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require "set"
require "pathname"
require "mutex_m"
module Spring
module Watcher
# A user of a watcher can use IO.select to wait for changes:
#
# watcher = MyWatcher.new(root, latency)
# IO.select([watcher]) # watcher is running in background
# watcher.stale? # => true
class Abstract
include Mutex_m
attr_reader :files, :directories, :root, :latency
def initialize(root, latency)
super()
@root = File.realpath(root)
@latency = latency
@files = Set.new
@directories = Set.new
@stale = false
@listeners = []
@on_debug = nil
end
def on_debug(&block)
@on_debug = block
end
def debug
@on_debug.call(yield) if @on_debug
end
def add(*items)
debug { "watcher: add: #{items.inspect}" }
items = items.flatten.map do |item|
item = Pathname.new(item)
if item.relative?
Pathname.new("#{root}/#{item}")
else
item
end
end
items = items.select do |item|
if item.symlink?
item.readlink.exist?.tap do |exists|
if !exists
debug { "add: ignoring dangling symlink: #{item.inspect} -> #{item.readlink.inspect}" }
end
end
else
item.exist?
end
end
synchronize {
items.each do |item|
if item.directory?
directories << item.realpath.to_s
else
begin
files << item.realpath.to_s
rescue Errno::ENOENT
# Race condition. Ignore symlinks whose target was removed
# since the check above, or are deeply chained.
debug { "add: ignoring now-dangling symlink: #{item.inspect} -> #{item.readlink.inspect}" }
end
end
end
subjects_changed
}
end
def stale?
@stale
end
def on_stale(&block)
debug { "added listener: #{block.inspect}" }
@listeners << block
end
def mark_stale
return if stale?
@stale = true
debug { "marked stale, calling listeners: listeners=#{@listeners.inspect}" }
@listeners.each(&:call)
end
def restart
debug { "restarting" }
stop
start
end
def start
raise NotImplementedError
end
def stop
raise NotImplementedError
end
def subjects_changed
raise NotImplementedError
end
end
end
end
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