From e4c9211edcf0c3fca25690ae5719896f5f8be086 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Mon, 8 Jan 2024 19:04:04 +0100
Subject: [PATCH] terminal: Use os::Timer and EventLoop::register_fd_listener

---
 terminal/TerminalWidget.cpp | 58 ++++++++++++++++---------------------
 terminal/TerminalWidget.h   | 10 +++----
 terminal/main.cpp           |  8 +----
 3 files changed, 30 insertions(+), 46 deletions(-)

diff --git a/terminal/TerminalWidget.cpp b/terminal/TerminalWidget.cpp
index e6a28f26..6058e95f 100644
--- a/terminal/TerminalWidget.cpp
+++ b/terminal/TerminalWidget.cpp
@@ -29,20 +29,14 @@ static constexpr auto BRIGHT_MAGENTA = ui::Color::from_u32(0xffff00ff);
 static constexpr auto BRIGHT_CYAN = ui::Color::from_u32(0xff00ffff);
 static constexpr auto BRIGHT_GRAY = ui::Color::from_u32(0xffffffff);
 
-static long get_time_in_milliseconds()
-{
-    struct timespec ts;
-    check(clock_gettime(CLOCK_REALTIME, &ts) == 0);
-
-    return ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
-}
-
 static void sigchld_handler(int)
 {
     wait(NULL);
     ui::App::the().set_should_close(true);
 }
 
+TerminalWidget* s_main = nullptr;
+
 Result<void> TerminalWidget::init(char* const* args)
 {
     m_font = ui::Font::default_font();
@@ -51,6 +45,8 @@ Result<void> TerminalWidget::init(char* const* args)
     m_terminal_canvas = ui::App::the().main_window()->canvas();
     m_terminal_canvas.fill(ui::BLACK);
 
+    m_cursor_timer = TRY(os::Timer::create_repeating(500, [this]() { this->tick_cursor(); }));
+
     signal(SIGCHLD, sigchld_handler);
 
     int master;
@@ -64,11 +60,18 @@ Result<void> TerminalWidget::init(char* const* args)
 
     m_pty = master;
 
-    fcntl(master, F_SETFL, O_NONBLOCK);
+    fcntl(m_pty, F_SETFL, O_NONBLOCK);
+
+    // FIXME: Find a better solution for this. What if the caller needs several TerminalWidgets in one app? We can't
+    // just use a singleton, can we?
+    os::EventLoop::the().register_fd_listener(m_pty, [](int, int) {
+        check(s_main);
+        s_main->process();
+    });
 
     m_child_pid = child;
 
-    m_last_cursor_tick = get_time_in_milliseconds();
+    s_main = this;
 
     return {};
 }
@@ -91,7 +94,7 @@ Result<void> TerminalWidget::draw(ui::Canvas&)
     return {};
 }
 
-Result<bool> TerminalWidget::process()
+Result<void> TerminalWidget::process()
 {
     char buffer[BUFSIZ];
     ssize_t nread = read(m_pty, buffer, BUFSIZ);
@@ -102,8 +105,6 @@ Result<bool> TerminalWidget::process()
             return err(errno);
     }
 
-    bool should_update_cursor = tick_cursor();
-
     ssize_t drawn = 0;
 
     for (ssize_t i = 0; i < nread; i++)
@@ -112,32 +113,23 @@ Result<bool> TerminalWidget::process()
         if (did_draw) drawn++;
     }
 
-    if (should_update_cursor || drawn > 0) ui::App::the().main_window()->draw();
+    if (drawn > 0) ui::App::the().main_window()->draw();
 
-    return nread == 0;
+    return {};
 }
 
-bool TerminalWidget::tick_cursor()
+void TerminalWidget::tick_cursor()
 {
-    if (!m_cursor_enabled) return false;
+    if (!m_cursor_enabled) return;
 
-    long now = get_time_in_milliseconds();
-    long diff = now - m_last_cursor_tick;
-    m_last_cursor_tick = now;
+    m_cursor_timer->restart();
+    m_cursor_activated = !m_cursor_activated;
 
-    m_current_cursor_timeout -= (int)diff;
-    if (m_current_cursor_timeout <= 0)
-    {
-        m_current_cursor_timeout = CURSOR_TIMEOUT;
-        m_cursor_activated = !m_cursor_activated;
+    if (m_cursor_activated) draw_cursor();
+    else
+        erase_current_char();
 
-        if (m_cursor_activated) draw_cursor();
-        else
-            erase_current_char();
-        return true;
-    }
-
-    return false;
+    ui::App::the().main_window()->draw();
 }
 
 void TerminalWidget::draw_glyph(wchar_t c, int x, int y)
@@ -471,7 +463,7 @@ bool TerminalWidget::put_code_point(wchar_t c)
 
     if (should_draw_cursor)
     {
-        m_current_cursor_timeout = CURSOR_TIMEOUT;
+        m_cursor_timer->restart();
         m_cursor_activated = true;
         draw_cursor();
     }
diff --git a/terminal/TerminalWidget.h b/terminal/TerminalWidget.h
index 85a397ef..375fb74e 100644
--- a/terminal/TerminalWidget.h
+++ b/terminal/TerminalWidget.h
@@ -2,6 +2,7 @@
 #include <luna/EscapeSequence.h>
 #include <luna/Utf8.h>
 #include <luna/Vector.h>
+#include <os/Timer.h>
 #include <stdio.h>
 #include <termios.h>
 #include <ui/Font.h>
@@ -16,8 +17,6 @@ class TerminalWidget : public ui::Widget
 
     Result<void> draw(ui::Canvas& canvas) override;
 
-    Result<bool> process();
-
   private:
     ui::Canvas m_terminal_canvas;
     Vector<u8> m_line_buffer;
@@ -29,9 +28,7 @@ class TerminalWidget : public ui::Widget
     SharedPtr<ui::Font> m_font;
     SharedPtr<ui::Font> m_bold_font;
 
-    static constexpr int CURSOR_TIMEOUT = 500;
-
-    int m_current_cursor_timeout = CURSOR_TIMEOUT;
+    OwnedPtr<os::Timer> m_cursor_timer;
     bool m_cursor_activated = false;
     bool m_cursor_enabled = true;
 
@@ -45,7 +42,7 @@ class TerminalWidget : public ui::Widget
     ui::Color m_foreground_color { ui::WHITE };
     ui::Color m_background_color { ui::BLACK };
 
-    bool tick_cursor();
+    void tick_cursor();
 
     Utf8StateDecoder m_decoder;
     Option<EscapeSequenceParser> m_escape_parser;
@@ -63,4 +60,5 @@ class TerminalWidget : public ui::Widget
     bool handle_escape_sequence(wchar_t c);
     Result<bool> putchar(char c);
     bool put_code_point(wchar_t c);
+    Result<void> process();
 };
diff --git a/terminal/main.cpp b/terminal/main.cpp
index fa6043d2..d957565c 100644
--- a/terminal/main.cpp
+++ b/terminal/main.cpp
@@ -20,11 +20,5 @@ Result<int> luna_main(int argc, char** argv)
 
     window->draw();
 
-    while (app.process_events())
-    {
-        bool should_sleep = TRY(terminal.process());
-        if (should_sleep) usleep(10000);
-    }
-
-    return 0;
+    return app.run();
 }