Achievements: Drain outstanding requests when switching games

Stops data being lost when loading state due to data not being
downloaded yet.

src/common/http_downloader.cpp

@@ -70,6 +70,12 @@ void HTTPDownloader::CreatePostRequest(std::string url, std::string post_data, R
   LockedAddRequest(req);
 }
 
+bool HTTPDownloader::HasAnyRequests()
+{
+  std::unique_lock<std::mutex> lock(m_pending_http_request_lock);
+  return !m_pending_http_requests.empty();
+}
+
 void HTTPDownloader::LockedPollRequests(std::unique_lock<std::mutex>& lock)
 {
   if (m_pending_http_requests.empty())

src/common/http_downloader.h

@@ -64,6 +64,8 @@ class HTTPDownloader
 
   void CreateRequest(std::string url, Request::Callback callback);
   void CreatePostRequest(std::string url, std::string post_data, Request::Callback callback);
+
+  bool HasAnyRequests();
   void PollRequests();
   void WaitForAllRequests();
 

src/frontend-common/achievements.cpp

@@ -707,6 +707,14 @@ bool Achievements::DoState(StateWrapper& sw)
 
   if (sw.IsReading())
   {
+    // if we're active, make sure we've downloaded and activated all the achievements
+    // before deserializing, otherwise that state's going to get lost.
+    if (s_http_downloader->HasAnyRequests())
+    {
+      Host::DisplayLoadingScreen("Downloading achievements data...");
+      s_http_downloader->WaitForAllRequests();
+    }
+
     u32 data_size = 0;
     sw.Do(&data_size);
     if (data_size == 0)
@@ -1321,6 +1329,7 @@ void Achievements::GameChanged(const std::string& path, CDImage* image)
     if (!temp_image)
     {
       Log_ErrorPrintf("Failed to open temporary CD image '%s'", path.c_str());
+      s_http_downloader->WaitForAllRequests();
       std::unique_lock lock(s_achievements_mutex);
       DisableChallengeMode();
       ClearGameInfo();
@@ -1341,7 +1350,11 @@ void Achievements::GameChanged(const std::string& path, CDImage* image)
     }
   }
 
-  s_http_downloader->WaitForAllRequests();
+  if (s_http_downloader->HasAnyRequests())
+  {
+    Host::DisplayLoadingScreen("Downloading achievements data...");
+    s_http_downloader->WaitForAllRequests();
+  }
 
   if (image && image->HasSubImages() && image->GetCurrentSubImage() != 0)
   {