Remove DecryptionResource

Reference count was built into DrmSession

PiperOrigin-RevId: 250449988

library/core/src/main/java/com/google/android/exoplayer2/drm/DecryptionResource.java

-/*
- * 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.
- */
-package com.google.android.exoplayer2.drm;
-
-/**
- * A reference-counted resource used in the decryption of media samples.
- *
- * @param <T> The reference type with which to make {@link Owner#onLastReferenceReleased} calls.
- *     Subclasses are expected to pass themselves.
- */
-public abstract class DecryptionResource<T extends DecryptionResource<T>> {
-
-  /**
-   * Implemented by the class in charge of managing a {@link DecryptionResource resource's}
-   * lifecycle.
-   */
-  public interface Owner<T extends DecryptionResource<T>> {
-
-    /**
-     * Called when the last reference to a {@link DecryptionResource} is {@link #releaseReference()
-     * released}.
-     */
-    void onLastReferenceReleased(T resource);
-  }
-
-  // TODO: Consider adding a handler on which the owner should be called.
-  private final DecryptionResource.Owner<T> owner;
-  private int referenceCount;
-
-  /**
-   * Creates a new instance with reference count zero.
-   *
-   * @param owner The owner of this instance.
-   */
-  public DecryptionResource(Owner<T> owner) {
-    this.owner = owner;
-    referenceCount = 0;
-  }
-
-  /** Increases by one the reference count for this resource. */
-  public void acquireReference() {
-    referenceCount++;
-  }
-
-  /**
-   * Decreases by one the reference count for this resource, and notifies the owner if said count
-   * reached zero as a result of this operation.
-   *
-   * <p>Must only be called as releasing counter-part of {@link #acquireReference()}.
-   */
-  @SuppressWarnings("unchecked")
-  public void releaseReference() {
-    if (--referenceCount == 0) {
-      owner.onLastReferenceReleased((T) this);
-    } else if (referenceCount < 0) {
-      throw new IllegalStateException("Illegal release of resource.");
-    }
-  }
-}