File: PlatformDisplay.cpp

package info (click to toggle)
webkit2gtk 2.42.2-1~deb12u1
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 362,452 kB
  • sloc: cpp: 2,881,971; javascript: 282,447; ansic: 134,088; python: 43,789; ruby: 18,308; perl: 15,872; asm: 14,389; xml: 4,395; yacc: 2,350; sh: 2,074; java: 1,734; lex: 1,323; makefile: 288; pascal: 60
file content (601 lines) | stat: -rw-r--r-- 19,303 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
/*
 * Copyright (C) 2015 Igalia S.L
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "PlatformDisplay.h"

#include "GLContext.h"
#include <cstdlib>
#include <mutex>

#if PLATFORM(X11)
#include "PlatformDisplayX11.h"
#endif

#if PLATFORM(WAYLAND)
#include "PlatformDisplayWayland.h"
#endif

#if PLATFORM(WIN)
#include "PlatformDisplayWin.h"
#endif

#if USE(WPE_RENDERER)
#include "PlatformDisplayLibWPE.h"
#endif

#if PLATFORM(GTK)
#include "GtkVersioning.h"
#endif

#if PLATFORM(GTK) && PLATFORM(X11)
#if USE(GTK4)
#include <gdk/x11/gdkx.h>
#else
#include <gdk/gdkx.h>
#endif
#if defined(None)
#undef None
#endif
#endif

#if PLATFORM(GTK) && PLATFORM(WAYLAND)
#if USE(GTK4)
#include <gdk/wayland/gdkwayland.h>
#else
#include <gdk/gdkwayland.h>
#endif
#endif

#if USE(EGL)
#if USE(LIBEPOXY)
#include "EpoxyEGL.h"
#else
#include <EGL/egl.h>
#include <EGL/eglext.h>
#endif
#include <wtf/HashSet.h>
#include <wtf/NeverDestroyed.h>
#endif

#if USE(EGL) && USE(GBM)
#include "GBMDevice.h"
#include <xf86drm.h>
#ifndef EGL_DRM_RENDER_NODE_FILE_EXT
#define EGL_DRM_RENDER_NODE_FILE_EXT 0x3377
#endif
#endif

#if USE(ATSPI)
#include <wtf/glib/GUniquePtr.h>
#endif

#if USE(GLIB)
#include <wtf/glib/GRefPtr.h>
#endif

#if USE(EGL) && !USE(LIBEPOXY)
#if !defined(PFNEGLCREATEIMAGEPROC)
typedef EGLImage (*PFNEGLCREATEIMAGEPROC) (EGLDisplay, EGLContext, EGLenum, EGLClientBuffer, const EGLAttrib*);
#endif
#if !defined(PFNEGLDESTROYIMAGEPROC)
typedef EGLBoolean (*PFNEGLDESTROYIMAGEPROC) (EGLDisplay, EGLImage);
#endif
#if !defined(PFNEGLCREATEIMAGEKHRPROC)
typedef EGLImageKHR (*PFNEGLCREATEIMAGEKHRPROC) (EGLDisplay, EGLContext, EGLenum target, EGLClientBuffer, const EGLint* attribList);
#endif
#if !defined(PFNEGLDESTROYIMAGEKHRPROC)
typedef EGLBoolean (*PFNEGLDESTROYIMAGEKHRPROC) (EGLDisplay, EGLImageKHR);
#endif
#endif

namespace WebCore {

std::unique_ptr<PlatformDisplay> PlatformDisplay::createPlatformDisplay()
{
#if PLATFORM(GTK)
    if (gtk_init_check(nullptr, nullptr)) {
        GdkDisplay* display = gdk_display_manager_get_default_display(gdk_display_manager_get());
#if PLATFORM(X11)
        if (GDK_IS_X11_DISPLAY(display))
            return PlatformDisplayX11::create(display);
#endif

#if PLATFORM(WAYLAND)
        if (GDK_IS_WAYLAND_DISPLAY(display))
            return PlatformDisplayWayland::create(display);
#endif
    }
#endif // PLATFORM(GTK)

#if PLATFORM(WAYLAND)
    if (auto platformDisplay = PlatformDisplayWayland::create())
        return platformDisplay;
#endif

#if PLATFORM(X11)
    if (auto platformDisplay = PlatformDisplayX11::create())
        return platformDisplay;
#endif

    // If at this point we still don't have a display, just create a fake display with no native.
#if PLATFORM(WAYLAND)
    return PlatformDisplayWayland::create(nullptr);
#elif PLATFORM(X11)
    return PlatformDisplayX11::create(nullptr);
#endif

