Mark all methods accessing SQLite databases as potentially blocking.

They are all marked with a JavaDoc comment and the @WorkerThread annotation
which is useful if apps are using threading annotations. All other public
methods in the same classes are marked with @AnyThread to avoid the impression
we forgot to annotate them.

PiperOrigin-RevId: 281490301

library/core/src/main/java/com/google/android/exoplayer2/offline/ActionFileUpgradeUtil.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.offline;
 import static com.google.android.exoplayer2.offline.Download.STATE_QUEUED;
 import static com.google.android.exoplayer2.offline.Download.STATE_QUEUED;
 
 
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import java.io.File;
 import java.io.File;
 import java.io.IOException;
 import java.io.IOException;
@@ -47,6 +48,8 @@ public final class ActionFileUpgradeUtil {
    * <p>This method must not be called while the {@link DefaultDownloadIndex} is being used by a
    * <p>This method must not be called while the {@link DefaultDownloadIndex} is being used by a
    * {@link DownloadManager}.
    * {@link DownloadManager}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param actionFilePath The action file path.
    * @param actionFilePath The action file path.
    * @param downloadIdProvider A download ID provider, or {@code null}. If {@code null} then ID of
    * @param downloadIdProvider A download ID provider, or {@code null}. If {@code null} then ID of
    *     each download will be its custom cache key if one is specified, or else its URL.
    *     each download will be its custom cache key if one is specified, or else its URL.
@@ -55,6 +58,7 @@ public final class ActionFileUpgradeUtil {
    * @param addNewDownloadsAsCompleted Whether to add new downloads as completed.
    * @param addNewDownloadsAsCompleted Whether to add new downloads as completed.
    * @throws IOException If an error occurs loading or merging the requests.
    * @throws IOException If an error occurs loading or merging the requests.
    */
    */
+  @WorkerThread
   @SuppressWarnings("deprecation")
   @SuppressWarnings("deprecation")
   public static void upgradeAndDelete(
   public static void upgradeAndDelete(
       File actionFilePath,
       File actionFilePath,

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadIndex.java

@@ -16,14 +16,18 @@
 package com.google.android.exoplayer2.offline;
 package com.google.android.exoplayer2.offline;
 
 
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
+import androidx.annotation.WorkerThread;
 import java.io.IOException;
 import java.io.IOException;
 
 
 /** An index of {@link Download Downloads}. */
 /** An index of {@link Download Downloads}. */
+@WorkerThread
 public interface DownloadIndex {
 public interface DownloadIndex {
 
 
   /**
   /**
    * Returns the {@link Download} with the given {@code id}, or null.
    * Returns the {@link Download} with the given {@code id}, or null.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param id ID of a {@link Download}.
    * @param id ID of a {@link Download}.
    * @return The {@link Download} with the given {@code id}, or null if a download state with this
    * @return The {@link Download} with the given {@code id}, or null if a download state with this
    *     id doesn't exist.
    *     id doesn't exist.
@@ -35,6 +39,8 @@ public interface DownloadIndex {
   /**
   /**
    * Returns a {@link DownloadCursor} to {@link Download}s with the given {@code states}.
    * Returns a {@link DownloadCursor} to {@link Download}s with the given {@code states}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param states Returns only the {@link Download}s with this states. If empty, returns all.
    * @param states Returns only the {@link Download}s with this states. If empty, returns all.
    * @return A cursor to {@link Download}s with the given {@code states}.
    * @return A cursor to {@link Download}s with the given {@code states}.
    * @throws IOException If an error occurs reading the state.
    * @throws IOException If an error occurs reading the state.

library/core/src/main/java/com/google/android/exoplayer2/offline/WritableDownloadIndex.java

@@ -15,14 +15,18 @@
  */
  */
 package com.google.android.exoplayer2.offline;
 package com.google.android.exoplayer2.offline;
 
 
+import androidx.annotation.WorkerThread;
 import java.io.IOException;
 import java.io.IOException;
 
 
 /** A writable index of {@link Download Downloads}. */
 /** A writable index of {@link Download Downloads}. */
+@WorkerThread
 public interface WritableDownloadIndex extends DownloadIndex {
 public interface WritableDownloadIndex extends DownloadIndex {
 
