summaryrefslogtreecommitdiff
path: root/app/finders/snippets_finder.rb
blob: 941abb704005a47c69b8ae9d5f256c896fd09284 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
# frozen_string_literal: true

# Finder for retrieving snippets that a user can see, optionally scoped to a
# project or snippets author.
#
# Basic usage:
#
#     user = User.find(1)
#
#     SnippetsFinder.new(user).execute
#
# To limit the snippets to a specific project, supply the `project:` option:
#
#     user = User.find(1)
#     project = Project.find(1)
#
#     SnippetsFinder.new(user, project: project).execute
#
# Limiting snippets to an author can be done by supplying the `author:` option:
#
#     user = User.find(1)
#     project = Project.find(1)
#
#     SnippetsFinder.new(user, author: user).execute
#
# To filter snippets using a specific visibility level, you can provide the
# `scope:` option:
#
#     user = User.find(1)
#     project = Project.find(1)
#
#     SnippetsFinder.new(user, author: user, scope: :are_public).execute
#
# Valid `scope:` values are:
#
# * `:are_private`
# * `:are_internal`
# * `:are_public`
#
# Any other value will be ignored.
class SnippetsFinder < UnionFinder
  include FinderMethods
  include Gitlab::Utils::StrongMemoize

  attr_accessor :current_user, :params
  delegate :explore, :only_personal, :only_project, :scope, :sort, to: :params

  def initialize(current_user = nil, params = {})
    @current_user = current_user
    @params = OpenStruct.new(params)

    if project && author
      raise(
        ArgumentError,
        'Filtering by both an author and a project is not supported, ' \
          'as this finder is not optimised for this use case'
      )
    end
  end

  def execute
    # The snippet query can be expensive, therefore if the
    # author or project params have been passed and they don't
    # exist, or if a Project has been passed and has snippets
    # disabled, it's better to return
    return Snippet.none if author.nil? && params[:author].present?
    return Snippet.none if project.nil? && params[:project].present?
    return Snippet.none if project && !project.feature_available?(:snippets, current_user)

    items = init_collection
    items = by_ids(items)
    items = items.with_optional_visibility(visibility_from_scope)

    items.order_by(sort_param)
  end

  private

  def init_collection
    if explore
      snippets_for_explore
    elsif only_personal
      personal_snippets
    elsif project
      snippets_for_a_single_project
    else
      snippets_for_personal_and_multiple_projects
    end
  end

  # Produces a query that retrieves snippets for the Explore page
  #
  # We only show personal snippets here because this page is meant for
  # discovery, and project snippets are of limited interest here.
  def snippets_for_explore
    Snippet.public_to_user(current_user).only_personal_snippets
  end

  # Produces a query that retrieves snippets from multiple projects.
  #
  # The resulting query will, depending on the user's permissions, include the
  # following collections of snippets:
  #
  # 1. Snippets that don't belong to any project.
  # 2. Snippets of projects that are visible to the current user (e.g. snippets
  #    in public projects).
  # 3. Snippets of projects that the current user is a member of.
  #
  # Each collection is constructed in isolation, allowing for greater control
  # over the resulting SQL query.
  def snippets_for_personal_and_multiple_projects
    queries = []
    queries << personal_snippets unless only_project

    if Ability.allowed?(current_user, :read_cross_project)
      queries << snippets_of_visible_projects
      queries << snippets_of_authorized_projects if current_user
    end

    prepared_union(queries)
  end

  def snippets_for_a_single_project
    Snippet.for_project_with_user(project, current_user)
  end

  def personal_snippets
    snippets_for_author_or_visible_to_user.only_personal_snippets
  end

  # Returns the snippets that the current user (logged in or not) can view.
  def snippets_of_visible_projects
    snippets_for_author_or_visible_to_user
      .only_include_projects_visible_to(current_user)
      .only_include_projects_with_snippets_enabled
  end

  # Returns the snippets that the currently logged in user has access to by
  # being a member of the project the snippets belong to.
  #
  # This method requires that `current_user` returns a `User` instead of `nil`,
  # and is optimised for this specific scenario.
  def snippets_of_authorized_projects
    base = author ? author.snippets : Snippet.all

    base
      .only_include_projects_with_snippets_enabled(include_private: true)
      .only_include_authorized_projects(current_user)
  end

  def snippets_for_author_or_visible_to_user
    if author
      snippets_for_author
    elsif current_user
      Snippet.visible_to_or_authored_by(current_user)
    else
      Snippet.public_to_user
    end
  end

  def snippets_for_author
    base = author.snippets

    if author == current_user
      # If the current user is also the author of all snippets, then we can
      # include private snippets.
      base
    else
      base.public_to_user(current_user)
    end
  end

  def visibility_from_scope
    case scope.to_s
    when 'are_private'
      Snippet::PRIVATE
    when 'are_internal'
      Snippet::INTERNAL
    when 'are_public'
      Snippet::PUBLIC
    else
      nil
    end
  end

  def by_ids(items)
    return items unless params[:ids].present?

    items.id_in(params[:ids])
  end

  def author
    strong_memoize(:author) do
      next unless params[:author].present?

      params[:author].is_a?(User) ? params[:author] : User.find_by_id(params[:author])
    end
  end

  def project
    strong_memoize(:project) do
      next unless params[:project].present?

      params[:project].is_a?(Project) ? params[:project] : Project.find_by_id(params[:project])
    end
  end

  def sort_param
    sort.presence || 'id_desc'
  end

  def prepared_union(queries)
    return Snippet.none if queries.empty?
    return queries.first if queries.length == 1

    # The queries are going to be part of a global `where`
    # therefore we only need to retrieve the `id` column
    # which will speed the query
    queries.map! { |rel| rel.select(:id) }
    Snippet.id_in(find_union(queries, Snippet))
  end
end

SnippetsFinder.prepend_if_ee('EE::SnippetsFinder')