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1 /*
2  *  Copyright 2010 The WebRTC Project Authors. All rights reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "webrtc/base/x11windowpicker.h"
12 
13 #include <math.h>
14 #include <string.h>
15 
16 #include <algorithm>
17 #include <string>
18 
19 #include <X11/Xatom.h>
20 #include <X11/extensions/Xcomposite.h>
21 #include <X11/extensions/Xrender.h>
22 #include <X11/Xutil.h>
23 
24 #include "webrtc/base/logging.h"
25 
26 namespace rtc {
27 
28 // Convenience wrapper for XGetWindowProperty results.
29 template <class PropertyType>
30 class XWindowProperty {
31  public:
XWindowProperty(Display * display,Window window,Atom property)32   XWindowProperty(Display* display, Window window, Atom property)
33       : data_(NULL) {
34     const int kBitsPerByte = 8;
35     Atom actual_type;
36     int actual_format;
37     unsigned long bytes_after;  // NOLINT: type required by XGetWindowProperty
38     int status = XGetWindowProperty(display, window, property, 0L, ~0L, False,
39                                     AnyPropertyType, &actual_type,
40                                     &actual_format, &size_,
41                                     &bytes_after, &data_);
42     succeeded_ = (status == Success);
43     if (!succeeded_) {
44       data_ = NULL;  // Ensure nothing is freed.
45     } else if (sizeof(PropertyType) * kBitsPerByte != actual_format) {
46       LOG(LS_WARNING) << "Returned type size differs from "
47           "requested type size.";
48       succeeded_ = false;
49       // We still need to call XFree in this case, so leave data_ alone.
50     }
51     if (!succeeded_) {
52       size_ = 0;
53     }
54   }
55 
~XWindowProperty()56   ~XWindowProperty() {
57     if (data_) {
58       XFree(data_);
59     }
60   }
61 
succeeded() const62   bool succeeded() const { return succeeded_; }
size() const63   size_t size() const { return size_; }
data() const64   const PropertyType* data() const {
65     return reinterpret_cast<PropertyType*>(data_);
66   }
data()67   PropertyType* data() {
68     return reinterpret_cast<PropertyType*>(data_);
69   }
70 
71  private:
72   bool succeeded_;
73   unsigned long size_;  // NOLINT: type required by XGetWindowProperty
74   unsigned char* data_;
75 
76   RTC_DISALLOW_COPY_AND_ASSIGN(XWindowProperty);
77 };
78 
79 // Stupid X11.  It seems none of the synchronous returns codes from X11 calls
80 // are meaningful unless an asynchronous error handler is configured.  This
81 // RAII class registers and unregisters an X11 error handler.
82 class XErrorSuppressor {
83  public:
XErrorSuppressor(Display * display)84   explicit XErrorSuppressor(Display* display)
85       : display_(display), original_error_handler_(NULL) {
86     SuppressX11Errors();
87   }
~XErrorSuppressor()88   ~XErrorSuppressor() {
89     UnsuppressX11Errors();
90   }
91 
92  private:
ErrorHandler(Display * display,XErrorEvent * e)93   static int ErrorHandler(Display* display, XErrorEvent* e) {
94     char buf[256];
95     XGetErrorText(display, e->error_code, buf, sizeof buf);
96     LOG(LS_WARNING) << "Received X11 error \"" << buf << "\" for request code "
97                     << static_cast<unsigned int>(e->request_code);
98     return 0;
99   }
100 
SuppressX11Errors()101   void SuppressX11Errors() {
102     XFlush(display_);
103     XSync(display_, False);
104     original_error_handler_ = XSetErrorHandler(&ErrorHandler);
105   }
106 
UnsuppressX11Errors()107   void UnsuppressX11Errors() {
108     XFlush(display_);
109     XSync(display_, False);
110     XErrorHandler handler = XSetErrorHandler(original_error_handler_);
111     if (handler != &ErrorHandler) {
112       LOG(LS_WARNING) << "Unbalanced XSetErrorHandler() calls detected. "
113                       << "Final error handler may not be what you expect!";
114     }
115     original_error_handler_ = NULL;
116   }
117 
118   Display* display_;
119   XErrorHandler original_error_handler_;
120 
121   RTC_DISALLOW_COPY_AND_ASSIGN(XErrorSuppressor);
122 };
123 
124 // Hiding all X11 specifics inside its own class. This to avoid
125 // conflicts between talk and X11 header declarations.
