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.h b/services/inputflinger/dispatcher/InputState.h
new file mode 100644
index 0000000..bccef0f
--- /dev/null
+++ b/services/inputflinger/dispatcher/InputState.h
@@ -0,0 +1,125 @@
+/*
+ * 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.
+ */
+
+#ifndef _UI_INPUT_INPUTDISPATCHER_INPUTSTATE_H
+#define _UI_INPUT_INPUTDISPATCHER_INPUTSTATE_H
+
+#include "CancelationOptions.h"
+#include "Entry.h"
+
+#include <utils/Timers.h>
+
+namespace android::inputdispatcher {
+
+// Sequence number for synthesized or injected events.
+constexpr uint32_t SYNTHESIZED_EVENT_SEQUENCE_NUM = 0;
+
+/* Tracks dispatched key and motion event state so that cancellation events can be
+ * synthesized when events are dropped. */
+class InputState {
+public:
+    InputState();
+    ~InputState();
+
+    // Returns true if there is no state to be canceled.
+    bool isNeutral() const;
+
+    // Returns true if the specified source is known to have received a hover enter
+    // motion event.
+    bool isHovering(int32_t deviceId, uint32_t source, int32_t displayId) const;
+
+    // Records tracking information for a key event that has just been published.
+    // Returns true if the event should be delivered, false if it is inconsistent
+    // and should be skipped.
+    bool trackKey(const KeyEntry* entry, int32_t action, int32_t flags);
+
+    // Records tracking information for a motion event that has just been published.
+    // Returns true if the event should be delivered, false if it is inconsistent
+    // and should be skipped.
+    bool trackMotion(const MotionEntry* entry, int32_t action, int32_t flags);
+
+    // Synthesizes cancelation events for the current state and resets the tracked state.
+    void synthesizeCancelationEvents(nsecs_t currentTime, std::vector<EventEntry*>& outEvents,
+                                     const CancelationOptions& options);
+
+    // Clears the current state.
+    void clear();
+
+    // Copies pointer-related parts of the input state to another instance.
+    void copyPointerStateTo(InputState& other) const;
+
+    // Gets the fallback key associated with a keycode.
+    // Returns -1 if none.
+    // Returns AKEYCODE_UNKNOWN if we are only dispatching the unhandled key to the policy.
+    int32_t getFallbackKey(int32_t originalKeyCode);
+
+    // Sets the fallback key for a particular keycode.
+    void setFallbackKey(int32_t originalKeyCode, int32_t fallbackKeyCode);
+
+    // Removes the fallback key for a particular keycode.
+    void removeFallbackKey(int32_t originalKeyCode);
+
+    inline const KeyedVector<int32_t, int32_t>& getFallbackKeys() const { return mFallbackKeys; }
+
+private:
+    struct KeyMemento {
+        int32_t deviceId;
+        uint32_t source;
+        int32_t displayId;
+        int32_t keyCode;
+        int32_t scanCode;
+        int32_t metaState;
+        int32_t flags;
+        nsecs_t downTime;
+        uint32_t policyFlags;
+    };
+
+    struct MotionMemento {
+        int32_t deviceId;
+        uint32_t source;
+        int32_t displayId;
+        int32_t flags;
+        float xPrecision;
+        float yPrecision;
+        float xCursorPosition;
+        float yCursorPosition;
+        nsecs_t downTime;
+        uint32_t pointerCount;
+        PointerProperties pointerProperties[MAX_POINTERS];
+        PointerCoords pointerCoords[MAX_POINTERS];
+        bool hovering;
+        uint32_t policyFlags;
+
+        void setPointers(const MotionEntry* entry);
+    };
+
+    std::vector<KeyMemento> mKeyMementos;
+    std::vector<MotionMemento> mMotionMementos;
+    KeyedVector<int32_t, int32_t> mFallbackKeys;
+
+    ssize_t findKeyMemento(const KeyEntry* entry) const;
+    ssize_t findMotionMemento(const MotionEntry* entry, bool hovering) const;
+
+    void addKeyMemento(const KeyEntry* entry, int32_t flags);
+    void addMotionMemento(const MotionEntry* entry, int32_t flags, bool hovering);
+
+    static bool shouldCancelKey(const KeyMemento& memento, const CancelationOptions& options);
+    static bool shouldCancelMotion(const MotionMemento& memento, const CancelationOptions& options);
+};
+
+} // namespace android::inputdispatcher
+
+#endif // _UI_INPUT_INPUTDISPATCHER_INPUTSTATE_H