EncryptedCameraApp.java

/*
 * Copyright (C) 2014 Andrew Reitz
 *
 * 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.andrewreitz.encryptedcamera;

import android.app.Application;
import android.content.Context;
import android.graphics.Bitmap;
import android.support.v4.util.LruCache;

import com.andrewreitz.encryptedcamera.bus.EncryptionEvent;
import com.andrewreitz.encryptedcamera.di.module.AndroidModule;
import com.andrewreitz.encryptedcamera.encryption.KeyManager;
import com.andrewreitz.encryptedcamera.logging.CrashlyticsTree;
import com.andrewreitz.encryptedcamera.sharedpreference.AppPreferenceManager;
import com.andrewreitz.encryptedcamera.ui.dialog.ErrorDialog;
import com.crashlytics.android.Crashlytics;
import com.squareup.otto.Bus;
import com.squareup.otto.Produce;
import com.squareup.otto.Subscribe;

import java.io.IOException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.util.Arrays;
import java.util.List;

import javax.crypto.SecretKey;
import javax.inject.Inject;

import dagger.ObjectGraph;
import timber.log.Timber;

public class EncryptedCameraApp extends Application {
  public static final String KEY_STORE_ALIAS = EncryptedCameraApp.class.getSimpleName() + ":ALIAS";
  public static final String ENCRYPTED_DIRECTORY = "Encrypted";
  public static final String DECRYPTED_DIRECTORY = "Decrypted";
  public static final String MEDIA_OUTPUT_DATE_FORMAT = "yyyyMMdd_HHmmss";
  public static final String CIPHER_TRANSFORMATION = "AES/CBC/PKCS5Padding";

  @Inject AppPreferenceManager preferenceManager;
  @Inject KeyManager keyManager;
  @Inject Bus bus;
  @Inject LruCache<String, Bitmap> cache;

  private ObjectGraph applicationGraph;
  private EncryptionEvent.EncryptionState lastSate = EncryptionEvent.EncryptionState.NONE;

  @Override public void onCreate() {
    super.onCreate();

    // Logging Setup
    if (BuildConfig.DEBUG) {
      Timber.plant(new Timber.DebugTree());
    } else {
      Crashlytics.start(this);
      Timber.plant(new CrashlyticsTree());
    }

    // Setup DI
    applicationGraph = ObjectGraph.create(getModules().toArray());
    applicationGraph.inject(this);

    // Get on the bus!
    bus.register(this);

    // Generate an encryption key if there isn't one already
    generateKey();
  }

  @Override
  public void onTrimMemory(int level) {
    Timber.i("onTrimMemory() with level=%s", level);

    // Memory we can release here will help overall system performance, and
    // make us a smaller target as the system looks for memory

    if (level >= Application.TRIM_MEMORY_MODERATE) { // 60
      // Nearing middle of list of cached background apps; evict our
      // entire thumbnail cache
      Timber.i("evicting entire thumbnail cache");
      cache.evictAll();
    } else if (level >= Application.TRIM_MEMORY_BACKGROUND) { // 40
      // Entering list of cached background apps; evict oldest half of our
      // thumbnail cache
      Timber.i("evicting oldest half of thumbnail cache");
      cache.trimToSize(cache.size() / 2);
    }
  }

  /**
   * A list of modules to use for the application graph. Subclasses can override this method to
   * provide additional modules provided they call {@code super.getModules()}.
   */
  protected List<Object> getModules() {
    return Arrays.<Object>asList(new AndroidModule(this));
  }

  public ObjectGraph getApplicationGraph() {
    return applicationGraph;
  }

  public void inject(Object o) {
    applicationGraph.inject(o);
  }

  public static EncryptedCameraApp get(Context context) {
    return (EncryptedCameraApp) context.getApplicationContext();
  }

  private void generateKey() {
    if (!preferenceManager.hasGeneratedKey()) {
      try {
        SecretKey secretKey = keyManager.generateKeyNoPassword();
        keyManager.saveKey(KEY_STORE_ALIAS, secretKey);
        keyManager.saveKeyStore();
        preferenceManager.setGeneratedKey(true);
      } catch (NoSuchAlgorithmException | KeyStoreException | CertificateException | IOException e) {
        Timber.e(e, "Error saving key with out a password set");
        ErrorDialog.newInstance(getString(R.string.encryption_error),
            getString(R.string.error_saving_encryption_key));
      }
    }
  }

  @Subscribe public void answerEncryptionEvent(EncryptionEvent event) {
    lastSate = event.state;
  }

  @Produce public EncryptionEvent produceEncryptionEvent() {
    return new EncryptionEvent(lastSate);
  }
}