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      1 /*
      2  * Copyright (C) 2011 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 
     18 package android.filterfw.core;
     19 
     20 /**
     21  * @hide
     22  */
     23 public abstract class GraphRunner {
     24 
     25     protected FilterContext mFilterContext = null;
     26 
     27     /** Interface for listeners waiting for the runner to complete. */
     28     public interface OnRunnerDoneListener {
     29         /** Callback method to be called when the runner completes a
     30          * {@link #run()} call.
     31          *
     32          * @param result will be RESULT_FINISHED if the graph finished running
     33          *        on its own, RESULT_STOPPED if the runner was stopped by a call
     34          *        to stop(), RESULT_BLOCKED if no filters could run due to lack
     35          *        of inputs or outputs or due to scheduling policies, and
     36          *        RESULT_SLEEPING if a filter node requested sleep.
     37          */
     38         public void onRunnerDone(int result);
     39     }
     40 
     41     public static final int RESULT_UNKNOWN  = 0;
     42     public static final int RESULT_RUNNING  = 1;
     43     public static final int RESULT_FINISHED = 2;
     44     public static final int RESULT_SLEEPING = 3;
     45     public static final int RESULT_BLOCKED  = 4;
     46     public static final int RESULT_STOPPED  = 5;
     47     public static final int RESULT_ERROR    = 6;
     48 
     49     public GraphRunner(FilterContext context) {
     50         mFilterContext = context;
     51     }
     52 
     53     public abstract FilterGraph getGraph();
     54 
     55     public FilterContext getContext() {
     56         return mFilterContext;
     57     }
     58 
     59     /**
     60      * Helper function for subclasses to activate the GL environment before running.
     61      * @return true, if the GL environment was activated. Returns false, if the GL environment
     62      *         was already active.
     63      */
     64     protected boolean activateGlContext() {
     65         GLEnvironment glEnv = mFilterContext.getGLEnvironment();
     66         if (glEnv != null && !glEnv.isActive()) {
     67             glEnv.activate();
     68             return true;
     69         }
     70         return false;
     71     }
     72 
     73     /**
     74      * Helper function for subclasses to deactivate the GL environment after running.
     75      */
     76     protected void deactivateGlContext() {
     77         GLEnvironment glEnv = mFilterContext.getGLEnvironment();
     78         if (glEnv != null) {
     79             glEnv.deactivate();
     80         }
     81     }
     82 
     83     /** Starts running the graph. Will open the filters in the graph if they are not already open. */
     84     public abstract void run();
     85 
     86     public abstract void setDoneCallback(OnRunnerDoneListener listener);
     87     public abstract boolean isRunning();
     88 
     89     /** Stops graph execution. As part of stopping, also closes the graph nodes. */
     90     public abstract void stop();
     91 
     92     /** Closes the filters in a graph. Can only be called if the graph is not running. */
     93     public abstract void close();
     94 
     95     /**
     96      * Returns the last exception that happened during an asynchronous run. Returns null if
     97      * there is nothing to report.
     98      */
     99     public abstract Exception getError();
    100 }
    101