Eliminate MediaNetworkRequirement style attachment job handling

// FREEBIE

src/org/thoughtcrime/securesms/util/AttachmentUtil.java

@@ -0,0 +1,73 @@
+package org.thoughtcrime.securesms.util;
+
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.thoughtcrime.securesms.attachments.Attachment;
+
+import java.util.Collections;
+import java.util.Set;
+
+public class AttachmentUtil {
+
+  private static final String TAG = AttachmentUtil.class.getSimpleName();
+
+  public static boolean isAutoDownloadPermitted(@NonNull Context context, @Nullable Attachment attachment) {
+    if (attachment == null) {
+      Log.w(TAG, "attachment was null, returning vacuous true");
+      return true;
+    }
+
+    Set<String> allowedTypes = getAllowedAutoDownloadTypes(context);
+    String      contentType  = attachment.getContentType();
+
+    if (attachment.isVoiceNote() || (MediaUtil.isAudio(attachment) && TextUtils.isEmpty(attachment.getFileName()))) {
+      return true;
+    } else if (isNonDocumentType(contentType)) {
+      return allowedTypes.contains(MediaUtil.getDiscreteMimeType(contentType));
+    } else {
+      return allowedTypes.contains("documents");
+    }
+  }
+
+  private static boolean isNonDocumentType(String contentType) {
+    return
+        MediaUtil.isImageType(contentType) ||
+        MediaUtil.isVideoType(contentType) ||
+        MediaUtil.isAudioType(contentType);
+  }
+
+  private static @NonNull Set<String> getAllowedAutoDownloadTypes(@NonNull Context context) {
+    if      (isConnectedWifi(context))    return TextSecurePreferences.getWifiMediaDownloadAllowed(context);
+    else if (isConnectedRoaming(context)) return TextSecurePreferences.getRoamingMediaDownloadAllowed(context);
+    else if (isConnectedMobile(context))  return TextSecurePreferences.getMobileMediaDownloadAllowed(context);
+    else                                  return Collections.emptySet();
+  }
+
+  private static NetworkInfo getNetworkInfo(@NonNull Context context) {
+    return ServiceUtil.getConnectivityManager(context).getActiveNetworkInfo();
+  }
+
+  private static boolean isConnectedWifi(@NonNull Context context) {
+    final NetworkInfo info = getNetworkInfo(context);
+    return info != null && info.isConnected() && info.getType() == ConnectivityManager.TYPE_WIFI;
+  }
+
+  private static boolean isConnectedMobile(@NonNull Context context) {
+    final NetworkInfo info = getNetworkInfo(context);
+    return info != null && info.isConnected() && info.getType() == ConnectivityManager.TYPE_MOBILE;
+  }
+
+  private static boolean isConnectedRoaming(@NonNull Context context) {
+    final NetworkInfo info = getNetworkInfo(context);
+    return info != null && info.isConnected() && info.isRoaming() && info.getType() == ConnectivityManager.TYPE_MOBILE;
+  }
+
+
+}