Divide InputDispatcher into several files.

This CL does:
1) Isolate implementation details of InputDispatcher from outside and
only expose necessary header files;
2) Move implementation details into android::inputdispatcher namespace;
3) Make input dispatcher a static library for inputflinger to link
against;
4) Add InputDispatcherFactory.{h,cpp} to isolate implementation details
in InputDispatcher.h from InputManager.

Bug: 140139676
Test: Touches on touchscreen can be dispatched to right windows.
Change-Id: Ib61c16fd41f3f76f538a3de9b54f31ac304e03a5
diff --git a/services/inputflinger/dispatcher/InputState.cpp b/services/inputflinger/dispatcher/InputState.cpp
new file mode 100644
index 0000000..c60700e
--- /dev/null
+++ b/services/inputflinger/dispatcher/InputState.cpp
@@ -0,0 +1,373 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "InputState.h"
+
+namespace android::inputdispatcher {
+
+InputState::InputState() {}
+
+InputState::~InputState() {}
+
+bool InputState::isNeutral() const {
+    return mKeyMementos.empty() && mMotionMementos.empty();
+}
+
+bool InputState::isHovering(int32_t deviceId, uint32_t source, int32_t displayId) const {
+    for (const MotionMemento& memento : mMotionMementos) {
+        if (memento.deviceId == deviceId && memento.source == source &&
+            memento.displayId == displayId && memento.hovering) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool InputState::trackKey(const KeyEntry* entry, int32_t action, int32_t flags) {
+    switch (action) {
+        case AKEY_EVENT_ACTION_UP: {
+            if (entry->flags & AKEY_EVENT_FLAG_FALLBACK) {
+                for (size_t i = 0; i < mFallbackKeys.size();) {
+                    if (mFallbackKeys.valueAt(i) == entry->keyCode) {
+                        mFallbackKeys.removeItemsAt(i);
+                    } else {
+                        i += 1;
+                    }
+                }
+            }
+            ssize_t index = findKeyMemento(entry);
+            if (index >= 0) {
+                mKeyMementos.erase(mKeyMementos.begin() + index);
+                return true;
+            }
+            /* FIXME: We can't just drop the key up event because that prevents creating
+             * popup windows that are automatically shown when a key is held and then
+             * dismissed when the key is released.  The problem is that the popup will
+             * not have received the original key down, so the key up will be considered
+             * to be inconsistent with its observed state.  We could perhaps handle this
+             * by synthesizing a key down but that will cause other problems.
+             *
+             * So for now, allow inconsistent key up events to be dispatched.
+             *
+    #if DEBUG_OUTBOUND_EVENT_DETAILS
+            ALOGD("Dropping inconsistent key up event: deviceId=%d, source=%08x, "
+                    "keyCode=%d, scanCode=%d",
+                    entry->deviceId, entry->source, entry->keyCode, entry->scanCode);
+    #endif
+            return false;
+            */
+            return true;
+        }
+
+        case AKEY_EVENT_ACTION_DOWN: {
+            ssize_t index = findKeyMemento(entry);
+            if (index >= 0) {
+                mKeyMementos.erase(mKeyMementos.begin() + index);
+            }
+            addKeyMemento(entry, flags);
+            return true;
+        }
+
+        default:
+            return true;
+    }
+}
+
+bool InputState::trackMotion(const MotionEntry* entry, int32_t action, int32_t flags) {
+    int32_t actionMasked = action & AMOTION_EVENT_ACTION_MASK;
+    switch (actionMasked) {
+        case AMOTION_EVENT_ACTION_UP:
+        case AMOTION_EVENT_ACTION_CANCEL: {
+            ssize_t index = findMotionMemento(entry, false /*hovering*/);
+            if (index >= 0) {
+                mMotionMementos.erase(mMotionMementos.begin() + index);
+                return true;
+            }
+#if DEBUG_OUTBOUND_EVENT_DETAILS
+            ALOGD("Dropping inconsistent motion up or cancel event: deviceId=%d, source=%08x, "
+                  "displayId=%" PRId32 ", actionMasked=%d",
+                  entry->deviceId, entry->source, entry->displayId, actionMasked);
+#endif
+            return false;
+        }
+
+        case AMOTION_EVENT_ACTION_DOWN: {
+            ssize_t index = findMotionMemento(entry, false /*hovering*/);
+            if (index >= 0) {
+                mMotionMementos.erase(mMotionMementos.begin() + index);
+            }
+            addMotionMemento(entry, flags, false /*hovering*/);
+            return true;
+        }
+
+        case AMOTION_EVENT_ACTION_POINTER_UP:
+        case AMOTION_EVENT_ACTION_POINTER_DOWN:
+        case AMOTION_EVENT_ACTION_MOVE: {
+            if (entry->source & AINPUT_SOURCE_CLASS_NAVIGATION) {
+                // Trackballs can send MOVE events with a corresponding DOWN or UP. There's no need
+                // to generate cancellation events for these since they're based in relative rather
+                // than absolute units.