#if USE(WPE_RENDERER)
    return PlatformDisplayLibWPE::create();
#elif PLATFORM(WIN)
    return PlatformDisplayWin::create();
#endif

    RELEASE_ASSERT_NOT_REACHED();
}

PlatformDisplay& PlatformDisplay::sharedDisplay()
{
#if PLATFORM(WIN)
    // ANGLE D3D renderer isn't thread-safe. Don't destruct it on non-main threads which calls _exit().
    static PlatformDisplay* display = createPlatformDisplay().release();
    return *display;
#else
    static std::once_flag onceFlag;
    IGNORE_CLANG_WARNINGS_BEGIN("exit-time-destructors")
    static std::unique_ptr<PlatformDisplay> display;
    IGNORE_CLANG_WARNINGS_END
    std::call_once(onceFlag, []{
        display = createPlatformDisplay();
    });
    return *display;
#endif
}

static PlatformDisplay* s_sharedDisplayForCompositing;

PlatformDisplay& PlatformDisplay::sharedDisplayForCompositing()
{
    return s_sharedDisplayForCompositing ? *s_sharedDisplayForCompositing : sharedDisplay();
}

void PlatformDisplay::setSharedDisplayForCompositing(PlatformDisplay& display)
{
    s_sharedDisplayForCompositing = &display;
}

PlatformDisplay::PlatformDisplay()
#if USE(EGL)
    : m_eglDisplay(EGL_NO_DISPLAY)
#endif
{
}

#if PLATFORM(GTK)
PlatformDisplay::PlatformDisplay(GdkDisplay* display)
    : m_sharedDisplay(display)
#if USE(EGL)
    , m_eglDisplay(EGL_NO_DISPLAY)
#endif
{
    if (m_sharedDisplay) {
#if USE(ATSPI) && USE(GTK4)
        if (const char* atspiBusAddress = static_cast<const char*>(g_object_get_data(G_OBJECT(m_sharedDisplay.get()), "-gtk-atspi-bus-address")))
            m_accessibilityBusAddress = String::fromUTF8(atspiBusAddress);
#endif

        g_signal_connect(m_sharedDisplay.get(), "closed", G_CALLBACK(+[](GdkDisplay*, gboolean, gpointer userData) {
            auto& platformDisplay = *static_cast<PlatformDisplay*>(userData);
            platformDisplay.sharedDisplayDidClose();
        }), this);
    }
}

void PlatformDisplay::sharedDisplayDidClose()
{
#if USE(EGL)
    terminateEGLDisplay();
#endif
}
#endif

#if USE(EGL)
static HashSet<PlatformDisplay*>& eglDisplays()
{
    static NeverDestroyed<HashSet<PlatformDisplay*>> displays;
    return displays;
}
#endif

PlatformDisplay::~PlatformDisplay()
{
#if USE(EGL)
    if (m_eglDisplay != EGL_NO_DISPLAY && eglDisplays().remove(this))
        terminateEGLDisplay();
#endif

#if PLATFORM(GTK)
    if (m_sharedDisplay)
        g_signal_handlers_disconnect_by_data(m_sharedDisplay.get(), this);
#endif
    if (s_sharedDisplayForCompositing == this)
        s_sharedDisplayForCompositing = nullptr;
}

#if USE(EGL)
GLContext* PlatformDisplay::sharingGLContext()
{
    if (!m_sharingGLContext)
        m_sharingGLContext = GLContext::createSharing(*this);
    return m_sharingGLContext.get();
}

void PlatformDisplay::clearSharingGLContext()
{
#if ENABLE(VIDEO) && USE(GSTREAMER_GL)
    m_gstGLContext = nullptr;
#endif
#if ENABLE(WEBGL) && !PLATFORM(WIN)
    clearANGLESharingGLContext();
#endif
    m_sharingGLContext = nullptr;
}
#endif

#if USE(EGL)
EGLDisplay PlatformDisplay::eglDisplay() const
{
    if (!m_eglDisplayInitialized)
        const_cast<PlatformDisplay*>(this)->initializeEGLDisplay();
    return m_eglDisplay;
}

bool PlatformDisplay::eglCheckVersion(int major, int minor) const
{
    if (!m_eglDisplayInitialized)
        const_cast<PlatformDisplay*>(this)->initializeEGLDisplay();

    return (m_eglMajorVersion > major) || ((m_eglMajorVersion == major) && (m_eglMinorVersion >= minor));
}

const PlatformDisplay::EGLExtensions& PlatformDisplay::eglExtensions() const
{
    if (!m_eglDisplayInitialized)
        const_cast<PlatformDisplay*>(this)->initializeEGLDisplay();
    return m_eglExtensions;
}

void PlatformDisplay::initializeEGLDisplay()
{
    m_eglDisplayInitialized = true;

    if (m_eglDisplay == EGL_NO_DISPLAY) {
        m_eglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
        if (m_eglDisplay == EGL_NO_DISPLAY) {
            WTFLogAlways("Cannot get default EGL display: %s\n", GLContext::lastErrorString());
            return;
        }
    }

