Update the SystemUpdater

- Use update engine to install updates
- More car UX cleanup
- Request permissions to access storage

bug: 72832693
Test: make SystemUpdater; install and test update on device.
Change-Id: Iebca00a9a8c9bff735b63c62d99f51975c2f9264

8 files changed, 295 insertions, 161 deletions

diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index fb2e14e..e03b9c7 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -17,17 +17,11 @@
 
 <manifest
         xmlns:android="http://schemas.android.com/apk/res/android"
-        package="com.android.car.systemupdater" >
-    <uses-sdk android:minSdkVersion="21" />
+        package="com.android.car.systemupdater">
+
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.ACCESS_CACHE_FILESYSTEM" />
-    <uses-permission android:name="android.permission.DELETE_CACHE_FILES" />
     <uses-permission android:name="android.permission.REBOOT" />
-    <uses-permission android:name="android.permission.RECOVERY" />
-    <uses-permission android:name="android.permission.WRITE_MEDIA_STORAGE" />
     <uses-feature android:name="android.hardware.usb.host" />
 
     <application
diff --git a/res/layout/folder_list.xml b/res/layout/folder_list.xml
index ba3eeff..33982d6 100644
--- a/res/layout/folder_list.xml
+++ b/res/layout/folder_list.xml
@@ -14,12 +14,20 @@
   See the License for the specific language governing permissions and
   limitations under the License.
 -->
-<FrameLayout
-      xmlns:android="http://schemas.android.com/apk/res/android"
-      xmlns:app="http://schemas.android.com/apk/res-auto"
-      android:orientation="vertical"
-      android:layout_width="match_parent"
-      android:layout_height="match_parent">
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <TextView
+        android:id="@+id/current_path"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:textAppearance="@style/ListPath"
+        android:layout_marginStart="@dimen/car_gutter_size"
+        android:layout_marginEnd="@dimen/car_margin"/>
 
     <androidx.car.widget.PagedListView
         android:id="@+id/folder_list"
@@ -27,4 +35,4 @@
         android:layout_height="match_parent"
         app:showPagedListViewDivider="true"
         app:gutter="start"/>
-</FrameLayout>
+</LinearLayout>
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 0aa33b0..d72f65a 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -40,10 +40,6 @@
     <string name="verify_in_progress">Verifying update&#8230;</string>
     <!-- An error message indicating that verification failed. [CHAR LIMIT=40] -->
     <string name="verify_failure">Verification Failed. Please select a valid update file.</string>
-    <!-- A status that indicates that the update is being copied before installation. [CHAR LIMIT=40] -->
-    <string name="copy_in_progress">Copying to device&#8230;</string>
-    <!-- An error message indicating that copying failed. [CHAR LIMIT=40] -->
-    <string name="copy_failure">Failed to copy to the device. Check disk space and try again.</string>
     <!-- A status that indicates that the update is ready to be installed. [CHAR LIMIT=40] -->
     <string name="install_ready">The update is ready to be installed.</string>
     <!-- A status that indicates the installation process is running. [CHAR LIMIT=40] -->
@@ -52,4 +48,10 @@
     <string name="install_success">The update is successful.</string>
     <!-- A status that indicates that installation failed. [CHAR LIMIT=40] -->
     <string name="install_failed">System update installation failed.</string>
+    <!-- A status that indicates the system is about to reboot. [CHAR LIMIT=40] -->
+    <string name="rebooting">The update is successful. Rebooting now&#8230;</string>
+    <!-- The volumes found on the device. [CHAR LIMIT=40] -->
+    <string name="volumes">Volumes (%d)</string>
+    <!-- The path of the current directory. [CHAR LIMIT=20] -->
+    <string name="path">Path: %s</string>
 </resources>
diff --git a/res/values/styles.xml b/res/values/styles.xml
index c8e0f0b..e3a19e6 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -60,4 +60,8 @@
     <item name="android:background">?android:selectableItemBackground</item>
     <item name="android:gravity">center</item>
   </style>
+
+  <style name="ListPath" parent="CarBody2">
+      <item name="android:textColor">@color/car_accent</item>
+  </style>
 </resources>
diff --git a/src/com/android/car/systemupdater/DeviceListFragment.java b/src/com/android/car/systemupdater/DeviceListFragment.java
index a19e652..d32cb7e 100644
--- a/src/com/android/car/systemupdater/DeviceListFragment.java
+++ b/src/com/android/car/systemupdater/DeviceListFragment.java
@@ -25,31 +25,39 @@ import android.support.annotation.NonNull;
 import android.support.v4.app.Fragment;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AppCompatActivity;
+import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.TextView;
 import android.widget.Toast;
-import android.util.Log;
-
-import androidx.car.widget.PagedListView;
-import androidx.car.widget.ListItem;
-import androidx.car.widget.ListItemAdapter;
-import androidx.car.widget.ListItemProvider;
-import androidx.car.widget.TextListItem;
 
