Allow for modification of OS thread priority for Glide threads via Glide Options

PiperOrigin-RevId: 767679718

Author: falhassen

library/src/main/java/com/bumptech/glide/GlideBuilder.java

@@ -487,6 +487,17 @@ public GlideBuilder setImageDecoderEnabledForBitmaps(boolean isEnabled) {
     return this;
   }
 
+  /**
+   * Override the OS thread priority of threads created in {@link
+   * com.bumptech.glide.load.engine.executor.GlideExecutor}.
+   *
+   * <p>This is an experimental API that may be removed in the future.
+   */
+  public GlideBuilder setOverrideGlideThreadPriority(boolean isEnabled) {
+    glideExperimentsBuilder.update(new OverrideGlideThreadPriority(), isEnabled);
+    return this;
+  }
+
   /**
    * @deprecated This method does nothing. It will be hard coded and removed in a future release
    *     without further warning.
@@ -622,4 +633,7 @@ static final class EnableImageDecoderForBitmaps implements Experiment {}
 
   /** See {@link #setLogRequestOrigins(boolean)}. */
   public static final class LogRequestOrigins implements Experiment {}
+
+  /** See {@link #setOverrideGlideThreadPriority(boolean)}. */
+  public static final class OverrideGlideThreadPriority implements Experiment {}
 }

library/src/main/java/com/bumptech/glide/load/engine/DecodeJob.java

@@ -1,15 +1,20 @@
 package com.bumptech.glide.load.engine;
 
 import android.os.Build;
+import android.os.Process;
 import android.util.Log;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.util.Pools;
+import com.bumptech.glide.GlideBuilder.OverrideGlideThreadPriority;
 import com.bumptech.glide.GlideContext;
+import com.bumptech.glide.GlideExperiments;
 import com.bumptech.glide.Priority;
 import com.bumptech.glide.Registry;
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.EncodeStrategy;
 import com.bumptech.glide.load.Key;
+import com.bumptech.glide.load.Option;
 import com.bumptech.glide.load.Options;
 import com.bumptech.glide.load.ResourceEncoder;
 import com.bumptech.glide.load.Transformation;
@@ -25,6 +30,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Supplier;
 
 /**
  * A class responsible for decoding resources either from cached data or from the original source
@@ -41,6 +47,10 @@ class DecodeJob<R>
         Comparable<DecodeJob<?>>,
         Poolable {
   private static final String TAG = "DecodeJob";
+  private static final Option<Supplier<Integer>> GLIDE_THREAD_PRIORITY =
+      Option.memory("glide_thread_priority");
+  private static final int DEFAULT_THREAD_PRIORITY =
+      Process.THREAD_PRIORITY_BACKGROUND + Process.THREAD_PRIORITY_MORE_FAVORABLE;
 
   private final DecodeHelper<R> decodeHelper = new DecodeHelper<>();
   private final List<Throwable> throwables = new ArrayList<>();
@@ -65,6 +75,8 @@ class DecodeJob<R>
   private long startFetchTime;
   private boolean onlyRetrieveFromCache;
   private Object model;
+  private GlideExperiments experiments;
+  @Nullable private Supplier<Integer> glideThreadPriorityOverride;
 
   private Thread currentThread;
   private Key currentSourceKey;
@@ -129,6 +141,8 @@ DecodeJob<R> init(
     this.order = order;
     this.runReason = RunReason.INITIALIZE;
     this.model = model;
+    this.experiments = glideContext.getExperiments();
+    this.glideThreadPriorityOverride = options.get(GLIDE_THREAD_PRIORITY);
     return this;
   }
 
@@ -326,7 +340,20 @@ private void runGenerators() {
     // onDataFetcherReady.
   }
 
+  /**
+   * Restores the OS priority of the Glide thread to the default thread priority of {@link
+   * com.bumptech.glide.load.engine.executor.GlideExecutor}.
+   */
+  private void restoreThreadPriority() {
+    if (experiments.isEnabled(OverrideGlideThreadPriority.class)
+        && glideThreadPriorityOverride != null
+        && glideThreadPriorityOverride.get() != null) {
+      Process.setThreadPriority(Process.myTid(), DEFAULT_THREAD_PRIORITY);
+    }
+  }
+
   private void notifyFailed() {
+    restoreThreadPriority();
     setNotifiedOrThrow();
     GlideException e = new GlideException("Failed to load resource", new ArrayList<>(throwables));
     callback.onLoadFailed(e);
@@ -335,6 +362,7 @@ private void notifyFailed() {
 
   private void notifyComplete(
       Resource<R> resource, DataSource dataSource, boolean isLoadedFromAlternateCacheKey) {
+    restoreThreadPriority();
     setNotifiedOrThrow();
     callback.onResourceReady(resource, dataSource, isLoadedFromAlternateCacheKey);
   }
@@ -429,6 +457,11 @@ private void decodeFromRetrievedData() {
               + ", fetcher: "
               + currentFetcher);
     }
+    if (experiments.isEnabled(OverrideGlideThreadPriority.class)
+        && glideThreadPriorityOverride != null
+        && glideThreadPriorityOverride.get() != null) {
+      Process.setThreadPriority(Process.myTid(), glideThreadPriorityOverride.get().intValue());
+    }
     Resource<R> resource = null;
     try {
       resource = decodeFromData(currentFetcher, currentData, currentDataSource);