1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/src/X11Util.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,142 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * vim: sw=2 ts=8 et :
1.6 + */
1.7 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.8 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.9 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.10 +
1.11 +#ifndef mozilla_X11Util_h
1.12 +#define mozilla_X11Util_h
1.13 +
1.14 +// Utilities common to all X clients, regardless of UI toolkit.
1.15 +
1.16 +#if defined(MOZ_WIDGET_GTK)
1.17 +# include <gdk/gdk.h>
1.18 +# include <gdk/gdkx.h>
1.19 +#elif defined(MOZ_WIDGET_QT)
1.20 +#include "gfxQtPlatform.h"
1.21 +#undef CursorShape
1.22 +# include <X11/Xlib.h>
1.23 +#else
1.24 +# error Unknown toolkit
1.25 +#endif
1.26 +
1.27 +#include <string.h> // for memset
1.28 +#include "gfxCore.h" // for NS_GFX
1.29 +#include "mozilla/Scoped.h" // for SCOPED_TEMPLATE
1.30 +
1.31 +namespace mozilla {
1.32 +
1.33 +/**
1.34 + * Return the default X Display created and used by the UI toolkit.
1.35 + */
1.36 +inline Display*
1.37 +DefaultXDisplay()
1.38 +{
1.39 +#if defined(MOZ_WIDGET_GTK)
1.40 + return GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
1.41 +#elif defined(MOZ_WIDGET_QT)
1.42 + return gfxQtPlatform::GetXDisplay();
1.43 +#endif
1.44 +}
1.45 +
1.46 +/**
1.47 + * Sets *aVisual to point to aDisplay's Visual struct corresponding to
1.48 + * aVisualID, and *aDepth to its depth. When aVisualID is None, these are set
1.49 + * to nullptr and 0 respectively. Both out-parameter pointers are assumed
1.50 + * non-nullptr.
1.51 + */
1.52 +void
1.53 +FindVisualAndDepth(Display* aDisplay, VisualID aVisualID,
1.54 + Visual** aVisual, int* aDepth);
1.55 +
1.56 +
1.57 +/**
1.58 + * Ensure that all X requests have been processed.
1.59 + *
1.60 + * This is similar to XSync, but doesn't need a round trip if the previous
1.61 + * request was synchronous or if events have been received since the last
1.62 + * request. Subsequent FinishX calls will be noops if there have been no
1.63 + * intermediate requests.
1.64 + */
1.65 +
1.66 +void
1.67 +FinishX(Display* aDisplay);
1.68 +
1.69 +/**
1.70 + * Invoke XFree() on a pointer to memory allocated by Xlib (if the
1.71 + * pointer is nonnull) when this class goes out of scope.
1.72 + */
1.73 +template <typename T>
1.74 +struct ScopedXFreePtrTraits
1.75 +{
1.76 + typedef T *type;
1.77 + static T *empty() { return nullptr; }
1.78 + static void release(T *ptr) { if (ptr != nullptr) XFree(ptr); }
1.79 +};
1.80 +SCOPED_TEMPLATE(ScopedXFree, ScopedXFreePtrTraits)
1.81 +
1.82 +/**
1.83 + * On construction, set a graceful X error handler that doesn't crash the application and records X errors.
1.84 + * On destruction, restore the X error handler to what it was before construction.
1.85 + *
1.86 + * The SyncAndGetError() method allows to know whether a X error occurred, optionally allows to get the full XErrorEvent,
1.87 + * and resets the recorded X error state so that a single X error will be reported only once.
1.88 + *
1.89 + * Nesting is correctly handled: multiple nested ScopedXErrorHandler's don't interfere with each other's state. However,
1.90 + * if SyncAndGetError is not called on the nested ScopedXErrorHandler, then any X errors caused by X calls made while the nested
1.91 + * ScopedXErrorHandler was in place may then be caught by the other ScopedXErrorHandler. This is just a result of X being
1.92 + * asynchronous and us not doing any implicit syncing: the only method in this class what causes syncing is SyncAndGetError().
1.93 + *
1.94 + * This class is not thread-safe at all. It is assumed that only one thread is using any ScopedXErrorHandler's. Given that it's
1.95 + * not used on Mac, it should be easy to make it thread-safe by using thread-local storage with __thread.
1.96 + */
1.97 +class NS_GFX ScopedXErrorHandler
1.98 +{
1.99 +public:
1.100 + // trivial wrapper around XErrorEvent, just adding ctor initializing by zero.
1.101 + struct ErrorEvent
1.102 + {
1.103 + XErrorEvent mError;
1.104 +
1.105 + ErrorEvent()
1.106 + {
1.107 + memset(this, 0, sizeof(ErrorEvent));
1.108 + }
1.109 + };
1.110 +
1.111 +private:
1.112 +
1.113 + // this ScopedXErrorHandler's ErrorEvent object
1.114 + ErrorEvent mXError;
1.115 +
1.116 + // static pointer for use by the error handler
1.117 + static ErrorEvent* sXErrorPtr;
1.118 +
1.119 + // what to restore sXErrorPtr to on destruction
1.120 + ErrorEvent* mOldXErrorPtr;
1.121 +
1.122 + // what to restore the error handler to on destruction
1.123 + int (*mOldErrorHandler)(Display *, XErrorEvent *);
1.124 +
1.125 +public:
1.126 +
1.127 + static int
1.128 + ErrorHandler(Display *, XErrorEvent *ev);
1.129 +
1.130 + ScopedXErrorHandler();
1.131 +
1.132 + ~ScopedXErrorHandler();
1.133 +
1.134 + /** \returns true if a X error occurred since the last time this method was called on this ScopedXErrorHandler object,
1.135 + * or since the creation of this ScopedXErrorHandler object if this method was never called on it.
1.136 + *
1.137 + * \param ev this optional parameter, if set, will be filled with the XErrorEvent object. If multiple errors occurred,
1.138 + * the first one will be returned.
1.139 + */
1.140 + bool SyncAndGetError(Display *dpy, XErrorEvent *ev = nullptr);
1.141 +};
1.142 +
1.143 +} // namespace mozilla
1.144 +
1.145 +#endif // mozilla_X11Util_h