 import java.io.File;
+import java.io.FileFilter;
+import java.io.FilenameFilter;
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Stack;
 
+import androidx.car.widget.ListItem;
+import androidx.car.widget.ListItemAdapter;
+import androidx.car.widget.ListItemProvider;
+import androidx.car.widget.PagedListView;
+import androidx.car.widget.TextListItem;
+
 /**
-* Display a list of files and directories.
-*/
+ * Display a list of files and directories.
+ */
 public class DeviceListFragment extends Fragment {
 
     private static final String TAG = "DeviceListFragment";
     private static final String UPDATE_FILE_SUFFIX = ".zip";
+    private static final FileFilter UPDATE_FILE_FILTER =
+            file -> !file.isHidden() && (file.isDirectory()
+                    || file.getName().toLowerCase().endsWith(UPDATE_FILE_SUFFIX));
+
 
     private final Stack<File> mFileStack = new Stack<>();
     private StorageManager mStorageManager;
@@ -57,6 +65,7 @@ public class DeviceListFragment extends Fragment {
     private List<File> mListItems;
     private ListItemAdapter mAdapter;
     private FileItemProvider mItemProvider;
+    private TextView mCurrentPathView;
 
     private final StorageEventListener mListener = new StorageEventListener() {
         @Override
@@ -91,21 +100,22 @@ public class DeviceListFragment extends Fragment {
             Toast.makeText(context, R.string.cannot_access_storage, Toast.LENGTH_LONG).show();
             return;
         }
-        showMountedVolumes();
     }
 
-   @Override
-   public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
-           Bundle savedInstanceState) {
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+            Bundle savedInstanceState) {
         mAdapter = new ListItemAdapter(getContext(), mItemProvider);
         return inflater.inflate(R.layout.folder_list, container, false);
-   }
+    }
 
-   @Override
+    @Override
     public void onViewCreated(@NonNull View view, Bundle savedInstanceState) {
         PagedListView folderListView = (PagedListView) view.findViewById(R.id.folder_list);
         folderListView.setMaxPages(PagedListView.ItemCap.UNLIMITED);
         folderListView.setAdapter(mAdapter);
+
+        mCurrentPathView = (TextView) view.findViewById(R.id.current_path);
     }
 
     @Override
@@ -118,6 +128,8 @@ public class DeviceListFragment extends Fragment {
         actionBar.setDisplayShowTitleEnabled(false);
         activity.findViewById(R.id.action_bar_icon_container)
                 .setOnClickListener(v -> onBackPressed());
+
+        showMountedVolumes();
     }
 
