MTP host: Add support for reading files from an MTP device via ParcelFileDescriptor

Also added some support for sending files to the device that hasn't been debugged yet.
Add locking to MtpDevice to prevent it from attempting multiple transactions simultaneously.

Change-Id: I2b995ba0af086cc6920bd6b8c869f540ad78560a
Signed-off-by: Mike Lockwood <lockwood@android.com>

media/java/android/media/MtpClient.java

@@ -16,6 +16,7 @@
 
 package android.media;
 
+import android.os.ParcelFileDescriptor;
 import android.util.Log;
 
 /**
@@ -64,6 +65,11 @@ public class MtpClient {
         return native_get_storage_id(deviceID, objectID);
     }
 
+    // create a file descriptor for reading the contents of an object over MTP
+    public ParcelFileDescriptor openFile(int deviceID, int objectID) {
+        return native_open_file(deviceID, objectID);
+    }
+
     public interface Listener {
         // called when a new MTP device has been discovered
         void deviceAdded(int id);
@@ -94,4 +100,5 @@ public class MtpClient {
     private native boolean native_delete_object(int deviceID, int objectID);
     private native int native_get_parent(int deviceID, int objectID);
     private native int native_get_storage_id(int deviceID, int objectID);
+    private native ParcelFileDescriptor native_open_file(int deviceID, int objectID);
 }

media/jni/android_media_MtpClient.cpp

@@ -29,6 +29,7 @@
 
 #include "MtpClient.h"
 #include "MtpDevice.h"
+#include "MtpObjectInfo.h"
 
 using namespace android;
 
@@ -38,6 +39,19 @@ static jmethodID method_deviceAdded;
 static jmethodID method_deviceRemoved;
 static jfieldID field_context;
 
+static struct file_descriptor_offsets_t
+{
+    jclass mClass;
+    jmethodID mConstructor;
+    jfieldID mDescriptor;
+} gFileDescriptorOffsets;
+
+static struct parcel_file_descriptor_offsets_t
+{
+    jclass mClass;
+    jmethodID mConstructor;
+} gParcelFileDescriptorOffsets;
+
 #ifdef HAVE_ANDROID_OS
 
 static void checkAndClearExceptionFromCallback(JNIEnv* env, const char* methodName) {
@@ -187,6 +201,38 @@ android_media_MtpClient_get_storage_id(JNIEnv *env, jobject thiz,
         return -1;
 }
 
+static jobject
+android_media_MtpClient_open_file(JNIEnv *env, jobject thiz,
+        jint device_id, jint object_id)
+{
+#ifdef HAVE_ANDROID_OS
+    MyClient *client = (MyClient *)env->GetIntField(thiz, field_context);
+    MtpDevice* device = client->getDevice(device_id);
+    if (!device)
+        return NULL;
+
+    MtpObjectInfo* info = device->getObjectInfo(object_id);
+    if (!info)
+        return NULL;
+    int object_size = info->mCompressedSize;
+    delete info;
+    int fd = device->readObject(object_id, object_size);
+    if (fd < 0)
+        return NULL;
+
+    jobject fileDescriptor = env->NewObject(gFileDescriptorOffsets.mClass,
+        gFileDescriptorOffsets.mConstructor);
+    if (fileDescriptor != NULL) {
+        env->SetIntField(fileDescriptor, gFileDescriptorOffsets.mDescriptor, fd);
+    } else {
+        return NULL;
+    }
+    return env->NewObject(gParcelFileDescriptorOffsets.mClass,
+        gParcelFileDescriptorOffsets.mConstructor, fileDescriptor);
+#endif
+    return NULL;
+}
+
 // ----------------------------------------------------------------------------
 
 static JNINativeMethod gMethods[] = {
@@ -197,6 +243,8 @@ static JNINativeMethod gMethods[] = {
     {"native_delete_object",   "(II)Z", (void *)android_media_MtpClient_delete_object},
     {"native_get_parent",      "(II)I", (void *)android_media_MtpClient_get_parent},
     {"native_get_storage_id",  "(II)I", (void *)android_media_MtpClient_get_storage_id},
+    {"native_open_file",       "(II)Landroid/os/ParcelFileDescriptor;",
+                                        (void *)android_media_MtpClient_open_file},
 };
 
 static const char* const kClassPathName = "android/media/MtpClient";
@@ -228,6 +276,21 @@ int register_android_media_MtpClient(JNIEnv *env)
         return -1;
     }
 
