Bug 1886711: Implement the UIA Toggle pattern. r=nlapre

Differential Revision: https://phabricator.services.mozilla.com/D205552

accessible/tests/browser/windows/uia/browser_simplePatterns.js

@@ -4,6 +4,12 @@
 
 "use strict";
 
+/* eslint-disable camelcase */
+const ToggleState_Off = 0;
+const ToggleState_On = 1;
+const ToggleState_Indeterminate = 2;
+/* eslint-enable camelcase */
+
 /**
  * Test the Invoke pattern.
  */
@@ -11,6 +17,7 @@ addUiaTask(
   `
 <button id="button">button</button>
 <p id="p">p</p>
+<input id="checkbox" type="checkbox">
   `,
   async function testInvoke() {
     await definePyVar("doc", `getDocUia()`);
@@ -32,10 +39,105 @@ addUiaTask(
       ok(true, "button got Invoked event");
     }
 
-    let hasPattern = await runPython(`
-      p = findUiaByDomId(doc, "p")
-      return bool(getUiaPattern(p, "Invoke"))
-    `);
-    ok(!hasPattern, "p doesn't have Invoke pattern");
+    await testPatternAbsent("p", "Invoke");
+    // The Microsoft IA2 -> UIA proxy doesn't follow Microsoft's own rules.
+    if (gIsUiaEnabled) {
+      // Check boxes expose the Toggle pattern, so they should not expose the
+      // Invoke pattern.
+      await testPatternAbsent("checkbox", "Invoke");
+    }
+  }
+);
+
+/**
+ * Test the Toggle pattern.
+ */
+addUiaTask(
+  `
+<input id="checkbox" type="checkbox" checked>
+<button id="toggleButton" aria-pressed="false">toggle</button>
+<button id="button">button</button>
+<p id="p">p</p>
+
+<script>
+  // When checkbox is clicked and it is not checked, make it indeterminate.
+  document.getElementById("checkbox").addEventListener("click", evt => {
+    // Within the event listener, .checked is reversed and you can't set
+    // .indeterminate. Work around this by deferring and handling the changes
+    // ourselves.
+    evt.preventDefault();
+    const target = evt.target;
+    setTimeout(() => {
+      if (target.checked) {
+        target.checked = false;
+      } else {
+        target.indeterminate = true;
+      }
+    }, 0);
+  });
+
+  // When toggleButton is clicked, set aria-pressed to true.
+  document.getElementById("toggleButton").addEventListener("click", evt => {
+    evt.target.ariaPressed = "true";
+  });
+</script>
+  `,
+  async function testToggle() {
+    await definePyVar("doc", `getDocUia()`);
+    await assignPyVarToUiaWithId("checkbox");
+    await definePyVar("pattern", `getUiaPattern(checkbox, "Toggle")`);
+    ok(await runPython(`bool(pattern)`), "checkbox has Toggle pattern");
+    is(
+      await runPython(`pattern.CurrentToggleState`),
+      ToggleState_On,
+      "checkbox has ToggleState_On"
+    );
+    // The IA2 -> UIA proxy doesn't fire ToggleState prop change events.
+    if (gIsUiaEnabled) {
+      info("Calling Toggle on checkbox");
+      await setUpWaitForUiaPropEvent("ToggleToggleState", "checkbox");
+      await runPython(`pattern.Toggle()`);
+      await waitForUiaEvent();
+      ok(true, "Got ToggleState prop change event on checkbox");
+      is(
+        await runPython(`pattern.CurrentToggleState`),
+        ToggleState_Off,
+        "checkbox has ToggleState_Off"
+      );
+      info("Calling Toggle on checkbox");
+      await setUpWaitForUiaPropEvent("ToggleToggleState", "checkbox");
+      await runPython(`pattern.Toggle()`);
+      await waitForUiaEvent();
+      ok(true, "Got ToggleState prop change event on checkbox");
+      is(
+        await runPython(`pattern.CurrentToggleState`),
+        ToggleState_Indeterminate,
+        "checkbox has ToggleState_Indeterminate"
+      );
+    }
+
+    await assignPyVarToUiaWithId("toggleButton");
+    await definePyVar("pattern", `getUiaPattern(toggleButton, "Toggle")`);
+    ok(await runPython(`bool(pattern)`), "toggleButton has Toggle pattern");
+    is(
+      await runPython(`pattern.CurrentToggleState`),
+      ToggleState_Off,
+      "toggleButton has ToggleState_Off"
+    );
+    if (gIsUiaEnabled) {
+      info("Calling Toggle on toggleButton");
+      await setUpWaitForUiaPropEvent("ToggleToggleState", "toggleButton");
+      await runPython(`pattern.Toggle()`);
+      await waitForUiaEvent();
+      ok(true, "Got ToggleState prop change event on toggleButton");
+      is(
+        await runPython(`pattern.CurrentToggleState`),
+        ToggleState_On,
+        "toggleButton has ToggleState_Off"
+      );
+    }
+
+    await testPatternAbsent("button", "Toggle");
+    await testPatternAbsent("p", "Toggle");
   }
 );

