Bug 1819160 - Map Android ids to doc/accessible id pairs. r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D179737

accessible/android/SessionAccessibility.cpp

@@ -269,12 +269,9 @@ RefPtr<SessionAccessibility> SessionAccessibility::GetInstanceFor(
       return GetInstanceFor(doc->GetPresShell());
     }
   } else {
-    DocAccessibleParent* remoteDoc = aAccessible->AsRemote()->Document();
-    if (remoteDoc->mSessionAccessibility) {
-      return remoteDoc->mSessionAccessibility;
-    }
     dom::CanonicalBrowsingContext* cbc =
-        static_cast<dom::BrowserParent*>(remoteDoc->Manager())
+        static_cast<dom::BrowserParent*>(
+            aAccessible->AsRemote()->Document()->Manager())
             ->GetBrowsingContext()
             ->Top();
     dom::BrowserParent* bp = cbc->GetBrowserParent();
@@ -285,10 +282,7 @@ RefPtr<SessionAccessibility> SessionAccessibility::GetInstanceFor(
     if (auto element = bp->GetOwnerElement()) {
       if (auto doc = element->OwnerDoc()) {
         if (nsPresContext* presContext = doc->GetPresContext()) {
-          RefPtr<SessionAccessibility> sessionAcc =
-              GetInstanceFor(presContext->PresShell());
-          remoteDoc->mSessionAccessibility = sessionAcc;
-          return sessionAcc;
+          return GetInstanceFor(presContext->PresShell());
         }
       } else {
         MOZ_ASSERT_UNREACHABLE(
@@ -684,14 +678,7 @@ void SessionAccessibility::PopulateNodeInfo(
 }
 
 Accessible* SessionAccessibility::GetAccessibleByID(int32_t aID) const {
-  Accessible* accessible = mIDToAccessibleMap.Get(aID);
-  if (accessible && accessible->IsLocal() &&
-      accessible->AsLocal()->IsDefunct()) {
-    MOZ_ASSERT_UNREACHABLE("Registered accessible is defunct!");
-    return nullptr;
-  }
-
-  return accessible;
+  return mIDToAccessibleMap.Get(aID);
 }
 
 #ifdef DEBUG
@@ -705,6 +692,58 @@ static bool IsDetachedDoc(Accessible* aAccessible) {
 }
 #endif
 
+SessionAccessibility::IDMappingEntry::IDMappingEntry(Accessible* aAccessible)
+    : mInternalID(0) {
+  *this = aAccessible;
+}
+
+SessionAccessibility::IDMappingEntry&
+SessionAccessibility::IDMappingEntry::operator=(Accessible* aAccessible) {
+  mInternalID = aAccessible->ID();
+  MOZ_ASSERT(!(mInternalID & IS_REMOTE), "First bit is used in accessible ID!");
+  if (aAccessible->IsRemote()) {
+    mInternalID |= IS_REMOTE;
+  }
+
+  Accessible* docAcc = nsAccUtils::DocumentFor(aAccessible);
+  MOZ_ASSERT(docAcc);
+  if (docAcc) {
+    MOZ_ASSERT(docAcc->IsRemote() == aAccessible->IsRemote());
+    if (docAcc->IsRemote()) {
+      mDoc = docAcc->AsRemote()->AsDoc();
+    } else {
+      mDoc = docAcc->AsLocal();
+    }
+  }
+
+  return *this;
+}
+
+SessionAccessibility::IDMappingEntry::operator Accessible*() const {
+  if (mInternalID == 0) {
+    return static_cast<LocalAccessible*>(mDoc.get());
+  }
+
+  if (mInternalID == IS_REMOTE) {
+    return static_cast<DocAccessibleParent*>(mDoc.get());
+  }
+
+  if (mInternalID & IS_REMOTE) {
+    return static_cast<DocAccessibleParent*>(mDoc.get())
+        ->GetAccessible(mInternalID & ~IS_REMOTE);
+  }
+
+  Accessible* accessible =
+      static_cast<LocalAccessible*>(mDoc.get())
+          ->AsDoc()
+          ->GetAccessibleByUniqueID(reinterpret_cast<void*>(mInternalID));
+  // If the accessible is retrievable from the DocAccessible, it can't be
+  // defunct.
+  MOZ_ASSERT(!accessible->AsLocal()->IsDefunct());
+
+  return accessible;
+}
+
 void SessionAccessibility::RegisterAccessible(Accessible* aAccessible) {
   if (IPCAccessibilityActive()) {
     // Don't register accessible in content process.
@@ -766,7 +805,6 @@ void SessionAccessibility::UnregisterAccessible(Accessible* aAccessible) {
   }
 
