sparrowwallet/usb4java
sparrowwallet/usb4java
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Remove freeDeviceDescriptor() function, which was not present in libusb, to avoid confusion.

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The memory for the device descriptor is now allocated in an appropriately sized direct ByteBuffer.
The size is calculated directly in native code, to avoid any possible issues with alignment, padding or
compilers calculating something different from the expected 18 bytes.
This way users don't have to care about freeing the device descriptor, and can easily reuse the same while
looping over different devices.
This commit is contained in:
Luca Longinotti 2014-02-15 15:51:01 +01:00
parent 989d98f9a4
commit 984eaf1cfa
3 changed files with 55 additions and 58 deletions
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29
src/main/c/src/LibUsb.c
View File

@ -609,12 +609,16 @@ JNIEXPORT jint JNICALL METHOD_NAME(LibUsb, getDeviceDescriptor)
{
NOT_NULL(env, device, return 0);
NOT_NULL(env, descriptor, return 0);
NOT_SET(env, descriptor, "deviceDescriptorPointer", return 0);
libusb_device *dev = unwrapDevice(env, device);
if (!dev) return 0;
struct libusb_device_descriptor *dev_desc = calloc(1, sizeof(*dev_desc));
if (!dev_desc) return LIBUSB_ERROR_NO_MEM;
jclass cls = (*env)->GetObjectClass(env, descriptor);
jfieldID field = (*env)->GetFieldID(env, cls, "deviceDescriptorBuffer", "Ljava/nio/ByteBuffer;");
jobject buffer = (*env)->GetObjectField(env, descriptor, field);
// The Java code ensures this is an appropriately sized direct ByteBuffer.
struct libusb_device_descriptor *dev_desc = (*env)->GetDirectBufferAddress(env, buffer);
int result = libusb_get_device_descriptor(dev, dev_desc);
if (result == LIBUSB_SUCCESS)
@ -623,27 +627,22 @@ JNIEXPORT jint JNICALL METHOD_NAME(LibUsb, getDeviceDescriptor)
}
else
{
// Free memory again on error.
free(dev_desc);
// Reset pointer on error, to ensure subsequent accesses will throw exceptions.
resetDeviceDescriptor(env, descriptor);
}
return result;
}
/**
* void freeDeviceDescriptor(DeviceDescriptor)
* int deviceDescriptorStructSize()
*/
JNIEXPORT void JNICALL METHOD_NAME(LibUsb, freeDeviceDescriptor)
JNIEXPORT jint JNICALL METHOD_NAME(LibUsb, deviceDescriptorStructSize)
(
JNIEnv *env, jclass class, jobject descriptor
JNIEnv *env, jclass class
)
{
if (!descriptor) return;
struct libusb_device_descriptor *dev_desc = unwrapDeviceDescriptor(env,
descriptor);
if (!dev_desc) return;
free(dev_desc);
resetDeviceDescriptor(env, descriptor);
return sizeof(struct libusb_device_descriptor);
}
/**

9
src/main/java/de/ailis/usb4java/libusb/DeviceDescriptor.java
View File

@ -18,11 +18,14 @@
package de.ailis.usb4java.libusb;
import java.nio.ByteBuffer;
import javax.usb.UsbDeviceDescriptor;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import de.ailis.usb4java.utils.BufferUtils;
import de.ailis.usb4java.utils.DescriptorUtils;
/**
@ -38,13 +41,17 @@ public final class DeviceDescriptor implements UsbDeviceDescriptor
/** The native pointer to the descriptor structure. */
private long deviceDescriptorPointer;
/** The Java ByteBuffer which contains the descriptor structure. */
private final ByteBuffer deviceDescriptorBuffer;
/**
* Constructs a new device descriptor which can be passed to the
* {@link LibUsb#getDeviceDescriptor(Device, DeviceDescriptor)} method.
*/
public DeviceDescriptor()
{
// Empty
// Assign new buffer.
this.deviceDescriptorBuffer = BufferUtils.allocateByteBuffer(LibUsb.deviceDescriptorStructSize());
}
/**