+   clazz = env->FindClass("java/io/FileDescriptor");
+    LOG_FATAL_IF(clazz == NULL, "Unable to find class java.io.FileDescriptor");
+    gFileDescriptorOffsets.mClass = (jclass) env->NewGlobalRef(clazz);
+    gFileDescriptorOffsets.mConstructor = env->GetMethodID(clazz, "<init>", "()V");
+    gFileDescriptorOffsets.mDescriptor = env->GetFieldID(clazz, "descriptor", "I");
+    LOG_FATAL_IF(gFileDescriptorOffsets.mDescriptor == NULL,
+                 "Unable to find descriptor field in java.io.FileDescriptor");
+
+   clazz = env->FindClass("android/os/ParcelFileDescriptor");
+    LOG_FATAL_IF(clazz == NULL, "Unable to find class android.os.ParcelFileDescriptor");
+    gParcelFileDescriptorOffsets.mClass = (jclass) env->NewGlobalRef(clazz);
+    gParcelFileDescriptorOffsets.mConstructor = env->GetMethodID(clazz, "<init>", "(Ljava/io/FileDescriptor;)V");
+    LOG_FATAL_IF(gParcelFileDescriptorOffsets.mConstructor == NULL,
+                 "Unable to find constructor for android.os.ParcelFileDescriptor");
+
     return AndroidRuntime::registerNativeMethods(env,
                 "android/media/MtpClient", gMethods, NELEM(gMethods));
 }

media/mtp/MtpDataPacket.cpp

@@ -20,6 +20,8 @@
 #include <sys/types.h>
 #include <fcntl.h>
 
+#include <usbhost/usbhost.h>
+
 #include "MtpDataPacket.h"
 #include "MtpStringBuffer.h"
 
@@ -391,6 +393,35 @@ int MtpDataPacket::read(struct usb_endpoint *ep) {
     return length;
 }
 
+int MtpDataPacket::readData(struct usb_endpoint *ep, void* buffer, int length) {
+    int packetSize = usb_endpoint_max_packet(ep);
+    int read = 0;
+    while (read < length) {
+        int ret = transfer(ep, (char *)buffer + read, packetSize);
+        if (ret < 0) {
+printf("MtpDataPacket::readData returning %d\n", ret);
+            return ret;
+        }
+        read += ret;
+    }
+printf("MtpDataPacket::readData returning %d\n", read);
+    return read;
+}
+
+int MtpDataPacket::readDataHeader(struct usb_endpoint *ep) {
+    int length = transfer(ep, mBuffer, usb_endpoint_max_packet(ep));
+    if (length >= 0)
+        mPacketSize = length;
+    return length;
+}
+
+int MtpDataPacket::writeDataHeader(struct usb_endpoint *ep, uint32_t length) {
+    MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, length);
+    MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
+    int ret = transfer(ep, mBuffer, MTP_CONTAINER_HEADER_SIZE);
+    return (ret < 0 ? ret : 0);
+}
+
 int MtpDataPacket::write(struct usb_endpoint *ep) {
     MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
     MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
@@ -403,6 +434,19 @@ int MtpDataPacket::write(struct usb_endpoint *ep) {
     return (ret < 0 ? ret : 0);
 }
 
+int MtpDataPacket::write(struct usb_endpoint *ep, void* buffer, uint32_t length) {
+    int ret = 0;
+    int packetSize = usb_endpoint_max_packet(ep);
+    while (length > 0) {
+        int write = (length > packetSize ? packetSize : length);
+        int ret = transfer(ep, buffer, write);
+        if (ret < 0)
+            break;
+        length -= ret;
+    }
+    return (ret < 0 ? ret : 0);
+}
+
 #endif // MTP_HOST
 
 void* MtpDataPacket::getData(int& outLength) const {

media/mtp/MtpDataPacket.h

@@ -98,7 +98,12 @@ public:
 
