fix(ResourceModel): use a single ConcurrentTask for parsing tasks

This avoids creating a bunch of threads that fills up the maximum amount
allowed by QThreadPool, and causes a deadlock between the helper threads
and the main thread (main thread tries to create threads in painting
code, but isn't able to, so it keeps waiting for a thread to free up,
but all the threads are waiting on the main thread to process some
events).

Signed-off-by: flow <flowlnlnln@gmail.com>

2 files changed, 8 insertions, 1 deletions

diff --git a/launcher/minecraft/mod/ResourceFolderModel.cpp b/launcher/minecraft/mod/ResourceFolderModel.cpp
index 0310c8f6..a52c5db3 100644
--- a/launcher/minecraft/mod/ResourceFolderModel.cpp
+++ b/launcher/minecraft/mod/ResourceFolderModel.cpp
@@ -20,6 +20,7 @@ ResourceFolderModel::ResourceFolderModel(QDir dir, QObject* parent) : QAbstractL
     m_dir.setSorting(QDir::Name | QDir::IgnoreCase | QDir::LocaleAware);
 
     connect(&m_watcher, &QFileSystemWatcher::directoryChanged, this, &ResourceFolderModel::directoryChanged);
+    connect(&m_helper_thread_task, &ConcurrentTask::finished, this, [this]{ m_helper_thread_task.clear(); });
 }
 
 ResourceFolderModel::~ResourceFolderModel()
@@ -275,7 +276,11 @@ void ResourceFolderModel::resolveResource(Resource* res)
     connect(
         task, &Task::finished, this, [=] { m_active_parse_tasks.remove(ticket); }, Qt::ConnectionType::QueuedConnection);
 
-    QThreadPool::globalInstance()->start(task);
+    m_helper_thread_task.addTask(task);
+
+    if (!m_helper_thread_task.isRunning()) {
+        QThreadPool::globalInstance()->start(&m_helper_thread_task);
+    }
 }
 
 void ResourceFolderModel::onUpdateSucceeded()
diff --git a/launcher/minecraft/mod/ResourceFolderModel.h b/launcher/minecraft/mod/ResourceFolderModel.h
index fe283b04..f1bc2dd7 100644
--- a/launcher/minecraft/mod/ResourceFolderModel.h
+++ b/launcher/minecraft/mod/ResourceFolderModel.h
@@ -10,6 +10,7 @@
 #include "Resource.h"
 
 #include "tasks/Task.h"
+#include "tasks/ConcurrentTask.h"
 
 class QSortFilterProxyModel;
 
@@ -197,6 +198,7 @@ class ResourceFolderModel : public QAbstractListModel {
     // Represents the relationship between a resource's internal ID and it's row position on the model.
     QMap<QString, int> m_resources_index;
 
+    ConcurrentTask m_helper_thread_task;
     QMap<int, Task::Ptr> m_active_parse_tasks;
     std::atomic<int> m_next_resolution_ticket = 0;
 };