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
|
require "set"
require "pathname"
require "concurrent/atomic/atomic_boolean"
module ActiveSupport
# Allows you to "listen" to changes in a file system.
# The evented file updater does not hit disk when checking for updates
# instead it uses platform specific file system events to trigger a change
# in state.
#
# The file checker takes an array of files to watch or a hash specifying directories
# and file extensions to watch. It also takes a block that is called when
# EventedFileUpdateChecker#execute is run or when EventedFileUpdateChecker#execute_if_updated
# is run and there have been changes to the file system.
#
# Note: Forking will cause the first call to `updated?` to return `true`.
#
# Example:
#
# checker = ActiveSupport::EventedFileUpdateChecker.new(["/tmp/foo"]) { puts "changed" }
# checker.updated?
# # => false
# checker.execute_if_updated
# # => nil
#
# FileUtils.touch("/tmp/foo")
#
# checker.updated?
# # => true
# checker.execute_if_updated
# # => "changed"
#
class EventedFileUpdateChecker #:nodoc: all
def initialize(files, dirs = {}, &block)
unless block
raise ArgumentError, "A block is required to initialize an EventedFileUpdateChecker"
end
@ph = PathHelper.new
@files = files.map { |f| @ph.xpath(f) }.to_set
@dirs = {}
dirs.each do |dir, exts|
@dirs[@ph.xpath(dir)] = Array(exts).map { |ext| @ph.normalize_extension(ext) }
end
@block = block
@updated = Concurrent::AtomicBoolean.new(false)
@lcsp = @ph.longest_common_subpath(@dirs.keys)
@pid = Process.pid
@boot_mutex = Mutex.new
if (@dtw = directories_to_watch).any?
# Loading listen triggers warnings. These are originated by a legit
# usage of attr_* macros for private attributes, but adds a lot of noise
# to our test suite. Thus, we lazy load it and disable warnings locally.
silence_warnings do
begin
require "listen"
rescue LoadError => e
raise LoadError, "Could not load the 'listen' gem. Add `gem 'listen'` to the development group of your Gemfile", e.backtrace
end
end
end
boot!
end
def updated?
@boot_mutex.synchronize do
if @pid != Process.pid
boot!
@pid = Process.pid
@updated.make_true
end
end
@updated.true?
end
def execute
@updated.make_false
@block.call
end
def execute_if_updated
if updated?
yield if block_given?
execute
true
end
end
private
def boot!
Listen.to(*@dtw, &method(:changed)).start
end
def changed(modified, added, removed)
unless updated?
@updated.make_true if (modified + added + removed).any? { |f| watching?(f) }
end
end
def watching?(file)
file = @ph.xpath(file)
if @files.member?(file)
true
elsif file.directory?
false
else
ext = @ph.normalize_extension(file.extname)
file.dirname.ascend do |dir|
if @dirs.fetch(dir, []).include?(ext)
break true
elsif dir == @lcsp || dir.root?
break false
end
end
end
end
def directories_to_watch
dtw = (@files + @dirs.keys).map { |f| @ph.existing_parent(f) }
dtw.compact!
dtw.uniq!
normalized_gem_paths = Gem.path.map { |path| File.join path, "" }
dtw = dtw.reject do |path|
normalized_gem_paths.any? { |gem_path| path.to_s.start_with?(gem_path) }
end
@ph.filter_out_descendants(dtw)
end
class PathHelper
def xpath(path)
Pathname.new(path).expand_path
end
def normalize_extension(ext)
ext.to_s.sub(/\A\./, "")
end
# Given a collection of Pathname objects returns the longest subpath
# common to all of them, or +nil+ if there is none.
def longest_common_subpath(paths)
return if paths.empty?
lcsp = Pathname.new(paths[0])
paths[1..-1].each do |path|
until ascendant_of?(lcsp, path)
if lcsp.root?
# If we get here a root directory is not an ascendant of path.
# This may happen if there are paths in different drives on
# Windows.
return
else
lcsp = lcsp.parent
end
end
end
lcsp
end
# Returns the deepest existing ascendant, which could be the argument itself.
def existing_parent(dir)
dir.ascend do |ascendant|
break ascendant if ascendant.directory?
end
end
# Filters out directories which are descendants of others in the collection (stable).
def filter_out_descendants(dirs)
return dirs if dirs.length < 2
dirs_sorted_by_nparts = dirs.sort_by { |dir| dir.each_filename.to_a.length }
descendants = []
until dirs_sorted_by_nparts.empty?
dir = dirs_sorted_by_nparts.shift
dirs_sorted_by_nparts.reject! do |possible_descendant|
ascendant_of?(dir, possible_descendant) && descendants << possible_descendant
end
end
# Array#- preserves order.
dirs - descendants
end
private
def ascendant_of?(base, other)
base != other && other.ascend do |ascendant|
break true if base == ascendant
end
end
end
end
end
|
