Merge #19935: Move SaltedHashers to separate file and add some new ones

281fd1a4a032cded7f9ea9857e3e99fc793c714b Replace KeyIDHasher with SaltedSipHasher (Andrew Chow)
210b693db66e7c5b618014b5a287aee15af00045 Add generic SaltedSipHasher (Andrew Chow)
95e61c1cf2a91d041c8025306ba36f0ea2806894 Move Hashers to util/hasher.{cpp/h} (Andrew Chow)

Pull request description:

  There are existing `SaltedOutPointHasher` and `SaltedTxidHasher` classes used for `std::unordered_map` and `std::unordered_set` that could be useful in other places in the codebase. So we these to their own `saltedhash.{cpp/h}` file. An existing `KeyIDHasher` is moved there too. Additionally, `ScriptIDHasher`, `SaltedPubkeyHasher`, and `SaltedScriptHasher` are added so that they can be used in future work.

  `KeyIDHasher` and `ScriptIDHasher` are not salted so that equality comparisons of maps and sets keyed by `CKeyID` and `CScriptID` will actually work.

  Split from #19602 (and a few other PRs/branches I have).

ACKs for top commit:
  laanwj:
    Code review ACK 281fd1a4a032cded7f9ea9857e3e99fc793c714b
  jonatack:
    ACK 281fd1a4a032cded7f9ea9857e3e99fc793c714b, code review, debug build and ran bitcoind after rebasing to master @ dff0f6f753ea
  fjahr:
    utACK 281fd1a4a032cded7f9ea9857e3e99fc793c714b

Tree-SHA512: bb03b231ccf3c9ecefc997b8da9c3770af4819f9be5b0a72997a103864e84046a2ac39b8eadf0dc9247bdccd53f86f433642e3a098882e6748341a9e7736271b

1 files changed, 1 insertions, 15 deletions

diff --git a/src/txmempool.h b/src/txmempool.h
index 15797cbc00..9a1aa9bc2b 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -15,13 +15,13 @@
 
 #include <amount.h>
 #include <coins.h>
-#include <crypto/siphash.h>
 #include <indirectmap.h>
 #include <optional.h>
 #include <policy/feerate.h>
 #include <primitives/transaction.h>
 #include <sync.h>
 #include <random.h>
+#include <util/hasher.h>
 
 #include <boost/multi_index_container.hpp>
 #include <boost/multi_index/hashed_index.hpp>
@@ -398,20 +398,6 @@ enum class MemPoolRemovalReason {
     REPLACED,    //!< Removed for replacement
 };
 
-class SaltedTxidHasher
-{
-private:
-    /** Salt */
-    const uint64_t k0, k1;
-
-public:
-    SaltedTxidHasher();
-
-    size_t operator()(const uint256& txid) const {
-        return SipHashUint256(k0, k1, txid);
-    }
-};
-
 /**
  * CTxMemPool stores valid-according-to-the-current-best-chain transactions
  * that may be included in the next block.