Documentation | StorageKit | The Node Monitor

SYNOPSIS

use HaikuR1::NodeMonitor qw(watch_node B_WATCH_NAME);

watch_node($node, B_WATCH_NAME, $target);

from HaikuR1.StorageKit import watch_node, B_WATCH_NAME

watch_node(node, B_WATCH_NAME, $target);

DESCRIPTION

Exposes the node monitor function.

For more information on the node monitor, see the Be Book class description and the Haiku Book class description.

FUNCTIONS

Watching

watch_volume

watch_node

stop_watching

watch_node will watch a specific node for certain changes, or for volume mounting and unmounting.

watch_volume will watch all nodes on a volume for certain changes.

stop_watching will stop sending notifications to the given target.

The notification will come in the form of a Message with a what value of B_NODE_MONITOR and a field called opcode, which will be one of the opcode constants.

To watch for mounting and unmounting: Use watch_node with an empty value in place of the node. watch_volume is used to watch all nodes on a volume, not to watch volumes.

(Actually, the node does not have to be empty; you could combine node flags with B_WATCH_MOUNT, and you will get notifications for both the given node and for volume mounting.)

To stop watching a node: Use B_STOP_WATCHING with watch_node. stop_watching stops all notifications to a given target.

HaikuR1::NodeMonitor::watch_node($node, $flags, $target);
HaikuR1::NodeMonitor::watch_volume($volume, $flags, $target, $looper);
HaikuR1::NodeMonitor::stop_watching($target);

NodeMonitor.watch_node(node, flags, target)
NodeMonitor.watch_volume(volume, flags, target, looper)
NodeMonitor.stop_watching(target)

• volume

  An integer device id. You can get one from Volume.Device).

• node

  A native map representing the node. You can get one from Statable.GetNodeRef. (Remember that Node inherits from Statable.) Pass the empty value to watch for volume mounting and unmounting.

• flags

  An integer, one or more of the node monitor flags.

• target

  A Messenger or Handler, the target that will receive the notifications.

• looper

  A Looper; only used when target is a Handler. (If looper is used, handler must belong to looper.)

CONSTANTS

Cause

When the B_ATTR_CHANGED notification is sent, the message will have a cause field, which can either be B_ATTR_CHANGED itself, or one of the following:

use HaikuR1::NodeMonitor qw(:cause)

Python does not support export tags.

• B_ATTR_CREATED
• B_ATTR_REMOVED

Fields

When the B_STAT_CHANGED notification is sent, the message will have a fields field, which will be an integer combining the following values, representing which part of the stat actually changed.

use HaikuR1::NodeMonitor qw(:fields)

Python does not support export tags.

• B_STAT_MODE
• B_STAT_UID
• B_STAT_GID
• B_STAT_SIZE
• B_STAT_ACCESS_TIME
• B_STAT_MODIFICATION_TIME
• B_STAT_CREATION_TIME
• B_STAT_CHANGE_TIME
• B_STAT_INTERIM_UPDATE

Flags

These are the values you pass to watch_node or watch_volume.

use HaikuR1::NodeMonitor qw(:flags)

Python does not support export tags.

• B_STOP_WATCHING

  Use this to stop sending notifications for a given node (or for all nodes all on a given volume).

• B_WATCH_NAME

  Watches for name changes

• B_WATCH_STAT

  Watches for changes in stat values (size, modification date, owner, etc.)

• B_WATCH_ATTR

  Watches for changes in attributes

• B_WATCH_DIRECTORY

  Watches for new entries, deleted entries, renamed entries, etc., in the given directory. (It will cause an error when used on non-directories, but it will have no effect.)

• B_WATCH_ALL

  Combines B_WATCH_NAME, B_WATCH_STAT, B_WATCH_ATTR, and B_WATCH_DIRECTORY

• B_WATCH_MOUNT

  Watches for volumes being mounted and unmounted.

• B_WATCH_INTERIM_STAT

  If an open file is being written to frequently, the system will send B_WATCH_STAT less frequently. If you really want to catch every write, you can use this instead.

• B_WATCH_CHILDREN

  There is no documentation on this flag; presumably it is meant to be combined with other flags and used on a directory in order to watch its children as well.

Opcodes

These are sent in the opcode field of the notification message and indicate the type of notification.

use HaikuR1::NodeMonitor qw(:opcodes)

Python does not support export tags.

• B_ENTRY_CREATED
• B_ENTRY_REMOVED
• B_ENTRY_MOVED
• B_STAT_CHANGED
• B_ATTR_CHANGED
• B_DEVICE_MOUNTED
• B_DEVICE_UNMOUNTED