From 1a2a81b1378d0e60c72518e7b1cfc1194d58ced3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Simonis?= <simonisfrederic@gmail.com>
Date: Mon, 22 Nov 2021 13:19:54 +0100
Subject: [PATCH] logic: fix extensive wait for short-lived processes (#1227)

---
 src/lib_gui/utility/utilityApp.cpp | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/lib_gui/utility/utilityApp.cpp b/src/lib_gui/utility/utilityApp.cpp
index 175e67a0..402527c1 100644
--- a/src/lib_gui/utility/utilityApp.cpp
+++ b/src/lib_gui/utility/utilityApp.cpp
@@ -44,6 +44,20 @@ std::wstring utility::searchPath(const std::wstring& bin)
 	return searchPath(bin, ok);
 }
 
+namespace {
+template<typename Rep, typename Period> 
+bool safely_wait_for(boost::process::child& process, const std::chrono::duration< Rep, Period > & rel_time)
+{
+	// This wrapper around boost::process::wait_for handles the following edge case:
+	// Calling wait_for on an already exitted process will wait for the entire timeout.
+	if (process.running()) {
+		return process.wait_for(rel_time);
+	} else {
+		return true; // The process exitted
+	}
+}
+}
+
 utility::ProcessOutput utility::executeProcess(
 	const std::wstring& command,
 	const std::vector<std::wstring>& arguments,
@@ -148,7 +162,7 @@ utility::ProcessOutput utility::executeProcess(
 		{
 			if (waitUntilNoOutput)
 			{
-				while (!process->wait_for(std::chrono::milliseconds(timeout)))
+				while (!safely_wait_for(*process, std::chrono::milliseconds(timeout)))
 				{
 					if (!outputReceived)
 					{
@@ -164,7 +178,7 @@ utility::ProcessOutput utility::executeProcess(
 			}
 			else
 			{
-				if (!process->wait_for(std::chrono::milliseconds(timeout)))
+				if (!safely_wait_for(*process, std::chrono::milliseconds(timeout)))
 				{
 					LOG_WARNING(
 						"Canceling process because it timed out after " +