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| 1 # Copyright 2016 The Chromium Authors. All rights reserved. |
| 2 # Use of this source code is govered by a BSD-style |
| 3 # license that can be found in the LICENSE file or at |
| 4 # https://developers.google.com/open-source/licenses/bsd |
| 5 |
| 6 """Classes that help display pagination widgets for result sets.""" |
| 7 |
| 8 import logging |
| 9 |
| 10 from third_party import ezt |
| 11 |
| 12 import settings |
| 13 from framework import framework_helpers |
| 14 |
| 15 |
| 16 class VirtualPagination(object): |
| 17 """Class to calc Prev and Next pagination links based on result counts.""" |
| 18 |
| 19 def __init__(self, mr, total_count, items_per_page, |
| 20 list_page_url=None, count_up=True, |
| 21 start_param='start', num_param='num', max_num=None): |
| 22 """Given 'num' and 'start' params, determine Prev and Next links. |
| 23 |
| 24 Args: |
| 25 mr: commonly used info parsed from the request. |
| 26 total_count: total number of artifacts that satisfy the query. |
| 27 items_per_page: number of items to display on each page, e.g., 25. |
| 28 list_page_url: URL of the web application page that is displaying |
| 29 the list of artifacts. Used to build the Prev and Next URLs. |
| 30 If None, no URLs will be built. |
| 31 count_up: if False, count down from total_count. |
| 32 start_param: query string parameter name to use for the start |
| 33 of the pagination page. |
| 34 num_param: query string parameter name to use for the number of items |
| 35 to show on a pagination page. |
| 36 max_num: optional limit on the value of the num param. If not given, |
| 37 settings.max_artifact_search_results_per_page is used. |
| 38 """ |
| 39 self.total_count = total_count |
| 40 self.prev_url = '' |
| 41 self.reload_url = '' |
| 42 self.next_url = '' |
| 43 |
| 44 if max_num is None: |
| 45 max_num = settings.max_artifact_search_results_per_page |
| 46 |
| 47 self.num = mr.GetPositiveIntParam(num_param, items_per_page) |
| 48 self.num = min(self.num, max_num) |
| 49 |
| 50 if count_up: |
| 51 self.start = mr.GetPositiveIntParam(start_param, 0) |
| 52 self.last = min(self.total_count, self.start + self.num) |
| 53 prev_start = max(0, self.start - self.num) |
| 54 next_start = self.start + self.num |
| 55 else: |
| 56 self.start = mr.GetPositiveIntParam(start_param, self.total_count) |
| 57 self.last = max(0, self.start - self.num) |
| 58 prev_start = min(self.total_count, self.start + self.num) |
| 59 next_start = self.start - self.num |
| 60 |
| 61 if list_page_url: |
| 62 if mr.project_name: |
| 63 list_servlet_rel_url = '/p/%s%s' % ( |
| 64 mr.project_name, list_page_url) |
| 65 else: |
| 66 list_servlet_rel_url = list_page_url |
| 67 |
| 68 self.reload_url = framework_helpers.FormatURL( |
| 69 mr, list_servlet_rel_url, |
| 70 **{start_param: self.start, num_param: self.num}) |
| 71 |
| 72 if prev_start != self.start: |
| 73 self.prev_url = framework_helpers.FormatURL( |
| 74 mr, list_servlet_rel_url, |
| 75 **{start_param: prev_start, num_param: self.num}) |
| 76 if ((count_up and next_start < self.total_count) or |
| 77 (not count_up and next_start >= 1)): |
| 78 self.next_url = framework_helpers.FormatURL( |
| 79 mr, list_servlet_rel_url, |
| 80 **{start_param: next_start, num_param: self.num}) |
| 81 |
| 82 self.visible = ezt.boolean(self.last != self.start) |
| 83 |
| 84 # Adjust indices to one-based values for display to users. |
| 85 if count_up: |
| 86 self.start += 1 |
| 87 else: |
| 88 self.last += 1 |
| 89 |
| 90 def DebugString(self): |
| 91 """Return a string that is useful in on-page debugging.""" |
| 92 return '%s - %s of %s; prev_url:%s; next_url:%s' % ( |
| 93 self.start, self.last, self.total_count, self.prev_url, self.next_url) |
| 94 |
| 95 |
| 96 class ArtifactPagination(VirtualPagination): |
| 97 """Class to calc Prev and Next pagination links based on a results list.""" |
| 98 |
| 99 def __init__( |
| 100 self, mr, results, items_per_page, list_page_url, total_count=None, |
| 101 limit_reached=False, skipped=0): |
| 102 """Given 'num' and 'start' params, determine Prev and Next links. |
| 103 |
| 104 Args: |
| 105 mr: commonly used info parsed from the request. |
| 106 results: a list of artifact ids that satisfy the query. |
| 107 items_per_page: number of items to display on each page, e.g., 25. |
| 108 list_page_url: URL of the web application page that is displaying |
| 109 the list of artifacts. Used to build the Prev and Next URLs. |
| 110 total_count: specify total result count rather than the length of results |
| 111 limit_reached: optional boolean that indicates that more results could |
| 112 not be fetched because a limit was reached. |
| 113 skipped: optional int number of items that were skipped and left off the |
| 114 front of results. |
| 115 """ |
| 116 if total_count is None: |
| 117 total_count = skipped + len(results) |
| 118 super(ArtifactPagination, self).__init__( |
| 119 mr, total_count, items_per_page, list_page_url=list_page_url) |
| 120 |
| 121 self.limit_reached = ezt.boolean(limit_reached) |
| 122 # Determine which of those results should be visible on the current page. |
| 123 range_start = self.start - 1 - skipped |
| 124 range_end = range_start + self.num |
| 125 assert 0 <= range_start <= range_end |
| 126 self.visible_results = results[range_start:range_end] |
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