    EGLint majorVersion, minorVersion;
    if (eglInitialize(m_eglDisplay, &majorVersion, &minorVersion) == EGL_FALSE) {
        WTFLogAlways("EGLDisplay Initialization failed: %s\n", GLContext::lastErrorString());
        terminateEGLDisplay();
        return;
    }

    m_eglMajorVersion = majorVersion;
    m_eglMinorVersion = minorVersion;

    {
        const char* extensionsString = eglQueryString(m_eglDisplay, EGL_EXTENSIONS);
        auto displayExtensions = StringView::fromLatin1(extensionsString).split(' ');
        auto findExtension =
            [&](auto extensionName) {
                return std::any_of(displayExtensions.begin(), displayExtensions.end(),
                    [&](auto extensionEntry) {
                        return extensionEntry == extensionName;
                    });
            };

        m_eglExtensions.KHR_image_base = findExtension("EGL_KHR_image_base"_s);
        m_eglExtensions.KHR_surfaceless_context = findExtension("EGL_KHR_surfaceless_context"_s);
        m_eglExtensions.EXT_image_dma_buf_import = findExtension("EGL_EXT_image_dma_buf_import"_s);
        m_eglExtensions.EXT_image_dma_buf_import_modifiers = findExtension("EGL_EXT_image_dma_buf_import_modifiers"_s);
        m_eglExtensions.MESA_image_dma_buf_export = findExtension("EGL_MESA_image_dma_buf_export"_s);
    }

    if (!m_eglDisplayOwned)
        return;

    eglDisplays().add(this);

#if !PLATFORM(WIN)
    static bool eglAtexitHandlerInitialized = false;
    if (!eglAtexitHandlerInitialized) {
        // EGL registers atexit handlers to cleanup its global display list.
        // Since the global PlatformDisplay instance is created before,
        // when the PlatformDisplay destructor is called, EGL has already removed the
        // display from the list, causing eglTerminate() to crash. So, here we register
        // our own atexit handler, after EGL has been initialized and after the global
        // instance has been created to ensure we call eglTerminate() before the other
        // EGL atexit handlers and the PlatformDisplay destructor.
        // See https://bugs.webkit.org/show_bug.cgi?id=157973.
        eglAtexitHandlerInitialized = true;
        std::atexit([] {
            while (!eglDisplays().isEmpty()) {
                auto* display = eglDisplays().takeAny();
                display->terminateEGLDisplay();
            }
        });
    }
#endif
}

void PlatformDisplay::terminateEGLDisplay()
{
#if ENABLE(VIDEO) && USE(GSTREAMER_GL)
    m_gstGLDisplay = nullptr;
#endif
    clearSharingGLContext();
    ASSERT(m_eglDisplayInitialized);
    if (m_eglDisplay == EGL_NO_DISPLAY)
        return;

    if (m_eglDisplayOwned) {
        eglMakeCurrent(m_eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
        eglTerminate(m_eglDisplay);
    }
    m_eglDisplay = EGL_NO_DISPLAY;
}

EGLImage PlatformDisplay::createEGLImage(EGLContext context, EGLenum target, EGLClientBuffer clientBuffer, const Vector<EGLAttrib>& attributes) const
{
    if (eglCheckVersion(1, 5)) {
#if USE(LIBEPOXY)
        return eglCreateImage(m_eglDisplay, context, target, clientBuffer, attributes.isEmpty() ? nullptr : attributes.data());
#else
        static PFNEGLCREATEIMAGEPROC s_eglCreateImage = reinterpret_cast<PFNEGLCREATEIMAGEPROC>(eglGetProcAddress("eglCreateImage"));
        if (s_eglCreateImage)
            return s_eglCreateImage(m_eglDisplay, context, target, clientBuffer, attributes.isEmpty() ? nullptr : attributes.data());
        return EGL_NO_IMAGE;
#endif
    }

    if (!m_eglExtensions.KHR_image_base)
        return EGL_NO_IMAGE;

