Add EventForwarder for routing touch events

ui/android/view_android.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/android/view_android.h"
 
 #include <algorithm>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
+#include "base/containers/adapters.h"
 #include "cc/layers/layer.h"
 #include "jni/ViewAndroidDelegate_jni.h"
+#include "ui/android/event_handler.h"
+#include "ui/android/view_client.h"
 #include "ui/android/window_android.h"
-#include "ui/display/display.h"
-#include "ui/display/screen.h"
+#include "ui/base/layout.h"
+#include "ui/events/android/motion_event_android.h"
 #include "url/gurl.h"
 
 namespace ui {
 
 using base::android::ConvertUTF8ToJavaString;
 using base::android::JavaRef;
 using base::android::ScopedJavaLocalRef;
 
+namespace {
+
+struct TouchEventSender : ViewAndroid::EventSender {
+  TouchEventSender(bool for_touch_handle)
+      : for_touch_handle_(for_touch_handle) {}
+  bool SendToView(ViewAndroid* view,
+                  const MotionEventAndroid& e) const override {
+    return view->OnTouchEvent(e, for_touch_handle_);
+  }
+
+  bool SendToClient(ViewClient* client,
+                    const MotionEventAndroid& e) const override {
+    return client->OnTouchEvent(e, for_touch_handle_);
+  }
+
+ private:
+  bool for_touch_handle_;
+};
+
+struct MouseEventSender : ViewAndroid::EventSender {
+  MouseEventSender() {}
+  bool SendToView(ViewAndroid* view,
+                  const MotionEventAndroid& e) const override {
+    return view->OnMouseEvent(e);
+  }
+
+  bool SendToClient(ViewClient* client,
+                    const MotionEventAndroid& e) const override {
+    return client->OnMouseEvent(e);
+  }
+};
+
+}  // namespace
+
 ViewAndroid::ScopedAnchorView::ScopedAnchorView(
     JNIEnv* env,
     const JavaRef<jobject>& jview,
     const JavaRef<jobject>& jdelegate)
     : view_(env, jview.obj()), delegate_(env, jdelegate.obj()) {
   // If there's a view, then we need a delegate to remove it.
   DCHECK(!jdelegate.is_null() || jview.is_null());
 }
 
 ViewAndroid::ScopedAnchorView::ScopedAnchorView() { }
@@ skipping 30 matching lines @@
   view_.reset();
   delegate_.reset();
 }
 
 const base::android::ScopedJavaLocalRef<jobject>
 ViewAndroid::ScopedAnchorView::view() const {
   JNIEnv* env = base::android::AttachCurrentThread();
   return view_.get(env);
 }
 
-ViewAndroid::ViewAndroid(const JavaRef<jobject>& delegate)
-    : parent_(nullptr),
-      delegate_(base::android::AttachCurrentThread(), delegate.obj()) {}
+ViewAndroid::ViewAndroid(ViewClient* view_client)
+    : parent_(nullptr), client_(view_client) {}
 
-ViewAndroid::ViewAndroid() : parent_(nullptr) {}
+ViewAndroid::ViewAndroid() : ViewAndroid(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
   RemoveFromParent();
 
   for (std::list<ViewAndroid*>::iterator it = children_.begin();
        it != children_.end(); it++) {
     DCHECK_EQ((*it)->parent_, this);
     (*it)->parent_ = nullptr;
   }
 }
 
 void ViewAndroid::SetDelegate(const JavaRef<jobject>& delegate) {
+  // A ViewAndroid may have its own delegate or otherwise will use the next
+  // available parent's delegate.
   JNIEnv* env = base::android::AttachCurrentThread();
   delegate_ = JavaObjectWeakGlobalRef(env, delegate);
 }
 
+float ViewAndroid::GetDipScale() {
+  return ui::GetScaleFactorForNativeView(this);
+}
+
+ScopedJavaLocalRef<jobject> ViewAndroid::GetEventHandler() {
+  if (!event_handler_) {
+    DCHECK(!ViewTreeHasEventHandler(this))
+        << "Root of the ViewAndroid can have at most one handler.";
+    event_handler_.reset(new EventHandler(this));
+  }
+  return event_handler_->GetJavaObject();
+}
+
 void ViewAndroid::AddChild(ViewAndroid* child) {
   DCHECK(child);
   DCHECK(std::find(children_.begin(), children_.end(), child) ==
          children_.end());
+  DCHECK(!SubtreeHasEventHandler(child) || !ViewTreeHasEventHandler(this))
+      << "Only one event handler is allowed.";
 
+  // The new child goes to the top, which is the end of the list.
   children_.push_back(child);
   if (child->parent_)
     child->RemoveFromParent();
   child->parent_ = this;
 }
 
+// static
+bool ViewAndroid::ViewTreeHasEventHandler(ViewAndroid* view) {
+  ViewAndroid* v = view;
+  do {
+    if (v->has_event_handler())
+      return true;
+    v = v->parent_;
+  } while (v);
+  return SubtreeHasEventHandler(view);
+}
+
+// static
+bool ViewAndroid::SubtreeHasEventHandler(ViewAndroid* view) {
+  if (view->has_event_handler())
+    return true;
+  for (auto* child : view->children_) {
+    if (SubtreeHasEventHandler(child))
+      return true;
+  }
+  return false;
+}
+
+void ViewAndroid::MoveToFront(ViewAndroid* child) {
+  DCHECK(child);
+  auto it = std::find(children_.begin(), children_.end(), child);
+  DCHECK(it != children_.end());
+
+  // Top element is placed at the end of the list.
+  if (*it != children_.back())
+    children_.splice(children_.end(), children_, it);
+}
+
 void ViewAndroid::RemoveFromParent() {
   if (parent_)
     parent_->RemoveChild(this);
 }
 