 #ifdef MTP_HOST
     int                 read(struct usb_endpoint *ep);
+    int                 readData(struct usb_endpoint *ep, void* buffer, int length);
+    int                 readDataHeader(struct usb_endpoint *ep);
+
+    int                 writeDataHeader(struct usb_endpoint *ep, uint32_t length);
     int                 write(struct usb_endpoint *ep);
+    int                 write(struct usb_endpoint *ep, void* buffer, uint32_t length);
 #endif
 
     inline bool         hasData() const { return mPacketSize > MTP_CONTAINER_HEADER_SIZE; }

media/mtp/MtpDevice.cpp

@@ -23,6 +23,7 @@
 #include "MtpProperty.h"
 #include "MtpStorageInfo.h"
 #include "MtpStringBuffer.h"
+#include "MtpUtils.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -31,6 +32,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <endian.h>
 
 #include <usbhost/usbhost.h>
 
@@ -93,6 +95,8 @@ const char* MtpDevice::getDeviceName() {
 }
 
 bool MtpDevice::openSession() {
+    Mutex::Autolock autoLock(mMutex);
+
     mSessionID = 0;
     mTransactionID = 0;
     MtpSessionID newSession = 1;
@@ -117,6 +121,8 @@ bool MtpDevice::closeSession() {
 }
 
 MtpDeviceInfo* MtpDevice::getDeviceInfo() {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     if (!sendRequest(MTP_OPERATION_GET_DEVICE_INFO))
         return NULL;
@@ -132,6 +138,8 @@ MtpDeviceInfo* MtpDevice::getDeviceInfo() {
 }
 
 MtpStorageIDList* MtpDevice::getStorageIDs() {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     if (!sendRequest(MTP_OPERATION_GET_STORAGE_IDS))
         return NULL;
@@ -145,6 +153,8 @@ MtpStorageIDList* MtpDevice::getStorageIDs() {
 }
 
 MtpStorageInfo* MtpDevice::getStorageInfo(MtpStorageID storageID) {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     mRequest.setParameter(1, storageID);
     if (!sendRequest(MTP_OPERATION_GET_STORAGE_INFO))
@@ -162,6 +172,8 @@ MtpStorageInfo* MtpDevice::getStorageInfo(MtpStorageID storageID) {
 
 MtpObjectHandleList* MtpDevice::getObjectHandles(MtpStorageID storageID,
             MtpObjectFormat format, MtpObjectHandle parent) {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     mRequest.setParameter(1, storageID);
     mRequest.setParameter(2, format);
@@ -178,6 +190,8 @@ MtpObjectHandleList* MtpDevice::getObjectHandles(MtpStorageID storageID,
 }
 
 MtpObjectInfo* MtpDevice::getObjectInfo(MtpObjectHandle handle) {
+    Mutex::Autolock autoLock(mMutex);
+
     // FIXME - we might want to add some caching here
 
     mRequest.reset();
@@ -196,6 +210,8 @@ MtpObjectInfo* MtpDevice::getObjectInfo(MtpObjectHandle handle) {
 }
 
 void* MtpDevice::getThumbnail(MtpObjectHandle handle, int& outLength) {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     mRequest.setParameter(1, handle);
     if (sendRequest(MTP_OPERATION_GET_THUMB) && readData()) {
@@ -208,7 +224,90 @@ void* MtpDevice::getThumbnail(MtpObjectHandle handle, int& outLength) {
     return NULL;
 }
 
