Implement CacheFileMetadataIndex using SQLite

PiperOrigin-RevId: 232670039

library/core/src/main/java/com/google/android/exoplayer2/database/VersionTable.java

@@ -35,8 +35,10 @@ public final class VersionTable {
   public static final int VERSION_UNSET = -1;
   /** Version of tables used for offline functionality. */
   public static final int FEATURE_OFFLINE = 0;
-  /** Version of tables used for cache functionality. */
+  /** Version of tables used for cache content metadata. */
-  public static final int FEATURE_CACHE = 1;
+  public static final int FEATURE_CACHE_CONTENT_METADATA = 1;
+  /** Version of tables used for cache file metadata. */
+  public static final int FEATURE_CACHE_FILE_METADATA = 2;
 
   private static final String TABLE_NAME = DatabaseProvider.TABLE_PREFIX + "Versions";
 
@@ -54,7 +56,7 @@ public final class VersionTable {
 
   @Documented
   @Retention(RetentionPolicy.SOURCE)
-  @IntDef({FEATURE_OFFLINE, FEATURE_CACHE})
+  @IntDef({FEATURE_OFFLINE, FEATURE_CACHE_CONTENT_METADATA, FEATURE_CACHE_FILE_METADATA})
   private @interface Feature {}
 
   private VersionTable() {}

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

@@ -15,19 +15,72 @@
  */
 package com.google.android.exoplayer2.upstream.cache;
 
-import java.util.Collections;
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import com.google.android.exoplayer2.database.DatabaseProvider;
+import com.google.android.exoplayer2.database.VersionTable;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 
 /** Maintains an index of cache file metadata. */
-/* package */ class CacheFileMetadataIndex {
+/* package */ final class CacheFileMetadataIndex {
+
+  private static final String TABLE_NAME = DatabaseProvider.TABLE_PREFIX + "CacheFileMetadata";
+  private static final int TABLE_VERSION = 1;
+
+  private static final String COLUMN_NAME = "name";
+  private static final String COLUMN_LENGTH = "length";
+  private static final String COLUMN_LAST_ACCESS_TIMESTAMP = "last_access_timestamp";
+
+  private static final int COLUMN_INDEX_NAME = 0;
+  private static final int COLUMN_INDEX_LENGTH = 1;
+  private static final int COLUMN_INDEX_LAST_ACCESS_TIMESTAMP = 2;
+
+  private static final String WHERE_NAME_EQUALS = COLUMN_INDEX_NAME + " = ?";
+
+  private static final String[] COLUMNS =
+      new String[] {
+        COLUMN_NAME, COLUMN_LENGTH, COLUMN_LAST_ACCESS_TIMESTAMP,
+      };
+
+  private static final String SQL_DROP_TABLE_IF_EXISTS = "DROP TABLE IF EXISTS " + TABLE_NAME;
+  private static final String SQL_CREATE_TABLE =
+      "CREATE TABLE "
+          + TABLE_NAME
+          + " ("
+          + COLUMN_NAME
+          + " TEXT PRIMARY KEY NOT NULL,"
+          + COLUMN_LENGTH
+          + " INTEGER NOT NULL,"
+          + COLUMN_LAST_ACCESS_TIMESTAMP
+          + " INTEGER NOT NULL)";
+
+  private final DatabaseProvider databaseProvider;
+
+  private boolean initialized;
+
+  public CacheFileMetadataIndex(DatabaseProvider databaseProvider) {
+    this.databaseProvider = databaseProvider;
+  }
 