     @Override
@@ -145,10 +157,15 @@ public class DeviceListFragment extends Fragment {
         ArrayList<File> volumes = new ArrayList<>(vols.size());
         for (VolumeInfo vol : vols) {
             File path = vol.getPathForUser(getActivity().getUserId());
-            if (vol.getState() == VolumeInfo.STATE_MOUNTED && path != null) {
+            if (vol.getState() == VolumeInfo.STATE_MOUNTED
+                    && vol.getType() == VolumeInfo.TYPE_PUBLIC
+                    && path != null) {
                 volumes.add(path);
             }
         }
+
+        // Otherwise show all of the available volumes.
+        mCurrentPathView.setText(getString(R.string.volumes, volumes.size()));
         setFileList(volumes);
     }
 
@@ -198,11 +215,13 @@ public class DeviceListFragment extends Fragment {
             return;
         }
 
+        mCurrentPathView.setText(getString(R.string.path, folder.getAbsolutePath()));
+
         // Retrieve the list of files and update the displayed list.
         new AsyncTask<File, Void, File[]>() {
             @Override
             protected File[] doInBackground(File... file) {
-                return file[0].listFiles();
+                return file[0].listFiles(UPDATE_FILE_FILTER);
             }
 
             @Override
@@ -210,6 +229,8 @@ public class DeviceListFragment extends Fragment {
                 super.onPostExecute(results);
                 if (results == null) {
                     results = new File[0];
+                    Toast.makeText(getContext(), R.string.cannot_access_storage,
+                            Toast.LENGTH_LONG).show();
                 }
                 setFileList(Arrays.asList(results));
             }
@@ -232,7 +253,7 @@ public class DeviceListFragment extends Fragment {
             TextListItem item = new TextListItem(mContext);
             File file = mListItems.get(position);
             if (file != null) {
-                item.setTitle(file.getAbsolutePath());
+                item.setTitle(file.getName());
                 item.setOnClickListener(v -> onFileSelected(file));
             } else {
                 item.setTitle(getString(R.string.unknown_file));
@@ -242,7 +263,7 @@ public class DeviceListFragment extends Fragment {
 
         @Override
         public int size() {
-            return mListItems.size();
+            return mListItems == null ? 0 : mListItems.size();
         }
     }
 
diff --git a/src/com/android/car/systemupdater/SystemUpdaterActivity.java b/src/com/android/car/systemupdater/SystemUpdaterActivity.java
index e5fd9fb..91cbe6b 100644
--- a/src/com/android/car/systemupdater/SystemUpdaterActivity.java
+++ b/src/com/android/car/systemupdater/SystemUpdaterActivity.java
@@ -15,7 +15,11 @@
  */
 package com.android.car.systemupdater;
 
+import android.Manifest;
+import android.content.pm.PackageManager;
 import android.os.Bundle;
+import android.support.v4.app.ActivityCompat;
+import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 
@@ -27,9 +31,22 @@ import java.io.File;
 public class SystemUpdaterActivity extends AppCompatActivity
         implements DeviceListFragment.SystemUpdater {
 
+    private static final int STORAGE_PERMISSIONS_REQUEST_CODE = 0;
+    private static final String[] REQUIRED_STORAGE_PERMISSIONS = new String[]{
+            Manifest.permission.READ_EXTERNAL_STORAGE,
+            Manifest.permission.WRITE_EXTERNAL_STORAGE
+    };
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                != PackageManager.PERMISSION_GRANTED) {
+            ActivityCompat.requestPermissions(this, REQUIRED_STORAGE_PERMISSIONS,
+                    STORAGE_PERMISSIONS_REQUEST_CODE);
+        }
+
         setContentView(R.layout.activity_main);
         Toolbar toolbar = findViewById(R.id.toolbar);
         setSupportActionBar(toolbar);
@@ -43,6 +60,22 @@ public class SystemUpdaterActivity extends AppCompatActivity
     }
 