126 class XWindowEnumerator {
127  public:
XWindowEnumerator()128   XWindowEnumerator()
129       : display_(NULL),
130         has_composite_extension_(false),
131         has_render_extension_(false) {
132   }
133 
~XWindowEnumerator()134   ~XWindowEnumerator() {
135     if (display_ != NULL) {
136       XCloseDisplay(display_);
137     }
138   }
139 
Init()140   bool Init() {
141     if (display_ != NULL) {
142       // Already initialized.
143       return true;
144     }
145     display_ = XOpenDisplay(NULL);
146     if (display_ == NULL) {
147       LOG(LS_ERROR) << "Failed to open display.";
148       return false;
149     }
150 
151     XErrorSuppressor error_suppressor(display_);
152 
153     wm_state_ = XInternAtom(display_, "WM_STATE", True);
154     net_wm_icon_ = XInternAtom(display_, "_NET_WM_ICON", False);
155 
156     int event_base, error_base, major_version, minor_version;
157     if (XCompositeQueryExtension(display_, &event_base, &error_base) &&
158         XCompositeQueryVersion(display_, &major_version, &minor_version) &&
159         // XCompositeNameWindowPixmap() requires version 0.2
160         (major_version > 0 || minor_version >= 2)) {
161       has_composite_extension_ = true;
162     } else {
163       LOG(LS_INFO) << "Xcomposite extension not available or too old.";
164     }
165 
166     if (XRenderQueryExtension(display_, &event_base, &error_base) &&
167         XRenderQueryVersion(display_, &major_version, &minor_version) &&
168         // XRenderSetPictureTransform() requires version 0.6
169         (major_version > 0 || minor_version >= 6)) {
170       has_render_extension_ = true;
171     } else {
172       LOG(LS_INFO) << "Xrender extension not available or too old.";
173     }
174     return true;
175   }
176 
EnumerateWindows(WindowDescriptionList * descriptions)177   bool EnumerateWindows(WindowDescriptionList* descriptions) {
178     if (!Init()) {
179       return false;
180     }
181     XErrorSuppressor error_suppressor(display_);
182     int num_screens = XScreenCount(display_);
183     bool result = false;
184     for (int i = 0; i < num_screens; ++i) {
185       if (EnumerateScreenWindows(descriptions, i)) {
186         // We know we succeded on at least one screen.
187         result = true;
188       }
189     }
190     return result;
191   }
192 
EnumerateDesktops(DesktopDescriptionList * descriptions)193   bool EnumerateDesktops(DesktopDescriptionList* descriptions) {
194     if (!Init()) {
195       return false;
196     }
197     XErrorSuppressor error_suppressor(display_);
198     Window default_root_window = XDefaultRootWindow(display_);
199     int num_screens = XScreenCount(display_);
200     for (int i = 0; i < num_screens; ++i) {
201       Window root_window = XRootWindow(display_, i);
202       DesktopId id(DesktopId(root_window, i));
203       // TODO: Figure out an appropriate desktop title.
204       DesktopDescription desc(id, "");
205       desc.set_primary(root_window == default_root_window);
206       descriptions->push_back(desc);
207     }
208     return num_screens > 0;
209   }
210 
IsVisible(const WindowId & id)211   bool IsVisible(const WindowId& id) {
212     if (!Init()) {
213       return false;
214     }
215     XErrorSuppressor error_suppressor(display_);
216     XWindowAttributes attr;
217     if (!XGetWindowAttributes(display_, id.id(), &attr)) {
218       LOG(LS_ERROR) << "XGetWindowAttributes() failed";
219       return false;
220     }
221     return attr.map_state == IsViewable;
222   }
223 
MoveToFront(const WindowId & id)224   bool MoveToFront(const WindowId& id) {
225     if (!Init()) {
226       return false;
227     }
228     XErrorSuppressor error_suppressor(display_);
229     unsigned int num_children;
230     Window* children;
231     Window parent;
232     Window root;
233 
234     // Find root window to pass event to.
235     int status = XQueryTree(display_, id.id(), &root, &parent, &children,
236                             &num_children);
237     if (status == 0) {
238       LOG(LS_WARNING) << "Failed to query for child windows.";
239       return false;
240     }
241     if (children != NULL) {
242       XFree(children);
243     }
244 
245     // Move the window to front.