 
   /**
   /**
    * Adds or replaces a {@link Download}.
    * Adds or replaces a {@link Download}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param download The {@link Download} to be added.
    * @param download The {@link Download} to be added.
    * @throws IOException If an error occurs setting the state.
    * @throws IOException If an error occurs setting the state.
    */
    */
@@ -32,6 +36,8 @@ public interface WritableDownloadIndex extends DownloadIndex {
    * Removes the download with the given ID. Does nothing if a download with the given ID does not
    * Removes the download with the given ID. Does nothing if a download with the given ID does not
    * exist.
    * exist.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param id The ID of the download to remove.
    * @param id The ID of the download to remove.
    * @throws IOException If an error occurs removing the state.
    * @throws IOException If an error occurs removing the state.
    */
    */
@@ -40,6 +46,8 @@ public interface WritableDownloadIndex extends DownloadIndex {
   /**
   /**
    * Sets all {@link Download#STATE_DOWNLOADING} states to {@link Download#STATE_QUEUED}.
    * Sets all {@link Download#STATE_DOWNLOADING} states to {@link Download#STATE_QUEUED}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @throws IOException If an error occurs updating the state.
    * @throws IOException If an error occurs updating the state.
    */
    */
   void setDownloadingStatesToQueued() throws IOException;
   void setDownloadingStatesToQueued() throws IOException;
@@ -47,6 +55,8 @@ public interface WritableDownloadIndex extends DownloadIndex {
   /**
   /**
    * Sets all states to {@link Download#STATE_REMOVING}.
    * Sets all states to {@link Download#STATE_REMOVING}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @throws IOException If an error occurs updating the state.
    * @throws IOException If an error occurs updating the state.
    */
    */
   void setStatesToRemoving() throws IOException;
   void setStatesToRemoving() throws IOException;
@@ -55,6 +65,8 @@ public interface WritableDownloadIndex extends DownloadIndex {
    * Sets the stop reason of the downloads in a terminal state ({@link Download#STATE_COMPLETED},
    * Sets the stop reason of the downloads in a terminal state ({@link Download#STATE_COMPLETED},
    * {@link Download#STATE_FAILED}).
    * {@link Download#STATE_FAILED}).
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param stopReason The stop reason.
    * @param stopReason The stop reason.
    * @throws IOException If an error occurs updating the state.
    * @throws IOException If an error occurs updating the state.
    */
    */
@@ -65,6 +77,8 @@ public interface WritableDownloadIndex extends DownloadIndex {
    * Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}). Does nothing if a download with the
    * Download#STATE_COMPLETED}, {@link Download#STATE_FAILED}). Does nothing if a download with the
    * given ID does not exist, or if it's not in a terminal state.
    * given ID does not exist, or if it's not in a terminal state.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param id The ID of the download to update.
    * @param id The ID of the download to update.
    * @param stopReason The stop reason.
    * @param stopReason The stop reason.
    * @throws IOException If an error occurs updating the state.
    * @throws IOException If an error occurs updating the state.

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/Cache.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.upstream.cache;
 package com.google.android.exoplayer2.upstream.cache;
 
 
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import java.io.File;
 import java.io.File;
 import java.io.IOException;
 import java.io.IOException;
@@ -100,7 +101,10 @@ public interface Cache {
   /**
   /**
    * Releases the cache. This method must be called when the cache is no longer required. The cache
    * Releases the cache. This method must be called when the cache is no longer required. The cache
    * must not be used after calling this method.
    * must not be used after calling this method.
+   *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
    */
    */
+  @WorkerThread
   void release();
   void release();
 
 
   /**
   /**
@@ -162,23 +166,29 @@ public interface Cache {
    * calling {@link #commitFile(File, long)}. When the caller has finished writing, it must release
    * calling {@link #commitFile(File, long)}. When the caller has finished writing, it must release
    * the lock by calling {@link #releaseHoleSpan}.
    * the lock by calling {@link #releaseHoleSpan}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param key The key of the data being requested.
    * @param key The key of the data being requested.
    * @param position The position of the data being requested.
    * @param position The position of the data being requested.
    * @return The {@link CacheSpan}.
    * @return The {@link CacheSpan}.
    * @throws InterruptedException If the thread was interrupted.
    * @throws InterruptedException If the thread was interrupted.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   CacheSpan startReadWrite(String key, long position) throws InterruptedException, CacheException;
   CacheSpan startReadWrite(String key, long position) throws InterruptedException, CacheException;
 
