Instruction::PushBytes(bytes))) => Some(bytes),
+                _ => None,
+            }
+        }
+
+        #[inline]
+        fn count_with_prevout(
+            prevout: &TxOut,
+            script_sig: &script::Script,
+            witness: &Witness,
+        ) -> usize {
+            let mut n = 0;
+
+            let script = if prevout.script_pubkey.is_witness_program() {
+                prevout.script_pubkey.clone()
+            } else if prevout.script_pubkey.is_p2sh()
+                && is_push_only(script_sig)
+                && !script_sig.is_empty()
+            {
+                script::Script::from_byte_iter(
+                    last_pushdata(script_sig).unwrap().iter().map(|v| Ok(*v)),
+                )
+                .unwrap()
+            } else {
+                return 0;
+            };
+
+            if script.is_v0_p2wsh() {
+                let bytes = script.as_bytes();
+                n += sig_ops(witness, bytes[0], &bytes[2..]);
+            } else if script.is_v0_p2wpkh() {
+                n += 1;
+            }
+            n
+        }
+
+        for (input, prevout) in tx.input.iter().zip(previous_outputs.iter()) {
+            n += count_with_prevout(prevout, &input.script_sig, &input.witness);
+        }
+        n
+    }
+
+    /// Get the sigop cost for this transaction.
+    fn get_sigop_cost(
+        tx: &Transaction,
+        previous_outputs: &[&TxOut],
+        verify_p2sh: bool,
+        verify_witness: bool,
+    ) -> Result<usize, script::Error> {
+        let mut n_sigop_cost = get_legacy_sigop_count(tx) * 4;
+        #[cfg(not(feature = "liquid"))]
+        if tx.is_coin_base() {
+            return Ok(n_sigop_cost);
+        }
+        #[cfg(feature = "liquid")]
+        if tx.is_coinbase() {
+            return Ok(n_sigop_cost);
+        }
+        if tx.input.len() != previous_outputs.len() {
+            return Err(script::Error::EarlyEndOfScript);
+        }
+        if verify_witness && !verify_p2sh {
+            return Err(script::Error::EarlyEndOfScript);
+        }
+        if verify_p2sh {
+            n_sigop_cost += get_p2sh_sigop_count(tx, previous_outputs) * 4;
+        }
+        if verify_witness {
+            n_sigop_cost += get_witness_sigop_count(tx, previous_outputs);
+        }
+
+        Ok(n_sigop_cost)
+    }
+
+    /// Get sigops for the Witness
+    ///
+    /// witness_version is the raw opcode. OP_0 is 0, OP_1 is 81, etc.
+    fn sig_ops(witness: &Witness, witness_version: u8, witness_program: &[u8]) -> usize {
+        #[cfg(feature = "liquid")]
+        let last_witness = witness.script_witness.last();
+        #[cfg(not(feature = "liquid"))]
+        let last_witness = witness.last();
+        match (witness_version, witness_program.len()) {
+            (0, 20) => 1,
+            (0, 32) => {
+                if let Some(n) = last_witness
+                    .map(|sl| sl.iter().map(|v| Ok(*v)))
+                    .map(script::Script::from_byte_iter)
+                    // I only return Ok 2 lines up, so there is no way to error
+                    .map(|s| count_sigops(&s.unwrap(), true))
+                {
+                    n
+                } else {
+                    0
+                }
+            }
+            _ => 0,
+        }
+    }
+}