Bug 1035774 - Introduce functions to get the capabilities for the primary pointer and for all available pointers on Windows. r=masayuki

Note that the logic of IsTabletDevice() and relevant stuff are mostly a mimic of
IsTabletDevice [1] and IsDeviceUsedAsATablet [2] in chromium.

As for the primary pointer's capabilities, there seems no API to tell which
device is the primary, so here we determine it as following priorities;

1) if the machine is in tablet mode, the tablet (touch screen) is the primary
2) if the machine has a mouse, the mouse is the primary
3) if the machine has a digitizer, it's the primary

This priority is also the same as what chromium does in
GetPrimaryPointerType [2] and GetAvailablePointerTypes [3].

[1] d4c8983688/base/win/win_util.cc (450)
[2] d4c8983688/base/win/win_util.cc (468)
[3] d4c8983688/ui/base/touch/touch_device_win.cc (37)
[4] d4c8983688/ui/base/touch/touch_device_win.cc (82)

Differential Revision: https://phabricator.services.mozilla.com/D3300

widget/windows/WinUtils.cpp

@@ -24,6 +24,7 @@
 #include "mozilla/WindowsVersion.h"
 #include "mozilla/Unused.h"
 #include "nsIContentPolicy.h"
+#include "nsIWindowsUIUtils.h"
 #include "nsContentUtils.h"
 
 #include "mozilla/Logging.h"
@@ -1802,6 +1803,120 @@ WinUtils::GetPowerPlatformRole()
   return power_determine_platform_role(POWER_PLATFORM_ROLE_V2);
 }
 
+static bool
+IsWindows10TabletMode()
+{
+  nsCOMPtr<nsIWindowsUIUtils>
+    uiUtils(do_GetService("@mozilla.org/windows-ui-utils;1"));
+  if (NS_WARN_IF(!uiUtils)) {
+    return false;
+  }
+  bool isInTabletMode = false;
+  uiUtils->GetInTabletMode(&isInTabletMode);
+  return isInTabletMode;
+}
+
+static bool
+CallGetAutoRotationState(AR_STATE* aRotationState)
+{
+  typedef BOOL (WINAPI* GetAutoRotationStateFunc)(PAR_STATE pState);
+  static GetAutoRotationStateFunc get_auto_rotation_state_func =
+      reinterpret_cast<GetAutoRotationStateFunc>(::GetProcAddress(
+          GetModuleHandleW(L"user32.dll"), "GetAutoRotationState"));
+  if (get_auto_rotation_state_func) {
+    ZeroMemory(aRotationState, sizeof(AR_STATE));
+    return get_auto_rotation_state_func(aRotationState);
+  }
+  return false;
+}
+
+static bool
+IsTabletDevice()
+{
+  // Guarantees that:
+  // - The device has a touch screen.
+  // - It is used as a tablet which means that it has no keyboard connected.
+  // On Windows 10 it means that it is verifying with ConvertibleSlateMode.
+
+  if (!IsWin8OrLater()) {
+    return false;
+  }
+
+  if (IsWindows10TabletMode()) {
+    return true;
+  }
+
+  if (!GetSystemMetrics(SM_MAXIMUMTOUCHES)) {
+    return false;
+  }
+
+  // If the device is docked, the user is treating the device as a PC.
+  if (GetSystemMetrics(SM_SYSTEMDOCKED)) {
+    return false;
+  }
+
+  // If the device is not supporting rotation, it's unlikely to be a tablet,
+  // a convertible or a detachable. See:
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/dn629263(v=vs.85).aspx
+  AR_STATE rotation_state;
+  if (CallGetAutoRotationState(&rotation_state) &&
+      (rotation_state & (AR_NOT_SUPPORTED | AR_LAPTOP | AR_NOSENSOR))) {
+    return false;
+  }
+
+  // PlatformRoleSlate was added in Windows 8+.
+  POWER_PLATFORM_ROLE role = WinUtils::GetPowerPlatformRole();
+  if (role == PlatformRoleMobile || role == PlatformRoleSlate) {
+    return !GetSystemMetrics(SM_CONVERTIBLESLATEMODE);
+  }
+  return false;
+}
+
+static bool
+IsMousePresent()
+{
+  return ::GetSystemMetrics(SM_MOUSEPRESENT);
+}
+
+/* static */
+PointerCapabilities
+WinUtils::GetPrimaryPointerCapabilities()
+{
+  if (IsTabletDevice()) {
+    return PointerCapabilities::Coarse;
+  }
+
+  if (IsMousePresent()) {
+    return PointerCapabilities::Fine|
+           PointerCapabilities::Hover;
+  }
+
+  if (IsTouchDeviceSupportPresent()) {
+    return PointerCapabilities::Coarse;
+  }
+
+  return PointerCapabilities::None;
+}
+
+/* static */
+PointerCapabilities
+WinUtils::GetAllPointerCapabilities()
+{
+  PointerCapabilities result = PointerCapabilities::None;
+
+  if (IsTabletDevice() ||
+      IsTouchDeviceSupportPresent()) {
+    result |= PointerCapabilities::Coarse;
+  }
+
+  if (IsMousePresent()) {
+    result |= PointerCapabilities::Fine |
+              PointerCapabilities::Hover;
+  }
+
+  return result;
+}
+
 /* static */
 bool
 WinUtils::ResolveJunctionPointsAndSymLinks(std::wstring& aPath)

widget/windows/WinUtils.h

@@ -105,6 +105,7 @@ typedef DPI_AWARENESS_CONTEXT(WINAPI * SetThreadDpiAwarenessContextProc)(DPI_AWA
 typedef BOOL(WINAPI * EnableNonClientDpiScalingProc)(HWND);
 
 namespace mozilla {
+enum class PointerCapabilities : uint8_t;
 #if defined(ACCESSIBILITY)
 namespace a11y {
 class Accessible;
@@ -474,6 +475,11 @@ public:
    */
   static POWER_PLATFORM_ROLE GetPowerPlatformRole();
 
+  // For pointer and hover media queries features.
+  static PointerCapabilities GetPrimaryPointerCapabilities();
+  // For any-pointer and any-hover media queries features.
+  static PointerCapabilities GetAllPointerCapabilities();
+
   /**
    * Fully resolves a path to its final path name. So if path contains
    * junction points or symlinks to other folders, we'll resolve the path

widget/windows/nsLookAndFeel.cpp

@@ -615,6 +615,18 @@ nsLookAndFeel::GetIntImpl(IntID aID, int32_t &aResult)
         aResult = enableAnimation ? 0 : 1;
         break;
     }
+    case eIntID_PrimaryPointerCapabilities: {
+        PointerCapabilities caps =
+            widget::WinUtils::GetPrimaryPointerCapabilities();
+        aResult = static_cast<int32_t>(caps);
+        break;
+    }
+    case eIntID_AllPointerCapabilities: {
+        PointerCapabilities caps =
+            widget::WinUtils::GetAllPointerCapabilities();
+        aResult = static_cast<int32_t>(caps);
+        break;
+    }
     default:
         aResult = 0;
         res = NS_ERROR_FAILURE;