246     XRaiseWindow(display_, id.id());
247 
248     // Some window managers (e.g., metacity in GNOME) consider it illegal to
249     // raise a window without also giving it input focus with
250     // _NET_ACTIVE_WINDOW, so XRaiseWindow() on its own isn't enough.
251     Atom atom = XInternAtom(display_, "_NET_ACTIVE_WINDOW", True);
252     if (atom != None) {
253       XEvent xev;
254       long event_mask;
255 
256       xev.xclient.type = ClientMessage;
257       xev.xclient.serial = 0;
258       xev.xclient.send_event = True;
259       xev.xclient.window = id.id();
260       xev.xclient.message_type = atom;
261 
262       // The format member is set to 8, 16, or 32 and specifies whether the
263       // data should be viewed as a list of bytes, shorts, or longs.
264       xev.xclient.format = 32;
265 
266       xev.xclient.data.l[0] = 0;
267       xev.xclient.data.l[1] = 0;
268       xev.xclient.data.l[2] = 0;
269       xev.xclient.data.l[3] = 0;
270       xev.xclient.data.l[4] = 0;
271 
272       event_mask = SubstructureRedirectMask | SubstructureNotifyMask;
273 
274       XSendEvent(display_, root, False, event_mask, &xev);
275     }
276     XFlush(display_);
277     return true;
278   }
279 
GetWindowIcon(const WindowId & id,int * width,int * height)280   uint8_t* GetWindowIcon(const WindowId& id, int* width, int* height) {
281     if (!Init()) {
282       return NULL;
283     }
284     XErrorSuppressor error_suppressor(display_);
285     Atom ret_type;
286     int format;
287     unsigned long length, bytes_after, size;
288     unsigned char* data = NULL;
289 
290     // Find out the size of the icon data.
291     if (XGetWindowProperty(
292             display_, id.id(), net_wm_icon_, 0, 0, False, XA_CARDINAL,
293             &ret_type, &format, &length, &size, &data) == Success &&
294         data) {
295       XFree(data);
296     } else {
297       LOG(LS_ERROR) << "Failed to get size of the icon.";
298       return NULL;
299     }
300     // Get the icon data, the format is one uint32_t each for width and height,
301     // followed by the actual pixel data.
302     if (size >= 2 &&
303         XGetWindowProperty(
304             display_, id.id(), net_wm_icon_, 0, size, False, XA_CARDINAL,
305             &ret_type, &format, &length, &bytes_after, &data) == Success &&
306         data) {
307       uint32_t* data_ptr = reinterpret_cast<uint32_t*>(data);
308       int w, h;
309       w = data_ptr[0];
310       h = data_ptr[1];
311       if (size < static_cast<unsigned long>(w * h + 2)) {
312         XFree(data);
313         LOG(LS_ERROR) << "Not a vaild icon.";
314         return NULL;
315       }
316       uint8_t* rgba = ArgbToRgba(&data_ptr[2], 0, 0, w, h, w, h, true);
317       XFree(data);
318       *width = w;
319       *height = h;
320       return rgba;
321     } else {
322       LOG(LS_ERROR) << "Failed to get window icon data.";
323       return NULL;
324     }
325   }
326 
GetWindowThumbnail(const WindowId & id,int width,int height)327   uint8_t* GetWindowThumbnail(const WindowId& id, int width, int height) {
328     if (!Init()) {
329       return NULL;
330     }
331 
332     if (!has_composite_extension_) {
333       // Without the Xcomposite extension we would only get a good thumbnail if
334       // the whole window is visible on screen and not covered by any
335       // other window. This is not something we want so instead, just
336       // bail out.
337       LOG(LS_INFO) << "No Xcomposite extension detected.";
338       return NULL;
339     }
340     XErrorSuppressor error_suppressor(display_);
341 
342     Window root;
343     int x;
344     int y;
345     unsigned int src_width;
346     unsigned int src_height;
347     unsigned int border_width;
348     unsigned int depth;
349 
350     // In addition to needing X11 server-side support for Xcomposite, it
351     // actually needs to be turned on for this window in order to get a good
352     // thumbnail. If the user has modern hardware/drivers but isn't using a
353     // compositing window manager, that won't be the case. Here we
354     // automatically turn it on for shareable windows so that we can get
355     // thumbnails. We used to avoid it because the transition is visually ugly,
356     // but recent window managers don't always redirect windows which led to
357     // no thumbnails at all, which is a worse experience.
