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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 /**
     20  * This is the base class for frame statistics.
     21  */
     22 public abstract class FrameStats {
     23     /**
     24      * Undefined time.
     25      */
     26     public static final long UNDEFINED_TIME_NANO = -1;
     27 
     28     /** @hide */
     29     protected long mRefreshPeriodNano;
     30 
     31     /** @hide */
     32     protected long[] mFramesPresentedTimeNano;
     33 
     34     /**
     35      * Gets the refresh period of the display hosting the window(s) for
     36      * which these statistics apply.
     37      *
     38      * @return The refresh period in nanoseconds.
     39      */
     40     public final long getRefreshPeriodNano() {
     41         return mRefreshPeriodNano;
     42     }
     43 
     44     /**
     45      * Gets the number of frames for which there is data.
     46      *
     47      * @return The number of frames.
     48      */
     49     public final int getFrameCount() {
     50         return mFramesPresentedTimeNano != null
     51                 ? mFramesPresentedTimeNano.length : 0;
     52     }
     53 
     54     /**
     55      * Gets the start time of the interval for which these statistics
     56      * apply. The start interval is the time when the first frame was
     57      * presented.
     58      *
     59      * @return The start time in nanoseconds or {@link #UNDEFINED_TIME_NANO}
     60      *         if there is no frame data.
     61      */
     62     public final long getStartTimeNano() {
     63         if (getFrameCount() <= 0) {
     64             return UNDEFINED_TIME_NANO;
     65         }
     66         return mFramesPresentedTimeNano[0];
     67     }
     68 
     69     /**
     70      * Gets the end time of the interval for which these statistics
     71      * apply. The end interval is the time when the last frame was
     72      * presented.
     73      *
     74      * @return The end time in nanoseconds or {@link #UNDEFINED_TIME_NANO}
     75      *         if there is no frame data.
     76      */
     77     public final long getEndTimeNano() {
     78         if (getFrameCount() <= 0) {
     79             return UNDEFINED_TIME_NANO;
     80         }
     81         return mFramesPresentedTimeNano[mFramesPresentedTimeNano.length - 1];
     82     }
     83 
     84     /**
     85      * Get the time a frame at a given index was presented.
     86      *
     87      * @param index The frame index.
     88      * @return The presented time in nanoseconds or {@link #UNDEFINED_TIME_NANO}
     89      *         if the frame is not presented yet.
     90      */
     91     public final long getFramePresentedTimeNano(int index) {
     92         if (mFramesPresentedTimeNano == null) {
     93             throw new IndexOutOfBoundsException();
     94         }
     95         return mFramesPresentedTimeNano[index];
     96     }
     97 }
     98