C++ BDiskDevice::VisitEachDescendant方法代码示例

/*!	\brief Pre-order traverses the trees spanned by the BDiskDevices and their
		   subobjects.

	The supplied visitor's Visit(BDiskDevice*) method is invoked for each
	disk device and Visit(BPartition*) for each (non-disk device) partition.
	If Visit() returns \c true, the iteration is terminated and this method
	returns \c true. If supplied, \a device is set to the concerned device
	and in \a partition the pointer to the partition object is returned.

	\param visitor The visitor.
	\param device Pointer to a pre-allocated BDiskDevice to be initialized
		   to the device at which the iteration was terminated.
		   May be \c NULL.
	\param partition Pointer to a pre-allocated BPartition pointer to be set
		   to the partition at which the iteration was terminated.
		   May be \c NULL.
	\return \c true, if the iteration was terminated, \c false otherwise.
*/
bool
BDiskDeviceRoster::VisitEachPartition(BDiskDeviceVisitor* visitor,
	BDiskDevice* device, BPartition** partition)
{
	bool terminatedEarly = false;
	if (visitor) {
		int32 oldCookie = fDeviceCookie;
		fDeviceCookie = 0;
		BDiskDevice deviceOnStack;
		BDiskDevice* useDevice = device ? device : &deviceOnStack;
		BPartition* foundPartition = NULL;
		while (GetNextDevice(useDevice) == B_OK) {
			foundPartition = useDevice->VisitEachDescendant(visitor);
			if (foundPartition) {
				terminatedEarly = true;
				break;
			}
		}
		fDeviceCookie = oldCookie;
		if (!terminatedEarly)
			useDevice->Unset();
		else if (device && partition)
			*partition = foundPartition;
	}
	return terminatedEarly;
}

void
AutoMounter::_UnmountAndEjectVolume(BPartition* partition, BPath& mountPoint,
	const char* name)
{
	BDiskDevice deviceStorage;
	BDiskDevice* device;
	if (partition == NULL) {
		// Try to retrieve partition
		BDiskDeviceRoster().FindPartitionByMountPoint(mountPoint.Path(),
			&deviceStorage, &partition);
			device = &deviceStorage;
	} else {
		device = partition->Device();
	}

	status_t status;
	if (partition != NULL)
		status = partition->Unmount();
	else
		status = fs_unmount_volume(mountPoint.Path(), 0);

	if (status != B_OK) {
		if (!_SuggestForceUnmount(name, status))
			return;

		if (partition != NULL)
			status = partition->Unmount(B_FORCE_UNMOUNT);
		else
			status = fs_unmount_volume(mountPoint.Path(), B_FORCE_UNMOUNT);
	}

	if (status != B_OK) {
		_ReportUnmountError(name, status);
		return;
	}

	if (fEjectWhenUnmounting && partition != NULL) {
		// eject device if it doesn't have any mounted partitions left
		class IsMountedVisitor : public BDiskDeviceVisitor {
		public:
			IsMountedVisitor()
				:
				fHasMounted(false)
			{
			}

			virtual bool Visit(BDiskDevice* device)
			{
				return Visit(device, 0);
			}

			virtual bool Visit(BPartition* partition, int32 level)
			{
				if (partition->IsMounted()) {
					fHasMounted = true;
					return true;
				}

				return false;
			}

			bool HasMountedPartitions() const
			{
				return fHasMounted;
			}

		private:
			bool	fHasMounted;
		} visitor;

		device->VisitEachDescendant(&visitor);

		if (!visitor.HasMountedPartitions())
			device->Eject();
	}

	// remove the directory if it's a directory in rootfs
	if (dev_for_path(mountPoint.Path()) == dev_for_path("/"))
		rmdir(mountPoint.Path());
}