358 
359     // Redirect drawing to an offscreen buffer (ie, turn on compositing).
360     // X11 remembers what has requested this and will turn it off for us when
361     // we exit.
362     XCompositeRedirectWindow(display_, id.id(), CompositeRedirectAutomatic);
363     Pixmap src_pixmap = XCompositeNameWindowPixmap(display_, id.id());
364     if (!src_pixmap) {
365       // Even if the backing pixmap doesn't exist, this still should have
366       // succeeded and returned a valid handle (it just wouldn't be a handle to
367       // anything). So this is a real error path.
368       LOG(LS_ERROR) << "XCompositeNameWindowPixmap() failed";
369       return NULL;
370     }
371     if (!XGetGeometry(display_, src_pixmap, &root, &x, &y,
372                       &src_width, &src_height, &border_width,
373                       &depth)) {
374       // If the window does not actually have a backing pixmap, this is the path
375       // that will "fail", so it's a warning rather than an error.
376       LOG(LS_WARNING) << "XGetGeometry() failed (probably composite is not in "
377                       << "use)";
378       XFreePixmap(display_, src_pixmap);
379       return NULL;
380     }
381 
382     // If we get to here, then composite is in use for this window and it has a
383     // valid backing pixmap.
384 
385     XWindowAttributes attr;
386     if (!XGetWindowAttributes(display_, id.id(), &attr)) {
387       LOG(LS_ERROR) << "XGetWindowAttributes() failed";
388       XFreePixmap(display_, src_pixmap);
389       return NULL;
390     }
391 
392     uint8_t* data = GetDrawableThumbnail(src_pixmap, attr.visual, src_width,
393                                          src_height, width, height);
394     XFreePixmap(display_, src_pixmap);
395     return data;
396   }
397 
GetNumDesktops()398   int GetNumDesktops() {
399     if (!Init()) {
400       return -1;
401     }
402 
403     return XScreenCount(display_);
404   }
405 
GetDesktopThumbnail(const DesktopId & id,int width,int height)406   uint8_t* GetDesktopThumbnail(const DesktopId& id, int width, int height) {
407     if (!Init()) {
408       return NULL;
409     }
410     XErrorSuppressor error_suppressor(display_);
411 
412     Window root_window = id.id();
413     XWindowAttributes attr;
414     if (!XGetWindowAttributes(display_, root_window, &attr)) {
415       LOG(LS_ERROR) << "XGetWindowAttributes() failed";
416       return NULL;
417     }
418 
419     return GetDrawableThumbnail(root_window,
420                                 attr.visual,
421                                 attr.width,
422                                 attr.height,
423                                 width,
424                                 height);
425   }
426 
GetDesktopDimensions(const DesktopId & id,int * width,int * height)427   bool GetDesktopDimensions(const DesktopId& id, int* width, int* height) {
428     if (!Init()) {
429       return false;
430     }
431     XErrorSuppressor error_suppressor(display_);
432     XWindowAttributes attr;
433     if (!XGetWindowAttributes(display_, id.id(), &attr)) {
434       LOG(LS_ERROR) << "XGetWindowAttributes() failed";
435       return false;
436     }
437     *width = attr.width;
438     *height = attr.height;
439     return true;
440   }
441 
442  private:
GetDrawableThumbnail(Drawable src_drawable,Visual * visual,int src_width,int src_height,int dst_width,int dst_height)443   uint8_t* GetDrawableThumbnail(Drawable src_drawable,
444                                 Visual* visual,
445                                 int src_width,
446                                 int src_height,
447                                 int dst_width,
448                                 int dst_height) {
449     if (!has_render_extension_) {
450       // Without the Xrender extension we would have to read the full window and
451       // scale it down in our process. Xrender is over a decade old so we aren't
452       // going to expend effort to support that situation. We still need to
453       // check though because probably some virtual VNC displays are in this
454       // category.
455       LOG(LS_INFO) << "No Xrender extension detected.";
456       return NULL;
457     }
458 
459     XRenderPictFormat* format = XRenderFindVisualFormat(display_,
460                                                         visual);
461     if (!format) {
462       LOG(LS_ERROR) << "XRenderFindVisualFormat() failed";
463       return NULL;
464     }
465 
466     // Create a picture to reference the window pixmap.
