Deduplicate SignatureCacheHasher

This moves the SignatureCacheHasher to the sigcache header, out of the anonymous
namespace, so that the tests can import it.

Author: JeremyRubin

src/script/sigcache.cpp

@@ -15,28 +15,6 @@
 #include <boost/thread.hpp>
 
 namespace {
-
-/**
- * We're hashing a nonce into the entries themselves, so we don't need extra
- * blinding in the set hash computation.
- *
- * This may exhibit platform endian dependent behavior but because these are
- * nonced hashes (random) and this state is only ever used locally it is safe.
- * All that matters is local consistency.
- */
-class SignatureCacheHasher
-{
-public:
-    template <uint8_t hash_select>
-    uint32_t operator()(const uint256& key) const
-    {
-        static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
-        uint32_t u;
-        std::memcpy(&u, key.begin()+4*hash_select, 4);
-        return u;
-    }
-};
-
 /**
  * Valid signature cache, to avoid doing expensive ECDSA signature checking
  * twice for every transaction (once when accepted into memory pool, and

src/script/sigcache.h

@@ -19,6 +19,27 @@ static const int64_t MAX_MAX_SIG_CACHE_SIZE = 16384;
 
 class CPubKey;
 
+/**
+ * We're hashing a nonce into the entries themselves, so we don't need extra
+ * blinding in the set hash computation.
+ *
+ * This may exhibit platform endian dependent behavior but because these are
+ * nonced hashes (random) and this state is only ever used locally it is safe.
+ * All that matters is local consistency.
+ */
+class SignatureCacheHasher
+{
+public:
+    template <uint8_t hash_select>
+    uint32_t operator()(const uint256& key) const
+    {
+        static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
+        uint32_t u;
+        std::memcpy(&u, key.begin()+4*hash_select, 4);
+        return u;
+    }
+};
+
 class CachingTransactionSignatureChecker : public TransactionSignatureChecker
 {
 private:

src/test/cuckoocache_tests.cpp

@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 #include <boost/test/unit_test.hpp>
 #include "cuckoocache.h"
+#include "script/sigcache.h"
 #include "test/test_bitcoin.h"
 #include "random.h"
 #include <thread>
@@ -36,20 +37,6 @@ void insecure_GetRandHash(uint256& t)
         *(ptr++) = insecure_rand.rand32();
 }
 
-/** Definition copied from /src/script/sigcache.cpp
- */
-class uint256Hasher
-{
-public:
-    template <uint8_t hash_select>
-    uint32_t operator()(const uint256& key) const
-    {
-        static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
-        uint32_t u;
-        std::memcpy(&u, key.begin() + 4 * hash_select, 4);
-        return u;
-    }
-};
 
 
 /* Test that no values not inserted into the cache are read out of it.
@@ -59,7 +46,7 @@ class uint256Hasher
 BOOST_AUTO_TEST_CASE(test_cuckoocache_no_fakes)
 {
     insecure_rand = FastRandomContext(true);
-    CuckooCache::cache<uint256, uint256Hasher> cc{};
+    CuckooCache::cache<uint256, SignatureCacheHasher> cc{};
     size_t megabytes = 4;
     cc.setup_bytes(megabytes << 20);
     uint256 v;
@@ -138,7 +125,7 @@ BOOST_AUTO_TEST_CASE(cuckoocache_hit_rate_ok)
     double HitRateThresh = 0.98;
     size_t megabytes = 4;
     for (double load = 0.1; load < 2; load *= 2) {
-        double hits = test_cache<CuckooCache::cache<uint256, uint256Hasher>>(megabytes, load);
+        double hits = test_cache<CuckooCache::cache<uint256, SignatureCacheHasher>>(megabytes, load);
         BOOST_CHECK(normalize_hit_rate(hits, load) > HitRateThresh);
     }
 }
@@ -206,7 +193,7 @@ void test_cache_erase(size_t megabytes)
 BOOST_AUTO_TEST_CASE(cuckoocache_erase_ok)
 {
     size_t megabytes = 4;
-    test_cache_erase<CuckooCache::cache<uint256, uint256Hasher>>(megabytes);
+    test_cache_erase<CuckooCache::cache<uint256, SignatureCacheHasher>>(megabytes);
 }
 
 template <typename Cache>
@@ -293,7 +280,7 @@ void test_cache_erase_parallel(size_t megabytes)
 BOOST_AUTO_TEST_CASE(cuckoocache_erase_parallel_ok)
 {
     size_t megabytes = 4;
-    test_cache_erase_parallel<CuckooCache::cache<uint256, uint256Hasher>>(megabytes);
+    test_cache_erase_parallel<CuckooCache::cache<uint256, SignatureCacheHasher>>(megabytes);
 }
 
 
@@ -389,7 +376,7 @@ void test_cache_generations()
 }
 BOOST_AUTO_TEST_CASE(cuckoocache_generations)
 {
-    test_cache_generations<CuckooCache::cache<uint256, uint256Hasher>>();
+    test_cache_generations<CuckooCache::cache<uint256, SignatureCacheHasher>>();
 }
 
 BOOST_AUTO_TEST_SUITE_END();