   /**
    * Returns all file metadata keyed by file name. The returned map is mutable and may be modified
    * by the caller.
    */
   public Map<String, CacheFileMetadata> getAll() {
-    return Collections.emptyMap();
+    ensureInitialized();
+    try (Cursor cursor = getCursor()) {
+      Map<String, CacheFileMetadata> fileMetadata = new HashMap<>(cursor.getCount());
+      while (cursor.moveToNext()) {
+        String name = cursor.getString(COLUMN_INDEX_NAME);
+        long length = cursor.getLong(COLUMN_INDEX_LENGTH);
+        long lastAccessTimestamp = cursor.getLong(COLUMN_INDEX_LAST_ACCESS_TIMESTAMP);
+        fileMetadata.put(name, new CacheFileMetadata(length, lastAccessTimestamp));
+      }
+      return fileMetadata;
+    }
   }
 
   /**
@@ -36,11 +89,15 @@ import java.util.Set;
    * @param name The name of the file.
    * @param length The file length.
    * @param lastAccessTimestamp The file last access timestamp.
-   * @return Whether the index was updated successfully.
    */
-  public boolean set(String name, long length, long lastAccessTimestamp) {
+  public void set(String name, long length, long lastAccessTimestamp) {
-    // TODO.
+    ensureInitialized();
-    return false;
+    SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
+    ContentValues values = new ContentValues();
+    values.put(COLUMN_NAME, name);
+    values.put(COLUMN_LENGTH, length);
+    values.put(COLUMN_LAST_ACCESS_TIMESTAMP, lastAccessTimestamp);
+    writableDatabase.replace(TABLE_NAME, /* nullColumnHack= */ null, values);
   }
 
   /**
@@ -49,7 +106,9 @@ import java.util.Set;
    * @param name The name of the file whose metadata is to be removed.
    */
   public void remove(String name) {
-    // TODO.
+    ensureInitialized();
+    SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
+    writableDatabase.delete(TABLE_NAME, WHERE_NAME_EQUALS, new String[] {name});
   }
 
   /**
@@ -58,6 +117,55 @@ import java.util.Set;
    * @param names The names of the files whose metadata is to be removed.
    */
   public void removeAll(Set<String> names) {
-    // TODO.
+    ensureInitialized();
+    SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
+    writableDatabase.beginTransaction();
+    try {
+      for (String name : names) {
+        writableDatabase.delete(TABLE_NAME, WHERE_NAME_EQUALS, new String[] {name});
+      }
+      writableDatabase.setTransactionSuccessful();
+    } finally {
+      writableDatabase.endTransaction();
+    }
+  }
+
+  private void ensureInitialized() {
+    if (initialized) {
+      return;
+    }
+    SQLiteDatabase readableDatabase = databaseProvider.getReadableDatabase();
+    int version =
+        VersionTable.getVersion(readableDatabase, VersionTable.FEATURE_CACHE_FILE_METADATA);
+    if (version == VersionTable.VERSION_UNSET || version > TABLE_VERSION) {
+      SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
+      writableDatabase.beginTransaction();
+      try {
+        VersionTable.setVersion(
+            writableDatabase, VersionTable.FEATURE_CACHE_FILE_METADATA, TABLE_VERSION);
+        writableDatabase.execSQL(SQL_DROP_TABLE_IF_EXISTS);
+        writableDatabase.execSQL(SQL_CREATE_TABLE);
+        writableDatabase.setTransactionSuccessful();
+      } finally {
+        writableDatabase.endTransaction();
+      }
+    } else if (version < TABLE_VERSION) {
+      // There is no previous version currently.
+      throw new IllegalStateException();
+    }
+    initialized = true;
+  }
+
+  private Cursor getCursor() {
+    return databaseProvider
+        .getReadableDatabase()
+        .query(
+            TABLE_NAME,
+            COLUMNS,
+            /* selection */ null,
+            /* selectionArgs= */ null,
+            /* groupBy= */ null,
+            /* having= */ null,
+            /* orderBy= */ null);
   }
 }

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

@@ -678,7 +678,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
   //    the entire table. Currently this implementation only encrypts new and updated entries.
   private static final class SQLiteStorage implements Storage {
 