467     XRenderPictureAttributes pa;
468     pa.subwindow_mode = IncludeInferiors;  // Don't clip child widgets
469     Picture src = XRenderCreatePicture(display_,
470                                        src_drawable,
471                                        format,
472                                        CPSubwindowMode,
473                                        &pa);
474     if (!src) {
475       LOG(LS_ERROR) << "XRenderCreatePicture() failed";
476       return NULL;
477     }
478 
479     // Create a picture to reference the destination pixmap.
480     Pixmap dst_pixmap = XCreatePixmap(display_,
481                                       src_drawable,
482                                       dst_width,
483                                       dst_height,
484                                       format->depth);
485     if (!dst_pixmap) {
486       LOG(LS_ERROR) << "XCreatePixmap() failed";
487       XRenderFreePicture(display_, src);
488       return NULL;
489     }
490 
491     Picture dst = XRenderCreatePicture(display_, dst_pixmap, format, 0, NULL);
492     if (!dst) {
493       LOG(LS_ERROR) << "XRenderCreatePicture() failed";
494       XFreePixmap(display_, dst_pixmap);
495       XRenderFreePicture(display_, src);
496       return NULL;
497     }
498 
499     // Clear the background.
500     XRenderColor transparent = {0};
501     XRenderFillRectangle(display_,
502                          PictOpSrc,
503                          dst,
504                          &transparent,
505                          0,
506                          0,
507                          dst_width,
508                          dst_height);
509 
510     // Calculate how much we need to scale the image.
511     double scale_x = static_cast<double>(dst_width) /
512         static_cast<double>(src_width);
513     double scale_y = static_cast<double>(dst_height) /
514         static_cast<double>(src_height);
515     double scale = std::min(scale_y, scale_x);
516 
517     int scaled_width = round(src_width * scale);
518     int scaled_height = round(src_height * scale);
519 
520     // Render the thumbnail centered on both axis.
521     int centered_x = (dst_width - scaled_width) / 2;
522     int centered_y = (dst_height - scaled_height) / 2;
523 
524     // Scaling matrix
525     XTransform xform = { {
526         { XDoubleToFixed(1), XDoubleToFixed(0), XDoubleToFixed(0) },
527         { XDoubleToFixed(0), XDoubleToFixed(1), XDoubleToFixed(0) },
528         { XDoubleToFixed(0), XDoubleToFixed(0), XDoubleToFixed(scale) }
529         } };
530     XRenderSetPictureTransform(display_, src, &xform);
531 
532     // Apply filter to smooth out the image.
533     XRenderSetPictureFilter(display_, src, FilterBest, NULL, 0);
534 
535     // Render the image to the destination picture.
536     XRenderComposite(display_,
537                      PictOpSrc,
538                      src,
539                      None,
540                      dst,
541                      0,
542                      0,
543                      0,
544                      0,
545                      centered_x,
546                      centered_y,
547                      scaled_width,
548                      scaled_height);
549 
550     // Get the pixel data from the X server. TODO: XGetImage
551     // might be slow here, compare with ShmGetImage.
552     XImage* image = XGetImage(display_,
553                               dst_pixmap,
554                               0,
555                               0,
556                               dst_width,
557                               dst_height,
558                               AllPlanes, ZPixmap);
559     uint8_t* data = ArgbToRgba(reinterpret_cast<uint32_t*>(image->data),
560                                centered_x, centered_y, scaled_width,
561                                scaled_height, dst_width, dst_height, false);
562     XDestroyImage(image);
563     XRenderFreePicture(display_, dst);
564     XFreePixmap(display_, dst_pixmap);
565     XRenderFreePicture(display_, src);
566     return data;
567   }
568 
ArgbToRgba(uint32_t * argb_data,int x,int y,int w,int h,int stride_x,int stride_y,bool has_alpha)569   uint8_t* ArgbToRgba(uint32_t* argb_data,
570                       int x,
571                       int y,
572                       int w,
573                       int h,
574                       int stride_x,
575                       int stride_y,
576                       bool has_alpha) {
577     uint8_t* p;
578     int len = stride_x * stride_y * 4;
579     uint8_t* data = new uint8_t[len];
580     memset(data, 0, len);
581     p = data + 4 * (y * stride_x + x);
582     for (int i = 0; i < h; ++i) {
583       for (int j = 0; j < w; ++j) {
584         uint32_t argb;
585         uint32_t rgba;
586         argb = argb_data[stride_x * (y + i) + x + j];
587         rgba = (argb << 8) | (argb >> 24);
588         *p = rgba >> 24;
589         ++p;
590         *p = (rgba >> 16) & 0xff;
591         ++p;
592         *p = (rgba >> 8) & 0xff;
593         ++p;
594         *p = has_alpha ? rgba & 0xFF : 0xFF;
595         ++p;
596       }
597       p += (stride_x - w) * 4;
598     }
599     return data;
600   }
601 
EnumerateScreenWindows(WindowDescriptionList * descriptions,int screen)602   bool EnumerateScreenWindows(WindowDescriptionList* descriptions, int screen) {
603     Window parent;
604     Window *children;
605     int status;
606     unsigned int num_children;
607     Window root_window = XRootWindow(display_, screen);
608     status = XQueryTree(display_, root_window, &root_window, &parent, &children,
609                         &num_children);
610     if (status == 0) {
611       LOG(LS_ERROR) << "Failed to query for child windows.";
612       return false;
613     }
614     for (unsigned int i = 0; i < num_children; ++i) {
615       // Iterate in reverse order to display windows from front to back.
