set file "//xvfs:/example/foo"

set fd [open $file]
seek $fd 0 end
seek $fd -1 current
set check [read $fd 1]
if {$check != "\n"} {
	error "EXPECTED: (new line); GOT: [binary encode hex $check]"
}
close $fd

set fd1 [open $file]
set fd2 [open $file]
set data1 [read $fd1]
close $fd1
set data2 [read $fd2]
close $fd2
if {$data1 != $data2} {
	error "EXPECTED match, differs"
}

set fd [open $file]
seek $fd 0 end
set size [tell $fd]
close $fd
set fd [open $file]
set done false
set calls 0
set output ""
fileevent $fd readable [list apply {{fd} {
	set pos [tell $fd]
	set x [read $fd 1]
	if {[string length $x] == 0} {
		set ::done true
		fileevent $fd readable ""
	}

	lappend ::output $pos
	incr ::calls
}} $fd]
vwait done
if {$calls != ($size + 1)} {
	error "EXPECTED [expr {$size + 1}], got $calls"
}
if {[lsort -integer $output] != $output} {
	error "EXPECTED [lsort -integer $output], GOT $output"
}

puts "ALL TESTS PASSED"

 */
struct xvfs_tclfs_channel_id {
	Tcl_Channel channel;
	struct xvfs_tclfs_instance_info *fsInstanceInfo;
	Tcl_Obj *path;
	Tcl_WideInt currentOffset;
	Tcl_WideInt fileSize;
	int eofMarked;
};
struct xvfs_tclfs_channel_event {
	Tcl_Event tcl;
	struct xvfs_tclfs_channel_id *channelInstanceData;
};
static Tcl_ChannelType xvfs_tclfs_channelType;

static Tcl_Channel xvfs_tclfs_openChannel(Tcl_Obj *path, struct xvfs_tclfs_instance_info *instanceInfo) {
	struct xvfs_tclfs_channel_id *channelInstanceData;
	Tcl_Channel channel;
	Tcl_StatBuf fileInfo;
	Tcl_Obj *channelName;
	int statRet;

	statRet = instanceInfo->fsInfo->getStatProc(Tcl_GetString(path), &fileInfo);
	if (statRet < 0) {
		return(NULL);
	}

	channelInstanceData = (struct xvfs_tclfs_channel_id *) Tcl_Alloc(sizeof(*channelInstanceData));
	channelInstanceData->currentOffset = 0;
	channelInstanceData->eofMarked = 0;
	channelInstanceData->channel = NULL;

	channelName = Tcl_ObjPrintf("xvfs0x%llx", (unsigned long long) channelInstanceData);
	if (!channelName) {
		Tcl_Free((char *) channelInstanceData);

		return(NULL);
	}
	Tcl_IncrRefCount(channelName);

	channelInstanceData->fsInstanceInfo = instanceInfo;
	channelInstanceData->fileSize = fileInfo.st_size;
	channelInstanceData->path = path;
	Tcl_IncrRefCount(path);

	channel = Tcl_CreateChannel(&xvfs_tclfs_channelType, Tcl_GetString(channelName), channelInstanceData, TCL_READABLE);
	Tcl_DecrRefCount(channelName);
	if (!channel) {
		Tcl_DecrRefCount(path);
		Tcl_Free((char *) channelInstanceData);

		return(NULL);
	}

static int xvfs_tclfs_readChannel(ClientData channelInstanceData_p, char *buf, int bufSize, int *errorCodePtr) {
	struct xvfs_tclfs_channel_id *channelInstanceData;
	const unsigned char *data;
	Tcl_WideInt offset, length;
	char *path;

	channelInstanceData = (struct xvfs_tclfs_channel_id *) channelInstanceData_p;

	/*
	 * If we are already at the end of the file we can skip
	 * attempting to read it
	 */
	if (channelInstanceData->eofMarked) {
		return(0);
	}

	path = Tcl_GetString(channelInstanceData->path);
	offset = channelInstanceData->currentOffset;
	length = bufSize;

	data = channelInstanceData->fsInstanceInfo->fsInfo->getDataProc(path, offset, &length);

	if (length < 0) {
		*errorCodePtr = xvfs_errorToErrno(length);

		return(-1);
	}

	if (length == 0) {
		channelInstanceData->eofMarked = 1;
	} else {
		memcpy(buf, data, length);

		channelInstanceData->currentOffset += length;
	}

	return(length);
}

static int xvfs_tclfs_watchChannelEvent(Tcl_Event *event_p, int flags) {
	struct xvfs_tclfs_channel_id *channelInstanceData;
	struct xvfs_tclfs_channel_event *event;

	event = (struct xvfs_tclfs_channel_event *) event_p;
	channelInstanceData = event->channelInstanceData;

	Tcl_NotifyChannel(channelInstanceData->channel, TCL_READABLE);

	return(0);
}

static void xvfs_tclfs_watchChannel(ClientData channelInstanceData_p, int mask) {
	struct xvfs_tclfs_channel_id *channelInstanceData;
	struct xvfs_tclfs_channel_event *event;

	if ((mask & TCL_READABLE) != TCL_READABLE) {
		return;
	}

	channelInstanceData = (struct xvfs_tclfs_channel_id *) channelInstanceData_p;

	/*
	 * If the read call has marked that we have reached EOF,
	 * do not signal any further
	 */
	if (channelInstanceData->eofMarked) {
		return;
	}

	event = (struct xvfs_tclfs_channel_event *) Tcl_Alloc(sizeof(*event));
	event->tcl.proc = xvfs_tclfs_watchChannelEvent;
	event->tcl.nextPtr = NULL;
	event->channelInstanceData = channelInstanceData;

	Tcl_QueueEvent((Tcl_Event *) event, TCL_QUEUE_TAIL);

	return;
}

static int xvfs_tclfs_seekChannel(ClientData channelInstanceData_p, long offset, int mode, int *errorCodePtr) {
	struct xvfs_tclfs_channel_id *channelInstanceData;
	Tcl_WideInt newOffset, fileSize;

	 */
	if (newOffset < 0 || newOffset > fileSize) {
		*errorCodePtr = xvfs_errorToErrno(XVFS_RV_ERR_EINVAL);

		return(-1);
	}

	if (newOffset != channelInstanceData->currentOffset) {
		channelInstanceData->eofMarked = 0;
		channelInstanceData->currentOffset = newOffset;
	}

	return(channelInstanceData->currentOffset);
}

static void xvfs_tclfs_prepareChannelType(void) {
	xvfs_tclfs_channelType.typeName = "xvfs";
	xvfs_tclfs_channelType.version = TCL_CHANNEL_VERSION_2;