    Vector<EGLint> intAttributes = attributes.map<Vector<EGLint>>([] (EGLAttrib value) {
        return value;
    });
#if USE(LIBEPOXY)
    return eglCreateImageKHR(m_eglDisplay, context, target, clientBuffer, intAttributes.isEmpty() ? nullptr : intAttributes.data());
#else
    static PFNEGLCREATEIMAGEKHRPROC s_eglCreateImageKHR = reinterpret_cast<PFNEGLCREATEIMAGEKHRPROC>(eglGetProcAddress("eglCreateImageKHR"));
    if (s_eglCreateImageKHR)
        return s_eglCreateImageKHR(m_eglDisplay, context, target, clientBuffer, intAttributes.isEmpty() ? nullptr : intAttributes.data());
    return EGL_NO_IMAGE_KHR;
#endif
}

bool PlatformDisplay::destroyEGLImage(EGLImage image) const
{
    if (eglCheckVersion(1, 5)) {
#if USE(LIBEPOXY)
        return eglDestroyImage(m_eglDisplay, image);
#else
        static PFNEGLDESTROYIMAGEPROC s_eglDestroyImage = reinterpret_cast<PFNEGLDESTROYIMAGEPROC>(eglGetProcAddress("eglDestroyImage"));
        if (s_eglDestroyImage)
            return s_eglDestroyImage(m_eglDisplay, image);
        return false;
#endif
    }

    if (!m_eglExtensions.KHR_image_base)
        return false;

#if USE(LIBEPOXY)
    return eglDestroyImageKHR(m_eglDisplay, image);
#else
    static PFNEGLDESTROYIMAGEKHRPROC s_eglDestroyImageKHR = reinterpret_cast<PFNEGLDESTROYIMAGEKHRPROC>(eglGetProcAddress("eglDestroyImageKHR"));
    if (s_eglDestroyImageKHR)
        return s_eglDestroyImageKHR(m_eglDisplay, image);
    return false;
#endif
}

#if USE(GBM)
EGLDeviceEXT PlatformDisplay::eglDevice()
{
    if (!GLContext::isExtensionSupported(eglQueryString(nullptr, EGL_EXTENSIONS), "EGL_EXT_device_query"))
        return nullptr;

    if (!m_eglDisplayInitialized)
        const_cast<PlatformDisplay*>(this)->initializeEGLDisplay();

    EGLDeviceEXT eglDevice;
    if (eglQueryDisplayAttribEXT(m_eglDisplay, EGL_DEVICE_EXT, reinterpret_cast<EGLAttrib*>(&eglDevice)))
        return eglDevice;

    return nullptr;
}

const String& PlatformDisplay::drmDeviceFile()
{
    if (!m_drmDeviceFile.has_value()) {
        if (EGLDeviceEXT device = eglDevice()) {
            if (GLContext::isExtensionSupported(eglQueryDeviceStringEXT(device, EGL_EXTENSIONS), "EGL_EXT_device_drm")) {
                m_drmDeviceFile = String::fromUTF8(eglQueryDeviceStringEXT(device, EGL_DRM_DEVICE_FILE_EXT));
                return m_drmDeviceFile.value();
            }
        }
        m_drmDeviceFile = String();
    }

    return m_drmDeviceFile.value();
}

static void drmForeachDevice(Function<bool(drmDevice*)>&& functor)
{
    drmDevicePtr devices[64];
    memset(devices, 0, sizeof(devices));

    int numDevices = drmGetDevices2(0, devices, std::size(devices));
    if (numDevices <= 0)
        return;

    for (int i = 0; i < numDevices; ++i) {
        if (!functor(devices[i]))
            break;
    }
    drmFreeDevices(devices, numDevices);
}

static String drmFirstRenderNode()
{
    String renderNodeDeviceFile;
    drmForeachDevice([&](drmDevice* device) {
        if (!(device->available_nodes & (1 << DRM_NODE_RENDER)))
            return true;

        renderNodeDeviceFile = String::fromUTF8(device->nodes[DRM_NODE_RENDER]);
        return false;
    });
    return renderNodeDeviceFile;
}

static String drmRenderNodeFromPrimaryDeviceFile(const String& primaryDeviceFile)
{
    if (primaryDeviceFile.isEmpty())
        return drmFirstRenderNode();

