| author |
Steve Losh <steve@stevelosh.com> |
| date |
Wed, 06 Oct 2010 12:30:46 -0400 |
| parents |
(none) |
| children |
(none) |
import os
class ResourceObserver(object):
"""Provides the interface for observing resources
`ResourceObserver`\s can be registered using `Project.
add_observer()`. But most of the time `FilteredResourceObserver`
should be used. `ResourceObserver`\s report all changes passed
to them and they don't report changes to all resources. For
example if a folder is removed, it only calls `removed()` for that
folder and not its contents. You can use
`FilteredResourceObserver` if you are interested in changes only
to a list of resources. And you want changes to be reported on
individual resources.
"""
def __init__(self, changed=None, moved=None, created=None,
removed=None, validate=None):
self.changed = changed
self.moved = moved
self.created = created
self.removed = removed
self._validate = validate
def resource_changed(self, resource):
"""It is called when the resource changes"""
if self.changed is not None:
self.changed(resource)
def resource_moved(self, resource, new_resource):
"""It is called when a resource is moved"""
if self.moved is not None:
self.moved(resource, new_resource)
def resource_created(self, resource):
"""Is called when a new resource is created"""
if self.created is not None:
self.created(resource)
def resource_removed(self, resource):
"""Is called when a new resource is removed"""
if self.removed is not None:
self.removed(resource)
def validate(self, resource):
"""Validate the existence of this resource and its children.
This function is called when rope need to update its resource
cache about the files that might have been changed or removed
by other processes.
"""
if self._validate is not None:
self._validate(resource)
class FilteredResourceObserver(object):
"""A useful decorator for `ResourceObserver`
Most resource observers have a list of resources and are
interested only in changes to those files. This class satisfies
this need. It dispatches resource changed and removed messages.
It performs these tasks:
* Changes to files and folders are analyzed to check whether any
of the interesting resources are changed or not. If they are,
it reports these changes to `resource_observer` passed to the
constructor.
* When a resource is removed it checks whether any of the
interesting resources are contained in that folder and reports
them to `resource_observer`.
* When validating a folder it validates all of the interesting
files in that folder.
Since most resource observers are interested in a list of
resources that change over time, `add_resource` and
`remove_resource` might be useful.
"""
def __init__(self, resource_observer, initial_resources=None,
timekeeper=None):
self.observer = resource_observer
self.resources = {}
if timekeeper is not None:
self.timekeeper = timekeeper
else:
self.timekeeper = ChangeIndicator()
if initial_resources is not None:
for resource in initial_resources:
self.add_resource(resource)
def add_resource(self, resource):
"""Add a resource to the list of interesting resources"""
if resource.exists():
self.resources[resource] = self.timekeeper.get_indicator(resource)
else:
self.resources[resource] = None
def remove_resource(self, resource):
"""Add a resource to the list of interesting resources"""
if resource in self.resources:
del self.resources[resource]
def clear_resources(self):
"""Removes all registered resources"""
self.resources.clear()
def resource_changed(self, resource):
changes = _Changes()
self._update_changes_caused_by_changed(changes, resource)
self._perform_changes(changes)
def _update_changes_caused_by_changed(self, changes, changed):
if changed in self.resources:
changes.add_changed(changed)
if self._is_parent_changed(changed):
changes.add_changed(changed.parent)
def _update_changes_caused_by_moved(self, changes, resource,
new_resource=None):
if resource in self.resources:
changes.add_removed(resource, new_resource)
if new_resource in self.resources:
changes.add_created(new_resource)
if resource.is_folder():
for file in list(self.resources):
if resource.contains(file):
new_file = self._calculate_new_resource(
resource, new_resource, file)
changes.add_removed(file, new_file)
if self._is_parent_changed(resource):
changes.add_changed(resource.parent)
if new_resource is not None:
if self._is_parent_changed(new_resource):
changes.add_changed(new_resource.parent)
def _is_parent_changed(self, child):
return child.parent in self.resources
def resource_moved(self, resource, new_resource):
changes = _Changes()
self._update_changes_caused_by_moved(changes, resource, new_resource)
self._perform_changes(changes)
def resource_created(self, resource):
changes = _Changes()
self._update_changes_caused_by_created(changes, resource)
self._perform_changes(changes)
def _update_changes_caused_by_created(self, changes, resource):
if resource in self.resources:
changes.add_created(resource)
if self._is_parent_changed(resource):
changes.add_changed(resource.parent)
def resource_removed(self, resource):
changes = _Changes()
self._update_changes_caused_by_moved(changes, resource)
self._perform_changes(changes)
def _perform_changes(self, changes):
for resource in changes.changes:
self.observer.resource_changed(resource)
self.resources[resource] = self.timekeeper.get_indicator(resource)
for resource, new_resource in changes.moves.items():
self.resources[resource] = None
if new_resource is not None:
self.observer.resource_moved(resource, new_resource)
else:
self.observer.resource_removed(resource)
for resource in changes.creations:
self.observer.resource_created(resource)
self.resources[resource] = self.timekeeper.get_indicator(resource)
def validate(self, resource):
changes = _Changes()
for file in self._search_resource_moves(resource):
if file in self.resources:
self._update_changes_caused_by_moved(changes, file)
for file in self._search_resource_changes(resource):
if file in self.resources:
self._update_changes_caused_by_changed(changes, file)
for file in self._search_resource_creations(resource):
if file in self.resources:
changes.add_created(file)
self._perform_changes(changes)
def _search_resource_creations(self, resource):
creations = set()
if resource in self.resources and resource.exists() and \
self.resources[resource] is None:
creations.add(resource)
if resource.is_folder():
for file in self.resources:
if file.exists() and resource.contains(file) and \
self.resources[file] is None:
creations.add(file)
return creations
def _search_resource_moves(self, resource):
all_moved = set()
if resource in self.resources and not resource.exists():
all_moved.add(resource)
if resource.is_folder():
for file in self.resources:
if resource.contains(file):
if not file.exists():
all_moved.add(file)
moved = set(all_moved)
for folder in [file for file in all_moved if file.is_folder()]:
if folder in moved:
for file in list(moved):
if folder.contains(file):
moved.remove(file)
return moved
def _search_resource_changes(self, resource):
changed = set()
if resource in self.resources and self._is_changed(resource):
changed.add(resource)
if resource.is_folder():
for file in self.resources:
if file.exists() and resource.contains(file):
if self._is_changed(file):
changed.add(file)
return changed
def _is_changed(self, resource):
if self.resources[resource] is None:
return False
return self.resources[resource] != self.timekeeper.get_indicator(resource)
def _calculate_new_resource(self, main, new_main, resource):
if new_main is None:
return None
diff = resource.path[len(main.path):]
return resource.project.get_resource(new_main.path + diff)
class ChangeIndicator(object):
def get_indicator(self, resource):
"""Return the modification time and size of a `Resource`."""
path = resource.real_path
# on dos, mtime does not change for a folder when files are added
if os.name != 'posix' and os.path.isdir(path):
return (os.path.getmtime(path),
len(os.listdir(path)),
os.path.getsize(path))
return (os.path.getmtime(path),
os.path.getsize(path))
class _Changes(object):
def __init__(self):
self.changes = set()
self.creations = set()
self.moves = {}
def add_changed(self, resource):
self.changes.add(resource)
def add_removed(self, resource, new_resource=None):
self.moves[resource] = new_resource
def add_created(self, resource):
self.creations.add(resource)