1 files changed, 170 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/database/VersionTable.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/database/VersionTable.java
new file mode 100644
index 0000000000..d3174e67b2
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/database/VersionTable.java
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2018 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 org.mozilla.thirdparty.com.google.android.exoplayer2.database;
+
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.DatabaseUtils;
+import android.database.SQLException;
+import android.database.sqlite.SQLiteDatabase;
+import androidx.annotation.IntDef;
+import androidx.annotation.VisibleForTesting;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * Utility methods for accessing versions of ExoPlayer database components. This allows them to be
+ * versioned independently to the version of the containing database.
+ */
+public final class VersionTable {
+
+  /** Returned by {@link #getVersion(SQLiteDatabase, int, String)} if the version is unset. */
+  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 content metadata. */
+  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";
+
+  private static final String COLUMN_FEATURE = "feature";
+  private static final String COLUMN_INSTANCE_UID = "instance_uid";
+  private static final String COLUMN_VERSION = "version";
+
+  private static final String WHERE_FEATURE_AND_INSTANCE_UID_EQUALS =
+      COLUMN_FEATURE + " = ? AND " + COLUMN_INSTANCE_UID + " = ?";
+
+  private static final String PRIMARY_KEY =
+      "PRIMARY KEY (" + COLUMN_FEATURE + ", " + COLUMN_INSTANCE_UID + ")";
+  private static final String SQL_CREATE_TABLE_IF_NOT_EXISTS =
+      "CREATE TABLE IF NOT EXISTS "
+          + TABLE_NAME
+          + " ("
+          + COLUMN_FEATURE
+          + " INTEGER NOT NULL,"
+          + COLUMN_INSTANCE_UID
+          + " TEXT NOT NULL,"
+          + COLUMN_VERSION
+          + " INTEGER NOT NULL,"
+          + PRIMARY_KEY
+          + ")";
+
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef({FEATURE_OFFLINE, FEATURE_CACHE_CONTENT_METADATA, FEATURE_CACHE_FILE_METADATA})
+  private @interface Feature {}
+
+  private VersionTable() {}
+
+  /**
+   * Sets the version of a specified instance of a specified feature.
+   *
+   * @param writableDatabase The database to update.
+   * @param feature The feature.
+   * @param instanceUid The unique identifier of the instance of the feature.
+   * @param version The version.
+   * @throws DatabaseIOException If an error occurs executing the SQL.
+   */
+  public static void setVersion(
+      SQLiteDatabase writableDatabase, @Feature int feature, String instanceUid, int version)
+      throws DatabaseIOException {
+    try {
+      writableDatabase.execSQL(SQL_CREATE_TABLE_IF_NOT_EXISTS);
+      ContentValues values = new ContentValues();
+      values.put(COLUMN_FEATURE, feature);
+      values.put(COLUMN_INSTANCE_UID, instanceUid);
+      values.put(COLUMN_VERSION, version);
+      writableDatabase.replaceOrThrow(TABLE_NAME, /* nullColumnHack= */ null, values);
+    } catch (SQLException e) {
+      throw new DatabaseIOException(e);
+    }
+  }
+
+  /**
+   * Removes the version of a specified instance of a feature.
+   *
+   * @param writableDatabase The database to update.
+   * @param feature The feature.
+   * @param instanceUid The unique identifier of the instance of the feature.
+   * @throws DatabaseIOException If an error occurs executing the SQL.
+   */
+  public static void removeVersion(
+      SQLiteDatabase writableDatabase, @Feature int feature, String instanceUid)
+      throws DatabaseIOException {
+    try {
+      if (!tableExists(writableDatabase, TABLE_NAME)) {
+        return;
+      }
+      writableDatabase.delete(
+          TABLE_NAME,
+          WHERE_FEATURE_AND_INSTANCE_UID_EQUALS,
+          featureAndInstanceUidArguments(feature, instanceUid));
+    } catch (SQLException e) {
+      throw new DatabaseIOException(e);
+    }
+  }
+
+  /**
+   * Returns the version of a specified instance of a feature, or {@link #VERSION_UNSET} if no
+   * version is set.
+   *
+   * @param database The database to query.
+   * @param feature The feature.
+   * @param instanceUid The unique identifier of the instance of the feature.
+   * @return The version, or {@link #VERSION_UNSET} if no version is set.
+   * @throws DatabaseIOException If an error occurs executing the SQL.
+   */
+  public static int getVersion(SQLiteDatabase database, @Feature int feature, String instanceUid)
+      throws DatabaseIOException {
+    try {
+      if (!tableExists(database, TABLE_NAME)) {
+        return VERSION_UNSET;
+      }
+      try (Cursor cursor =
+          database.query(
+              TABLE_NAME,
+              new String[] {COLUMN_VERSION},
+              WHERE_FEATURE_AND_INSTANCE_UID_EQUALS,
+              featureAndInstanceUidArguments(feature, instanceUid),
+              /* groupBy= */ null,
+              /* having= */ null,
+              /* orderBy= */ null)) {
+        if (cursor.getCount() == 0) {
+          return VERSION_UNSET;
+        }
+        cursor.moveToNext();
+        return cursor.getInt(/* COLUMN_VERSION index */ 0);
+      }
+    } catch (SQLException e) {
+      throw new DatabaseIOException(e);
+    }
+  }
+
+  @VisibleForTesting
+  /* package */ static boolean tableExists(SQLiteDatabase readableDatabase, String tableName) {
+    long count =
+        DatabaseUtils.queryNumEntries(
+            readableDatabase, "sqlite_master", "tbl_name = ?", new String[] {tableName});
+    return count > 0;
+  }
+
+  private static String[] featureAndInstanceUidArguments(int feature, String instance) {
+    return new String[] {Integer.toString(feature), instance};
+  }
+}