Add get_history() cursor and limit override.

include/bitcoin/database/error.hpp

@@ -35,6 +35,7 @@ enum error_t : uint8_t
     /// general
     success,
     canceled,
+    limited,
     unknown_state,
 
     /// integrity (internal fault)

include/bitcoin/database/impl/query/address/address_history.ipp

@@ -125,13 +125,23 @@ code CLASS::get_confirmed_history(const stopper& cancel, histories& out,
         });
 }
 
-// server/electrum
+// ununsed
 TEMPLATE
 code CLASS::get_history(const stopper& cancel, histories& out,
     const hash_digest& key, bool turbo) const NOEXCEPT
+{
+    address_link cursor{};
+    return get_history(cancel, cursor, out, key, max_size_t, turbo);
+}
+
+// server/electrum
+TEMPLATE
+code CLASS::get_history(const stopper& cancel, address_link& cursor,
+    histories& out, const hash_digest& key, size_t limit,
+    bool turbo) const NOEXCEPT
 {
     output_links outs{};
-    if (const auto ec = to_address_outputs(cancel, outs, key))
+    if (const auto ec = to_address_outputs(cancel, cursor, outs, key, limit))
         return ec;
 
     tx_links links{};

include/bitcoin/database/impl/query/navigate/navigate_reverse.ipp

@@ -105,7 +105,7 @@ code CLASS::to_address_outputs(const stopper& cancel, output_links& out,
 
 TEMPLATE
 code CLASS::to_address_outputs(const stopper& cancel, address_link& cursor,
-    output_links& out, const hash_digest& key) const NOEXCEPT
+    output_links& out, const hash_digest& key, size_t limit) const NOEXCEPT
 {
     out.clear();
     const auto end = cursor;
@@ -118,6 +118,9 @@ code CLASS::to_address_outputs(const stopper& cancel, address_link& cursor,
         if (it.get() == end)
             return error::success;
 
+        if (is_zero(limit--))
+            return error::limited;
+
         table::address::record address{};
         if (!store_.address.get(it, address))
             return error::integrity;

include/bitcoin/database/query.hpp

@@ -322,7 +322,8 @@ class query
     code to_address_outputs(const stopper& cancel, output_links& out,
         const hash_digest& key) const NOEXCEPT;
     code to_address_outputs(const stopper& cancel, address_link& cursor,
-        output_links& out, const hash_digest& key) const NOEXCEPT;
+        output_links& out, const hash_digest& key,
+        size_t limit=max_size_t) const NOEXCEPT;
 
     /// Archive reads.
     /// -----------------------------------------------------------------------
@@ -640,6 +641,9 @@ class query
         const hash_digest& key, bool turbo=false) const NOEXCEPT;
     code get_history(const stopper& cancel, histories& out,
         const hash_digest& key, bool turbo=false) const NOEXCEPT;
+    code get_history(const stopper& cancel, address_link& cursor,
+        histories& out, const hash_digest& key, size_t limit=max_size_t,
+        bool turbo=false) const NOEXCEPT;
 
     /// Electrum queries (unspents, deduped, electrum sort).
     code get_unconfirmed_unspent(const stopper& cancel, unspents& out,

src/error.cpp

@@ -29,6 +29,7 @@ DEFINE_ERROR_T_MESSAGE_MAP(error)
     // general
     { success, "success" },
     { canceled, "canceled" },
+    { limited, "limited" },
     { unknown_state, "unknown state" },
 
     // integrity (internal fault)

test/error.cpp

@@ -41,6 +41,15 @@ BOOST_AUTO_TEST_CASE(error_t__code__canceled__true_expected_message)
     BOOST_REQUIRE_EQUAL(ec.message(), "canceled");
 }
 
+BOOST_AUTO_TEST_CASE(error_t__code__limited__true_expected_message)
+{
+    constexpr auto value = error::limited;
+    const auto ec = code(value);
+    BOOST_REQUIRE(ec);
+    BOOST_REQUIRE(ec == value);
+    BOOST_REQUIRE_EQUAL(ec.message(), "limited");
+}
+
 BOOST_AUTO_TEST_CASE(error_t__code__unknown_state__true_expected_message)
 {
     constexpr auto value = error::unknown_state;

test/query/address/address_history.cpp

@@ -89,7 +89,6 @@ BOOST_AUTO_TEST_CASE(query_address__get_unconfirmed_history__turbo_block1a_addre
     BOOST_REQUIRE(!store.create(test::events_handler));
     BOOST_REQUIRE(test::setup_three_block_confirmed_address_store(query));
 
-    using namespace system;
     histories out{};
     const std::atomic_bool cancel{};
     BOOST_REQUIRE(!query.get_unconfirmed_history(cancel, out, test::block1a_address0, true));
@@ -116,6 +115,7 @@ BOOST_AUTO_TEST_CASE(query_address__get_unconfirmed_history__turbo_block1a_addre
     BOOST_CHECK_EQUAL(out.at(3).position, history::unconfirmed_position);
 
