Add move argument override to hasmap.it().

include/bitcoin/database/impl/primitives/hashmap.ipp

@@ -149,6 +149,13 @@ inline Link CLASS::first(const Key& key) const NOEXCEPT
     return first(get_memory(), head_.top(key), key);
 }
 
+TEMPLATE
+inline typename CLASS::iterator CLASS::it(Key&& key) const NOEXCEPT
+{
+    const auto top = head_.top(key);
+    return { get_memory(), top, std::forward<Key>(key) };
+}
+
 TEMPLATE
 inline typename CLASS::iterator CLASS::it(const Key& key) const NOEXCEPT
 {

include/bitcoin/database/impl/primitives/iterator.ipp

@@ -29,15 +29,15 @@ namespace libbitcoin {
 namespace database {
 
 TEMPLATE
-CLASS::iterator(const memory_ptr& data, const Link& start, Key&& key) NOEXCEPT
-  : memory_(data), key_(std::forward<Key>(key)), link_(to_match(start))
+CLASS::iterator(memory_ptr&& data, const Link& start, Key&& key) NOEXCEPT
+  : memory_(std::move(data)), key_(std::forward<Key>(key)),
+    link_(to_match(start))
 {
 }
 
 TEMPLATE
-CLASS::iterator(const memory_ptr& data, const Link& start,
-    const Key& key) NOEXCEPT
-  : memory_(data), key_(key), link_(to_match(start))
+CLASS::iterator(memory_ptr&& data, const Link& start, const Key& key) NOEXCEPT
+  : memory_(std::move(data)), key_(key), link_(to_match(start))
 {
 }
 

include/bitcoin/database/impl/query/confirm.ipp

@@ -247,30 +247,10 @@ TEMPLATE
 error::error_t CLASS::spent_prevout(const hash_digest& point_hash,
     index point_index, const tx_link& self) const NOEXCEPT
 {
-    ////if (table::spend::null_point(point_hash))
-    ////    return error::integrity6;
-    ////
-    ////if (table::spend::null_point(point_index))
-    ////    return error::integrity7;
-
     // TODO: pass comparitor to iterator construct to preclude composition copy.
     auto it = store_.spend.it(table::spend::compose(point_hash, point_index));
     if (!it)
-    {
-        if (self.is_terminal())
-            return error::success;
-
-        if (!it.get())
-            return error::integrity8;
-
-        if (it.self().is_terminal())
-            return error::integrity9;
-
-        if (!store_.spend.exists(it.key()))
-            return error::integrity10;
-
         return error::integrity3;
-    }
 
     // Get all txs that spend the point (non-terminal self must be a spender).
     tx_links spenders{};

include/bitcoin/database/primitives/hashmap.hpp

@@ -99,6 +99,7 @@ class hashmap
     inline Link first(const Key& key) const NOEXCEPT;
 
     /// Iterator holds shared lock on storage remap.
+    inline iterator it(Key&& key) const NOEXCEPT;
     inline iterator it(const Key& key) const NOEXCEPT;
 
     /// Allocate count or slab size at returned link (follow with set|put).

include/bitcoin/database/primitives/iterator.hpp

@@ -34,6 +34,9 @@ namespace database {
 /// THE hashmap.get(const iterator& it, ...) METHOD EXISTS TO PREVENT A CALL TO
 /// manager.get(), WHICH DESPITE BEING A READ WOULD CAUSE A DEADLOCK. THIS IS
 /// BECAUSE IT CANNOT COMPLETE ITS READ WHILE REMAP IS WAITING ON ACCESS.
+/// A SIMILAR RISK ARISES FROM HOLDING iterator WHILE READING/WRITING ANY OTHER
+/// TABLE AS A CYCLE CAUSING THE ABOVE WILL OCCUR. USE THE ITERATOR TO COLLECT
+/// A SET FROM ITS TABLE AND THEN CALL iterator.release() TO FREE THE POINTER.
 
 /// This class is not thread safe.
 /// Size non-max implies record manager (ordinal record links).
@@ -44,8 +47,8 @@ class iterator
     DEFAULT_COPY_MOVE_DESTRUCT(iterator);
 
     /// This advances to first match (or terminal).
-    iterator(const memory_ptr& data, const Link& start, Key&& key) NOEXCEPT;
-    iterator(const memory_ptr& data, const Link& start, const Key& key) NOEXCEPT;
+    iterator(memory_ptr&& data, const Link& start, Key&& key) NOEXCEPT;
+    iterator(memory_ptr&& data, const Link& start, const Key& key) NOEXCEPT;
 
     /// Advance to and return next iterator.
     inline bool advance() NOEXCEPT;

test/primitives/hashmap.cpp

@@ -627,7 +627,7 @@ BOOST_AUTO_TEST_CASE(hashmap__slab_first__exists__true)
     BOOST_REQUIRE(!instance.get_fault());
 }
 
-BOOST_AUTO_TEST_CASE(hashmap__record_it__exists__non_terminal)
+BOOST_AUTO_TEST_CASE(hashmap__record_it__exists_copy__non_terminal)
 {
     test::chunk_storage head_store{};
     test::chunk_storage body_store{};
@@ -644,6 +644,23 @@ BOOST_AUTO_TEST_CASE(hashmap__record_it__exists__non_terminal)
     BOOST_REQUIRE(!instance.get_fault());
 }
 
+BOOST_AUTO_TEST_CASE(hashmap__record_it__exists_move__non_terminal)
+{
+    test::chunk_storage head_store{};
+    test::chunk_storage body_store{};
+    hashmap<link5, key1, big_record::size, true> instance{ head_store, body_store, buckets };
+    BOOST_REQUIRE(instance.create());
+
+    constexpr key1 key{ 0x41 };
+    BOOST_REQUIRE(instance.it(key1{ 0x41 }).self().is_terminal());
+    BOOST_REQUIRE(!instance.put_link(key, big_record{ 0xa1b2c3d4_u32 }).is_terminal());
+    BOOST_REQUIRE(!instance.it(key1{ 0x41 }).self().is_terminal());
+
+    big_record record{};
+    BOOST_REQUIRE(instance.get(instance.it(key1{ 0x41 }).self(), record));
+    BOOST_REQUIRE(!instance.get_fault());
+}
+
 BOOST_AUTO_TEST_CASE(hashmap__record_it__multiple__iterated)
 {
     test::chunk_storage head_store{};