Style.

Author: evoskuil

src/chain/transaction_sighash_v0.cpp

@@ -72,10 +72,6 @@ bool transaction::version0_sighash(hash_digest& out,
     stream::out::fast stream{ out };
     hash::sha256x2::fast sink{ stream };
 
-    ///////////////////////////////////////////////////////////////////////////
-    // TODO: update cache calls.
-    ///////////////////////////////////////////////////////////////////////////
-
     sink.write_4_bytes_little_endian(version_);
     sink.write_bytes(!anyone ? double_hash_points() : null_hash);
     sink.write_bytes(!anyone && all ? double_hash_sequences() : null_hash);

src/chain/transaction_sighash_v1.cpp

@@ -57,14 +57,15 @@ uint32_t transaction::subscript_v1(const script& script) NOEXCEPT
 // ext_flags and annex flag are combined into one byte, who knows why.
 uint8_t transaction::spend_type_v1(bool annex, bool tapscript) const NOEXCEPT
 {
-    const auto ext_flags = to_value(tapscript ?
-        extension::tapscript : extension::taproot);
+    const auto ext_flag = to_value(tapscript ? extension::tapscript :
+        extension::taproot);
 
-    return set_right(shift_left(ext_flags), zero, annex);
+    return set_right(shift_left(ext_flag), zero, annex);
 }
 
 // NOT THREAD SAFE
 // Concurrent input validation for a tx unsafe due to on-demand hash caching.
+// TODO: may be more optimal to not cache single output hash as use is rare.
 bool transaction::version1_sighash(hash_digest& out,
     const input_iterator& input, const script& script, uint64_t value,
     const hash_cptr& tapleaf, uint8_t sighash_flags) const NOEXCEPT
@@ -80,6 +81,18 @@ bool transaction::version1_sighash(hash_digest& out,
     const auto single = (flag == coverage::hash_single);
     const auto all = (flag == coverage::hash_all);
 
+    // ************************************************************************
+    // CONSENSUS: Guards public interface only, node always populates prevout.
+    // ************************************************************************
+    if (anyone && is_null(in.prevout))
+        return false;
+
+    // ************************************************************************
+    // CONSENSUS: Taproot finally eliminates one_hash (null_hash in v0) return.
+    // ************************************************************************
+    if (single && output_overflow(input_index(input)))
+        return false;
+
     // Create tagged hash writer.
     stream::out::fast stream{ out };
     hash::sha256t::fast<"TapSighash"> sink{ stream };
@@ -106,10 +119,6 @@ bool transaction::version1_sighash(hash_digest& out,
 
     if (anyone)
     {
-        // This implies a parameterization error, and will fail the script.
-        if (is_null(in.prevout))
-            return false;
-
         in.point().to_data(sink);
         sink.write_8_bytes_little_endian(value);
         in.prevout->script().to_data(sink, true);
@@ -127,13 +136,8 @@ bool transaction::version1_sighash(hash_digest& out,
 
     if (single)
     {
-        const auto index = input_index(input);
-        if (output_overflow(index))
-            return false;
-
         // Hash is cached for use with each single sigop in the same script.
-        // TODO: it may be more optimal to not cache, since benefit is rare.
-        sink.write_bytes(outputs_->at(index)->get_hash());
+        sink.write_bytes(outputs_->at(input_index(input))->get_hash());
     }
 
     // Additional for tapscript [bip342].
@@ -145,11 +149,6 @@ bool transaction::version1_sighash(hash_digest& out,
         sink.write_4_bytes_little_endian(subscript_v1(script));
     }
 
-    // TODO: write position pertains to the hash instance (written at flush).
-    // Total length at most 206 bytes (!anyone, no epoch/tapscript) [bip341].
-    ////BC_ASSERT(!anyone && sink.get_write_position() == (add1(206u) + 37));
-    ////BC_ASSERT( anyone && sink.get_write_position() == (add1(157u) + 37));
-
     sink.flush();
     return true;
 }