     @Override
+    public void onRequestPermissionsResult(int requestCode, String permissions[],
+            int[] grantResults) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
+        if (STORAGE_PERMISSIONS_REQUEST_CODE == requestCode) {
+            if (grantResults.length == 0) {
+                finish();
+            }
+            for (int grantResult : grantResults) {
+                if (grantResult != PackageManager.PERMISSION_GRANTED) {
+                    finish();
+                }
+            }
+        }
+    }
+
+    @Override
     public void applyUpdate(File file) {
         UpdateLayoutFragment fragment = UpdateLayoutFragment.getInstance(file);
         getSupportFragmentManager().beginTransaction()
diff --git a/src/com/android/car/systemupdater/UpdateLayoutFragment.java b/src/com/android/car/systemupdater/UpdateLayoutFragment.java
index 70d41a8..699ae19 100644
--- a/src/com/android/car/systemupdater/UpdateLayoutFragment.java
+++ b/src/com/android/car/systemupdater/UpdateLayoutFragment.java
@@ -15,9 +15,13 @@
  */
 package com.android.car.systemupdater;
 
+import android.content.Context;
 import android.os.AsyncTask;
 import android.os.Bundle;
-import android.os.RecoverySystem;
+import android.os.Handler;
+import android.os.PowerManager;
+import android.os.UpdateEngine;
+import android.os.UpdateEngineCallback;
 import android.support.annotation.NonNull;
 import android.support.annotation.StringRes;
 import android.support.v4.app.Fragment;
@@ -32,20 +36,17 @@ import android.widget.Button;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
+import com.android.internal.util.Preconditions;
+
 import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.security.GeneralSecurityException;
 
 /** Display update state and progress. */
 public class UpdateLayoutFragment extends Fragment {
     private static final String TAG = "UpdateLayoutFragment";
-    private static final int COPY_BUF_SIZE = 0x10000; // 64k
     private static final String EXTRA_UPDATE_FILE = "extra_update_file";
-    private static final String UPDATE_FILE_NAME = "update.zip";
+    private static final int PERCENT_MAX = 100;
+    private static final String REBOOT_REASON = "reboot-ab-update";
 
     private ProgressBar mProgressBar;
     private TextView mContentTitle;
@@ -53,9 +54,11 @@ public class UpdateLayoutFragment extends Fragment {
     private TextView mContentDetails;
     private File mUpdateFile;
     private Button mSystemUpdateToolbarAction;
-    private PackageVerifier mPackageVerifier;
-    private CopyFile mCopyFile;
-    private InstallUpdate mInstallUpdate;
+    private PowerManager mPowerManager;
+    private final UpdateVerifier mPackageVerifier = new UpdateVerifier();
+    private final UpdateEngine mUpdateEngine = new UpdateEngine();
+
+    private final CarUpdateEngineCallback mCarUpdateEngineCallback = new CarUpdateEngineCallback();
 
     /** Create a {@link DeviceListFragment}. */
     public static UpdateLayoutFragment getInstance(File file) {
@@ -71,11 +74,12 @@ public class UpdateLayoutFragment extends Fragment {
         super.onCreate(savedInstanceState);
 
         mUpdateFile = new File(getArguments().getString(EXTRA_UPDATE_FILE));
+        mPowerManager = (PowerManager) getContext().getSystemService(Context.POWER_SERVICE);
     }
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
-           Bundle savedInstanceState) {
+            Bundle savedInstanceState) {
         return inflater.inflate(R.layout.system_update_auto_content, container, false);
     }
 
@@ -102,31 +106,28 @@ public class UpdateLayoutFragment extends Fragment {
         mProgressBar = (ProgressBar) activity.findViewById(R.id.progress_bar);
 
         mSystemUpdateToolbarAction = activity.findViewById(R.id.system_update_auto_toolbar_action);
+        mProgressBar.setIndeterminate(true);
+        mProgressBar.setVisibility(View.VISIBLE);
+        showStatus(R.string.verify_in_progress);
 
-        mPackageVerifier = new PackageVerifier();
         mPackageVerifier.execute(mUpdateFile);
     }
 
