From 71cb7663930af8792c12558b8e9f02a7ce145d07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Sat, 17 Jun 2023 22:31:47 +0200
Subject: [PATCH] Fix re-entrancy issue in Downloader

---
 Common/Net/HTTPClient.cpp | 13 +++++++++----
 Common/Net/HTTPClient.h   |  3 +++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/Common/Net/HTTPClient.cpp b/Common/Net/HTTPClient.cpp
index f1831ce297..43b30f7602 100644
--- a/Common/Net/HTTPClient.cpp
+++ b/Common/Net/HTTPClient.cpp
@@ -582,7 +582,7 @@ std::shared_ptr<Download> Downloader::StartDownload(const std::string &url, cons
 	std::shared_ptr<Download> dl(new Download(RequestMethod::GET, url, "", "", outfile));
 	if (acceptMime)
 		dl->SetAccept(acceptMime);
-	downloads_.push_back(dl);
+	newDownloads_.push_back(dl);
 	dl->Start();
 	return dl;
 }
@@ -596,7 +596,7 @@ std::shared_ptr<Download> Downloader::StartDownloadWithCallback(
 	if (acceptMime)
 		dl->SetAccept(acceptMime);
 	dl->SetCallback(callback);
-	downloads_.push_back(dl);
+	newDownloads_.push_back(dl);
 	dl->Start();
 	return dl;
 }
@@ -608,15 +608,20 @@ std::shared_ptr<Download> Downloader::AsyncPostWithCallback(
 	std::string postMime = "application/x-www-form-urlencoded";
 	std::shared_ptr<Download> dl(new Download(RequestMethod::POST, url, postData, postMime, Path()));
 	dl->SetCallback(callback);
-	downloads_.push_back(dl);
+	newDownloads_.push_back(dl);
 	dl->Start();
 	return dl;
 }
 
 void Downloader::Update() {
+	for (auto iter : newDownloads_) {
+		downloads_.push_back(iter);
+	}
+	newDownloads_.clear();
+
 	restart:
 	for (size_t i = 0; i < downloads_.size(); i++) {
-		auto &dl = downloads_[i];
+		auto dl = downloads_[i];
 		if (dl->Done()) {
 			dl->RunCallback();
 			dl->Join();
diff --git a/Common/Net/HTTPClient.h b/Common/Net/HTTPClient.h
index 0aeab09472..f6b832b834 100644
--- a/Common/Net/HTTPClient.h
+++ b/Common/Net/HTTPClient.h
@@ -214,6 +214,9 @@ public:
 
 private:
 	std::vector<std::shared_ptr<Download>> downloads_;
+	// These get copied to downloads_ in Update(). It's so that callbacks can add new downloads
+	// while running.
+	std::vector<std::shared_ptr<Download>> newDownloads_;
 };
 
 }	// http