MTP: Add support for sending events to the host when objects are added and removed

Change-Id: Ia1d5232b919c644c670ff9ca651eca92b3f9ad42
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/media/mtp/MtpEventPacket.cpp b/media/mtp/MtpEventPacket.cpp
new file mode 100644
index 0000000..651761e
--- /dev/null
+++ b/media/mtp/MtpEventPacket.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#define LOG_TAG "MtpEventPacket"
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+
+#include <f_mtp.h>
+
+#include "MtpEventPacket.h"
+
+namespace android {
+
+MtpEventPacket::MtpEventPacket()
+    :   MtpPacket(512)
+{
+}
+
+MtpEventPacket::~MtpEventPacket() {
+}
+
+#ifdef MTP_DEVICE
+int MtpEventPacket::write(int fd) {
+    struct mtp_event    event;
+
+    putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
+    putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_EVENT);
+
+    event.data = mBuffer;
+    event.length = mPacketSize;
+    int ret = ::ioctl(fd, MTP_SEND_EVENT, (unsigned long)&event);
+    return (ret < 0 ? ret : 0);
+}
+#endif
+
+#ifdef MTP_HOST
+    // read our buffer from the given endpoint
+int MtpEventPacket::read(struct usb_endpoint *ep) {
+    int ret = transfer(ep, mBuffer, mBufferSize);
+     if (ret >= 0)
+        mPacketSize = ret;
+    else
+        mPacketSize = 0;
+    return ret;
+}
+#endif
+
+}  // namespace android
+