     @Override
     public void onStop() {
         super.onStop();
-        if (mCopyFile != null) {
-            mCopyFile.cancel(true);
-        }
-        if (mInstallUpdate != null) {
-            mInstallUpdate.cancel(true);
-        }
         if (mPackageVerifier != null) {
             mPackageVerifier.cancel(true);
         }
     }
 
+    /** Update the status information. */
     private void showStatus(@StringRes int status) {
         mContentTitle.setText(status);
     }
 
     /** Show the install now button. */
-    private void showInstallNow(File update) {
+    private void showInstallNow(UpdateParser.ParsedUpdate update) {
         mContentTitle.setText(R.string.install_ready);
         mContentInfo.append(getString(R.string.update_file_name, mUpdateFile.getName()));
         mContentInfo.append(System.getProperty("line.separator"));
@@ -138,141 +139,92 @@ public class UpdateLayoutFragment extends Fragment {
         mSystemUpdateToolbarAction.setVisibility(View.VISIBLE);
     }
 
-    /** Attempt to install the update that is copied to the device. */
-    private void installUpdate(File update) {
-        mInstallUpdate = new InstallUpdate();
-        mInstallUpdate.execute(update);
+    /** Reboot the system. */
+    private void rebootNow() {
+        if (Log.isLoggable(TAG, Log.INFO)) {
+            Log.i(TAG, "Rebooting Now.");
+        }
+        mPowerManager.reboot(REBOOT_REASON);
     }
 
-    /** Attempt to verify the package. */
-    private class PackageVerifier extends AsyncTask<File, Void, File> {
+    /** Attempt to install the update that is copied to the device. */
+    private void installUpdate(UpdateParser.ParsedUpdate parsedUpdate) {
+        mProgressBar.setIndeterminate(false);
+        mProgressBar.setVisibility(View.VISIBLE);
+        mProgressBar.setMax(PERCENT_MAX);
+        mSystemUpdateToolbarAction.setVisibility(View.GONE);
+        showStatus(R.string.install_in_progress);
+
+        mUpdateEngine.bind(mCarUpdateEngineCallback,
+                new Handler(getContext().getMainLooper()));
+        mUpdateEngine.applyPayload(
+                parsedUpdate.mUrl, parsedUpdate.mOffset, parsedUpdate.mSize, parsedUpdate.mProps);
 
-        @Override
-        public void onPreExecute() {
-            mProgressBar.setIndeterminate(true);
-            mProgressBar.setVisibility(View.VISIBLE);
-            showStatus(R.string.verify_in_progress);
-        }
+    }
+
+    /** Attempt to verify the update and extract information needed for installation. */
+    private class UpdateVerifier extends AsyncTask<File, Void, UpdateParser.ParsedUpdate> {
 
         @Override
-        protected File doInBackground(File... files) {
+        protected UpdateParser.ParsedUpdate doInBackground(File... files) {
+            Preconditions.checkArgument(files.length > 0, "No file specified");
             File file = files[0];
             try {
-                RecoverySystem.verifyPackage(file, null, null);
-                return file;
-            } catch (GeneralSecurityException | IOException e) {
-                Log.e(TAG, String.format("While verifying package: %s", file), e);
+                return UpdateParser.parse(file);
+            } catch (IOException e) {
+                Log.e(TAG, String.format("For file %s", file), e);
                 return null;
             }
         }
 
