/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: sw=2 ts=8 et : */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef mozilla_X11Util_h #define mozilla_X11Util_h // Utilities common to all X clients, regardless of UI toolkit. #if defined(MOZ_WIDGET_GTK) # include <gdk/gdk.h> # include <gdk/gdkx.h> # include "X11UndefineNone.h" #else # error Unknown toolkit #endif #include <string.h> // for memset #include "mozilla/Scoped.h" // for SCOPED_TEMPLATE namespace mozilla { /** * Return the default X Display created and used by the UI toolkit. */ inline Display* DefaultXDisplay() { #if defined(MOZ_WIDGET_GTK) return GDK_DISPLAY_XDISPLAY(gdk_display_get_default()); #endif } /** * Sets *aVisual to point to aDisplay's Visual struct corresponding to * aVisualID, and *aDepth to its depth. When aVisualID is None, these are set * to nullptr and 0 respectively. Both out-parameter pointers are assumed * non-nullptr. */ void FindVisualAndDepth(Display* aDisplay, VisualID aVisualID, Visual** aVisual, int* aDepth); /** * Ensure that all X requests have been processed. * * This is similar to XSync, but doesn't need a round trip if the previous * request was synchronous or if events have been received since the last * request. Subsequent FinishX calls will be noops if there have been no * intermediate requests. */ void FinishX(Display* aDisplay); /** * Invoke XFree() on a pointer to memory allocated by Xlib (if the * pointer is nonnull) when this class goes out of scope. */ template <typename T> struct ScopedXFreePtrTraits { typedef T *type; static T *empty() { return nullptr; } static void release(T *ptr) { if (ptr != nullptr) XFree(ptr); } }; SCOPED_TEMPLATE(ScopedXFree, ScopedXFreePtrTraits) /** * On construction, set a graceful X error handler that doesn't crash the application and records X errors. * On destruction, restore the X error handler to what it was before construction. * * The SyncAndGetError() method allows to know whether a X error occurred, optionally allows to get the full XErrorEvent, * and resets the recorded X error state so that a single X error will be reported only once. * * Nesting is correctly handled: multiple nested ScopedXErrorHandler's don't interfere with each other's state. However, * if SyncAndGetError is not called on the nested ScopedXErrorHandler, then any X errors caused by X calls made while the nested * ScopedXErrorHandler was in place may then be caught by the other ScopedXErrorHandler. This is just a result of X being * asynchronous and us not doing any implicit syncing: the only method in this class what causes syncing is SyncAndGetError(). * * This class is not thread-safe at all. It is assumed that only one thread is using any ScopedXErrorHandler's. Given that it's * not used on Mac, it should be easy to make it thread-safe by using thread-local storage with __thread. */ class ScopedXErrorHandler { public: // trivial wrapper around XErrorEvent, just adding ctor initializing by zero. struct ErrorEvent { XErrorEvent mError; ErrorEvent() { memset(this, 0, sizeof(ErrorEvent)); } }; private: // this ScopedXErrorHandler's ErrorEvent object ErrorEvent mXError; // static pointer for use by the error handler static ErrorEvent* sXErrorPtr; // what to restore sXErrorPtr to on destruction ErrorEvent* mOldXErrorPtr; // what to restore the error handler to on destruction int (*mOldErrorHandler)(Display *, XErrorEvent *); public: static int ErrorHandler(Display *, XErrorEvent *ev); /** * @param aAllowOffMainThread whether to warn if used off main thread */ explicit ScopedXErrorHandler(bool aAllowOffMainThread = false); ~ScopedXErrorHandler(); /** \returns true if a X error occurred since the last time this method was called on this ScopedXErrorHandler object, * or since the creation of this ScopedXErrorHandler object if this method was never called on it. * * \param ev this optional parameter, if set, will be filled with the XErrorEvent object. If multiple errors occurred, * the first one will be returned. */ bool SyncAndGetError(Display *dpy, XErrorEvent *ev = nullptr); }; class OffMainThreadScopedXErrorHandler : public ScopedXErrorHandler { public: OffMainThreadScopedXErrorHandler() : ScopedXErrorHandler(true) { } }; } // namespace mozilla #endif // mozilla_X11Util_h