ozone/platform/wayland: Implement pointer handling

ui/ozone/platform/wayland/wayland_display.cc

Index: ui/ozone/platform/wayland/wayland_display.cc
diff --git a/ui/ozone/platform/wayland/wayland_display.cc b/ui/ozone/platform/wayland/wayland_display.cc
index 1c0f07e25154aada7420abe0f4f3b7100554f6df..50f1175ce2cc8224c11bdae46034d164f6847a7d 100644
--- a/ui/ozone/platform/wayland/wayland_display.cc
+++ b/ui/ozone/platform/wayland/wayland_display.cc
@@ -6,6 +6,7 @@
 
 #include <xdg-shell-unstable-v5-client-protocol.h>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/ozone/platform/wayland/wayland_object.h"
@@ -16,6 +17,7 @@ static_assert(XDG_SHELL_VERSION_CURRENT == 5, "Unsupported xdg-shell version");
 namespace ui {
 namespace {
 const uint32_t kMaxCompositorVersion = 4;
+const uint32_t kMaxSeatVersion = 4;
 const uint32_t kMaxShmVersion = 1;
 const uint32_t kMaxXdgShellVersion = 1;
 }  // namespace
@@ -52,6 +54,10 @@ bool WaylandDisplay::Initialize() {
     LOG(ERROR) << "No wl_shm object";
     return false;
   }
+  if (!seat_) {
+    LOG(ERROR) << "No wl_seat object";
+    return false;
+  }
   if (!shell_) {
     LOG(ERROR) << "No xdg_shell object";
     return false;
@@ -79,17 +85,20 @@ void WaylandDisplay::RemoveWindow(WaylandWindow* window) {
 }
 
 void WaylandDisplay::OnDispatcherListChanged() {
-  if (watching_)
+  if (watching_ || !base::MessageLoopForUI::IsCurrent())
     return;
 
   DCHECK(display_);
-  DCHECK(base::MessageLoopForUI::IsCurrent());

[spang, 2016/02/26 01:41:11]

I hope this cannot get called off the UI thread.. so why did it get relaxed from
a DCHECK to a conditional?

[Michael Forney, 2016/02/26 01:47:34]

I changed it to a conditional because this gets called from the tests when a new
WaylandWindow is created.

Maybe there is a better way to deal with this?

[spang, 2016/02/26 03:51:45]

Sure, create a UI message loop from the test before creating the window.

Ideally the test would actually use the message loop, too, so that it fully
tests the IO handling. You used wl_display_roundtrip() instead but it is not
completely realistic.

Anyway, simply creating the loop would avoid having special test-only handling
here.

[Michael Forney, 2016/02/27 00:01:37]

Cool. Looks like just creating a MessageLoopForUI and using
RunLoop().RunUntilIdle() does the job.

I've rebased this CL on a patch series that does this.

   base::MessageLoopForUI::current()->WatchFileDescriptor(
       wl_display_get_fd(display_.get()), true,
       base::MessagePumpLibevent::WATCH_READ, &controller_, this);
   watching_ = true;
 }
 
+void WaylandDisplay::DispatchUiEvent(Event* event) {
+  PlatformEventSource::DispatchEvent(event);
+}
+
 void WaylandDisplay::OnFileCanReadWithoutBlocking(int fd) {
   wl_display_dispatch(display_.get());
   for (const auto& window : window_map_)
@@ -104,6 +113,9 @@ void WaylandDisplay::Global(void* data,
                             uint32_t name,
                             const char* interface,
                             uint32_t version) {
+  static const wl_seat_listener seat_listener = {
+      &WaylandDisplay::Capabilities, &WaylandDisplay::Name,
+  };
   static const xdg_shell_listener shell_listener = {
       &WaylandDisplay::Ping,
   };
@@ -119,6 +131,14 @@ void WaylandDisplay::Global(void* data,
         wl::Bind<wl_shm>(registry, name, std::min(version, kMaxShmVersion));
     if (!display->shm_)
       LOG(ERROR) << "Failed to bind to wl_shm global";
+  } else if (!display->seat_ && strcmp(interface, "wl_seat") == 0) {
+    display->seat_ =
+        wl::Bind<wl_seat>(registry, name, std::min(version, kMaxSeatVersion));
+    if (!display->seat_) {
+      LOG(ERROR) << "Failed to bind to wl_seat global";
+      return;
+    }
+    wl_seat_add_listener(display->seat_.get(), &seat_listener, display);
   } else if (!display->shell_ && strcmp(interface, "xdg_shell") == 0) {
     display->shell_ = wl::Bind<xdg_shell>(
         registry, name, std::min(version, kMaxXdgShellVersion));
@@ -140,6 +160,30 @@ void WaylandDisplay::GlobalRemove(void* data,
 }
 
 // static
+void WaylandDisplay::Capabilities(void* data,
+                                  wl_seat* seat,
+                                  uint32_t capabilities) {
+  WaylandDisplay* display = static_cast<WaylandDisplay*>(data);
+  if (capabilities & WL_SEAT_CAPABILITY_POINTER) {
+    if (!display->pointer_) {
+      wl_pointer* pointer = wl_seat_get_pointer(display->seat_.get());
+      if (!pointer) {
+        LOG(ERROR) << "Failed to get wl_pointer from seat";
+        return;
+      }
+      display->pointer_ = make_scoped_ptr(new WaylandPointer(
+          pointer, base::Bind(&WaylandDisplay::DispatchUiEvent,
+                              base::Unretained(display))));
+    }
+  } else if (display->pointer_) {
+    display->pointer_.reset();

[spang, 2016/02/26 01:41:11]

How could the capability get revoked?

[Michael Forney, 2016/02/26 01:47:34]

The user unplugs their mouse, and seat no longer has a pointer.

+  }
+}
+
+// static
+void WaylandDisplay::Name(void* data, wl_seat* seat, const char* name) {}
+
+// static
 void WaylandDisplay::Ping(void* data, xdg_shell* shell, uint32_t serial) {
   xdg_shell_pong(shell, serial);
 }