core: faster find_blockchain_supplement

Since this queries block heights for blocks that may or may not
exist, queries for non existing blocks would throw an exception,
and that would slow down the loop a lot. 7 seconds to go through
a 30 hash list.

Fix this by adding an optional return block height to block_exists
and using this instead. Actual errors will still throw an
exception.

This also cuts down on log exception spam.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/unit_tests/hardfork.cpp b/tests/unit_tests/hardfork.cpp
index a279b6c68..b3bd47687 100644
--- a/tests/unit_tests/hardfork.cpp
+++ b/tests/unit_tests/hardfork.cpp
@@ -58,7 +58,7 @@ public:
   virtual void block_txn_stop() {}
   virtual void block_txn_abort() {}
   virtual void drop_hard_fork_info() {}
-  virtual bool block_exists(const crypto::hash& h) const { return false; }
+  virtual bool block_exists(const crypto::hash& h, uint64_t *height) const { return false; }
   virtual block get_block(const crypto::hash& h) const { return block(); }
   virtual uint64_t get_block_height(const crypto::hash& h) const { return 0; }
   virtual block_header get_block_header(const crypto::hash& h) const { return block_header(); }