 ViewAndroid::ScopedAnchorView ViewAndroid::AcquireAnchorView() {
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
   if (delegate.is_null())
     return ViewAndroid::ScopedAnchorView();
 
   JNIEnv* env = base::android::AttachCurrentThread();
   return ViewAndroid::ScopedAnchorView(
       env, Java_ViewAndroidDelegate_acquireView(env, delegate), delegate);
 }
 
 void ViewAndroid::SetAnchorRect(const JavaRef<jobject>& anchor,
                                 const gfx::RectF& bounds) {
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
   if (delegate.is_null())
     return;
 
-  float scale = display::Screen::GetScreen()
-                    ->GetDisplayNearestWindow(this)
-                    .device_scale_factor();
-  int left_margin = std::round(bounds.x() * scale);
-  int top_margin = std::round((content_offset().y() + bounds.y()) * scale);
+  float dip_scale = GetDipScale();
+  int left_margin = std::round(bounds.x() * dip_scale);
+  int top_margin = std::round((content_offset().y() + bounds.y()) * dip_scale);
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_ViewAndroidDelegate_setViewPosition(
       env, delegate, anchor, bounds.x(), bounds.y(), bounds.width(),
-      bounds.height(), scale, left_margin, top_margin);
+      bounds.height(), dip_scale, left_margin, top_margin);
 }
 
 ScopedJavaLocalRef<jobject> ViewAndroid::GetContainerView() {
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
   if (delegate.is_null())
     return nullptr;
 
   JNIEnv* env = base::android::AttachCurrentThread();
   return Java_ViewAndroidDelegate_getContainerView(env, delegate);
 }
@@ skipping 24 matching lines @@
 }
 
 cc::Layer* ViewAndroid::GetLayer() const {
   return layer_.get();
 }
 
 void ViewAndroid::SetLayer(scoped_refptr<cc::Layer> layer) {
   layer_ = layer;
 }
 
+void ViewAndroid::SetLayout(ViewAndroid::LayoutParams params) {
+  match_parent_ = params.match_parent;
+  if (!params.match_parent) {
+    origin_.SetPoint(params.x, params.y);
+    size_.SetSize(params.width, params.height);
+  }
+}
+
 bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                    const JavaRef<jobject>& jimage) {
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
   if (delegate.is_null())
     return false;
   JNIEnv* env = base::android::AttachCurrentThread();
   return Java_ViewAndroidDelegate_startDragAndDrop(env, delegate, jtext,
                                                    jimage);
 }
 
@@ skipping 30 matching lines @@
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
   if (delegate.is_null())
     return;
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jstring> jcontent_url =
       ConvertUTF8ToJavaString(env, content_url.spec());
   Java_ViewAndroidDelegate_onStartContentIntent(env, delegate, jcontent_url,
                                                 is_main_frame);
 }
 
+bool ViewAndroid::OnTouchEvent(const MotionEventAndroid& event,
+                               bool for_touch_handle) {
+  return HitTest(
+      base::Bind([for_touch_handle](ViewClient* client,
+                                    const MotionEventAndroid& event) -> bool {
+        return client->OnTouchEvent(event, for_touch_handle);
+      }),
+      base::Bind([for_touch_handle](ViewAndroid* view,
+                                    const MotionEventAndroid& event) -> bool {
+        return view->OnTouchEvent(event, for_touch_handle);
+      }),
+      event);
+}
+
+bool ViewAndroid::OnMouseEvent(const MotionEventAndroid& event) {
+  return HitTest(base::Bind(&ViewAndroid::SendToClient),
+                 base::Bind(&ViewAndroid::SendToView), event);
+}
+
+bool ViewAndroid::SendToClient(ViewClient* client,
+                               const MotionEventAndroid& event) {
+  return client->OnMouseEvent(event);
+}
+
+bool ViewAndroid::SendToView(ViewAndroid* view,
+                             const MotionEventAndroid& event) {
+  return view->OnMouseEvent(event);
+}
+
+bool ViewAndroid::HitTest(
+    const base::Callback<bool(ViewClient*, const MotionEventAndroid&)>
+        send_to_client,
+    const base::Callback<bool(ViewAndroid*, const MotionEventAndroid&)>
+        send_to_view,

[boliu, 2017/03/06 22:19:59]

you don't need send_to_view, HitTest can just recurse on itself?

ahh, you are right about lambda having to be captureless, no lambdas then :/

[Jinsuk Kim, 2017/03/07 05:02:23]

Sorry missed your comment... now made HitTest recurse itself. Then I only need
to have |SendXXXEventToClient| per event type. Will do it this way if you think
this is better than the EventSender functor.

[boliu, 2017/03/07 05:08:49]

I meant no lambda, but yes callbacks

[Jinsuk Kim, 2017/03/08 02:16:16]

Yes already done. PTAL

+    const MotionEventAndroid& event) {
+  if (client_ && send_to_client.Run(client_, event))
+    return true;
+
+  if (!children_.empty()) {
+    MotionEventAndroid e(event, -origin_.x(), -origin_.y());
+
+    // Match from back to front for hit testing.
+    for (auto* child : base::Reversed(children_)) {
+      bool matched = child->match_parent_;
+      if (!matched) {
+        gfx::Rect bound(child->origin_, child->size_);
+        matched = bound.Contains(e.GetX(0), e.GetY(0));
+      }
+      if (matched && send_to_view.Run(child, e))
+        return true;
+    }
+  }
+  return false;
+}
+
 }  // namespace ui