accessible/tests/browser/windows/uia/head.js

@@ -4,7 +4,7 @@
 
 "use strict";
 
-/* exported gIsUiaEnabled, addUiaTask, definePyVar, assignPyVarToUiaWithId, setUpWaitForUiaEvent, setUpWaitForUiaPropEvent, waitForUiaEvent */
+/* exported gIsUiaEnabled, addUiaTask, definePyVar, assignPyVarToUiaWithId, setUpWaitForUiaEvent, setUpWaitForUiaPropEvent, waitForUiaEvent, testPatternAbsent */
 
 // Load the shared-head file first.
 Services.scriptloader.loadSubScript(
@@ -102,3 +102,14 @@ function waitForUiaEvent() {
     onEvent.wait()
   `);
 }
+
+/**
+ * Verify that a UIA element does *not* support the given control pattern.
+ */
+async function testPatternAbsent(id, patternName) {
+  const hasPattern = await runPython(`
+    el = findUiaByDomId(doc, "${id}")
+    return bool(getUiaPattern(el, "${patternName}"))
+  `);
+  ok(!hasPattern, `${id} doesn't have ${patternName} pattern`);
+}

accessible/windows/msaa/Platform.cpp

@@ -72,8 +72,10 @@ void a11y::PlatformEvent(Accessible* aTarget, uint32_t aEventType) {
   uiaRawElmProvider::RaiseUiaEventForGeckoEvent(aTarget, aEventType);
 }
 
-void a11y::PlatformStateChangeEvent(Accessible* aTarget, uint64_t, bool) {
+void a11y::PlatformStateChangeEvent(Accessible* aTarget, uint64_t aState,
+                                    bool aEnabled) {
   MsaaAccessible::FireWinEvent(aTarget, nsIAccessibleEvent::EVENT_STATE_CHANGE);
+  uiaRawElmProvider::RaiseUiaEventForStateChange(aTarget, aState, aEnabled);
 }
 
 void a11y::PlatformFocusEvent(Accessible* aTarget,

accessible/windows/uia/uiaRawElmProvider.cpp

@@ -65,6 +65,38 @@ void uiaRawElmProvider::RaiseUiaEventForGeckoEvent(Accessible* aAcc,
   }
 }
 
+/* static */
+void uiaRawElmProvider::RaiseUiaEventForStateChange(Accessible* aAcc,
+                                                    uint64_t aState,
+                                                    bool aEnabled) {
+  if (!StaticPrefs::accessibility_uia_enable()) {
+    return;
+  }
+  auto* uia = MsaaAccessible::GetFrom(aAcc);
+  if (!uia) {
+    return;
+  }
+  PROPERTYID property = 0;
+  _variant_t newVal;
+  switch (aState) {
+    case states::CHECKED:
+    case states::MIXED:
+    case states::PRESSED:
+      property = UIA_ToggleToggleStatePropertyId;
+      newVal.vt = VT_I4;
+      newVal.lVal = ToToggleState(aEnabled ? aState : 0);
+      break;
+    default:
+      return;
+  }
+  MOZ_ASSERT(property);
+  if (::UiaClientsAreListening()) {
+    // We can't get the old value. Thankfully, clients don't seem to need it.
+    _variant_t oldVal;
+    ::UiaRaiseAutomationPropertyChangedEvent(uia, property, oldVal, newVal);
+  }
+}
+
 // IUnknown
 
