Use native POSIX polling syscalls to read input

No more awkward manual polling

src/btop.cpp

@@ -175,7 +175,7 @@ void term_resize(bool force) {
 	static atomic<bool> resizing (false);
 	if (Input::polling) {
 		Global::resized = true;
-		Input::interrupt = true;
+		Input::interrupt();
 		return;
 	}
 	atomic_lock lck(resizing, true);
@@ -234,7 +234,7 @@ void term_resize(bool force) {
 		else if (not Term::refresh()) break;
 	}
 
-	Input::interrupt = true;
+	Input::interrupt();
 }
 
 //* Exit handler; stops threads, restores terminal and saves config changes
@@ -304,7 +304,7 @@ void _signal_handler(const int sig) {
 			if (Runner::active) {
 				Global::should_quit = true;
 				Runner::stopping = true;
-				Input::interrupt = true;
+				Input::interrupt();
 			}
 			else {
 				clean_quit(0);
@@ -314,7 +314,7 @@ void _signal_handler(const int sig) {
 			if (Runner::active) {
 				Global::should_sleep = true;
 				Runner::stopping = true;
-				Input::interrupt = true;
+				Input::interrupt();
 			}
 			else {
 				_sleep();
@@ -326,6 +326,9 @@ void _signal_handler(const int sig) {
 		case SIGWINCH:
 			term_resize();
 			break;
+		case SIGUSR1:
+			// Input::poll interrupt
+			break;
 	}
 }
 
@@ -451,7 +454,7 @@ namespace Runner {
 		if (pt_lck.status != 0) {
 			Global::exit_error_msg = "Exception in runner thread -> pthread_mutex_lock error id: " + to_string(pt_lck.status);
 			Global::thread_exception = true;
-			Input::interrupt = true;
+			Input::interrupt();
 			stopping = true;
 		}
 
@@ -462,7 +465,7 @@ namespace Runner {
 			if (active) {
 				Global::exit_error_msg = "Runner thread failed to get active lock!";
 				Global::thread_exception = true;
-				Input::interrupt = true;
+				Input::interrupt();
 				stopping = true;
 			}
 			if (stopping or Global::resized) {
@@ -505,7 +508,7 @@ namespace Runner {
 							coreNum_reset = false;
 							Cpu::core_mapping = Cpu::get_core_mapping();
 							Global::resized = true;
-							Input::interrupt = true;
+							Input::interrupt();
 							continue;
 						}
 
@@ -584,7 +587,7 @@ namespace Runner {
 			catch (const std::exception& e) {
 				Global::exit_error_msg = "Exception in runner thread -> " + string{e.what()};
 				Global::thread_exception = true;
-				Input::interrupt = true;
+				Input::interrupt();
 				stopping = true;
 			}
 
@@ -937,6 +940,12 @@ int main(int argc, char **argv) {
 	std::signal(SIGTSTP, _signal_handler);
 	std::signal(SIGCONT, _signal_handler);
 	std::signal(SIGWINCH, _signal_handler);
+	std::signal(SIGUSR1, _signal_handler);
+
+	sigset_t mask;
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR1);
+	pthread_sigmask(SIG_BLOCK, &mask, &Input::signal_mask);
 
 	//? Start runner thread
 	Runner::thread_sem_init();
@@ -958,9 +967,10 @@ int main(int argc, char **argv) {
 	{
 		const auto [x, y] = Term::get_min_size(Config::getS("shown_boxes"));
 		if (Term::height < y or Term::width < x) {
+			pthread_sigmask(SIG_SETMASK, &Input::signal_mask, &mask);
 			term_resize(true);
+			pthread_sigmask(SIG_SETMASK, &mask, nullptr);
 			Global::resized = false;
-			Input::interrupt = false;
 		}
 
 	}

src/btop_input.cpp

@@ -16,12 +16,12 @@ indent = tab
 tab-size = 4
 */
 
-#include <iostream>
 #include <ranges>
 #include <vector>
 #include <thread>
 #include <mutex>
 #include <signal.h>
+#include <sys/select.h>
 
 #include "btop_input.hpp"
 #include "btop_tools.hpp"
@@ -30,9 +30,6 @@ tab-size = 4
 #include "btop_menu.hpp"
 #include "btop_draw.hpp"
 
-
-using std::cin;
-
 using namespace Tools;
 using namespace std::literals; // for operator""s
 namespace rng = std::ranges;
@@ -76,83 +73,46 @@ namespace Input {
 		{"[24~",	"f12"}
 	};
 
-	std::atomic<bool> interrupt (false);
+	sigset_t signal_mask;
 	std::atomic<bool> polling (false);
 	array<int, 2> mouse_pos;
 	unordered_flat_map<string, Mouse_loc> mouse_mappings;
 
 	deque<string> history(50, "");
 	string old_filter;
+	string input;
 
