Add TaprootSpendData data structure, equivalent to script map for P2[W]SH

This data structures stores all information necessary for spending a taproot
output (the internal key, the Merkle root, and the control blocks for every
script leaf).

It is added to signing providers, and populated by the tr() descriptor.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/pubkey.h b/src/pubkey.h
index 152a48dd18..194705c38f 100644
--- a/src/pubkey.h
+++ b/src/pubkey.h
@@ -234,6 +234,10 @@ public:
      *  fail. */
     bool IsFullyValid() const;
 
+    /** Test whether this is the 0 key (the result of default construction). This implies
+     *  !IsFullyValid(). */
+    bool IsNull() const { return m_keydata.IsNull(); }
+
     /** Construct an x-only pubkey from exactly 32 bytes. */
     explicit XOnlyPubKey(Span<const unsigned char> bytes);