 STDMETHODIMP
@@ -78,6 +110,8 @@ uiaRawElmProvider::QueryInterface(REFIID aIid, void** aInterface) {
     *aInterface = static_cast<IRawElementProviderFragment*>(this);
   } else if (aIid == IID_IInvokeProvider) {
     *aInterface = static_cast<IInvokeProvider*>(this);
+  } else if (aIid == IID_IToggleProvider) {
+    *aInterface = static_cast<IToggleProvider*>(this);
   } else {
     return E_NOINTERFACE;
   }
@@ -176,11 +210,20 @@ uiaRawElmProvider::GetPatternProvider(
   }
   switch (aPatternId) {
     case UIA_InvokePatternId:
-      if (acc->ActionCount() > 0) {
+      // Per the UIA documentation, we should only expose the Invoke pattern "if
+      // the same behavior is not exposed through another control pattern
+      // provider".
+      if (acc->ActionCount() > 0 && !HasTogglePattern()) {
         RefPtr<IInvokeProvider> invoke = this;
         invoke.forget(aPatternProvider);
       }
       return S_OK;
+    case UIA_TogglePatternId:
+      if (HasTogglePattern()) {
+        RefPtr<IToggleProvider> toggle = this;
+        toggle.forget(aPatternProvider);
+      }
+      return S_OK;
   }
   return S_OK;
 }
@@ -497,6 +540,31 @@ uiaRawElmProvider::Invoke() {
   return S_OK;
 }
 
+// IToggleProvider methods
+
+STDMETHODIMP
+uiaRawElmProvider::Toggle() {
+  Accessible* acc = Acc();
+  if (!acc) {
+    return CO_E_OBJNOTCONNECTED;
+  }
+  acc->DoAction(0);
+  return S_OK;
+}
+
+STDMETHODIMP
+uiaRawElmProvider::get_ToggleState(__RPC__out enum ToggleState* aRetVal) {
+  if (!aRetVal) {
+    return E_INVALIDARG;
+  }
+  Accessible* acc = Acc();
+  if (!acc) {
+    return CO_E_OBJNOTCONNECTED;
+  }
+  *aRetVal = ToToggleState(acc->State());
+  return S_OK;
+}
+
 // Private methods
 
 bool uiaRawElmProvider::IsControl() {
@@ -578,3 +646,21 @@ long uiaRawElmProvider::GetControlType() const {
   MOZ_CRASH("Unknown role.");
   return 0;
 }
+
+bool uiaRawElmProvider::HasTogglePattern() {
+  Accessible* acc = Acc();
+  MOZ_ASSERT(acc);
+  return acc->State() & states::CHECKABLE ||
+         acc->Role() == roles::TOGGLE_BUTTON;
+}
+
+/* static */
+ToggleState uiaRawElmProvider::ToToggleState(uint64_t aState) {
+  if (aState & states::MIXED) {
+    return ToggleState_Indeterminate;
+  }
+  if (aState & (states::CHECKED | states::PRESSED)) {
+    return ToggleState_On;
+  }
+  return ToggleState_Off;
+}

accessible/windows/uia/uiaRawElmProvider.h

@@ -22,10 +22,13 @@ class Accessible;
 class uiaRawElmProvider : public IAccessibleEx,
                           public IRawElementProviderSimple,
                           public IRawElementProviderFragment,
-                          public IInvokeProvider {
+                          public IInvokeProvider,
+                          public IToggleProvider {
  public:
   static void RaiseUiaEventForGeckoEvent(Accessible* aAcc,
                                          uint32_t aGeckoEvent);
+  static void RaiseUiaEventForStateChange(Accessible* aAcc, uint64_t aState,
+                                          bool aEnabled);
 
   // IUnknown
   STDMETHODIMP QueryInterface(REFIID aIid, void** aInterface);
@@ -85,10 +88,18 @@ class uiaRawElmProvider : public IAccessibleEx,
   // IInvokeProvider
   virtual HRESULT STDMETHODCALLTYPE Invoke(void);
 
+  // IToggleProvider
+  virtual HRESULT STDMETHODCALLTYPE Toggle(void);
+
+  virtual /* [propget] */ HRESULT STDMETHODCALLTYPE get_ToggleState(
+      /* [retval][out] */ __RPC__out enum ToggleState* aRetVal);
+
  private:
   Accessible* Acc() const;
   bool IsControl();
   long GetControlType() const;
+  bool HasTogglePattern();
+  static ToggleState ToToggleState(uint64_t aState);
 };
 
 }  // namespace a11y