android: add GDrive asynchronous cache layer

android/build.gradle

@@ -101,6 +101,7 @@ dependencies {
     kapt 'com.google.dagger:dagger-compiler:2.11'
     provided 'org.glassfish:javax.annotation:10.0-b28'
     kapt 'com.google.dagger:dagger-android-processor:2.11'
+    compile 'com.jakewharton:disklrucache:2.0.2'
 }
 
 apply plugin: 'com.google.gms.google-services'

android/src/main/java/de/x4fyr/paiman/app/utils.kt

@@ -10,14 +10,16 @@ import android.util.Log
 import android.util.LruCache
 import android.view.MenuItem
 import android.view.View
-import android.widget.EditText
 import android.widget.TextView
 import de.x4fyr.paiman.R
 import de.x4fyr.paiman.lib.adapter.AndroidGoogleDriveStorageAdapter
+import de.x4fyr.paiman.lib.adapter.StorageAdapter
 import kotlinx.coroutines.experimental.android.UI
 import kotlinx.coroutines.experimental.launch
+import org.jetbrains.anko.getStackTraceString
 import java.io.File
 import java.io.InputStream
+import java.io.OutputStream
 import javax.inject.Inject
 
 /** An dialog Fragment that has an apply action.
@@ -59,26 +61,6 @@ abstract class BaseActivity: AppCompatActivity() {
         }
     }
 
-    override fun onStart() {
-        storageAdapter.connect(this)
-        super.onStart()
-    }
-
-    override fun onResume() {
-        storageAdapter.connect(this)
-        super.onResume()
-    }
-
-    override fun onPause() {
-        storageAdapter.disconnect()
-        super.onPause()
-    }
-
-    override fun onStop() {
-        storageAdapter.disconnect()
-        super.onStop()
-    }
-
 }
 
 /** Safely get a valid stream from an android URL */
@@ -122,7 +104,8 @@ fun Activity.errorDialog(msg: Int, throwable: Throwable) {
         try {
             val view = layoutInflater.inflate(R.layout.dialog_error, null, false)
             view.findViewById<TextView>(R.id.message).text = getString(msg)
-            view.findViewById<EditText>(R.id.exception).setText(throwable.message!!)
+            view.findViewById<TextView>(
+                    R.id.exception).text = throwable.message!! + '\n' + throwable.getStackTraceString()
             AlertDialog.Builder(this@errorDialog)
                     .setView(view)
                     .create()
@@ -141,4 +124,31 @@ class BitmapCache<K>(maxKbSize: Int): LruCache<K, Bitmap>(maxKbSize) {
     override fun sizeOf(key: K, value: Bitmap): Int {
         return value.byteCount/1024
     }
+}
+
+/** Create [StorageAdapter.StorageException.General] with logging the error */
+fun StorageAdapter.error(msg: String): StorageAdapter.StorageException.General {
+    Log.e(this::class.simpleName, msg)
+    return StorageAdapter.StorageException.General(msg)
+}
+
+/** Create [StorageAdapter.StorageException.General] including `cause` with logging the error */
+fun StorageAdapter.error(msg: String, cause: Throwable): StorageAdapter.StorageException.General {
+    Log.e(this::class.simpleName, msg, cause)
+    return StorageAdapter.StorageException.General(msg, cause)
+}
+
+/** Writes an InputStream to an OutputStream */
+fun InputStream.writeTo(outputStream: OutputStream) {
+    this.use { inputStream ->
+        outputStream.use { outputStream ->
+            val buffer = ByteArray(1024)
+            var bytesRead = inputStream.read(buffer)
+            while (bytesRead != -1) {
+                outputStream.write(buffer)
+                bytesRead = inputStream.read(buffer)
+            }
+            outputStream.flush()
+        }
+    }
 }

android/src/main/java/de/x4fyr/paiman/dagger.kt

@@ -9,6 +9,7 @@ import dagger.android.ContributesAndroidInjector
 import dagger.android.DaggerApplication
 import dagger.android.support.AndroidSupportInjectionModule
 import de.x4fyr.paiman.lib.adapter.AndroidGoogleDriveStorageAdapter
+import de.x4fyr.paiman.lib.adapter.CachedGoogleDriveStorageAdapter
 import de.x4fyr.paiman.lib.provider.AndroidServiceProvider
 import de.x4fyr.paiman.lib.provider.ServiceProvider
 import de.x4fyr.paiman.lib.services.PaintingService
@@ -85,10 +86,11 @@ class ServicesModule {
         storageAdapter
     }
 
+
     @Provides
     @Singleton
     fun provideAndroidServiceProvider(context: android.app.Application,
-                                      storageAdapter: AndroidGoogleDriveStorageAdapter): AndroidServiceProvider = try {
+                                      storageAdapter: CachedGoogleDriveStorageAdapter): AndroidServiceProvider = try {
         provider
     } catch (e: UninitializedPropertyAccessException) {
         provider = AndroidServiceProvider(context, storageAdapter)