         @Override
-        protected void onPostExecute(File result) {
+        protected void onPostExecute(UpdateParser.ParsedUpdate result) {
             mProgressBar.setVisibility(View.GONE);
             if (result == null) {
                 showStatus(R.string.verify_failure);
                 return;
             }
-
-            mCopyFile = new CopyFile();
-            mCopyFile.execute(result);
-        }
-    }
-
-    /** Copy the update file to the data partition so it can be installed. */
-    private class CopyFile extends AsyncTask<File, Integer, File> {
-        private final File mCacheDir;
-
-        CopyFile() {
-            mCacheDir = getContext().getCacheDir();
-        }
-
-        @Override
-        public void onPreExecute() {
-            showStatus(R.string.copy_in_progress);
-            mProgressBar.setIndeterminate(false);
-            mProgressBar.setVisibility(View.VISIBLE);
-            mProgressBar.setMax((int)(mUpdateFile.length() / COPY_BUF_SIZE));
-        }
-
-        @Override
-        protected File doInBackground(File... files) {
-            final File file = files[0];
-            if (mCacheDir.getFreeSpace() < file.length()) {
-                Log.e(TAG, "Not enough cache space!");
-                return null;
-            }
-            final File dest = new File(mCacheDir, UPDATE_FILE_NAME);
-            try {
-                copy(file, dest);
-                return dest;
-            } catch (IOException e) {
-                Log.e(TAG, "Error when copying file to cache", e);
-                dest.delete();
-                return null;
-            }
-        }
-
-        @Override
-        protected void onPostExecute(File result) {
-            mProgressBar.setVisibility(View.GONE);
-            if (result == null) {
-                // Copy failed
-                showStatus(R.string.copy_failure);
+            if (!result.isValid()) {
+                showStatus(R.string.verify_failure);
+                Log.e(TAG, String.format("Failed verification %s", result));
                 return;
             }
+            if (Log.isLoggable(TAG, Log.INFO)) {
+                Log.i(TAG, result.toString());
+            }
 
             showInstallNow(result);
         }
-
-        protected void onProgressUpdate(Integer... progress) {
-            mProgressBar.incrementProgressBy(progress[0]);
-        }
-
-        /** Copy a file from {@code src} to {@code dest}. */
-        private void copy(File src, File dst) throws IOException {
-            try (InputStream in = new FileInputStream(src);
-                 OutputStream out = new FileOutputStream(dst)) {
-                final byte[] buf = new byte[COPY_BUF_SIZE];
-                int len;
-                int count = 0;
-                while ((len = in.read(buf)) > 0) {
-                    out.write(buf, 0, len);
-                    publishProgress(++count);
-                }
-            }
-        }
     }
 
-    /** Attempt to install the package. */
-    private class InstallUpdate extends AsyncTask<File, Void, Boolean> {
-
-        @Override
-        public void onPreExecute() {
-            mProgressBar.setIndeterminate(true);
-            mProgressBar.setVisibility(View.VISIBLE);
-            mSystemUpdateToolbarAction.setVisibility(View.GONE);
-            showStatus(R.string.install_in_progress);
-        }
+    /** Handles events from the UpdateEngine. */
+    public class CarUpdateEngineCallback extends UpdateEngineCallback {
 
         @Override
-        protected Boolean doInBackground(File... files) {
-            File file = files[0];
-            try {
-                RecoverySystem.installPackage(getContext(), file);
-                return true;
-            } catch (IOException e) {
-                Log.e(TAG, "While installing the update package", e);
-                return false;
+        public void onStatusUpdate(int status, float percent) {
+            if (Log.isLoggable(TAG, Log.DEBUG)) {
+                Log.d(TAG, String.format("onStatusUpdate %d, Percent %.2f", status, percent));
+            }
+            switch (status) {
+                case UpdateEngine.UpdateStatusConstants.UPDATED_NEED_REBOOT:
+                    rebootNow();
+                    break;
+                case UpdateEngine.UpdateStatusConstants.DOWNLOADING:
+                    mProgressBar.setProgress((int) (percent * 100));
+                    break;
+                default:
+                    // noop
             }
         }
 
