VirtualBox

source: vbox/trunk/src/VBox/Frontends/VBoxSDL/Helper.cpp@ 57348

Last change on this file since 57348 was 55401, checked in by vboxsync, 10 years ago

added a couple of missing Id headers

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 4.8 KB
Line 
1/* $Id: Helper.cpp 55401 2015-04-23 10:03:17Z vboxsync $ */
2/** @file
3 *
4 * VBox frontends: VBoxSDL (simple frontend based on SDL):
5 * Miscellaneous helpers
6 */
7
8/*
9 * Copyright (C) 2006-2011 Oracle Corporation
10 *
11 * This file is part of VirtualBox Open Source Edition (OSE), as
12 * available from http://www.virtualbox.org. This file is free software;
13 * you can redistribute it and/or modify it under the terms of the GNU
14 * General Public License (GPL) as published by the Free Software
15 * Foundation, in version 2 as it comes in the "COPYING" file of the
16 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
17 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
18 */
19
20#define LOG_GROUP LOG_GROUP_GUI
21#include <VBox/err.h>
22#include <VBox/log.h>
23#include <iprt/asm.h>
24#include <iprt/assert.h>
25#include <iprt/thread.h>
26#include <iprt/semaphore.h>
27#include "VBoxSDL.h"
28#include "Helper.h"
29
30
31/**
32 * Globals
33 */
34
35
36#ifdef USE_XPCOM_QUEUE_THREAD
37
38/** global flag indicating that the event queue thread should terminate */
39static bool volatile g_fTerminateXPCOMQueueThread = false;
40
41/** How many XPCOM user events are on air. Only allow one pending event to
42 * prevent an overflow of the SDL event queue. */
43static volatile int32_t g_s32XPCOMEventsPending;
44
45/** Semaphore the XPCOM event thread will sleep on while it waits for the main thread to process pending requests. */
46RTSEMEVENT g_EventSemXPCOMQueueThread = NULL;
47
48/**
49 * Thread method to wait for XPCOM events and notify the SDL thread.
50 *
51 * @returns Error code
52 * @param thread Thread ID
53 * @param pvUser User specific parameter, the file descriptor
54 * of the event queue socket
55 */
56DECLCALLBACK(int) xpcomEventThread(RTTHREAD thread, void *pvUser)
57{
58 int eqFD = (intptr_t)pvUser;
59 unsigned cErrors = 0;
60 int rc;
61
62 /* Wait with the processing till the main thread needs it. */
63 RTSemEventWait(g_EventSemXPCOMQueueThread, 2500);
64
65 do
66 {
67 fd_set fdset;
68 FD_ZERO(&fdset);
69 FD_SET(eqFD, &fdset);
70 int n = select(eqFD + 1, &fdset, NULL, NULL, NULL);
71
72 /* are there any events to process? */
73 if ((n > 0) && !g_fTerminateXPCOMQueueThread)
74 {
75 /*
76 * Wait until all XPCOM events are processed. 1s just for sanity.
77 */
78 int iWait = 1000;
79 /*
80 * Don't post an event if there is a pending XPCOM event to prevent an
81 * overflow of the SDL event queue.
82 */
83 if (g_s32XPCOMEventsPending < 1)
84 {
85 /*
86 * Post the event and wait for it to be processed. If we don't wait,
87 * we'll flood the queue on SMP systems and when the main thread is busy.
88 * In the event of a push error, we'll yield the timeslice and retry.
89 */
90 SDL_Event event = {0};
91 event.type = SDL_USEREVENT;
92 event.user.type = SDL_USER_EVENT_XPCOM_EVENTQUEUE;
93 rc = SDL_PushEvent(&event);
94 if (!rc)
95 {
96 /* success */
97 ASMAtomicIncS32(&g_s32XPCOMEventsPending);
98 cErrors = 0;
99 }
100 else
101 {
102 /* failure */
103 cErrors++;
104 if (!RTThreadYield())
105 RTThreadSleep(2);
106 iWait = (cErrors >= 10) ? RT_MIN(cErrors - 8, 50) : 0;
107 }
108 }
109 else
110 Log2(("not enqueueing SDL XPCOM event (%d)\n", g_s32XPCOMEventsPending));
111
112 if (iWait)
113 RTSemEventWait(g_EventSemXPCOMQueueThread, iWait);
114 }
115 } while (!g_fTerminateXPCOMQueueThread);
116 return VINF_SUCCESS;
117}
118
119/**
120 * Creates the XPCOM event thread
121 *
122 * @returns VBOX status code
123 * @param eqFD XPCOM event queue file descriptor
124 */
125int startXPCOMEventQueueThread(int eqFD)
126{
127 int rc = RTSemEventCreate(&g_EventSemXPCOMQueueThread);
128 if (RT_SUCCESS(rc))
129 {
130 RTTHREAD Thread;
131 rc = RTThreadCreate(&Thread, xpcomEventThread, (void *)(intptr_t)eqFD,
132 0, RTTHREADTYPE_MSG_PUMP, 0, "XPCOMEvent");
133 }
134 AssertRC(rc);
135 return rc;
136}
137
138/**
139 * Notify the XPCOM thread that we consumed an XPCOM event.
140 */
141void consumedXPCOMUserEvent(void)
142{
143 ASMAtomicDecS32(&g_s32XPCOMEventsPending);
144}
145
146/**
147 * Signal to the XPCOM even queue thread that it should select for more events.
148 */
149void signalXPCOMEventQueueThread(void)
150{
151 int rc = RTSemEventSignal(g_EventSemXPCOMQueueThread);
152 AssertRC(rc);
153}
154
155/**
156 * Indicates to the XPCOM thread that it should terminate now.
157 */
158void terminateXPCOMQueueThread(void)
159{
160 g_fTerminateXPCOMQueueThread = true;
161 if (g_EventSemXPCOMQueueThread)
162 {
163 RTSemEventSignal(g_EventSemXPCOMQueueThread);
164 RTThreadYield();
165 }
166}
167
168#endif /* USE_XPCOM_QUEUE_THREAD */
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