   RefPtr<SessionAccessibility> sessionAcc = GetInstanceFor(aAccessible);
-  MOZ_ASSERT(sessionAcc, "Need SessionAccessibility to unregister Accessible!");
   if (sessionAcc) {
     Accessible* registeredAcc =
         sessionAcc->mIDToAccessibleMap.Get(virtualViewID);

accessible/android/SessionAccessibility.h

@@ -110,10 +110,34 @@ class SessionAccessibility final
   jni::NativeWeakPtr<widget::GeckoViewSupport> mWindow;  // Parent only
   java::SessionAccessibility::NativeProvider::GlobalRef mSessionAccessibility;
 
+  class IDMappingEntry {
+   public:
+    explicit IDMappingEntry(Accessible* aAccessible);
+
+    IDMappingEntry& operator=(Accessible* aAccessible);
+
+    operator Accessible*() const;
+
+   private:
+    // A strong reference to a DocAccessible or DocAccessibleParent. They don't
+    // share any useful base class except nsISupports, so we use that.
+    // When we retrieve the document from this reference we cast it to
+    // LocalAccessible in the DocAccessible case because DocAccessible has
+    // multiple inheritance paths for nsISupports.
+    RefPtr<nsISupports> mDoc;
+    // The ID of the accessible as used in the internal doc mapping.
+    // We rely on this ID being pointer derived and therefore divisible by two
+    // so we can use the first bit to mark if it is remote or not.
+    uint64_t mInternalID;
+
+    static const uintptr_t IS_REMOTE = 0x1;
+  };
+
   /*
    * This provides a mapping from 32 bit id to accessible objects.
    */
-  nsTHashMap<nsUint32HashKey, Accessible*> mIDToAccessibleMap;
+  nsBaseHashtable<nsUint32HashKey, IDMappingEntry, Accessible*>
+      mIDToAccessibleMap;
 };
 
 }  // namespace a11y

accessible/ipc/DocAccessibleParent.cpp

@@ -29,7 +29,6 @@
 #endif
 
 #if defined(ANDROID)
-#  include "mozilla/a11y/SessionAccessibility.h"
 #  define ACQUIRE_ANDROID_LOCK \
     MonitorAutoLock mal(nsAccessibilityService::GetAndroidMonitor());
 #else

accessible/ipc/DocAccessibleParent.h

@@ -29,10 +29,6 @@ class xpcAccessibleGeneric;
 class DocAccessiblePlatformExtParent;
 #endif
 
-#ifdef ANDROID
-class SessionAccessibility;
-#endif
-
 /*
  * These objects live in the main process and comunicate with and represent
  * an accessible document in a content process.
@@ -348,10 +344,6 @@ class DocAccessibleParent : public RemoteAccessible,
 
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) override;
 
-#ifdef ANDROID
-  RefPtr<SessionAccessibility> mSessionAccessibility;
-#endif
-
  private:
   ~DocAccessibleParent();
 

accessible/ipc/moz.build

@@ -24,11 +24,6 @@ else:
         LOCAL_INCLUDES += [
             "/accessible/mac",
         ]
-    elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "android":
-        LOCAL_INCLUDES += [
-            "/accessible/android",
-            "/widget/android",
-        ]
     else:
         LOCAL_INCLUDES += [
             "/accessible/other",