# Example Python plugin.
#
# This example can be freely used for any purpose.

# Run it from the build directory like this:
#
#   ./src/nbdkit -f -v ./plugins/python/.libs/nbdkit-python-plugin.so  \
#       script=./plugins/python/example.py test1=foo test2=bar
#
# Or run it after installing nbdkit like this:
#
#   nbdkit -f -v python script=./plugins/python/example.py test1=foo test2=bar
#
# The -f -v arguments are optional.  They cause the server to stay in
# the foreground and print debugging, which is useful when testing.
#
# You can connect to the server using guestfish or qemu, eg:
#
#   guestfish --format=raw -a nbd://localhost
#   ><fs> run
#   ><fs> part-disk /dev/sda mbr
#   ><fs> mkfs ext2 /dev/sda1
#   ><fs> list-filesystems
#   ><fs> mount /dev/sda1 /
#   ><fs> [etc]

# This is the string used to store the emulated disk (initially all
# zero bytes).  There is one disk per nbdkit instance, so if you
# reconnect to the same server you should see the same disk.  You
# could also put this into the handle, so there would be a fresh disk
# per handle.
disk = "\0" * (1024*1024);

# This just prints the extra command line parameters, but real plugins
# should parse them and reject any unknown parameters.
def config(key, value):
    print ("ignored parameter %s=%s" % (key, value))

def open(readonly):
    print ("open: readonly=%d" % readonly)

    # You can return any non-NULL Python object from open, and the
    # same object will be passed as the first arg to the other
    # callbacks [in the client connected phase].
    return 1

def get_size(h):
    global disk
    return len (disk)

def pread(h, count, offset):
    global disk
    return bytearray (disk[offset:offset+count])

def pwrite(h, buf, offset):
    global disk
    end = offset + len (buf)
    disk = disk[:offset] + buf + disk[end:]