109 lines
3 KiB
Ruby
109 lines
3 KiB
Ruby
# Copyright (c) 2009 Michael Fellinger m.fellinger@gmail.com
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# Rack::Reloader is subject to the terms of an MIT-style license.
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# See COPYING or http://www.opensource.org/licenses/mit-license.php.
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require 'pathname'
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module Rack
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# High performant source reloader
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#
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# This class acts as Rack middleware.
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#
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# What makes it especially suited for use in a production environment is that
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# any file will only be checked once and there will only be made one system
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# call stat(2).
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#
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# Please note that this will not reload files in the background, it does so
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# only when actively called.
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#
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# It is performing a check/reload cycle at the start of every request, but
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# also respects a cool down time, during which nothing will be done.
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class Reloader
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def initialize(app, cooldown = 10, backend = Stat)
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@app = app
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@cooldown = cooldown
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@last = (Time.now - cooldown)
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@cache = {}
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@mtimes = {}
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extend backend
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end
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def call(env)
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if @cooldown and Time.now > @last + @cooldown
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if Thread.list.size > 1
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Thread.exclusive{ reload! }
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else
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reload!
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end
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@last = Time.now
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end
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@app.call(env)
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end
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def reload!(stderr = $stderr)
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rotation do |file, mtime|
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previous_mtime = @mtimes[file] ||= mtime
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safe_load(file, mtime, stderr) if mtime > previous_mtime
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end
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end
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# A safe Kernel::load, issuing the hooks depending on the results
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def safe_load(file, mtime, stderr = $stderr)
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load(file)
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stderr.puts "#{self.class}: reloaded `#{file}'"
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file
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rescue LoadError, SyntaxError => ex
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stderr.puts ex
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ensure
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@mtimes[file] = mtime
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end
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module Stat
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def rotation
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files = [$0, *$LOADED_FEATURES].uniq
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paths = ['./', *$LOAD_PATH].uniq
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files.map{|file|
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next if file =~ /\.(so|bundle)$/ # cannot reload compiled files
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found, stat = figure_path(file, paths)
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next unless found && stat && mtime = stat.mtime
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@cache[file] = found
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yield(found, mtime)
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}.compact
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end
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# Takes a relative or absolute +file+ name, a couple possible +paths+ that
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# the +file+ might reside in. Returns the full path and File::Stat for the
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# path.
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def figure_path(file, paths)
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found = @cache[file]
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found = file if !found and Pathname.new(file).absolute?
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found, stat = safe_stat(found)
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return found, stat if found
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paths.find do |possible_path|
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path = ::File.join(possible_path, file)
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found, stat = safe_stat(path)
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return ::File.expand_path(found), stat if found
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end
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return false, false
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end
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def safe_stat(file)
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return unless file
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stat = ::File.stat(file)
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return file, stat if stat.file?
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rescue Errno::ENOENT, Errno::ENOTDIR
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@cache.delete(file) and false
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end
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end
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end
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end
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