-	struct InputThr {
-		InputThr() : thr(run, this) {
-		}
-
-		static void run(InputThr* that) {
-			that->runImpl();
-		}
-
-		void runImpl() {
-			char ch = 0;
-
-			// TODO(pg83): read whole buffer
-			while (cin.get(ch)) {
-				std::lock_guard<std::mutex> g(lock);
-				current.push_back(ch);
-				if (current.size() > 100) {
-					current.clear();
-				}
-			}
-		}
-
-		size_t avail() {
-			std::lock_guard<std::mutex> g(lock);
-
-			return current.size();
+	bool poll(int timeout) {
+		atomic_lock lck(polling);
+		fd_set fds;
+		FD_ZERO(&fds);
+		FD_SET(STDIN_FILENO, &fds);
+		struct timespec wait;
+		struct timespec *waitptr = nullptr;
+
+		if(timeout < 0) timeout = 0;
+		if(timeout != INT_MAX) {
+			wait.tv_sec = timeout / 1000;
+			wait.tv_nsec = (timeout % 1000) * 1000000;
+			waitptr = &wait;
 		}
 
-		std::string get() {
-			std::string res;
-
-			{
-				std::lock_guard<std::mutex> g(lock);
-
-				res.swap(current);
+		if(pselect(STDIN_FILENO + 1, &fds, nullptr, nullptr, waitptr, &signal_mask) > 0) {
+			input.clear();
+			char buf[1024];
+			int count = 0;
+			while((count = read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
+				input.append(std::string_view(buf, count));
 			}
 
-			return res;
+			return true;
 		}
 
-		static InputThr& instance() {
-			// intentional memory leak, to simplify shutdown process
-			static InputThr* input = new InputThr();
-
-			return *input;
-		}
-
-		std::string current;
-		// TODO(pg83): use std::conditional_variable instead of sleep
-		std::mutex lock;
-		std::thread thr;
-	};
-
-	bool poll(int timeout) {
-		atomic_lock lck(polling);
-		if (timeout < 1) return InputThr::instance().avail() > 0;
-		while (timeout > 0) {
-			if (interrupt) {
-				interrupt = false;
-				return false;
-			}
-			if (InputThr::instance().avail() > 0) return true;
-			sleep_ms(timeout < 10 ? timeout : 10);
-			timeout -= 10;
-		}
 		return false;
 	}
 
 	string get() {
-		string key = InputThr::instance().get();
+		string key = input;
 		if (not key.empty()) {
 			//? Remove escape code prefix if present
 			if (key.substr(0, 2) == Fx::e) {
@@ -225,12 +185,14 @@ namespace Input {
 	}
 
 	string wait() {
-		while (InputThr::instance().avail() < 1) {
-			sleep_ms(10);
-		}
+		while(not poll(INT_MAX)) {}
 		return get();
 	}
 
+	void interrupt() {
+		kill(getpid(), SIGUSR1);
+	}
+
 	void clear() {
 		// do not need it, actually
 	}

src/btop_input.hpp

@@ -30,9 +30,9 @@ using std::atomic;
 using std::deque;
 using std::string;
 
-/* The input functions relies on the following std::cin options being set:
-	cin.sync_with_stdio(false);
-	cin.tie(nullptr);
+/* The input functions rely on the following termios parameters being set:
+	Non-canonical mode (c_lflags & ~(ICANON))
+	VMIN and VTIME (c_cc) set to 0
 	These will automatically be set when running Term::init() from btop_tools.cpp
 */
 
@@ -46,7 +46,9 @@ namespace Input {
 	//? line, col, height, width
 	extern unordered_flat_map<string, Mouse_loc> mouse_mappings;
 
-	extern atomic<bool> interrupt;
+	//* Signal mask used during polling read
+	extern sigset_t signal_mask;
+
 	extern atomic<bool> polling;
 
 	//* Mouse column and line position
@@ -64,6 +66,9 @@ namespace Input {
 	//* Wait until input is available and return key
 	string wait();
 
+	//* Interrupt poll/wait
+	void interrupt();
+
 	//* Clears last entered key
 	void clear();
 

src/btop_tools.cpp

@@ -36,7 +36,6 @@ tab-size = 4
 #include "btop_tools.hpp"
 #include "btop_config.hpp"
 
-using std::cin;
 using std::cout;
 using std::floor;
 using std::flush;
@@ -77,7 +76,11 @@ namespace Term {
 			struct termios settings;
 			if (tcgetattr(STDIN_FILENO, &settings)) return false;
 			if (on) settings.c_lflag |= ICANON;
-			else settings.c_lflag &= ~(ICANON);
+			else {
+				settings.c_lflag &= ~(ICANON);
+				settings.c_cc[VMIN] = 0;
+				settings.c_cc[VTIME] = 0;
+			}
 			if (tcsetattr(STDIN_FILENO, TCSANOW, &settings)) return false;
 			if (on) setlinebuf(stdin);
 			else setbuf(stdin, nullptr);
@@ -124,11 +127,9 @@ namespace Term {
 				current_tty = (ttyname(STDIN_FILENO) != nullptr ? static_cast<string>(ttyname(STDIN_FILENO)) : "unknown");
 
 				//? Disable stream sync
-				cin.sync_with_stdio(false);
 				cout.sync_with_stdio(false);
 
 				//? Disable stream ties
-				cin.tie(nullptr);
 				cout.tie(nullptr);
 				echo(false);
 				linebuffered(false);