         @Override
-        protected void onPostExecute(Boolean result) {
+        public void onPayloadApplicationComplete(int errorCode) {
+            Log.w(TAG, String.format("onPayloadApplicationComplete %d", errorCode));
+            showStatus(errorCode == UpdateEngine.ErrorCodeConstants.SUCCESS
+                    ? R.string.install_success
+                    : R.string.install_failed);
             mProgressBar.setVisibility(View.GONE);
             mSystemUpdateToolbarAction.setVisibility(View.GONE);
-
-            showStatus(result ? R.string.install_success : R.string.install_failed);
         }
     }
 }
diff --git a/src/com/android/car/systemupdater/UpdateParser.java b/src/com/android/car/systemupdater/UpdateParser.java
new file mode 100644
index 0000000..d48096d
--- /dev/null
+++ b/src/com/android/car/systemupdater/UpdateParser.java
@@ -0,0 +1,120 @@
+/*
+ * 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 com.android.car.systemupdater;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.util.Log;
+
+import com.android.internal.util.Preconditions;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.Enumeration;
+import java.util.Locale;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+/** Parse an A/B update zip file. */
+class UpdateParser {
+
+    private static final String TAG = "UpdateLayoutFragment";
+    private static final String PAYLOAD_BIN_FILE = "payload.bin";
+    private static final String PAYLOAD_PROPERTIES = "payload_properties.txt";
+    private static final String FILE_URL_PREFIX = "file://";
+    private static final int ZIP_FILE_HEADER = 30;
+
+    private UpdateParser() {
+    }
+
+    /**
+     * Parse a zip file containing a system update and return a non null ParsedUpdate.
+     */
+    @Nullable
+    static ParsedUpdate parse(@NonNull File file) throws IOException {
+        Preconditions.checkNotNull(file);
+
+        long payloadOffset = 0;
+        long payloadSize = 0;
+        boolean payloadFound = false;
+        String[] props = null;
+
+        try (ZipFile zipFile = new ZipFile(file)) {
+            Enumeration<? extends ZipEntry> entries = zipFile.entries();
+            while (entries.hasMoreElements()) {
+                ZipEntry entry = entries.nextElement();
+                long fileSize = entry.getCompressedSize();
+                if (!payloadFound) {
+                    payloadOffset += ZIP_FILE_HEADER + entry.getName().length();
+                    if (entry.getExtra() != null) {
+                        payloadOffset += entry.getExtra().length;
+                    }
+                }
+
+                if (entry.isDirectory()) {
+                    continue;
+                } else if (entry.getName().equals(PAYLOAD_BIN_FILE)) {
+                    payloadSize = fileSize;
+                    payloadFound = true;
+                } else if (entry.getName().equals(PAYLOAD_PROPERTIES)) {
+                    try (BufferedReader buffer = new BufferedReader(
+                            new InputStreamReader(zipFile.getInputStream(entry)))) {
+                        props = buffer.lines().toArray(String[]::new);
+                    }
+                }
+                if (!payloadFound) {
+                    payloadOffset += fileSize;
+                }
+
+                if (Log.isLoggable(TAG, Log.DEBUG)) {
+                    Log.d(TAG, String.format("Entry %s", entry.getName()));
+                }
+            }
+        }
+        return new ParsedUpdate(file, payloadOffset, payloadSize, props);
+    }
+
+    /** Information parsed from an update file. */
+    static class ParsedUpdate {
+        final String mUrl;
+        final long mOffset;
+        final long mSize;
+        final String[] mProps;
+
+        ParsedUpdate(File file, long offset, long size, String[] props) {
+            mUrl = FILE_URL_PREFIX + file.getAbsolutePath();
+            mOffset = offset;
+            mSize = size;
+            mProps = props;
+        }
+
+        /** Verify the update information is correct. */
+        boolean isValid() {
+            return mOffset >= 0 && mSize > 0 && mProps != null;
+        }
+
+        @Override
+        public String toString() {
+            return String.format(Locale.getDefault(),
+                    "ParsedUpdate: URL=%s, offset=%d, size=%s, props=%s",
+                    mUrl, mOffset, mSize, Arrays.toString(mProps));
+        }
+    }
+}