616 #ifdef CHROMEOS
617       // TODO(jhorwich): Short-term fix for crbug.com/120229: Don't need to
618       // filter, just return all windows and let the picker scan through them.
619       Window app_window = children[num_children - 1 - i];
620 #else
621       Window app_window = GetApplicationWindow(children[num_children - 1 - i]);
622 #endif
623       if (app_window &&
624           !X11WindowPicker::IsDesktopElement(display_, app_window)) {
625         std::string title;
626         if (GetWindowTitle(app_window, &title)) {
627           WindowId id(app_window);
628           WindowDescription desc(id, title);
629           descriptions->push_back(desc);
630         }
631       }
632     }
633     if (children != NULL) {
634       XFree(children);
635     }
636     return true;
637   }
638 
GetWindowTitle(Window window,std::string * title)639   bool GetWindowTitle(Window window, std::string* title) {
640     int status;
641     bool result = false;
642     XTextProperty window_name;
643     window_name.value = NULL;
644     if (window) {
645       status = XGetWMName(display_, window, &window_name);
646       if (status && window_name.value && window_name.nitems) {
647         int cnt;
648         char **list = NULL;
649         status = Xutf8TextPropertyToTextList(display_, &window_name, &list,
650                                              &cnt);
651         if (status >= Success && cnt && *list) {
652           if (cnt > 1) {
653             LOG(LS_INFO) << "Window has " << cnt
654                          << " text properties, only using the first one.";
655           }
656           *title = *list;
657           result = true;
658         }
659         if (list != NULL) {
660           XFreeStringList(list);
661         }
662       }
663       if (window_name.value != NULL) {
664         XFree(window_name.value);
665       }
666     }
667     return result;
668   }
669 
GetApplicationWindow(Window window)670   Window GetApplicationWindow(Window window) {
671     Window root, parent;
672     Window app_window = 0;
673     Window *children;
674     unsigned int num_children;
675     Atom type = None;
676     int format;
677     unsigned long nitems, after;
678     unsigned char *data;
679 
680     int ret = XGetWindowProperty(display_, window,
681                                  wm_state_, 0L, 2,
682                                  False, wm_state_, &type, &format,
683                                  &nitems, &after, &data);
684     if (ret != Success) {
685       LOG(LS_ERROR) << "XGetWindowProperty failed with return code " << ret
686                     << " for window " << window << ".";
687       return 0;
688     }
689     if (type != None) {
690       int64_t state = static_cast<int64_t>(*data);
691       XFree(data);
692       return state == NormalState ? window : 0;
693     }
694     XFree(data);
695     if (!XQueryTree(display_, window, &root, &parent, &children,
696                     &num_children)) {
697       LOG(LS_ERROR) << "Failed to query for child windows although window"
698                     << "does not have a valid WM_STATE.";
699       return 0;
700     }
701     for (unsigned int i = 0; i < num_children; ++i) {
702       app_window = GetApplicationWindow(children[i]);
703       if (app_window) {
704         break;
705       }
706     }
707     if (children != NULL) {
708       XFree(children);
709     }
710     return app_window;
711   }
712 
713   Atom wm_state_;
714   Atom net_wm_icon_;
715   Display* display_;
716   bool has_composite_extension_;
717   bool has_render_extension_;
718 };
719 
X11WindowPicker()720 X11WindowPicker::X11WindowPicker() : enumerator_(new XWindowEnumerator()) {
721 }
722 
~X11WindowPicker()723 X11WindowPicker::~X11WindowPicker() {
724 }
725 
IsDesktopElement(_XDisplay * display,Window window)726 bool X11WindowPicker::IsDesktopElement(_XDisplay* display, Window window) {
727   if (window == 0) {
728     LOG(LS_WARNING) << "Zero is never a valid window.";
729     return false;
730   }
731 
732   // First look for _NET_WM_WINDOW_TYPE. The standard
733   // (http://standards.freedesktop.org/wm-spec/latest/ar01s05.html#id2760306)
734   // says this hint *should* be present on all windows, and we use the existence
735   // of _NET_WM_WINDOW_TYPE_NORMAL in the property to indicate a window is not
736   // a desktop element (that is, only "normal" windows should be shareable).
