From 18347d8325cadd11ce732c7cdcb9b55c727e4938 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sun, 12 Feb 2017 20:11:23 +0100
Subject: [PATCH] Make ImageInput shutdown immediate, instead of waiting for
 the sleep to time out.

---
 image_input.cpp | 17 ++++++++++++-----
 image_input.h   |  6 +++++-
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/image_input.cpp b/image_input.cpp
index a224af9..5c9d796 100644
--- a/image_input.cpp
+++ b/image_input.cpp
@@ -246,7 +246,10 @@ void ImageInput::update_thread_func(const std::string &filename, const std::stri
 	timespec last_modified = first_modified;
 	struct stat buf;
 	for ( ;; ) {
-		sleep(1);
+		{
+			unique_lock<mutex> lock(threads_should_quit_mu);
+			threads_should_quit_modified.wait_for(lock, chrono::seconds(1), []() { return threads_should_quit; });
+		}
 
 		if (threads_should_quit) {
 			return;
@@ -275,9 +278,11 @@ void ImageInput::update_thread_func(const std::string &filename, const std::stri
 
 void ImageInput::shutdown_updaters()
 {
-	// TODO: Kick these out of the sleep before one second?
-	threads_should_quit = true;
-
+	{
+		unique_lock<mutex> lock(threads_should_quit_mu);
+		threads_should_quit = true;
+		threads_should_quit_modified.notify_all();
+	}
 	for (auto &it : update_threads) {
 		it.second.join();
 	}
@@ -286,4 +291,6 @@ void ImageInput::shutdown_updaters()
 mutex ImageInput::all_images_lock;
 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 map<string, thread> ImageInput::update_threads;
-volatile bool ImageInput::threads_should_quit = false;
+mutex ImageInput::threads_should_quit_mu;
+bool ImageInput::threads_should_quit = false;
+condition_variable ImageInput::threads_should_quit_modified;
diff --git a/image_input.h b/image_input.h
index df25a9f..02be497 100644
--- a/image_input.h
+++ b/image_input.h
@@ -5,6 +5,7 @@
 #include <movit/flat_input.h>
 #include <stdbool.h>
 #include <time.h>
+#include <condition_variable>
 #include <cstdint>
 #include <map>
 #include <memory>
@@ -39,7 +40,10 @@ private:
 	static std::mutex all_images_lock;
 	static std::map<std::string, std::shared_ptr<const Image>> all_images;
 	static std::map<std::string, std::thread> update_threads;
-	static volatile bool threads_should_quit;
+
+	static std::mutex threads_should_quit_mu;
+	static bool threads_should_quit;  // Under threads_should_quit_mu.
+	static std::condition_variable threads_should_quit_modified;  // Signals when threads_should_quit is set.
 };
 
 #endif // !defined(_IMAGE_INPUT_H)
-- 
2.39.2