Class: RGen::Util::FileChangeDetector

Inherits:
Object
  • Object
show all
Defined in:
lib/rgen/util/file_change_detector.rb

Overview

The FileChangeDetector detects changes in a set of files. Changes are detected between successive calls to check_files with a give set of files. Changes include files being added, removed or having changed their content.

Defined Under Namespace

Classes: FileInfo

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ FileChangeDetector

Create a FileChangeDetector, options include:

:file_added
  a proc which is called when a file is added, receives the filename

:file_removed
  a proc which is called when a file is removed, receives the filename

:file_changed
  a proc which is called when a file is changed, receives the filename



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# File 'lib/rgen/util/file_change_detector.rb', line 26

def initialize(options={})
  @file_added = options[:file_added]
  @file_removed = options[:file_removed]
  @file_changed = options[:file_changed]
  @file_info = {}
end

Instance Method Details

#check_files(files) ⇒ Object

Checks if any of the files has changed compared to the last call of check_files. When called for the first time on a new object, all files will be reported as being added.



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# File 'lib/rgen/util/file_change_detector.rb', line 36

def check_files(files)
  files_before = @file_info.keys
  used_files = {} 
  files.each do |file|
    begin
      if @file_info[file]
        if @file_info[file].timestamp != File.mtime(file)
          @file_info[file].timestamp = File.mtime(file)
          digest = calc_digest(file)
          if @file_info[file].digest != digest
            @file_info[file].digest = digest 
            @file_changed && @file_changed.call(file)
          end
        end
      else
        @file_info[file] = FileInfo.new
        @file_info[file].timestamp = File.mtime(file)
        @file_info[file].digest = calc_digest(file)
        @file_added && @file_added.call(file)
      end
      used_files[file] = true
    # protect against missing files
    rescue Errno::ENOENT
      # used_files is not set and @file_info will be removed below
      # notification hook hasn't been called yet since it comes after file accesses
    end
  end
  files_before.each do |file|
    if !used_files[file]
      @file_info.delete(file)
      @file_removed && @file_removed.call(file)
    end
  end
end