Method GetNewPrefixCursor

src/wallet/sqlite.cpp:616–656

}

std::unique_ptr<DatabaseCursor> SQLiteBatch::GetNewPrefixCursor(std::span<const std::byte> prefix)
{
    if (!m_database.m_db) return nullptr;

    // To get just the records we want, the SQL statement does a comparison of the binary data
    // where the data must be greater than or equal to the prefix, and less than
    // the prefix incremented by one (when interpreted as an integer)
    std::vector<std::byte> start_range(prefix.begin(), prefix.end());
    std::vector<std::byte> end_range(prefix.begin(), prefix.end());
    auto it = end_range.rbegin();
    for (; it != end_range.rend(); ++it) {
        if (*it == std::byte(std::numeric_limits<unsigned char>::max())) {
            *it = std::byte(0);
            continue;
        }
        *it = std::byte(std::to_integer<unsigned char>(*it) + 1);
        break;
    }
    if (it == end_range.rend()) {
        // If the prefix is all 0xff bytes, clear end_range as we won't need it
        end_range.clear();
    }

    auto cursor = std::make_unique<SQLiteCursor>(start_range, end_range);
    if (!cursor) return nullptr;

    const char* stmt_text = end_range.empty() ? "SELECT key, value FROM main WHERE key >= ?" :
                            "SELECT key, value FROM main WHERE key >= ? AND key < ?";
    int res = sqlite3_prepare_v2(m_database.m_db, stmt_text, -1, &cursor->m_cursor_stmt, nullptr);
    if (res != SQLITE_OK) {
        throw std::runtime_error(strprintf(
            "SQLiteDatabase: Failed to setup cursor SQL statement: %s\n", sqlite3_errstr(res)));
    }

    if (!BindBlobToStatement(cursor->m_cursor_stmt, 1, cursor->m_prefix_range_start, "prefix_start")) return nullptr;
    if (!end_range.empty()) {
        if (!BindBlobToStatement(cursor->m_cursor_stmt, 2, cursor->m_prefix_range_end, "prefix_end")) return nullptr;
    }

    return cursor;
}

bool SQLiteBatch::TxnBegin()
{