737   Atom window_type_atom = XInternAtom(display, "_NET_WM_WINDOW_TYPE", True);
738   XWindowProperty<uint32_t> window_type(display, window, window_type_atom);
739   if (window_type.succeeded() && window_type.size() > 0) {
740     Atom normal_window_type_atom = XInternAtom(
741         display, "_NET_WM_WINDOW_TYPE_NORMAL", True);
742     uint32_t* end = window_type.data() + window_type.size();
743     bool is_normal = (end != std::find(
744         window_type.data(), end, normal_window_type_atom));
745     return !is_normal;
746   }
747 
748   // Fall back on using the hint.
749   XClassHint class_hint;
750   Status s = XGetClassHint(display, window, &class_hint);
751   bool result = false;
752   if (s == 0) {
753     // No hints, assume this is a normal application window.
754     return result;
755   }
756   static const std::string gnome_panel("gnome-panel");
757   static const std::string desktop_window("desktop_window");
758 
759   if (gnome_panel.compare(class_hint.res_name) == 0 ||
760       desktop_window.compare(class_hint.res_name) == 0) {
761     result = true;
762   }
763   XFree(class_hint.res_name);
764   XFree(class_hint.res_class);
765   return result;
766 }
767 
Init()768 bool X11WindowPicker::Init() {
769   return enumerator_->Init();
770 }
771 
GetWindowList(WindowDescriptionList * descriptions)772 bool X11WindowPicker::GetWindowList(WindowDescriptionList* descriptions) {
773   return enumerator_->EnumerateWindows(descriptions);
774 }
775 
GetDesktopList(DesktopDescriptionList * descriptions)776 bool X11WindowPicker::GetDesktopList(DesktopDescriptionList* descriptions) {
777   return enumerator_->EnumerateDesktops(descriptions);
778 }
779 
IsVisible(const WindowId & id)780 bool X11WindowPicker::IsVisible(const WindowId& id) {
781   return enumerator_->IsVisible(id);
782 }
783 
MoveToFront(const WindowId & id)784 bool X11WindowPicker::MoveToFront(const WindowId& id) {
785   return enumerator_->MoveToFront(id);
786 }
787 
GetWindowIcon(const WindowId & id,int * width,int * height)788 uint8_t* X11WindowPicker::GetWindowIcon(const WindowId& id,
789                                         int* width,
790                                         int* height) {
791   return enumerator_->GetWindowIcon(id, width, height);
792 }
793 
GetWindowThumbnail(const WindowId & id,int width,int height)794 uint8_t* X11WindowPicker::GetWindowThumbnail(const WindowId& id,
795                                              int width,
796                                              int height) {
797   return enumerator_->GetWindowThumbnail(id, width, height);
798 }
799 
GetNumDesktops()800 int X11WindowPicker::GetNumDesktops() {
801   return enumerator_->GetNumDesktops();
802 }
803 
GetDesktopThumbnail(const DesktopId & id,int width,int height)804 uint8_t* X11WindowPicker::GetDesktopThumbnail(const DesktopId& id,
805                                               int width,
806                                               int height) {
807   return enumerator_->GetDesktopThumbnail(id, width, height);
808 }
809 
GetDesktopDimensions(const DesktopId & id,int * width,int * height)810 bool X11WindowPicker::GetDesktopDimensions(const DesktopId& id, int* width,
811                                              int* height) {
812   return enumerator_->GetDesktopDimensions(id, width, height);
813 }
814 
815 }  // namespace rtc
816