 
   /**
   /**
    * Same as {@link #startReadWrite(String, long)}. However, if the cache entry is locked, then
    * Same as {@link #startReadWrite(String, long)}. However, if the cache entry is locked, then
    * instead of blocking, this method will return null as the {@link CacheSpan}.
    * instead of blocking, this method will return null as the {@link CacheSpan}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param key The key of the data being requested.
    * @param key The key of the data being requested.
    * @param position The position of the data being requested.
    * @param position The position of the data being requested.
    * @return The {@link CacheSpan}. Or null if the cache entry is locked.
    * @return The {@link CacheSpan}. Or null if the cache entry is locked.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   @Nullable
   @Nullable
   CacheSpan startReadWriteNonBlocking(String key, long position) throws CacheException;
   CacheSpan startReadWriteNonBlocking(String key, long position) throws CacheException;
 
 
@@ -186,6 +196,8 @@ public interface Cache {
    * Obtains a cache file into which data can be written. Must only be called when holding a
    * Obtains a cache file into which data can be written. Must only be called when holding a
    * corresponding hole {@link CacheSpan} obtained from {@link #startReadWrite(String, long)}.
    * corresponding hole {@link CacheSpan} obtained from {@link #startReadWrite(String, long)}.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param key The cache key for the data.
    * @param key The cache key for the data.
    * @param position The starting position of the data.
    * @param position The starting position of the data.
    * @param length The length of the data being written, or {@link C#LENGTH_UNSET} if unknown. Used
    * @param length The length of the data being written, or {@link C#LENGTH_UNSET} if unknown. Used
@@ -193,16 +205,20 @@ public interface Cache {
    * @return The file into which data should be written.
    * @return The file into which data should be written.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   File startFile(String key, long position, long length) throws CacheException;
   File startFile(String key, long position, long length) throws CacheException;
 
 
   /**
   /**
    * Commits a file into the cache. Must only be called when holding a corresponding hole {@link
    * Commits a file into the cache. Must only be called when holding a corresponding hole {@link
-   * CacheSpan} obtained from {@link #startReadWrite(String, long)}
+   * CacheSpan} obtained from {@link #startReadWrite(String, long)}.
+   *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
    *
    *
    * @param file A newly written cache file.
    * @param file A newly written cache file.
    * @param length The length of the newly written cache file in bytes.
    * @param length The length of the newly written cache file in bytes.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   void commitFile(File file, long length) throws CacheException;
   void commitFile(File file, long length) throws CacheException;
 
 
   /**
   /**
@@ -216,9 +232,12 @@ public interface Cache {
   /**
   /**
    * Removes a cached {@link CacheSpan} from the cache, deleting the underlying file.
    * Removes a cached {@link CacheSpan} from the cache, deleting the underlying file.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param span The {@link CacheSpan} to remove.
    * @param span The {@link CacheSpan} to remove.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   void removeSpan(CacheSpan span) throws CacheException;
   void removeSpan(CacheSpan span) throws CacheException;
 
 
   /**
   /**
@@ -247,10 +266,13 @@ public interface Cache {
    * Applies {@code mutations} to the {@link ContentMetadata} for the given key. A new {@link
    * Applies {@code mutations} to the {@link ContentMetadata} for the given key. A new {@link
    * CachedContent} is added if there isn't one already with the given key.
    * CachedContent} is added if there isn't one already with the given key.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param key The cache key for the data.
    * @param key The cache key for the data.
    * @param mutations Contains mutations to be applied to the metadata.
    * @param mutations Contains mutations to be applied to the metadata.
    * @throws CacheException If an error is encountered.
    * @throws CacheException If an error is encountered.
    */
    */
+  @WorkerThread
   void applyContentMetadataMutations(String key, ContentMetadataMutations mutations)
   void applyContentMetadataMutations(String key, ContentMetadataMutations mutations)
       throws CacheException;
       throws CacheException;
 
 

