Merge "Catch exceptions we can't do anything about."

1 files changed, 99 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/dictionarypack/DownloadManagerWrapper.java b/java/src/com/android/inputmethod/dictionarypack/DownloadManagerWrapper.java
new file mode 100644
index 000000000..e95ca1799
--- /dev/null
+++ b/java/src/com/android/inputmethod/dictionarypack/DownloadManagerWrapper.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2014 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.android.inputmethod.dictionarypack;
+
+import android.app.DownloadManager;
+import android.app.DownloadManager.Query;
+import android.app.DownloadManager.Request;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteException;
+import android.os.ParcelFileDescriptor;
+import android.util.Log;
+
+import java.io.FileNotFoundException;
+
+/**
+ * A class to help with calling DownloadManager methods.
+ *
+ * Mostly, the problem here is that most methods from DownloadManager may throw SQL exceptions if
+ * they can't open the database on disk. We want to avoid crashing in these cases but can't do
+ * much more, so this class insulates the callers from these. SQLiteException also inherit from
+ * RuntimeException so they are unchecked :(
+ * While we're at it, we also insulate callers from the cases where DownloadManager is disabled,
+ * and getSystemService returns null.
+ */
+public class DownloadManagerWrapper {
+    private final static String TAG = DownloadManagerWrapper.class.getSimpleName();
+    private final DownloadManager mDownloadManager;
+
+    public DownloadManagerWrapper(final Context context) {
+        this((DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE));
+    }
+
+    private DownloadManagerWrapper(final DownloadManager downloadManager) {
+        mDownloadManager = downloadManager;
+    }
+
+    public void remove(final long... ids) {
+        try {
+            if (null != mDownloadManager) {
+                mDownloadManager.remove(ids);
+            }
+        } catch (SQLiteException e) {
+            // We couldn't remove the file from DownloadManager. Apparently, the database can't
+            // be opened. It may be a problem with file system corruption. In any case, there is
+            // not much we can do apart from avoiding crashing.
+            Log.e(TAG, "Can't remove files with ID " + ids + " from download manager", e);
+        }
+    }
+
+    public ParcelFileDescriptor openDownloadedFile(final long fileId) throws FileNotFoundException {
+        try {
+            if (null != mDownloadManager) {
+                return mDownloadManager.openDownloadedFile(fileId);
+            }
+        } catch (SQLiteException e) {
+            Log.e(TAG, "Can't open downloaded file with ID " + fileId, e);
+        }
+        // We come here if mDownloadManager is null or if an exception was thrown.
+        throw new FileNotFoundException();
+    }
+
+    public Cursor query(final Query query) {
+        try {
+            if (null != mDownloadManager) {
+                return mDownloadManager.query(query);
+            }
+        } catch (SQLiteException e) {
+            Log.e(TAG, "Can't query the download manager", e);
+        }
+        // We come here if mDownloadManager is null or if an exception was thrown.
+        return null;
+    }
+
+    public long enqueue(final Request request) {
+        try {
+            if (null != mDownloadManager) {
+                return mDownloadManager.enqueue(request);
+            }
+        } catch (SQLiteException e) {
+            Log.e(TAG, "Can't enqueue a request with the download manager", e);
+        }
+        return 0;
+    }
+}