Use cached anonymous contact info

app/src/main/java/eu/faircode/email/ContactInfo.java

@@ -29,6 +29,7 @@ import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.drawable.Drawable;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.net.Uri;
@@ -97,6 +98,8 @@ public class ContactInfo {
 
     static final int FAVICON_READ_BYTES = 50 * 1024;
 
+    private static final Object lock = new Object();
+    private static ContactInfo anonymous = null;
     private static Map<String, Lookup> emailLookup = new ConcurrentHashMap<>();
     private static final Map<String, ContactInfo> emailContactInfo = new HashMap<>();
 
@@ -226,14 +229,27 @@ public class ContactInfo {
     }
 
     private static ContactInfo[] get(Context context, long account, String folderType, String selector, Address[] addresses, boolean cacheOnly) {
-        if (addresses == null || addresses.length == 0)
-            return new ContactInfo[]{new ContactInfo()};
+        if (addresses == null || addresses.length == 0) {
+            ContactInfo anonymous = getAnonymous(context);
+            return new ContactInfo[]{anonymous == null ? new ContactInfo() : anonymous};
+        }
 
         ContactInfo[] result = new ContactInfo[addresses.length];
         for (int i = 0; i < addresses.length; i++) {
             result[i] = _get(context, account, folderType, selector, (InternetAddress) addresses[i], cacheOnly);
-            if (result[i] == null)
-                return null;
+            if (result[i] == null) {
+                if (cacheOnly)
+                    return null;
+                ContactInfo anonymous = getAnonymous(context);
+                if (anonymous == null)
+                    return null;
+                result[i] = anonymous;
+            } else if (result[i].bitmap == null) {
+                if (!cacheOnly) {
+                    ContactInfo anonymous = getAnonymous(context);
+                    result[i].bitmap = (anonymous == null ? null : anonymous.bitmap);
+                }
+            }
         }
 
         return result;
@@ -577,6 +593,35 @@ public class ContactInfo {
         return info;
     }
 
+    private static ContactInfo getAnonymous(Context context) {
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+        boolean avatars = prefs.getBoolean("avatars", true);
+        boolean bimi = (prefs.getBoolean("bimi", false) && !BuildConfig.PLAY_STORE_RELEASE);
+        boolean gravatars = (prefs.getBoolean("gravatars", false) && !BuildConfig.PLAY_STORE_RELEASE);
+        boolean libravatars = (prefs.getBoolean("libravatars", false) && !BuildConfig.PLAY_STORE_RELEASE);
+        boolean favicons = prefs.getBoolean("favicons", false);
+        boolean generated = prefs.getBoolean("generated_icons", true);
+        boolean identicons = prefs.getBoolean("identicons", false);
+        if (avatars || bimi || gravatars || libravatars || favicons || generated || identicons) {
+            synchronized (lock) {
+                if (anonymous == null) {
+                    Drawable d = context.getDrawable(R.drawable.twotone_person_24);
+                    Bitmap bitmap = Bitmap.createBitmap(d.getIntrinsicWidth(), d.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
+                    Canvas canvas = new Canvas(bitmap);
+                    d.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
+                    d.setTint(Helper.resolveColor(context, R.attr.colorSeparator));
+                    d.draw(canvas);
+
+                    anonymous = new ContactInfo();
+                    anonymous.bitmap = bitmap;
+                }
+                return anonymous;
+            }
+        }
+
+        return null;
+    }
+
     private static Favicon parseFavicon(URL base, int scaleToPixels, Context context) throws IOException {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         boolean favicons_partial = prefs.getBoolean("favicons_partial", true);