+                return true;
+            }
+
+            ssize_t index = findMotionMemento(entry, false /*hovering*/);
+
+            if (entry->source & AINPUT_SOURCE_CLASS_JOYSTICK) {
+                // Joysticks can send MOVE events without a corresponding DOWN or UP. Since all
+                // joystick axes are normalized to [-1, 1] we can trust that 0 means it's neutral.
+                // Any other value and we need to track the motion so we can send cancellation
+                // events for anything generating fallback events (e.g. DPad keys for joystick
+                // movements).
+                if (index >= 0) {
+                    if (entry->pointerCoords[0].isEmpty()) {
+                        mMotionMementos.erase(mMotionMementos.begin() + index);
+                    } else {
+                        MotionMemento& memento = mMotionMementos[index];
+                        memento.setPointers(entry);
+                    }
+                } else if (!entry->pointerCoords[0].isEmpty()) {
+                    addMotionMemento(entry, flags, false /*hovering*/);
+                }
+
+                // Joysticks and trackballs can send MOVE events without corresponding DOWN or UP.
+                return true;
+            }
+            if (index >= 0) {
+                MotionMemento& memento = mMotionMementos[index];
+                memento.setPointers(entry);
+                return true;
+            }
+#if DEBUG_OUTBOUND_EVENT_DETAILS
+            ALOGD("Dropping inconsistent motion pointer up/down or move event: "
+                  "deviceId=%d, source=%08x, displayId=%" PRId32 ", actionMasked=%d",
+                  entry->deviceId, entry->source, entry->displayId, actionMasked);
+#endif
+            return false;
+        }
+
+        case AMOTION_EVENT_ACTION_HOVER_EXIT: {
+            ssize_t index = findMotionMemento(entry, true /*hovering*/);
+            if (index >= 0) {
+                mMotionMementos.erase(mMotionMementos.begin() + index);
+                return true;
+            }
+#if DEBUG_OUTBOUND_EVENT_DETAILS
+            ALOGD("Dropping inconsistent motion hover exit event: deviceId=%d, source=%08x, "
+                  "displayId=%" PRId32,
+                  entry->deviceId, entry->source, entry->displayId);
+#endif
+            return false;
+        }
+
+        case AMOTION_EVENT_ACTION_HOVER_ENTER:
+        case AMOTION_EVENT_ACTION_HOVER_MOVE: {
+            ssize_t index = findMotionMemento(entry, true /*hovering*/);
+            if (index >= 0) {
+                mMotionMementos.erase(mMotionMementos.begin() + index);
+            }
+            addMotionMemento(entry, flags, true /*hovering*/);
+            return true;
+        }
+
+        default:
+            return true;
+    }
+}
+
+ssize_t InputState::findKeyMemento(const KeyEntry* entry) const {
+    for (size_t i = 0; i < mKeyMementos.size(); i++) {
+        const KeyMemento& memento = mKeyMementos[i];
+        if (memento.deviceId == entry->deviceId && memento.source == entry->source &&
+            memento.displayId == entry->displayId && memento.keyCode == entry->keyCode &&
+            memento.scanCode == entry->scanCode) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+ssize_t InputState::findMotionMemento(const MotionEntry* entry, bool hovering) const {
+    for (size_t i = 0; i < mMotionMementos.size(); i++) {
+        const MotionMemento& memento = mMotionMementos[i];
+        if (memento.deviceId == entry->deviceId && memento.source == entry->source &&
+            memento.displayId == entry->displayId && memento.hovering == hovering) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+void InputState::addKeyMemento(const KeyEntry* entry, int32_t flags) {
+    KeyMemento memento;
+    memento.deviceId = entry->deviceId;
+    memento.source = entry->source;
+    memento.displayId = entry->displayId;
+    memento.keyCode = entry->keyCode;
+    memento.scanCode = entry->scanCode;
+    memento.metaState = entry->metaState;
+    memento.flags = flags;
+    memento.downTime = entry->downTime;
+    memento.policyFlags = entry->policyFlags;
+    mKeyMementos.push_back(memento);
+}
+
+void InputState::addMotionMemento(const MotionEntry* entry, int32_t flags, bool hovering) {
+    MotionMemento memento;
+    memento.deviceId = entry->deviceId;
+    memento.source = entry->source;
+    memento.displayId = entry->displayId;
+    memento.flags = flags;
+    memento.xPrecision = entry->xPrecision;
+    memento.yPrecision = entry->yPrecision;
+    memento.xCursorPosition = entry->xCursorPosition;
+    memento.yCursorPosition = entry->yCursorPosition;
+    memento.downTime = entry->downTime;
+    memento.setPointers(entry);
+    memento.hovering = hovering;
+    memento.policyFlags = entry->policyFlags;
+    mMotionMementos.push_back(memento);
+}
+
+void InputState::MotionMemento::setPointers(const MotionEntry* entry) {
+    pointerCount = entry->pointerCount;
+    for (uint32_t i = 0; i < entry->pointerCount; i++) {
+        pointerProperties[i].copyFrom(entry->pointerProperties[i]);
+        pointerCoords[i].copyFrom(entry->pointerCoords[i]);
+    }
+}
+
