core: allow poll_timeout to be zero

src/config/utils.cpp

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// SPDX-FileCopyrightText: 2019-2025 Ivan Baidakou
+// SPDX-FileCopyrightText: 2019-2026 Ivan Baidakou
 
 #include "utils.h"
 
@@ -151,7 +151,7 @@ static main_t make_default_config(const bfs::path &config_path, const bfs::path
     cfg.timeout = 30000;
     cfg.device_name = device;
     cfg.hasher_threads = 3;
-    cfg.poll_timeout = 1;
+    cfg.poll_timeout = 0;
     cfg.log_configs = {
         // log_config_t {
         //     "default", spdlog::level::level_enum::trace, {"stdout"}

src/ui-fltk/config/properties.cpp

@@ -39,6 +39,32 @@ error_ptr_t positive_integer_t::validate_value() noexcept {
     return {};
 }
 
+non_negative_integer_t::non_negative_integer_t(std::string label, std::string explanation, uint64_t value,
+                                       uint64_t default_value)
+    : property_t(std::move(label), std::move(explanation), std::to_string(value), std::to_string(default_value),
+                 property_kind_t::positive_integer),
+      native_value{value} {}
+
+error_ptr_t non_negative_integer_t::validate_value() noexcept {
+    std::uint64_t r;
+    auto [ptr, ec] = std::from_chars(value.data(), value.data() + value.size(), r);
+
+    if (ec == std::errc::invalid_argument) {
+        return error_ptr_t(new std::string("not a number"));
+    } else if (ec == std::errc::result_out_of_range) {
+        return error_ptr_t(new std::string("too large number"));
+    }
+    assert(ec == std::errc());
+
+    if (r < 0) {
+        return error_ptr_t(new std::string("not a non-negative number"));
+    }
+
+    // all ok
+    native_value = static_cast<std::uint64_t>(r);
+    return {};
+}
+
 integer_t::integer_t(std::string label, std::string explanation, int64_t value, int64_t default_value)
     : property_t(std::move(label), std::move(explanation), std::to_string(value), std::to_string(default_value),
                  property_kind_t::positive_integer),

src/ui-fltk/config/properties.h

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// SPDX-FileCopyrightText: 2024-2025 Ivan Baidakou
+// SPDX-FileCopyrightText: 2024-2026 Ivan Baidakou
 
 #pragma once
 
@@ -20,6 +20,14 @@ struct positive_integer_t : property_t {
     std::uint64_t native_value;
 };
 
+struct non_negative_integer_t : property_t {
+    non_negative_integer_t(std::string label, std::string explanation, std::uint64_t value, std::uint64_t default_value);
+
+    error_ptr_t validate_value() noexcept override;
+
+    std::uint64_t native_value;
+};
+
 struct integer_t : property_t {
     integer_t(std::string label, std::string explanation, std::int64_t value, std::int64_t default_value);
 
@@ -394,8 +402,8 @@ struct hasher_threads_t final : impl::positive_integer_t {
     void reflect_to(syncspirit::config::main_t &main) override;
 };
 
-struct poll_timeout_t final : impl::positive_integer_t {
-    using parent_t = impl::positive_integer_t;
+struct poll_timeout_t final : impl::non_negative_integer_t {
+    using parent_t = impl::non_negative_integer_t;
 
     static const char *explanation_;