Package Camelot :: Package camelot :: Package view :: Module fifo
[frames] | no frames]

Source Code for Module Camelot.camelot.view.fifo

 1  #  ============================================================================
 
 2  #
 
 3  #  Copyright (C) 2007-2008 Conceptive Engineering bvba. All rights reserved.
 
 4  #  www.conceptive.be / project-camelot@conceptive.be
 
 5  #
 
 6  #  This file is part of the Camelot Library.
 
 7  #
 
 8  #  This file may be used under the terms of the GNU General Public
 
 9  #  License version 2.0 as published by the Free Software Foundation
 
10  #  and appearing in the file LICENSE.GPL included in the packaging of
 
11  #  this file.  Please review the following information to ensure GNU
 
12  #  General Public Licensing requirements will be met:
 
13  #  http://www.trolltech.com/products/qt/opensource.html
 
14  #
 
15  #  If you are unsure which license is appropriate for your use, please
 
16  #  review the following information:
 
17  #  http://www.trolltech.com/products/qt/licensing.html or contact
 
18  #  project-camelot@conceptive.be.
 
19  #
 
20  #  This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 
21  #  WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 
22  #
 
23  #  For use of this library in commercial applications, please contact
 
24  #  project-camelot@conceptive.be
 
25  #
 
26  #  ============================================================================
 
27  
 
28  
 
29 -class fifo(object):
30 """fifo, is the actual cache containing a limited set of copies of row data 31 so the data in fifo, is always immediately accessible to the gui thread, 32 with zero delay as you scroll down the table view, fifo is filled and 33 refilled with data queried from the database 34 35 the cache can be queried either by the row number or by object represented 36 by the row data. 37 """
38 - def __init__(self, max_entries):
39 self.max_entries = max_entries 40 self.entities = [] 41 self.data_by_rows = dict() 42 self.rows_by_entity = dict()
43
44 - def __unicode__(self):
45 return u','.join(unicode(e) for e in self.entities)
46
47 - def add_data(self, row, entity, value):
48 self.delete_by_entity(entity) 49 self.data_by_rows[row] = (entity, value) 50 self.rows_by_entity[entity] = row 51 self.entities.append(entity) 52 if len(self.entities)>self.max_entries: 53 entity = self.entities.pop(0) 54 self.delete_by_entity(entity)
55
56 - def delete_by_row(self, row):
57 (entity, value_) = self.data_by_rows[row] 58 del self.data_by_rows[row] 59 del self.rows_by_entity[entity] 60 return row
61
62 - def delete_by_entity(self, entity):
63 """Remove everything in the cache related to an entity instance 64 returns the row at which the data was stored if the data was in the 65 cache, return None otherwise""" 66 row = None 67 try: 68 row = self.rows_by_entity[entity] 69 del self.data_by_rows[row] 70 del self.rows_by_entity[entity] 71 except KeyError: 72 pass 73 try: 74 self.entities.remove(entity) 75 except ValueError: 76 pass 77 return row
78
79 - def get_data_at_row(self, row):
80 return self.data_by_rows[row][1]
81
82 - def get_row_by_entity(self, entity):
83 return self.rows_by_entity[entity]
84
85 - def get_entity_at_row(self, row):
86 return self.data_by_rows[row][0]
87