From 9bda455f7e710ba30d5fb98b0c485423a8cc499e Mon Sep 17 00:00:00 2001
From: eidheim <eidheim@gmail.com>
Date: Fri, 14 Aug 2020 10:09:29 +0200
Subject: [PATCH] Fixed deadlock in Terminal::process calls where waiting
 prints would stop a process from exiting

---
 src/terminal.cpp | 37 +++++++++++++++++++++----------------
 src/terminal.hpp |  3 ---
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/terminal.cpp b/src/terminal.cpp
index 74ee370..2da47f8 100644
--- a/src/terminal.cpp
+++ b/src/terminal.cpp
@@ -81,9 +81,9 @@ int Terminal::process(const std::string &command, const boost::filesystem::path
   std::unique_ptr<TinyProcessLib::Process> process;
   if(use_pipes)
     process = std::make_unique<TinyProcessLib::Process>(command, path.string(), [this](const char *bytes, size_t n) {
-      sync_print(std::string(bytes, n));
+      async_print(std::string(bytes, n));
     }, [this](const char *bytes, size_t n) {
-      sync_print(std::string(bytes, n), true);
+      async_print(std::string(bytes, n), true);
     });
   else
     process = std::make_unique<TinyProcessLib::Process>(command, path.string());
@@ -111,7 +111,7 @@ int Terminal::process(std::istream &stdin_stream, std::ostream &stdout_stream, c
     if(stderr_stream)
       stderr_stream->write(bytes, n);
     else
-      sync_print(std::string(bytes, n), true);
+      async_print(std::string(bytes, n), true);
   }, true);
 
   if(process.get_id() <= 0) {
@@ -140,11 +140,25 @@ void Terminal::async_process(const std::string &command, const boost::filesystem
     LockGuard lock(processes_mutex);
     stdin_buffer.clear();
     auto process = std::make_shared<TinyProcessLib::Process>(command, path.string(), [this, quiet](const char *bytes, size_t n) {
-      if(!quiet)
-        sync_print(std::string(bytes, n));
+      if(!quiet) {
+        // Print stdout message sequentially to avoid the GUI becoming unresponsive
+        std::promise<void> message_printed;
+        dispatcher.post([message = std::string(bytes, n), &message_printed]() mutable {
+          Terminal::get().print(std::move(message));
+          message_printed.set_value();
+        });
+        message_printed.get_future().get();
+      }
     }, [this, quiet](const char *bytes, size_t n) {
-      if(!quiet)
-        sync_print(std::string(bytes, n), true);
+      if(!quiet) {
+        // Print stderr message sequentially to avoid the GUI becoming unresponsive
+        std::promise<void> message_printed;
+        dispatcher.post([message = std::string(bytes, n), &message_printed]() mutable {
+          Terminal::get().print(std::move(message), true);
+          message_printed.set_value();
+        });
+        message_printed.get_future().get();
+      }
     }, true);
     auto pid = process->get_id();
     if(pid <= 0) {
@@ -328,15 +342,6 @@ void Terminal::async_print(std::string message, bool bold) {
   });
 }
 
-void Terminal::sync_print(std::string message, bool bold) {
-  std::promise<void> message_printed;
-  dispatcher.post([message = std::move(message), bold, &message_printed]() mutable {
-    Terminal::get().print(std::move(message), bold);
-    message_printed.set_value();
-  });
-  message_printed.get_future().get();
-}
-
 void Terminal::configure() {
   link_tag->property_foreground_rgba() = get_style_context()->get_color(Gtk::StateFlags::STATE_FLAG_LINK);
 
diff --git a/src/terminal.hpp b/src/terminal.hpp
index 4c4818e..f130727 100644
--- a/src/terminal.hpp
+++ b/src/terminal.hpp
@@ -49,9 +49,6 @@ private:
   Glib::RefPtr<Gdk::Cursor> default_mouse_cursor;
   size_t deleted_lines = 0;
 
-  /// Made for tiny-process-library handlers: prints in GUI thread, and waits until the message has been printed. Callable from any thread.
-  void sync_print(std::string message, bool bold = false);
-
   struct Link {
     int start_pos, end_pos;
     std::string path;