    String renderNodeDeviceFile;
    drmForeachDevice([&](drmDevice* device) {
        if (!(device->available_nodes & (1 << DRM_NODE_PRIMARY | 1 << DRM_NODE_RENDER)))
            return true;

        if (String::fromUTF8(device->nodes[DRM_NODE_PRIMARY]) == primaryDeviceFile) {
            renderNodeDeviceFile = String::fromUTF8(device->nodes[DRM_NODE_RENDER]);
            return false;
        }

        return true;
    });
    // If we fail to find a render node for the device file, just use the device file as render node.
    return !renderNodeDeviceFile.isEmpty() ? renderNodeDeviceFile : primaryDeviceFile;
}

const String& PlatformDisplay::drmRenderNodeFile()
{
    if (!m_drmRenderNodeFile.has_value()) {
        const char* envDeviceFile = getenv("WEBKIT_WEB_RENDER_DEVICE_FILE");
        if (envDeviceFile && *envDeviceFile) {
            m_drmRenderNodeFile = String::fromUTF8(envDeviceFile);
            return m_drmRenderNodeFile.value();
        }

        if (EGLDeviceEXT device = eglDevice()) {
            if (GLContext::isExtensionSupported(eglQueryDeviceStringEXT(device, EGL_EXTENSIONS), "EGL_EXT_device_drm_render_node")) {
                m_drmRenderNodeFile = String::fromUTF8(eglQueryDeviceStringEXT(device, EGL_DRM_RENDER_NODE_FILE_EXT));
                return m_drmRenderNodeFile.value();
            }

            // If EGL_EXT_device_drm_render_node is not present, try to get the render node using DRM API.
            m_drmRenderNodeFile = drmRenderNodeFromPrimaryDeviceFile(drmDeviceFile());
        } else {
            // If EGLDevice is not available, just get the first render node returned by DRM.
            m_drmRenderNodeFile = drmFirstRenderNode();
        }
    }

    return m_drmRenderNodeFile.value();
}

struct gbm_device* PlatformDisplay::gbmDevice()
{
    auto& device = GBMDevice::singleton();
    if (!device.isInitialized())
        device.initialize(drmRenderNodeFile());

    return device.device();
}
#endif

#endif // USE(EGL)

#if USE(LCMS)
cmsHPROFILE PlatformDisplay::colorProfile() const
{
    if (!m_iccProfile)
        m_iccProfile = LCMSProfilePtr(cmsCreate_sRGBProfile());
    return m_iccProfile.get();
}
#endif

#if USE(ATSPI)
const String& PlatformDisplay::accessibilityBusAddress() const
{
    if (m_accessibilityBusAddress)
        return m_accessibilityBusAddress.value();

    const char* address = g_getenv("AT_SPI_BUS_ADDRESS");
    if (address && *address) {
        m_accessibilityBusAddress = String::fromUTF8(address);
        return m_accessibilityBusAddress.value();
    }

    auto platformAddress = platformAccessibilityBusAddress();
    if (!platformAddress.isEmpty()) {
        m_accessibilityBusAddress = platformAddress;
        return m_accessibilityBusAddress.value();
    }

    GRefPtr<GDBusConnection> sessionBus = adoptGRef(g_bus_get_sync(G_BUS_TYPE_SESSION, nullptr, nullptr));
    if (sessionBus.get()) {
        GRefPtr<GDBusMessage> message = adoptGRef(g_dbus_message_new_method_call("org.a11y.Bus", "/org/a11y/bus", "org.a11y.Bus", "GetAddress"));
        g_dbus_message_set_body(message.get(), g_variant_new("()"));
        GRefPtr<GDBusMessage> reply = adoptGRef(g_dbus_connection_send_message_with_reply_sync(sessionBus.get(), message.get(),
            G_DBUS_SEND_MESSAGE_FLAGS_NONE, 30000, nullptr, nullptr, nullptr));
        if (reply) {
            GUniqueOutPtr<GError> error;
            if (g_dbus_message_to_gerror(reply.get(), &error.outPtr())) {
                if (!g_error_matches(error.get(), G_DBUS_ERROR, G_DBUS_ERROR_SERVICE_UNKNOWN))
                    WTFLogAlways("Can't find a11y bus: %s", error->message);
            } else {
                GUniqueOutPtr<char> a11yAddress;
                g_variant_get(g_dbus_message_get_body(reply.get()), "(s)", &a11yAddress.outPtr());
                m_accessibilityBusAddress = String::fromUTF8(a11yAddress.get());
                return m_accessibilityBusAddress.value();
            }
        }
    }

    WTFLogAlways("Could not determine the accessibility bus address");
    m_accessibilityBusAddress = String();
    return m_accessibilityBusAddress.value();
}
#endif

} // namespace WebCore