-    private static final String TABLE_NAME = DatabaseProvider.TABLE_PREFIX + "Cache";
+    private static final String TABLE_NAME = DatabaseProvider.TABLE_PREFIX + "CacheContentMetadata";
     private static final int TABLE_VERSION = 1;
 
     private static final String COLUMN_ID = "id";
@@ -736,7 +736,8 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
     public boolean exists() {
       return file.exists()
           && VersionTable.getVersion(
-                  databaseProvider.getReadableDatabase(), VersionTable.FEATURE_CACHE)
+                  databaseProvider.getReadableDatabase(),
+                  VersionTable.FEATURE_CACHE_CONTENT_METADATA)
               != VersionTable.VERSION_UNSET;
     }
 
@@ -755,7 +756,8 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
       try {
         int version =
             VersionTable.getVersion(
-                databaseProvider.getReadableDatabase(), VersionTable.FEATURE_CACHE);
+                databaseProvider.getReadableDatabase(),
+                VersionTable.FEATURE_CACHE_CONTENT_METADATA);
         if (version == VersionTable.VERSION_UNSET || version > TABLE_VERSION) {
           SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
           writableDatabase.beginTransaction();
@@ -870,7 +872,8 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
     }
 
     private void initializeTable(SQLiteDatabase writableDatabase) {
-      VersionTable.setVersion(writableDatabase, VersionTable.FEATURE_CACHE, TABLE_VERSION);
+      VersionTable.setVersion(
+          writableDatabase, VersionTable.FEATURE_CACHE_CONTENT_METADATA, TABLE_VERSION);
       writableDatabase.execSQL(SQL_DROP_TABLE_IF_EXISTS);
       writableDatabase.execSQL(SQL_CREATE_TABLE);
     }

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

@@ -253,13 +253,12 @@ public final class SimpleCache implements Cache {
       String fileName = span.file.getName();
       long length = span.length;
       long lastAccessTimestamp = System.currentTimeMillis();
-      // Updating the file itself to incorporate the new last access timestamp is much slower than
+      boolean updateFile = false;
-      // updating the file index. Hence we only update the file if we don't have a file index, or if
-      // updating the file index failed.
-      boolean updateFile;
       if (fileIndex != null) {
-        updateFile = !fileIndex.set(fileName, length, lastAccessTimestamp);
+        fileIndex.set(fileName, length, lastAccessTimestamp);
       } else {
+        // Updating the file itself to incorporate the new last access timestamp is much slower than
+        // updating the file index. Hence we only update the file if we don't have a file index.
         updateFile = true;
       }
       SimpleCacheSpan newSpan =

library/core/src/test/java/com/google/android/exoplayer2/database/VersionTableTest.java

@@ -15,7 +15,7 @@
  */
 package com.google.android.exoplayer2.database;
 
-import static com.google.android.exoplayer2.database.VersionTable.FEATURE_CACHE;
+import static com.google.android.exoplayer2.database.VersionTable.FEATURE_CACHE_CONTENT_METADATA;
 import static com.google.android.exoplayer2.database.VersionTable.FEATURE_OFFLINE;
 import static com.google.common.truth.Truth.assertThat;
 
@@ -61,8 +61,9 @@ public class VersionTableTest {
     VersionTable.setVersion(writableDatabase, FEATURE_OFFLINE, 10);
     assertThat(VersionTable.getVersion(readableDatabase, FEATURE_OFFLINE)).isEqualTo(10);
 
-    VersionTable.setVersion(writableDatabase, FEATURE_CACHE, 5);
+    VersionTable.setVersion(writableDatabase, FEATURE_CACHE_CONTENT_METADATA, 5);
-    assertThat(VersionTable.getVersion(readableDatabase, FEATURE_CACHE)).isEqualTo(5);
+    assertThat(VersionTable.getVersion(readableDatabase, FEATURE_CACHE_CONTENT_METADATA))
+        .isEqualTo(5);
     assertThat(VersionTable.getVersion(readableDatabase, FEATURE_OFFLINE)).isEqualTo(10);
   }