162 lines
4.9 KiB
Python
162 lines
4.9 KiB
Python
import collections
|
|
from math import ceil
|
|
|
|
from django.utils import six
|
|
|
|
|
|
class InvalidPage(Exception):
|
|
pass
|
|
|
|
|
|
class PageNotAnInteger(InvalidPage):
|
|
pass
|
|
|
|
|
|
class EmptyPage(InvalidPage):
|
|
pass
|
|
|
|
|
|
class Paginator(object):
|
|
|
|
def __init__(self, object_list, per_page, orphans=0,
|
|
allow_empty_first_page=True):
|
|
self.object_list = object_list
|
|
self.per_page = int(per_page)
|
|
self.orphans = int(orphans)
|
|
self.allow_empty_first_page = allow_empty_first_page
|
|
self._num_pages = self._count = None
|
|
|
|
def validate_number(self, number):
|
|
"""
|
|
Validates the given 1-based page number.
|
|
"""
|
|
try:
|
|
number = int(number)
|
|
except (TypeError, ValueError):
|
|
raise PageNotAnInteger('That page number is not an integer')
|
|
if number < 1:
|
|
raise EmptyPage('That page number is less than 1')
|
|
if number > self.num_pages:
|
|
if number == 1 and self.allow_empty_first_page:
|
|
pass
|
|
else:
|
|
raise EmptyPage('That page contains no results')
|
|
return number
|
|
|
|
def page(self, number):
|
|
"""
|
|
Returns a Page object for the given 1-based page number.
|
|
"""
|
|
number = self.validate_number(number)
|
|
bottom = (number - 1) * self.per_page
|
|
top = bottom + self.per_page
|
|
if top + self.orphans >= self.count:
|
|
top = self.count
|
|
return self._get_page(self.object_list[bottom:top], number, self)
|
|
|
|
def _get_page(self, *args, **kwargs):
|
|
"""
|
|
Returns an instance of a single page.
|
|
|
|
This hook can be used by subclasses to use an alternative to the
|
|
standard :cls:`Page` object.
|
|
"""
|
|
return Page(*args, **kwargs)
|
|
|
|
def _get_count(self):
|
|
"""
|
|
Returns the total number of objects, across all pages.
|
|
"""
|
|
if self._count is None:
|
|
try:
|
|
self._count = self.object_list.count()
|
|
except (AttributeError, TypeError):
|
|
# AttributeError if object_list has no count() method.
|
|
# TypeError if object_list.count() requires arguments
|
|
# (i.e. is of type list).
|
|
self._count = len(self.object_list)
|
|
return self._count
|
|
count = property(_get_count)
|
|
|
|
def _get_num_pages(self):
|
|
"""
|
|
Returns the total number of pages.
|
|
"""
|
|
if self._num_pages is None:
|
|
if self.count == 0 and not self.allow_empty_first_page:
|
|
self._num_pages = 0
|
|
else:
|
|
hits = max(1, self.count - self.orphans)
|
|
self._num_pages = int(ceil(hits / float(self.per_page)))
|
|
return self._num_pages
|
|
num_pages = property(_get_num_pages)
|
|
|
|
def _get_page_range(self):
|
|
"""
|
|
Returns a 1-based range of pages for iterating through within
|
|
a template for loop.
|
|
"""
|
|
return range(1, self.num_pages + 1)
|
|
page_range = property(_get_page_range)
|
|
|
|
|
|
QuerySetPaginator = Paginator # For backwards-compatibility.
|
|
|
|
|
|
class Page(collections.Sequence):
|
|
|
|
def __init__(self, object_list, number, paginator):
|
|
self.object_list = object_list
|
|
self.number = number
|
|
self.paginator = paginator
|
|
|
|
def __repr__(self):
|
|
return '<Page %s of %s>' % (self.number, self.paginator.num_pages)
|
|
|
|
def __len__(self):
|
|
return len(self.object_list)
|
|
|
|
def __getitem__(self, index):
|
|
if not isinstance(index, (slice,) + six.integer_types):
|
|
raise TypeError
|
|
# The object_list is converted to a list so that if it was a QuerySet
|
|
# it won't be a database hit per __getitem__.
|
|
if not isinstance(self.object_list, list):
|
|
self.object_list = list(self.object_list)
|
|
return self.object_list[index]
|
|
|
|
def has_next(self):
|
|
return self.number < self.paginator.num_pages
|
|
|
|
def has_previous(self):
|
|
return self.number > 1
|
|
|
|
def has_other_pages(self):
|
|
return self.has_previous() or self.has_next()
|
|
|
|
def next_page_number(self):
|
|
return self.paginator.validate_number(self.number + 1)
|
|
|
|
def previous_page_number(self):
|
|
return self.paginator.validate_number(self.number - 1)
|
|
|
|
def start_index(self):
|
|
"""
|
|
Returns the 1-based index of the first object on this page,
|
|
relative to total objects in the paginator.
|
|
"""
|
|
# Special case, return zero if no items.
|
|
if self.paginator.count == 0:
|
|
return 0
|
|
return (self.paginator.per_page * (self.number - 1)) + 1
|
|
|
|
def end_index(self):
|
|
"""
|
|
Returns the 1-based index of the last object on this page,
|
|
relative to total objects found (hits).
|
|
"""
|
|
# Special case for the last page because there can be orphans.
|
|
if self.number == self.paginator.num_pages:
|
|
return self.paginator.count
|
|
return self.number * self.paginator.per_page
|