+MtpObjectHandle MtpDevice::sendObjectInfo(MtpObjectInfo* info) {
+    Mutex::Autolock autoLock(mMutex);
+
+    mRequest.reset();
+    MtpObjectHandle parent = info->mParent;
+    if (parent == 0)
+        parent = MTP_PARENT_ROOT;
+
+    mRequest.setParameter(1, info->mStorageID);
+    mRequest.setParameter(2, info->mParent);
+
+    mData.putUInt32(info->mStorageID);
+    mData.putUInt16(info->mFormat);
+    mData.putUInt16(info->mProtectionStatus);
+    mData.putUInt32(info->mCompressedSize);
+    mData.putUInt16(info->mThumbFormat);
+    mData.putUInt32(info->mThumbCompressedSize);
+    mData.putUInt32(info->mThumbPixWidth);
+    mData.putUInt32(info->mThumbPixHeight);
+    mData.putUInt32(info->mImagePixWidth);
+    mData.putUInt32(info->mImagePixHeight);
+    mData.putUInt32(info->mImagePixDepth);
+    mData.putUInt32(info->mParent);
+    mData.putUInt16(info->mAssociationType);
+    mData.putUInt32(info->mAssociationDesc);
+    mData.putUInt32(info->mSequenceNumber);
+    mData.putString(info->mName);
+
+    char created[100], modified[100];
+    formatDateTime(info->mDateCreated, created, sizeof(created));
+    formatDateTime(info->mDateModified, modified, sizeof(modified));
+
+    mData.putString(created);
+    mData.putString(modified);
+    if (info->mKeywords)
+        mData.putString(info->mKeywords);
+    else
+        mData.putEmptyString();
+
+   if (sendRequest(MTP_OPERATION_SEND_OBJECT_INFO) && sendData()) {
+        printf("MTP_OPERATION_SEND_OBJECT_INFO sent\n");
+        MtpResponseCode ret = readResponse();
+        printf("sendObjectInfo response: %04X\n", ret);
+        if (ret == MTP_RESPONSE_OK) {
+            info->mStorageID = mResponse.getParameter(1);
+            info->mParent = mResponse.getParameter(2);
+            info->mHandle = mResponse.getParameter(3);
+            return info->mHandle;
+        }
+    }
+    return (MtpObjectHandle)-1;
+}
+
+bool MtpDevice::sendObject(MtpObjectInfo* info, int srcFD) {
+    Mutex::Autolock autoLock(mMutex);
+
+    int remaining = info->mCompressedSize;
+    mRequest.reset();
+    mRequest.setParameter(1, info->mHandle);
+    if (sendRequest(MTP_OPERATION_SEND_OBJECT)) {
+        printf("MTP_OPERATION_SEND_OBJECT sent\n");
+        // send data header
+        writeDataHeader(MTP_OPERATION_SEND_OBJECT, remaining);
+
+        char buffer[65536];
+        while (remaining > 0) {
+            int count = read(srcFD, buffer, sizeof(buffer));
+            if (count > 0) {
+                int written = mData.write(mEndpointOut, buffer, count);
+                printf("wrote %d\n", written);
+                // FIXME check error
+                remaining -= count;
+            } else {
+                break;
+            }
+        }
+    }
+    MtpResponseCode ret = readResponse();
+    return (remaining == 0 && ret == MTP_RESPONSE_OK);
+}
+
 bool MtpDevice::deleteObject(MtpObjectHandle handle) {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     mRequest.setParameter(1, handle);
     if (sendRequest(MTP_OPERATION_DELETE_OBJECT)) {
@@ -236,6 +335,8 @@ MtpObjectHandle MtpDevice::getStorageID(MtpObjectHandle handle) {
 }
 
 MtpProperty* MtpDevice::getDevicePropDesc(MtpDeviceProperty code) {
+    Mutex::Autolock autoLock(mMutex);
+
     mRequest.reset();
     mRequest.setParameter(1, code);
     if (!sendRequest(MTP_OPERATION_GET_DEVICE_PROP_DESC))
@@ -251,6 +352,98 @@ MtpProperty* MtpDevice::getDevicePropDesc(MtpDeviceProperty code) {
     return NULL;
 }
 
+class ReadObjectThread : public Thread {
+private:
+    MtpDevice*          mDevice;
+    MtpObjectHandle     mHandle;
+    int                 mObjectSize;
+    void*               mInitialData;
+    int                 mInitialDataLength;
+    int                 mFD;
+
+public:
+    ReadObjectThread(MtpDevice* device, MtpObjectHandle handle, int objectSize)
+        : mDevice(device),
+          mHandle(handle),
+          mObjectSize(objectSize),
+          mInitialData(NULL),
+          mInitialDataLength(0)
+    {
+    }
+
+    virtual ~ReadObjectThread() {
+        if (mFD >= 0)
+            close(mFD);
+        free(mInitialData);
+    }
+
+    // returns file descriptor
+    int init() {
+        mDevice->mRequest.reset();
+        mDevice->mRequest.setParameter(1, mHandle);
+        if (mDevice->sendRequest(MTP_OPERATION_GET_OBJECT)
+                && mDevice->mData.readDataHeader(mDevice->mEndpointIn)) {
+
+            // mData will contain header and possibly the beginning of the object data
+            mInitialData = mDevice->mData.getData(mInitialDataLength);
+
+            // create a pipe for the client to read from
+            int pipefd[2];
+            if (pipe(pipefd) < 0) {
+                LOGE("pipe failed (%s)", strerror(errno));
+                return -1;
+            }
+
+            mFD = pipefd[1];
+            return pipefd[0];
+        } else {
+           return -1;
+        }
+    }
+
+    virtual bool threadLoop() {
+        int remaining = mObjectSize;
+        if (mInitialData) {
+            write(mFD, mInitialData, mInitialDataLength);
+            remaining -= mInitialDataLength;
+            free(mInitialData);
+            mInitialData = NULL;
+        }
+
+        char buffer[65536];
+        while (remaining > 0) {
+            int readSize = (remaining > sizeof(buffer) ? sizeof(buffer) : remaining);
+            int count = mDevice->mData.readData(mDevice->mEndpointIn, buffer, readSize);
+            int written;
+            if (count >= 0) {
+                int written = write(mFD, buffer, count);
+                // FIXME check error
+                remaining -= count;
+            } else {
+                break;
+            }
+        }
+
+        MtpResponseCode ret = mDevice->readResponse();
+        mDevice->mMutex.unlock();
+        return false;
+    }
+};
+
+    // returns the file descriptor for a pipe to read the object's data
+int MtpDevice::readObject(MtpObjectHandle handle, int objectSize) {
+    mMutex.lock();
+
+    ReadObjectThread* thread = new ReadObjectThread(this, handle, objectSize);
+    int fd = thread->init();
+    if (fd < 0) {
+        delete thread;
+        mMutex.unlock();
+    } else {
+        thread->run("ReadObjectThread");
+    }
+    return fd;
+}
 
