Add spender to prevout metadata.

Author: evoskuil

include/bitcoin/system/chain/input.hpp

@@ -164,7 +164,7 @@ class BC_API input
     /// Public mutable metadata access, copied but not compared for equality.
     /// Defaults are set so non-population issues usually imply invalidity.
     mutable chain::output::cptr prevout{};
-    mutable chain::prevout metadata{ zero, max_uint32, true, true };
+    mutable chain::prevout metadata{ zero, max_uint32, true, true, true };
 };
 
 typedef std_vector<input> inputs;

include/bitcoin/system/chain/prevout.hpp

@@ -37,10 +37,10 @@ class BC_API prevout final
     {
         /// The confirmed chain height of the prevout (zero if not found).
         /// Unused if the input owning this prevout is null (coinbase).
-        size_t height;
+        size_t height{ zero };
 
-        /// node: populated with a database identifier for the parent tx.
-        uint32_t parent{ zero };
+        /// node: populated with database identifier for prevout's parent tx.
+        uint32_t parent;
     };
 
     ///************************************************************************
@@ -51,13 +51,10 @@ class BC_API prevout final
     {
         /// The median time past at height (max_uint32 if not found/confirmed).
         /// Unused if the input owning this prevout is null (coinbase).
-        /// node: unused as validation precedes prevout block association.
         uint32_t median_time_past{ max_uint32 };
 
-        /// node: set via block.populate() as internal spends do not
-        /// require prevout block association for relative locktime checks.
-        /// So median_time_past is not required as locked is determined here.
-        bool locked;
+        /// node: populated with database identifier for spender's parent tx.
+        uint32_t spender;
     };
 
     ///************************************************************************
@@ -77,6 +74,11 @@ class BC_API prevout final
         bool inside;
     };
 
+    /// node: set via block.populate() as internal spends do not
+    /// require prevout block association for relative locktime checks.
+    /// So median_time_past is not required as locked is determined here.
+    bool locked{ true };
+
     /// The previous output is of a coinbase transaction.
     /// node: populated, does not require prevout block association.
     bool coinbase{ true };