From c8a6dc6c23a5efe99b4bf937003ba3f2f7f8f200 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Lam?= <leo@innovatetechnologi.es>
Date: Sun, 15 Jan 2017 20:50:26 +0100
Subject: Use a single libusb context

libusb on Windows is limited to only a single context. Trying to open
more than one can cause device enumerations to fail randomly.

libusb is thread-safe and we don't use the manual polling support (with
`poll()`) so this should be safe.
---
 Source/Core/InputCommon/GCAdapter.cpp | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

(limited to 'Source/Core/InputCommon/GCAdapter.cpp')

diff --git a/Source/Core/InputCommon/GCAdapter.cpp b/Source/Core/InputCommon/GCAdapter.cpp
index e3dcb44739..fae7a81055 100644
--- a/Source/Core/InputCommon/GCAdapter.cpp
+++ b/Source/Core/InputCommon/GCAdapter.cpp
@@ -4,9 +4,11 @@
 
 #include <algorithm>
 #include <libusb.h>
+#include <memory>
 #include <mutex>
 
 #include "Common/Flag.h"
+#include "Common/LibusbContext.h"
 #include "Common/Logging/Log.h"
 #include "Common/Thread.h"
 #include "Core/ConfigManager.h"
@@ -50,7 +52,7 @@ static Common::Flag s_adapter_detect_thread_running;
 static std::function<void(void)> s_detect_callback;
 
 static bool s_libusb_driver_not_supported = false;
-static libusb_context* s_libusb_context = nullptr;
+static std::shared_ptr<libusb_context> s_libusb_context;
 #if defined(__FreeBSD__) && __FreeBSD__ >= 11
 static bool s_libusb_hotplug_enabled = true;
 #else
@@ -116,8 +118,8 @@ static void ScanThreadFunc()
   if (s_libusb_hotplug_enabled)
   {
     if (libusb_hotplug_register_callback(
-            s_libusb_context, (libusb_hotplug_event)(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
-                                                     LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
+            s_libusb_context.get(), (libusb_hotplug_event)(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
+                                                           LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
             LIBUSB_HOTPLUG_ENUMERATE, 0x057e, 0x0337, LIBUSB_HOTPLUG_MATCH_ANY, HotplugCallback,
             nullptr, &s_hotplug_handle) != LIBUSB_SUCCESS)
       s_libusb_hotplug_enabled = false;
@@ -131,7 +133,7 @@ static void ScanThreadFunc()
     if (s_libusb_hotplug_enabled)
     {
       static timeval tv = {0, 500000};
-      libusb_handle_events_timeout(s_libusb_context, &tv);
+      libusb_handle_events_timeout(s_libusb_context.get(), &tv);
     }
     else
     {
@@ -168,11 +170,9 @@ void Init()
 
   s_libusb_driver_not_supported = false;
 
-  int ret = libusb_init(&s_libusb_context);
-
-  if (ret)
+  s_libusb_context = LibusbContext::Get();
+  if (!s_libusb_context)
   {
-    ERROR_LOG(SERIALINTERFACE, "libusb_init failed with error: %d", ret);
     s_libusb_driver_not_supported = true;
     Shutdown();
   }
@@ -203,7 +203,7 @@ void StopScanThread()
 static void Setup()
 {
   libusb_device** list;
-  ssize_t cnt = libusb_get_device_list(s_libusb_context, &list);
+  ssize_t cnt = libusb_get_device_list(s_libusb_context.get(), &list);
 
   for (int i = 0; i < MAX_SI_CHANNELS; i++)
   {
@@ -335,16 +335,11 @@ void Shutdown()
   StopScanThread();
 #if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
   if (s_libusb_hotplug_enabled)
-    libusb_hotplug_deregister_callback(s_libusb_context, s_hotplug_handle);
+    libusb_hotplug_deregister_callback(s_libusb_context.get(), s_hotplug_handle);
 #endif
   Reset();
 
-  if (s_libusb_context)
-  {
-    libusb_exit(s_libusb_context);
-    s_libusb_context = nullptr;
-  }
-
+  s_libusb_context.reset();
   s_libusb_driver_not_supported = false;
 }
 
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