X-Git-Url: https://git.mdrn.pl/django-pagination.git/blobdiff_plain/86caf150984733eb5a0bb07af26cd8fc0a8d8496..abf535d21fd19b257e5d6fecfd60e470cc12de7f:/fnp_django_pagination/paginator.py

diff --git a/fnp_django_pagination/paginator.py b/fnp_django_pagination/paginator.py
new file mode 100644
index 0000000..cd3a0f7
--- /dev/null
+++ b/fnp_django_pagination/paginator.py
@@ -0,0 +1,204 @@
+# Copyright (c) 2008, Eric Florenzano
+# Copyright (c) 2010, 2011 Linaro Limited
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+#       copyright notice, this list of conditions and the following
+#       disclaimer in the documentation and/or other materials provided
+#       with the distribution.
+#     * Neither the name of the author nor the names of other
+#       contributors may be used to endorse or promote products derived
+#       from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+from django.core.paginator import Paginator, Page, PageNotAnInteger, EmptyPage
+
+
+class InfinitePaginator(Paginator):
+    """
+    Paginator designed for cases when it's not important to know how many total
+    pages.  This is useful for any object_list that has no count() method or
+    can be used to improve performance for MySQL by removing counts.
+
+    The orphans parameter has been removed for simplicity and there's a link
+    template string for creating the links to the next and previous pages.
+    """
+
+    def __init__(self, object_list, per_page, allow_empty_first_page=True,
+        link_template='/page/%d/'):
+        orphans = 0  # no orphans
+        super(InfinitePaginator, self).__init__(object_list, per_page, orphans,
+            allow_empty_first_page)
+        # no count or num pages
+        del self._num_pages, self._count
+        # bonus links
+        self.link_template = link_template
+
+    def validate_number(self, number):
+        """
+        Validates the given 1-based page number.
+        """
+        try:
+            number = int(number)
+        except ValueError:
+            raise PageNotAnInteger('That page number is not an integer')
+        if number < 1:
+            raise EmptyPage('That page number is less than 1')
+        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
+        page_items = self.object_list[bottom:top]
+        # check moved from validate_number
+        if not page_items:
+            if number == 1 and self.allow_empty_first_page:
+                pass
+            else:
+                raise EmptyPage('That page contains no results')
+        return InfinitePage(page_items, number, self)
+
+    def _get_count(self):
+        """
+        Returns the total number of objects, across all pages.
+        """
+        raise NotImplementedError
+    count = property(_get_count)
+
+    def _get_num_pages(self):
+        """
+        Returns the total number of pages.
+        """
+        raise NotImplementedError
+    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.
+        """
+        raise NotImplementedError
+    page_range = property(_get_page_range)
+
+
+class InfinitePage(Page):
+
+    def __repr__(self):
+        return '<Page %s>' % self.number
+
+    def has_next(self):
+        """
+        Checks for one more item than last on this page.
+        """
+        try:
+            self.paginator.object_list[self.number * self.paginator.per_page]
+        except IndexError:
+            return False
+        return True
+
+    def end_index(self):
+        """
+        Returns the 1-based index of the last object on this page,
+        relative to total objects found (hits).
+        """
+        return ((self.number - 1) * self.paginator.per_page +
+            len(self.object_list))
+
+    #Bonus methods for creating links
+
+    def next_link(self):
+        if self.has_next():
+            return self.paginator.link_template % (self.number + 1)
+        return None
+
+    def previous_link(self):
+        if self.has_previous():
+            return self.paginator.link_template % (self.number - 1)
+        return None
+
+
+class FinitePaginator(InfinitePaginator):
+    """
+    Paginator for cases when the list of items is already finite.
+
+    A good example is a list generated from an API call. This is a subclass
+    of InfinitePaginator because we have no idea how many items exist in the
+    full collection.
+
+    To accurately determine if the next page exists, a FinitePaginator MUST be
+    created with an object_list_plus that may contain more items than the
+    per_page count.  Typically, you'll have an object_list_plus with one extra
+    item (if there's a next page).  You'll also need to supply the offset from
+    the full collection in order to get the page start_index.
+
+    This is a very silly class but useful if you love the Django pagination
+    conventions.
+    """
+
+    def __init__(self, object_list_plus, per_page, offset=None,
+        allow_empty_first_page=True, link_template='/page/%d/'):
+        super(FinitePaginator, self).__init__(object_list_plus, per_page,
+            allow_empty_first_page, link_template)
+        self.offset = offset
+
+    def validate_number(self, number):
+        super(FinitePaginator, self).validate_number(number)
+        # check for an empty list to see if the page exists
+        if not self.object_list:
+            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)
+        # remove the extra item(s) when creating the page
+        page_items = self.object_list[:self.per_page]
+        return FinitePage(page_items, number, self)
+
+
+class FinitePage(InfinitePage):
+
+    def has_next(self):
+        """
+        Checks for one more item than last on this page.
+        """
+        try:
+            self.paginator.object_list[self.paginator.per_page]
+        except IndexError:
+            return False
+        return True
+
+    def start_index(self):
+        """
+        Returns the 1-based index of the first object on this page,
+        relative to total objects in the paginator.
+        """
+        ## TODO should this holler if you haven't defined the offset?
+        return self.paginator.offset