     // Unconfirmed system::encode_hash(hash) lexically sorted.
+    using namespace system;
     BOOST_CHECK(encode_hash(out.at(0).tx.hash()) < encode_hash(out.at(1).tx.hash()));
     BOOST_CHECK(encode_hash(out.at(2).tx.hash()) < encode_hash(out.at(3).tx.hash()));
 
@@ -178,7 +178,6 @@ BOOST_AUTO_TEST_CASE(query_address__get_history__turbo_block1a_address0__expecte
     BOOST_REQUIRE(!store.create(test::events_handler));
     BOOST_REQUIRE(test::setup_three_block_confirmed_address_store(query));
 
-    using namespace system;
     histories out{};
     const std::atomic_bool cancel{};
     BOOST_REQUIRE(!query.get_history(cancel, out, test::block1a_address0, true));
@@ -219,6 +218,7 @@ BOOST_AUTO_TEST_CASE(query_address__get_history__turbo_block1a_address0__expecte
     BOOST_REQUIRE_EQUAL(out.at(7).position, history::unconfirmed_position);     // tx7
 
     // Unconfirmed system::encode_hash(hash) lexically sorted.
+    using namespace system;
     BOOST_REQUIRE(encode_hash(out.at(6).tx.hash()) < encode_hash(out.at(7).tx.hash()));
 
     // Fee (not part of sort).
@@ -232,6 +232,42 @@ BOOST_AUTO_TEST_CASE(query_address__get_history__turbo_block1a_address0__expecte
     BOOST_REQUIRE_EQUAL(out.at(7).fee, history::missing_prevout);               // tx7
 }
 
+BOOST_AUTO_TEST_CASE(query_address__get_history__limited__limited_empty)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(test::setup_three_block_confirmed_address_store(query));
+
+    histories out{};
+    address_link cursor{};
+    const std::atomic_bool cancel{};
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 0, true), error::limited);
+    BOOST_REQUIRE(out.empty());
+
+    cursor = address_link::terminal;
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 1, true), error::limited);
+    BOOST_REQUIRE(out.empty());
+
+    cursor = address_link::terminal;
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 7, true), error::limited);
+    BOOST_REQUIRE(out.empty());
+
+    cursor = address_link::terminal;
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 8, true), error::limited);
+    BOOST_REQUIRE(out.empty());
+
+    cursor = address_link::terminal;
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 9, true), error::success);
+    BOOST_REQUIRE_EQUAL(out.size(), 8u);
+
+    cursor = address_link::terminal;
+    BOOST_REQUIRE_EQUAL(query.get_history(cancel, cursor, out, test::block1a_address0, 100, true), error::success);
+    BOOST_REQUIRE_EQUAL(out.size(), 8u);
+}
+
 // get_tx_history1
 // get_tx_history2
 

test/query/navigate/navigate_reverse.cpp

@@ -177,6 +177,31 @@ BOOST_AUTO_TEST_CASE(query_navigate__to_address_outputs3__terminal__not_reduced)
     BOOST_REQUIRE_EQUAL(out.at(5), 81u);
 }
 
+BOOST_AUTO_TEST_CASE(query_navigate__to_address_outputs3__limit__limited)
+{
+    settings settings{};
+    settings.path = TEST_DIRECTORY;
+    test::chunk_store store{ settings };
+    test::query_accessor query{ store };
+    BOOST_REQUIRE(!store.create(test::events_handler));
+    BOOST_REQUIRE(setup_three_block_unconfirmed_address_store(query));
+
+    output_links out{};
+    address_link end{};
+    const std::atomic_bool cancel{};
+    BOOST_REQUIRE_EQUAL(query.to_address_outputs(cancel, end, out, test::block1a_address0, 4), error::limited);
+
+    // The limit is applied before deduplication.
+    // There are 6 instances of the `script{ { { opcode::pick } } }` output, limited to 4.
+    BOOST_REQUIRE_EQUAL(out.size(), 4u);
+    BOOST_REQUIRE_EQUAL(out.at(0), 123u);
+    BOOST_REQUIRE_EQUAL(out.at(1), 116u);
+    BOOST_REQUIRE_EQUAL(out.at(2), 109u);
+    BOOST_REQUIRE_EQUAL(out.at(3), 102u);
+    ////BOOST_REQUIRE_EQUAL(out.at(4), 95u);
+    ////BOOST_REQUIRE_EQUAL(out.at(5), 81u);
+}
+
 BOOST_AUTO_TEST_CASE(query_navigate__to_address_outputs3__stop_mismatch__populated_not_found)
 {
     settings settings{};