Class: FileWatcher

Inherits:
Object
  • Object
show all
Defined in:
lib/file_watcher.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(files = nil, options = {}) ⇒ FileWatcher

Returns a new instance of FileWatcher.



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# File 'lib/file_watcher.rb', line 4

def initialize(files = nil, options = {})    
    @files = files || ['./*']
    @changed = nil
    @event = nil
    if not @files.empty?
        @snapshot = snapshot_filesystem
    end
    @options = options
end

Instance Attribute Details

#changed ⇒ Object (readonly)

Returns the value of attribute changed.



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# File 'lib/file_watcher.rb', line 2

def changed
  @changed
end

#event ⇒ Object (readonly)

Returns the value of attribute event.



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# File 'lib/file_watcher.rb', line 2

def event
  @event
end

#snapshot ⇒ Object (readonly)

Returns the value of attribute snapshot.



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# File 'lib/file_watcher.rb', line 2

def snapshot
  @snapshot
end

Instance Method Details

#files_changed? ⇒ Boolean

have the given files changed if they have then set the changed file and return true

Returns:

  • (Boolean) 


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# File 'lib/file_watcher.rb', line 36

def files_changed?
    # initialise variables for the 
    new_snapshot = snapshot_filesystem
    has_changed = false

    # take a new snapshot and subtract this from the old snapshot in order to get forward changes
    # then add the snapshot to the oposite subtraction to get backward changes
    changes = (@snapshot.to_a - new_snapshot.to_a) + (new_snapshot.to_a - @snapshot.to_a)
    
    # determine the event for each change
    changes.each do |change|
        if @snapshot.keys.include? change[0]
            @changed = {change[0] => change[1]}
            @event = (new_snapshot.keys.include? change[0]) ? :change : :delete
            has_changed = true
        else
            @changed = {change[0] => change[1]}
            @event = :new
            has_changed = true
        end
    end
    
    # lets reset the snapshot so that we don't create a forever loop
    @snapshot = new_snapshot

    return has_changed
end

#set_files(files) ⇒ Object 



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# File 'lib/file_watcher.rb', line 14

def set_files(files)
    @files = files
    @snapshot = snapshot_filesystem
end

#snapshot_filesystem ⇒ Object

take a snapshot of the given files so we can compare at a given date



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# File 'lib/file_watcher.rb', line 20

def snapshot_filesystem
    mtimes = {}

    files = @files.map { |file| Dir[file] }.flatten.uniq

    files.each do |file|
        if File.exists? file
            mtimes[file] = File.stat(file).mtime
        end
    end

    mtimes
end

#watch(have_changed, waiting = nil) ⇒ Object

watching the files given in initialize if the files change call the proc



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# File 'lib/file_watcher.rb', line 65

def watch(have_changed, waiting = nil)
    @watching = true

    while @watching
        if files_changed?
            @watching = have_changed.call(@changed, @event)
        end

        sleep(1)

        waiting.call if waiting
    end
end