Prepare SyntheticPointerAction to handle touch actions for multiple fingers

content/browser/renderer_host/input/synthetic_pointer_action.cc

 // Copyright 2015 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 "content/browser/renderer_host/input/synthetic_pointer_action.h"
 
 #include "base/logging.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/latency_info.h"
 
 namespace content {
 
 SyntheticPointerAction::SyntheticPointerAction(
     const SyntheticPointerActionParams& params)
     : params_(params) {}
 
 SyntheticPointerAction::SyntheticPointerAction(
-    const SyntheticPointerActionParams& params,
-    SyntheticPointer* synthetic_pointer)
-    : params_(params), synthetic_pointer_(synthetic_pointer) {}
+    std::unique_ptr<std::vector<SyntheticPointerActionParams>> param_list,
+    SyntheticPointer* synthetic_pointer,
+    IndexMap* index_map)
+    : param_list_(std::move(param_list)),
+      synthetic_pointer_(synthetic_pointer),
+      index_map_(index_map) {}

[samuong, 2016/07/08 18:38:34]

In a previous discussion, we decided that the SyntheticGestureController should
own the SyntheticMousePointer and SyntheticTouchPointer objects. I'm guessing it
should also own the IndexMap?

The SyntheticGesture/SyntheticPointerAction object gets created in
RenderWidgetHostImpl::OnQueueSyntheticGesture, which runs before the
SyntheticGestureController is created in
RenderWidgetHostImpl::QueueSyntheticGesture. So I think that rather than have
this second constructor, we should set the SyntheticPointer (and IndexMap?) via
a setter. WDYT?

[lanwei, 2016/07/12 19:54:55]

Yes, it is commented in its head file.
I think it maybe not clear if you just look at this class. Once I create the
SyntheticPointerActionController, it will be clear. 

SyntheticPointerActionController is always running, that is why I let it own and
keep the synthetic_pointer and index_map. When we receive a sequence of pointer
actions, we will create a new synthetic_pointer and index_map. We start queue
and forward each action, and we will create a new  SyntheticPointerAction for
each action. That is why we need this constructor. 

 
 SyntheticPointerAction::~SyntheticPointerAction() {}
 
 SyntheticGesture::Result SyntheticPointerAction::ForwardInputEvents(
     const base::TimeTicks& timestamp,
     SyntheticGestureTarget* target) {
-  if (params_.gesture_source_type == SyntheticGestureParams::DEFAULT_INPUT)
-    params_.gesture_source_type =
-        target->GetDefaultSyntheticGestureSourceType();
-
-  DCHECK_NE(params_.gesture_source_type, SyntheticGestureParams::DEFAULT_INPUT);
-
-  ForwardTouchOrMouseInputEvents(timestamp, target);
-  return SyntheticGesture::GESTURE_FINISHED;
+  DCHECK(synthetic_pointer_);
+  return ForwardTouchOrMouseInputEvents(timestamp, target);

[samuong, 2016/07/08 18:38:35]

Does this still need to be a separate function, or can it be inlined?

[lanwei, 2016/07/12 19:54:55]

This will be changed in the next patch, so I think it is better to leave like
this.

 }
 
-void SyntheticPointerAction::ForwardTouchOrMouseInputEvents(
+SyntheticGesture::Result SyntheticPointerAction::ForwardTouchOrMouseInputEvents(
     const base::TimeTicks& timestamp,
     SyntheticGestureTarget* target) {
-  switch (params_.pointer_action_type()) {
-    case SyntheticPointerActionParams::PointerActionType::PRESS:
-      synthetic_pointer_->Press(params_.position().x(), params_.position().y(),
-                                target, timestamp);
-      break;
-    case SyntheticPointerActionParams::PointerActionType::MOVE:
-      synthetic_pointer_->Move(params_.index(), params_.position().x(),
-                               params_.position().y(), target, timestamp);
-      break;
-    case SyntheticPointerActionParams::PointerActionType::RELEASE:
-      synthetic_pointer_->Release(params_.index(), target, timestamp);
-      break;
-    default:
-      NOTREACHED();
-      break;
+  int point_index;
+  for (const SyntheticPointerActionParams& params : *param_list_) {
+    if (!UserInputCheck(params))
+      return POINTER_ACTION_INPUT_INVALID;
+
+    switch (params.pointer_action_type()) {
+      case SyntheticPointerActionParams::PointerActionType::PRESS:
+        point_index = synthetic_pointer_->Press(
+            params.position().x(), params.position().y(), target, timestamp);
+        SetPointIndex(params.index(), point_index);
+        break;
+      case SyntheticPointerActionParams::PointerActionType::MOVE:
+        point_index = GetPointIndex(params.index());
+        synthetic_pointer_->Move(point_index, params.position().x(),
+                                 params.position().y(), target, timestamp);
+        break;
+      case SyntheticPointerActionParams::PointerActionType::RELEASE:
+        point_index = GetPointIndex(params.index());
+        synthetic_pointer_->Release(point_index, target, timestamp);
+        SetPointIndex(params.index(), -1);
+        break;
+      default:
+        return POINTER_ACTION_INPUT_INVALID;
+    }
   }
   synthetic_pointer_->DispatchEvent(target, timestamp);
+  return GESTURE_FINISHED;
+}
+
+bool SyntheticPointerAction::UserInputCheck(
+    const SyntheticPointerActionParams& params) {
+  if (params.index() < 0 || params.index() >= WebTouchEvent::touchesLengthCap)
+    return false;
+
+  if (synthetic_pointer_->PointerSourceType() != params.gesture_source_type)
+    return false;
+
+  if (params.pointer_action_type() ==
+          SyntheticPointerActionParams::PointerActionType::PRESS &&
+      GetPointIndex(params.index()) >= 0) {
+    return false;
+  }
+
+  if ((params.pointer_action_type() ==
+           SyntheticPointerActionParams::PointerActionType::MOVE ||
+       params.pointer_action_type() ==
+           SyntheticPointerActionParams::PointerActionType::RELEASE) &&
+      GetPointIndex(params.index()) < 0) {
+    return false;
+  }
+  return true;
 }
 
 }  // namespace content