 bool MtpDevice::sendRequest(MtpOperationCode operation) {
     LOGD("sendRequest: %s\n", MtpDebug::getOperationCodeName(operation));
@@ -262,7 +455,7 @@ bool MtpDevice::sendRequest(MtpOperationCode operation) {
     return (ret > 0);
 }
 
-bool MtpDevice::sendData(MtpOperationCode operation) {
+bool MtpDevice::sendData() {
     LOGD("sendData\n");
     mData.setOperationCode(mRequest.getOperationCode());
     mData.setTransactionID(mRequest.getTransactionID());
@@ -285,6 +478,12 @@ bool MtpDevice::readData() {
     }
 }
 
+bool MtpDevice::writeDataHeader(MtpOperationCode operation, int dataLength) {
+    mData.setOperationCode(operation);
+    mData.setTransactionID(mRequest.getTransactionID());
+    return (!mData.writeDataHeader(mEndpointOut, dataLength));
+}
+
 MtpResponseCode MtpDevice::readResponse() {
     LOGD("readResponse\n");
     int ret = mResponse.read(mEndpointIn);

media/mtp/MtpDevice.h

@@ -22,6 +22,8 @@
 #include "MtpResponsePacket.h"
 #include "MtpTypes.h"
 
+#include <utils/threads.h>
+
 struct usb_device;
 
 namespace android {
@@ -52,6 +54,9 @@ private:
     MtpDataPacket           mData;
     MtpResponsePacket       mResponse;
 
+    // to ensure only one MTP transaction at a time
+    Mutex                   mMutex;
+
 public:
                             MtpDevice(struct usb_device* device, int interface,
                                     struct usb_endpoint *ep_in, struct usb_endpoint *ep_out,
@@ -73,16 +78,24 @@ public:
     MtpObjectHandleList*    getObjectHandles(MtpStorageID storageID, MtpObjectFormat format, MtpObjectHandle parent);
     MtpObjectInfo*          getObjectInfo(MtpObjectHandle handle);
     void*                   getThumbnail(MtpObjectHandle handle, int& outLength);
+    MtpObjectHandle         sendObjectInfo(MtpObjectInfo* info);
+    bool                    sendObject(MtpObjectInfo* info, int srcFD);
     bool                    deleteObject(MtpObjectHandle handle);
     MtpObjectHandle         getParent(MtpObjectHandle handle);
     MtpObjectHandle         getStorageID(MtpObjectHandle handle);
 
     MtpProperty*            getDevicePropDesc(MtpDeviceProperty code);
 
+    // returns the file descriptor for a pipe to read the object's data
+    int                     readObject(MtpObjectHandle handle, int objectSize);
+
 private:
+    friend class ReadObjectThread;
+
     bool                    sendRequest(MtpOperationCode operation);
-    bool                    sendData(MtpOperationCode operation);
+    bool                    sendData();
     bool                    readData();
+    bool                    writeDataHeader(MtpOperationCode operation, int dataLength);
     MtpResponseCode         readResponse();
 
 };