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheFileMetadataIndex.java

@@ -19,6 +19,7 @@ import android.content.ContentValues;
 import android.database.Cursor;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteDatabase;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.database.VersionTable;
 import com.google.android.exoplayer2.database.VersionTable;
@@ -64,10 +65,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   /**
   /**
    * Deletes index data for the specified cache.
    * Deletes index data for the specified cache.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param databaseProvider Provides the database in which the index is stored.
    * @param databaseProvider Provides the database in which the index is stored.
    * @param uid The cache UID.
    * @param uid The cache UID.
    * @throws DatabaseIOException If an error occurs deleting the index data.
    * @throws DatabaseIOException If an error occurs deleting the index data.
    */
    */
+  @WorkerThread
   public static void delete(DatabaseProvider databaseProvider, long uid)
   public static void delete(DatabaseProvider databaseProvider, long uid)
       throws DatabaseIOException {
       throws DatabaseIOException {
     String hexUid = Long.toHexString(uid);
     String hexUid = Long.toHexString(uid);
@@ -96,9 +100,12 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   /**
   /**
    * Initializes the index for the given cache UID.
    * Initializes the index for the given cache UID.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param uid The cache UID.
    * @param uid The cache UID.
    * @throws DatabaseIOException If an error occurs initializing the index.
    * @throws DatabaseIOException If an error occurs initializing the index.
    */
    */
+  @WorkerThread
   public void initialize(long uid) throws DatabaseIOException {
   public void initialize(long uid) throws DatabaseIOException {
     try {
     try {
       String hexUid = Long.toHexString(uid);
       String hexUid = Long.toHexString(uid);
@@ -129,9 +136,12 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
    * Returns all file metadata keyed by file name. The returned map is mutable and may be modified
    * Returns all file metadata keyed by file name. The returned map is mutable and may be modified
    * by the caller.
    * by the caller.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @return The file metadata keyed by file name.
    * @return The file metadata keyed by file name.
    * @throws DatabaseIOException If an error occurs loading the metadata.
    * @throws DatabaseIOException If an error occurs loading the metadata.
    */
    */
+  @WorkerThread
   public Map<String, CacheFileMetadata> getAll() throws DatabaseIOException {
   public Map<String, CacheFileMetadata> getAll() throws DatabaseIOException {
     try (Cursor cursor = getCursor()) {
     try (Cursor cursor = getCursor()) {
       Map<String, CacheFileMetadata> fileMetadata = new HashMap<>(cursor.getCount());
       Map<String, CacheFileMetadata> fileMetadata = new HashMap<>(cursor.getCount());
@@ -150,11 +160,14 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   /**
   /**
    * Sets metadata for a given file.
    * Sets metadata for a given file.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param name The name of the file.
    * @param name The name of the file.
    * @param length The file length.
    * @param length The file length.
    * @param lastTouchTimestamp The file last touch timestamp.
    * @param lastTouchTimestamp The file last touch timestamp.
    * @throws DatabaseIOException If an error occurs setting the metadata.
    * @throws DatabaseIOException If an error occurs setting the metadata.
    */
    */
+  @WorkerThread
   public void set(String name, long length, long lastTouchTimestamp) throws DatabaseIOException {
   public void set(String name, long length, long lastTouchTimestamp) throws DatabaseIOException {
     Assertions.checkNotNull(tableName);
     Assertions.checkNotNull(tableName);
     try {
     try {
@@ -172,9 +185,12 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   /**
   /**
    * Removes metadata.
    * Removes metadata.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param name The name of the file whose metadata is to be removed.
    * @param name The name of the file whose metadata is to be removed.
    * @throws DatabaseIOException If an error occurs removing the metadata.
    * @throws DatabaseIOException If an error occurs removing the metadata.
    */
    */
+  @WorkerThread
   public void remove(String name) throws DatabaseIOException {
   public void remove(String name) throws DatabaseIOException {
     Assertions.checkNotNull(tableName);
     Assertions.checkNotNull(tableName);
     try {
     try {
@@ -188,9 +204,12 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   /**
   /**
    * Removes metadata.
    * Removes metadata.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param names The names of the files whose metadata is to be removed.
    * @param names The names of the files whose metadata is to be removed.
    * @throws DatabaseIOException If an error occurs removing the metadata.
    * @throws DatabaseIOException If an error occurs removing the metadata.
    */
    */
+  @WorkerThread
   public void removeAll(Set<String> names) throws DatabaseIOException {
   public void removeAll(Set<String> names) throws DatabaseIOException {
     Assertions.checkNotNull(tableName);
     Assertions.checkNotNull(tableName);
     try {
     try {

