GUI/TTY: fix UI deadlock when TTY is being spammed

rpcs3/rpcs3qt/log_frame.cpp

@@ -509,22 +509,25 @@ void log_frame::UpdateUI()
 	const std::chrono::time_point tty_timeout = start + 4ms;
 	const std::chrono::time_point log_timeout = start + 7ms;
 
-	// Check TTY logs
-	while (const u64 size = std::max<s64>(0, g_tty_size.load() - (m_tty_file ? m_tty_file.pos() : 0)))
+	// Check TTY logs (and try to complete pending work)
+	for (u64 size{}; !m_tty_buf_stream.view().empty() || (!size && (size = std::max<s64>(0, g_tty_size.load() - (m_tty_file ? m_tty_file.pos() : 0))));)
 	{
-		std::string buf;
-		buf.resize(size);
-		buf.resize(m_tty_file.read(&buf.front(), buf.size()));
+		if (!m_tty_buf_stream.view().empty() || m_tty_act->isChecked())
+		{
+			std::string buf;
+			buf.resize(size);
+			buf.resize(m_tty_file.read(&buf.front(), buf.size()));
 
-		// Ignore control characters and greater/equal to 0x80
-		buf.erase(std::remove_if(buf.begin(), buf.end(), [](s8 c) { return c <= 0x8 || c == 0x7F || (c >= 0xE && c <= 0x1F); }), buf.end());
+			// Ignore control characters and greater/equal to 0x80
+			buf.erase(std::remove_if(buf.begin(), buf.end(), [](s8 c) { return c <= 0x8 || c == 0x7F || (c >= 0xE && c <= 0x1F); }), buf.end());
+
+			if (!m_tty_buf_stream.view().empty())
+			{
+				m_tty_buf_stream.str(buf);
+			}
 
-		if (!buf.empty() && m_tty_act->isChecked())
-		{
-			std::stringstream buf_stream;
-			buf_stream.str(buf);
 			std::string buf_line;
-			while (std::getline(buf_stream, buf_line))
+			while (std::getline(m_tty_buf_stream, buf_line))
 			{
 				// save old scroll bar state
 				QScrollBar* sb = m_tty->verticalScrollBar();
@@ -582,11 +585,22 @@ void log_frame::UpdateUI()
 
 				// set scrollbar to max means auto-scroll
 				sb->setValue(is_max ? sb->maximum() : sb_pos);
+
+				// Limit processing time
+				if (steady_clock::now() >= tty_timeout) break;
 			}
-		}
 
-		// Limit processing time
-		if (steady_clock::now() >= tty_timeout || buf.empty()) break;
+			if (size)
+			{
+				break;
+			}
+		}
+		else
+		{
+			// Advance in position without printing
+			m_tty_file.seek(size, fs::seek_cur);
+			break;
+		}
 	}
 
 	const auto font_start_tag = [](const QColor& color) -> const QString { return QStringLiteral("<font color = \"") % color.name() % QStringLiteral("\">"); };

rpcs3/rpcs3qt/log_frame.h

@@ -7,6 +7,7 @@
 #include "find_dialog.h"
 
 #include <memory>
+#include <sstream>
 
 #include <QTabWidget>
 #include <QPlainTextEdit>
@@ -54,6 +55,7 @@ private Q_SLOTS:
 	std::string m_old_log_text;
 	QString m_old_tty_text;
 	QString m_log_text;
+	std::stringstream m_tty_buf_stream;
 	usz m_log_counter{};
 	usz m_tty_counter{};
 	bool m_stack_log{};