refactor: Avoid copies in FlatSigningProvider Merge

3 files changed, 12 insertions, 17 deletions

diff --git a/src/script/descriptor.cpp b/src/script/descriptor.cpp
index 9bcbe1ceef..8ace9c3136 100644
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -644,7 +644,7 @@ public:
             assert(outscripts.size() == 1);
             subscripts.emplace_back(std::move(outscripts[0]));
         }
-        out = Merge(std::move(out), std::move(subprovider));
+        out.Merge(std::move(subprovider));
 
         std::vector<CPubKey> pubkeys;
         pubkeys.reserve(entries.size());
diff --git a/src/script/signingprovider.cpp b/src/script/signingprovider.cpp
index c624a17628..a82a8b252a 100644
--- a/src/script/signingprovider.cpp
+++ b/src/script/signingprovider.cpp
@@ -77,20 +77,14 @@ bool FlatSigningProvider::GetTaprootBuilder(const XOnlyPubKey& output_key, Tapro
     return LookupHelper(tr_trees, output_key, builder);
 }
 
-FlatSigningProvider Merge(const FlatSigningProvider& a, const FlatSigningProvider& b)
-{
-    FlatSigningProvider ret;
-    ret.scripts = a.scripts;
-    ret.scripts.insert(b.scripts.begin(), b.scripts.end());
-    ret.pubkeys = a.pubkeys;
-    ret.pubkeys.insert(b.pubkeys.begin(), b.pubkeys.end());
-    ret.keys = a.keys;
-    ret.keys.insert(b.keys.begin(), b.keys.end());
-    ret.origins = a.origins;
-    ret.origins.insert(b.origins.begin(), b.origins.end());
-    ret.tr_trees = a.tr_trees;
-    ret.tr_trees.insert(b.tr_trees.begin(), b.tr_trees.end());
-    return ret;
+FlatSigningProvider& FlatSigningProvider::Merge(FlatSigningProvider&& b)
+{
+    scripts.merge(b.scripts);
+    pubkeys.merge(b.pubkeys);
+    keys.merge(b.keys);
+    origins.merge(b.origins);
+    tr_trees.merge(b.tr_trees);
+    return *this;
 }
 
 void FillableSigningProvider::ImplicitlyLearnRelatedKeyScripts(const CPubKey& pubkey)
diff --git a/src/script/signingprovider.h b/src/script/signingprovider.h
index 792cc903f2..2d4234ea0b 100644
--- a/src/script/signingprovider.h
+++ b/src/script/signingprovider.h
@@ -6,6 +6,7 @@
 #ifndef BITCOIN_SCRIPT_SIGNINGPROVIDER_H
 #define BITCOIN_SCRIPT_SIGNINGPROVIDER_H
 
+#include <attributes.h>
 #include <key.h>
 #include <pubkey.h>
 #include <script/keyorigin.h>
@@ -85,9 +86,9 @@ struct FlatSigningProvider final : public SigningProvider
     bool GetKey(const CKeyID& keyid, CKey& key) const override;
     bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
     bool GetTaprootBuilder(const XOnlyPubKey& output_key, TaprootBuilder& builder) const override;
-};
 
-FlatSigningProvider Merge(const FlatSigningProvider& a, const FlatSigningProvider& b);
+    FlatSigningProvider& Merge(FlatSigningProvider&& b) LIFETIMEBOUND;
+};
 
 /** Fillable signing provider that keeps keys in an address->secret map */
 class FillableSigningProvider : public SigningProvider