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheUtil.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.upstream.cache;
 import android.net.Uri;
 import android.net.Uri;
 import android.util.Pair;
 import android.util.Pair;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.upstream.DataSourceException;
 import com.google.android.exoplayer2.upstream.DataSourceException;
@@ -104,6 +105,8 @@ public final class CacheUtil {
    * Caches the data defined by {@code dataSpec}, skipping already cached data. Caching stops early
    * Caches the data defined by {@code dataSpec}, skipping already cached data. Caching stops early
    * if the end of the input is reached.
    * if the end of the input is reached.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param dataSpec Defines the data to be cached.
    * @param dataSpec Defines the data to be cached.
    * @param cache A {@link Cache} to store the data.
    * @param cache A {@link Cache} to store the data.
    * @param cacheKeyFactory An optional factory for cache keys.
    * @param cacheKeyFactory An optional factory for cache keys.
@@ -113,6 +116,7 @@ public final class CacheUtil {
    * @throws IOException If an error occurs reading from the source.
    * @throws IOException If an error occurs reading from the source.
    * @throws InterruptedException If the thread was interrupted directly or via {@code isCanceled}.
    * @throws InterruptedException If the thread was interrupted directly or via {@code isCanceled}.
    */
    */
+  @WorkerThread
   public static void cache(
   public static void cache(
       DataSpec dataSpec,
       DataSpec dataSpec,
       Cache cache,
       Cache cache,
@@ -144,6 +148,8 @@ public final class CacheUtil {
    * PriorityTaskManager#add} to register with the manager before calling this method, and to call
    * PriorityTaskManager#add} to register with the manager before calling this method, and to call
    * {@link PriorityTaskManager#remove} afterwards to unregister.
    * {@link PriorityTaskManager#remove} afterwards to unregister.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param dataSpec Defines the data to be cached.
    * @param dataSpec Defines the data to be cached.
    * @param cache A {@link Cache} to store the data.
    * @param cache A {@link Cache} to store the data.
    * @param cacheKeyFactory An optional factory for cache keys.
    * @param cacheKeyFactory An optional factory for cache keys.
@@ -159,6 +165,7 @@ public final class CacheUtil {
    * @throws IOException If an error occurs reading from the source.
    * @throws IOException If an error occurs reading from the source.
    * @throws InterruptedException If the thread was interrupted directly or via {@code isCanceled}.
    * @throws InterruptedException If the thread was interrupted directly or via {@code isCanceled}.
    */
    */
+  @WorkerThread
   public static void cache(
   public static void cache(
       DataSpec dataSpec,
       DataSpec dataSpec,
       Cache cache,
       Cache cache,
@@ -333,10 +340,13 @@ public final class CacheUtil {
   /**
   /**
    * Removes all of the data specified by the {@code dataSpec}.
    * Removes all of the data specified by the {@code dataSpec}.
    *
    *
+   * <p>This methods blocks until the operation is complete.
+   *
    * @param dataSpec Defines the data to be removed.
    * @param dataSpec Defines the data to be removed.
    * @param cache A {@link Cache} to store the data.
    * @param cache A {@link Cache} to store the data.
    * @param cacheKeyFactory An optional factory for cache keys.
    * @param cacheKeyFactory An optional factory for cache keys.
    */
    */
+  @WorkerThread
   public static void remove(
   public static void remove(
       DataSpec dataSpec, Cache cache, @Nullable CacheKeyFactory cacheKeyFactory) {
       DataSpec dataSpec, Cache cache, @Nullable CacheKeyFactory cacheKeyFactory) {
     remove(cache, buildCacheKey(dataSpec, cacheKeyFactory));
     remove(cache, buildCacheKey(dataSpec, cacheKeyFactory));
@@ -345,9 +355,12 @@ public final class CacheUtil {
   /**
   /**
    * Removes all of the data specified by the {@code key}.
    * Removes all of the data specified by the {@code key}.
    *
    *
+   * <p>This methods blocks until the operation is complete.
+   *
    * @param cache A {@link Cache} to store the data.
    * @param cache A {@link Cache} to store the data.
    * @param key The key whose data should be removed.
    * @param key The key whose data should be removed.
    */
    */
+  @WorkerThread
   public static void remove(Cache cache, String key) {
   public static void remove(Cache cache, String key) {
     NavigableSet<CacheSpan> cachedSpans = cache.getCachedSpans(key);
     NavigableSet<CacheSpan> cachedSpans = cache.getCachedSpans(key);
     for (CacheSpan cachedSpan : cachedSpans) {
     for (CacheSpan cachedSpan : cachedSpans) {

