Home | History | Annotate | Download | only in manager 
      1 package com.bumptech.glide.manager;
      2 
      3 import com.bumptech.glide.request.Request;
      4 
      5 import java.util.Collections;
      6 import java.util.Set;
      7 import java.util.WeakHashMap;
      8 
      9 /**
     10  * A class for tracking, canceling, and restarting in progress, completed, and failed requests.
     11  */
     12 public class RequestTracker {
     13     // Most requests will be for views and will therefore be held strongly (and safely) by the view via the tag.
     14     // However, a user can always pass in a different type of target which may end up not being strongly referenced even
     15     // though the user still would like the request to finish. Weak references are therefore only really functional in
     16     // this context for view targets. Despite the side affects, WeakReferences are still essentially required. A user
     17     // can always make repeated requests into targets other than views, or use an activity manager in a fragment pager
     18     // where holding strong references would steadily leak bitmaps and/or views.
     19     private final Set<Request> requests = Collections.newSetFromMap(new WeakHashMap<Request, Boolean>());
     20     private boolean isPaused;
     21 
     22     /**
     23      * Starts tracking the given request.
     24      */
     25     public void runRequest(Request request) {
     26         requests.add(request);
     27         if (!isPaused) {
     28             request.begin();
     29         }
     30     }
     31 
     32     // Exposed for testing.
     33     void addRequest(Request request) {
     34         requests.add(request);
     35     }
     36 
     37     /**
     38      * Stops tracking the given request.
     39      */
     40     public void removeRequest(Request request) {
     41         requests.remove(request);
     42     }
     43 
     44     /**
     45      * Returns {@code true} if requests are currently paused, and {@code false} otherwise.
     46      */
     47     public boolean isPaused() {
     48         return isPaused;
     49     }
     50 
     51     /**
     52      * Stops any in progress requests.
     53      */
     54     public void pauseRequests() {
     55         isPaused = true;
     56         for (Request request : requests) {
     57             if (request.isRunning()) {
     58                 request.pause();
     59             }
     60         }
     61     }
     62 
     63     /**
     64      * Starts any not yet completed or failed requests.
     65      */
     66     public void resumeRequests() {
     67         isPaused = false;
     68         for (Request request : requests) {
     69             if (!request.isComplete() && !request.isCancelled() && !request.isRunning()) {
     70                 request.begin();
     71             }
     72         }
     73     }
     74 
     75     /**
     76      * Cancels all requests and clears their resources.
     77      */
     78     public void clearRequests() {
     79         for (Request request : requests) {
     80             request.clear();
     81         }
     82     }
     83 
     84     /**
     85      * Restarts failed requests and cancels and restarts in progress requests.
     86      */
     87     public void restartRequests() {
     88         for (Request request : requests) {
     89             if (!request.isComplete() && !request.isCancelled()) {
     90                 // Ensure the request will be restarted in onResume.
     91                 request.pause();
     92                 if (!isPaused) {
     93                     request.begin();
     94                 }
     95             }
     96         }
     97     }
     98 }
     99