75
src/main/java/de/ailis/usb4java/libusb/LibUsb.java
View File

@ -808,7 +808,7 @@ public final class LibUsb
* array is too small
*/
@Deprecated
public static int getPortPath(final Context context, final Device device,
public static int getPortPath(final Context context, final Device device,
final ByteBuffer path)
{
return getPortNumbers(device, path);
@ -1389,21 +1389,12 @@ public final class LibUsb
final DeviceDescriptor descriptor);
/**
* Free a device descriptor obtained from
* {@link #getDeviceDescriptor(Device, DeviceDescriptor)}.
* Returns the size in bytes of the buffer that's required to hold all
* of a device descriptor's data.
*
* It is safe to call this function with a NULL device parameter, in which
* case the function simply returns.
*
* This function is not present in the libusb-1.0 API, but since
* getDeviceDescriptor() requires memory to be allocated manually,
* a way to deallocate it from Java is required to avoid a memory leak.
*
* @param descriptor
* The device descriptor to free
* @return buffer size in bytes
*/
public static native void freeDeviceDescriptor(
final DeviceDescriptor descriptor);
public static native int deviceDescriptorStructSize();
/**
* Retrieve a string descriptor in C style ASCII.
@ -2430,15 +2421,15 @@ public final class LibUsb
/**
* Get the data section of a control transfer.
*
*
* This convenience function is here to remind you that the data does not
* start until 8 bytes into the actual buffer, as the setup packet comes
* first.
*
*
* Calling this function only makes sense from a transfer callback function,
* or situations where you have already allocated a suitably sized buffer at
* {@link Transfer#buffer()}.
*
*
* @param transfer
* A transfer.
* @return The data section.
@ -2451,14 +2442,14 @@ public final class LibUsb
/**
* Get the control setup packet of a control transfer.
*
*
* This convenience function is here to remind you that the control setup
* occupies the first 8 bytes of the transfer data buffer.
*
*
* Calling this function only makes sense from a transfer callback function,
* or situations where you have already allocated a suitably sized buffer at
* {@link Transfer#buffer()}.
*
*
* @param transfer
* A transfer.
* @return The setup section.
@ -2471,10 +2462,10 @@ public final class LibUsb
/**
* Helper function to populate the setup packet (first 8 bytes of the data
* buffer) for a control transfer.
*
*
* The wIndex, wValue and wLength values should be given in host-endian byte
* order.
*
*
* @param buffer
* Buffer to output the setup packet into.
* @param bmRequestType
@ -2503,29 +2494,29 @@ public final class LibUsb
/**
* Helper function to populate the required {@link Transfer} fields for a
* control transfer.
*
*
* If you pass a transfer buffer to this function, the first 8 bytes will be
* interpreted as a control setup packet, and the wLength field will be used
* to automatically populate the length field of the transfer. Therefore the
* recommended approach is:
*
*
* 1. Allocate a suitably sized data buffer (including space for control
* setup).
*
*
* 2. Call
* {@link #fillControlSetup(ByteBuffer, byte, byte, short, short, short)}.
*
*
* 3. If this is a host-to-device transfer with a data stage, put the data
* in place after the setup packet.
*
*
* 4. Call this function.
*
*
* 5. Call {@link #submitTransfer(Transfer)}.
*
*
* It is also legal to pass a NULL buffer to this function, in which case
* this function will not attempt to populate the length field. Remember
* that you must then populate the buffer and length fields later.
*
*
* @param transfer
* The transfer to populate.
* @param handle
@ -2562,7 +2553,7 @@ public final class LibUsb
/**
* Helper function to populate the required {@link Transfer} fields for a
* bulk transfer.
*
*
* @param transfer
* The transfer to populate.
* @param handle
@ -2595,7 +2586,7 @@ public final class LibUsb
/**
* Helper function to populate the required {@link Transfer} fields for an
* interrupt transfer.
*
*
* @param transfer
* The transfer to populate.
* @param handle
@ -2628,7 +2619,7 @@ public final class LibUsb
/**
* Helper function to populate the required {@link Transfer} fields for an
* isochronous transfer.
*
*
* @param transfer
* The transfer to populate.
* @param handle
@ -2665,7 +2656,7 @@ public final class LibUsb
/**
* Convenience function to set the length of all packets in an isochronous
* transfer, based on the {@link Transfer#numIsoPackets()} field.
*
*
* @param transfer
* A transfer.
* @param length
@ -2684,13 +2675,13 @@ public final class LibUsb
/**
* Convenience function to locate the position of an isochronous packet
* within the buffer of an isochronous transfer.
*
*
* This is a thorough function which loops through all preceding packets,
* accumulating their lengths to find the position of the specified packet.
* Typically you will assign equal lengths to each packet in the transfer,
* and hence the above method is sub-optimal. You may wish to use
* {@link #getIsoPacketBufferSimple(Transfer, int)} instead.
*
*
* @param transfer
* A transfer.
* @param packet
@ -2723,15 +2714,15 @@ public final class LibUsb
* Convenience function to locate the position of an isochronous packet
* within the buffer of an isochronous transfer, for transfers where each
* packet is of identical size.
*
*
* This function relies on the assumption that every packet within the
* transfer is of identical size to the first packet. Calculating the
* location of the packet buffer is then just a simple calculation: buffer +
* (packet_size * packet)
*
*
* Do not use this function on transfers other than those that have
* identical packet lengths for each packet.
*
*
* @param transfer
* A transfer.
* @param packet
@ -2757,7 +2748,7 @@ public final class LibUsb
/**
* Processes a hotplug event from native code.
*
*
* @param context
* Context of this notification.
* @param device
@ -2861,7 +2852,7 @@ public final class LibUsb
/**
* Internally called native method for registering a hotplug callback.
*
*
* @param context
* Context to register this callback with.
* @param events
@ -2880,7 +2871,7 @@ public final class LibUsb
* @param hotplugId
* The hotplug callback ID.
* @return {@link #SUCCESS} on success, some ERROR code on failure.
*/
*/
static native int hotplugRegisterCallbackNative(final Context context,
final int events, final int flags, final int vendorId,
final int productId, final int deviceClass,