Support for incoming attachments.

1) Refactored MMS layer to use abstracted types.

2) Added support for retrieving attachment IDs.

src/org/thoughtcrime/securesms/mms/IncomingMediaMessage.java

@@ -0,0 +1,86 @@
+package org.thoughtcrime.securesms.mms;
+
+import android.util.Log;
+
+import org.thoughtcrime.securesms.util.Util;
+import org.whispersystems.textsecure.push.IncomingPushMessage;
+import org.whispersystems.textsecure.push.PushAttachmentPointer;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.List;
+
+import ws.com.google.android.mms.pdu.CharacterSets;
+import ws.com.google.android.mms.pdu.EncodedStringValue;
+import ws.com.google.android.mms.pdu.PduBody;
+import ws.com.google.android.mms.pdu.PduHeaders;
+import ws.com.google.android.mms.pdu.PduPart;
+import ws.com.google.android.mms.pdu.RetrieveConf;
+
+public class IncomingMediaMessage {
+
+  private final PduHeaders headers;
+  private final PduBody    body;
+
+  public IncomingMediaMessage(RetrieveConf retreived) {
+    this.headers = retreived.getPduHeaders();
+    this.body    = retreived.getBody();
+  }
+
+  public IncomingMediaMessage(String localNumber, IncomingPushMessage message, List<File> attachments)
+      throws IOException
+  {
+    this.headers = new PduHeaders();
+    this.body    = new PduBody();
+
+    this.headers.setEncodedStringValue(new EncodedStringValue(message.getSource()), PduHeaders.FROM);
+    this.headers.appendEncodedStringValue(new EncodedStringValue(localNumber), PduHeaders.TO);
+
+    for (String destination : message.getDestinations()) {
+      if (!destination.equals(localNumber)) {
+        this.headers.appendEncodedStringValue(new EncodedStringValue(destination), PduHeaders.CC);
+      }
+    }
+
+    this.headers.setLongInteger(message.getTimestampMillis() / 1000, PduHeaders.DATE);
+
+    if (message.getMessageText() != null && message.getMessageText().length() > 0) {
+      PduPart text = new PduPart();
+      text.setData(message.getMessageText().getBytes());
+      text.setContentType("text/plain".getBytes(CharacterSets.MIMENAME_ISO_8859_1));
+      body.addPart(text);
+    }
+
+    Iterator<PushAttachmentPointer> descriptors = message.getAttachments().iterator();
+
+    if (attachments != null) {
+      for (File attachment : attachments) {
+        PduPart               media      = new PduPart();
+        FileInputStream       fin        = new FileInputStream(attachment);
+        byte[]                data       = Util.readFully(fin);
+        PushAttachmentPointer descriptor = descriptors.next();
+
+        Log.w("IncomingMediaMessage", "Adding part: " + descriptor.getContentType() + " with length: " + data.length);
+
+        media.setContentType(descriptor.getContentType().getBytes(CharacterSets.MIMENAME_ISO_8859_1));
+        media.setData(data);
+        body.addPart(media);
+      }
+    }
+  }
+
+  public PduHeaders getPduHeaders() {
+    return headers;
+  }
+
+  public PduBody getBody() {
+    return body;
+  }
+
+  public boolean isGroupMessage() {
+    return !Util.isEmpty(headers.getEncodedStringValues(PduHeaders.CC));
+  }
+
+}