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedContentIndex.java

@@ -25,6 +25,7 @@ import android.util.SparseArray;
 import android.util.SparseBooleanArray;
 import android.util.SparseBooleanArray;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.annotation.VisibleForTesting;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.database.VersionTable;
 import com.google.android.exoplayer2.database.VersionTable;
@@ -104,10 +105,13 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
   /**
   /**
    * Deletes index data for the specified cache.
    * Deletes index data for the specified cache.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param databaseProvider Provides the database in which the index is stored.
    * @param databaseProvider Provides the database in which the index is stored.
    * @param uid The cache UID.
    * @param uid The cache UID.
    * @throws DatabaseIOException If an error occurs deleting the index data.
    * @throws DatabaseIOException If an error occurs deleting the index data.
    */
    */
+  @WorkerThread
   public static void delete(DatabaseProvider databaseProvider, long uid)
   public static void delete(DatabaseProvider databaseProvider, long uid)
       throws DatabaseIOException {
       throws DatabaseIOException {
     DatabaseStorage.delete(databaseProvider, uid);
     DatabaseStorage.delete(databaseProvider, uid);
@@ -174,9 +178,12 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
   /**
   /**
    * Loads the index data for the given cache UID.
    * Loads the index data for the given cache UID.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param uid The UID of the cache whose index is to be loaded.
    * @param uid The UID of the cache whose index is to be loaded.
    * @throws IOException If an error occurs initializing the index data.
    * @throws IOException If an error occurs initializing the index data.
    */
    */
+  @WorkerThread
   public void initialize(long uid) throws IOException {
   public void initialize(long uid) throws IOException {
     storage.initialize(uid);
     storage.initialize(uid);
     if (previousStorage != null) {
     if (previousStorage != null) {
@@ -199,8 +206,11 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
   /**
   /**
    * Stores the index data to index file if there is a change.
    * Stores the index data to index file if there is a change.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @throws IOException If an error occurs storing the index data.
    * @throws IOException If an error occurs storing the index data.
    */
    */
+  @WorkerThread
   public void store() throws IOException {
   public void store() throws IOException {
     storage.storeIncremental(keyToContent);
     storage.storeIncremental(keyToContent);
     // Make ids that were removed since the index was last stored eligible for re-use.
     // Make ids that were removed since the index was last stored eligible for re-use.

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/SimpleCache.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.upstream.cache;
 import android.os.ConditionVariable;
 import android.os.ConditionVariable;
 import androidx.annotation.NonNull;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
+import androidx.annotation.WorkerThread;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseIOException;
 import com.google.android.exoplayer2.database.DatabaseProvider;
 import com.google.android.exoplayer2.database.DatabaseProvider;
@@ -85,10 +86,13 @@ public final class SimpleCache implements Cache {
   /**
   /**
    * Deletes all content belonging to a cache instance.
    * Deletes all content belonging to a cache instance.
    *
    *
+   * <p>This method may be slow and shouldn't normally be called on the main thread.
+   *
    * @param cacheDir The cache directory.
    * @param cacheDir The cache directory.
    * @param databaseProvider The database in which index data is stored, or {@code null} if the
    * @param databaseProvider The database in which index data is stored, or {@code null} if the
    *     cache used a legacy index.
    *     cache used a legacy index.
    */
    */
+  @WorkerThread
   public static void delete(File cacheDir, @Nullable DatabaseProvider databaseProvider) {
   public static void delete(File cacheDir, @Nullable DatabaseProvider databaseProvider) {
     if (!cacheDir.exists()) {
     if (!cacheDir.exists()) {
       return;
       return;
@@ -147,6 +151,7 @@ public final class SimpleCache implements Cache {
    * @deprecated Use a constructor that takes a {@link DatabaseProvider} for improved performance.
    * @deprecated Use a constructor that takes a {@link DatabaseProvider} for improved performance.
    */
    */
   @Deprecated
   @Deprecated
+  @SuppressWarnings("deprecation")
   public SimpleCache(File cacheDir, CacheEvictor evictor, @Nullable byte[] secretKey) {
   public SimpleCache(File cacheDir, CacheEvictor evictor, @Nullable byte[] secretKey) {
     this(cacheDir, evictor, secretKey, secretKey != null);
     this(cacheDir, evictor, secretKey, secretKey != null);
   }
   }