+void InputState::synthesizeCancelationEvents(nsecs_t currentTime,
+                                             std::vector<EventEntry*>& outEvents,
+                                             const CancelationOptions& options) {
+    for (KeyMemento& memento : mKeyMementos) {
+        if (shouldCancelKey(memento, options)) {
+            outEvents.push_back(new KeyEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, currentTime,
+                                             memento.deviceId, memento.source, memento.displayId,
+                                             memento.policyFlags, AKEY_EVENT_ACTION_UP,
+                                             memento.flags | AKEY_EVENT_FLAG_CANCELED,
+                                             memento.keyCode, memento.scanCode, memento.metaState,
+                                             0, memento.downTime));
+        }
+    }
+
+    for (const MotionMemento& memento : mMotionMementos) {
+        if (shouldCancelMotion(memento, options)) {
+            const int32_t action = memento.hovering ? AMOTION_EVENT_ACTION_HOVER_EXIT
+                                                    : AMOTION_EVENT_ACTION_CANCEL;
+            outEvents.push_back(
+                    new MotionEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, currentTime, memento.deviceId,
+                                    memento.source, memento.displayId, memento.policyFlags, action,
+                                    0 /*actionButton*/, memento.flags, AMETA_NONE,
+                                    0 /*buttonState*/, MotionClassification::NONE,
+                                    AMOTION_EVENT_EDGE_FLAG_NONE, memento.xPrecision,
+                                    memento.yPrecision, memento.xCursorPosition,
+                                    memento.yCursorPosition, memento.downTime, memento.pointerCount,
+                                    memento.pointerProperties, memento.pointerCoords, 0 /*xOffset*/,
+                                    0 /*yOffset*/));
+        }
+    }
+}
+
+void InputState::clear() {
+    mKeyMementos.clear();
+    mMotionMementos.clear();
+    mFallbackKeys.clear();
+}
+
+void InputState::copyPointerStateTo(InputState& other) const {
+    for (size_t i = 0; i < mMotionMementos.size(); i++) {
+        const MotionMemento& memento = mMotionMementos[i];
+        if (memento.source & AINPUT_SOURCE_CLASS_POINTER) {
+            for (size_t j = 0; j < other.mMotionMementos.size();) {
+                const MotionMemento& otherMemento = other.mMotionMementos[j];
+                if (memento.deviceId == otherMemento.deviceId &&
+                    memento.source == otherMemento.source &&
+                    memento.displayId == otherMemento.displayId) {
+                    other.mMotionMementos.erase(other.mMotionMementos.begin() + j);
+                } else {
+                    j += 1;
+                }
+            }
+            other.mMotionMementos.push_back(memento);
+        }
+    }
+}
+
+int32_t InputState::getFallbackKey(int32_t originalKeyCode) {
+    ssize_t index = mFallbackKeys.indexOfKey(originalKeyCode);
+    return index >= 0 ? mFallbackKeys.valueAt(index) : -1;
+}
+
+void InputState::setFallbackKey(int32_t originalKeyCode, int32_t fallbackKeyCode) {
+    ssize_t index = mFallbackKeys.indexOfKey(originalKeyCode);
+    if (index >= 0) {
+        mFallbackKeys.replaceValueAt(index, fallbackKeyCode);
+    } else {
+        mFallbackKeys.add(originalKeyCode, fallbackKeyCode);
+    }
+}
+
+void InputState::removeFallbackKey(int32_t originalKeyCode) {
+    mFallbackKeys.removeItem(originalKeyCode);
+}
+
+bool InputState::shouldCancelKey(const KeyMemento& memento, const CancelationOptions& options) {
+    if (options.keyCode && memento.keyCode != options.keyCode.value()) {
+        return false;
+    }
+
+    if (options.deviceId && memento.deviceId != options.deviceId.value()) {
+        return false;
+    }
+
+    if (options.displayId && memento.displayId != options.displayId.value()) {
+        return false;
+    }
+
+    switch (options.mode) {
+        case CancelationOptions::CANCEL_ALL_EVENTS:
+        case CancelationOptions::CANCEL_NON_POINTER_EVENTS:
+            return true;
+        case CancelationOptions::CANCEL_FALLBACK_EVENTS:
+            return memento.flags & AKEY_EVENT_FLAG_FALLBACK;
+        default:
+            return false;
+    }
+}
+
+bool InputState::shouldCancelMotion(const MotionMemento& memento,
+                                    const CancelationOptions& options) {
+    if (options.deviceId && memento.deviceId != options.deviceId.value()) {
+        return false;
+    }
+
+    if (options.displayId && memento.displayId != options.displayId.value()) {
+        return false;
+    }
+
+    switch (options.mode) {
+        case CancelationOptions::CANCEL_ALL_EVENTS:
+            return true;
+        case CancelationOptions::CANCEL_POINTER_EVENTS:
+            return memento.source & AINPUT_SOURCE_CLASS_POINTER;
+        case CancelationOptions::CANCEL_NON_POINTER_EVENTS:
+            return !(memento.source & AINPUT_SOURCE_CLASS_POINTER);
+        default:
+            return false;
+    }
+}
+
+} // namespace android::inputdispatcher