From: Alan Davies <NOSPAMcs96and@...>
Date: 2003-09-23T02:10:36+09:00
Subject: Re: Dir.foreach not with patterns?

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> Attatched.  Its faster at most things than Dir#[].  I think the reason 
> it is faster is because it never actually changes the working directory.

And again.  This one has much faster implementations of each_filename 
and each_dirname, by doing the regexp before doing the file/directory test.

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# Filescan.rb
#
# Class to recursively scan through files from a given dir.
#
# Copyright (C) 2003 by Alan Davies
#
# This software is provided 'as-is', without any express or implied
# warranty.  In no event will the authors be held liable for any damages
# arising from the use of this software.
#
# Permission is granted to anyone to use this software for any purpose,
# including commercial applications, and to alter it and redistribute it
# freely, subject to the following restrictions:
#
# 1. The origin of this software must not be misrepresented; you must not
#    claim that you wrote the original software. If you use this software
#    in a product, an acknowledgment in the product documentation would be
#    appreciated but is not required.
# 2. Altered source versions must be plainly marked as such, and must not be
#    misrepresented as being the original software.
# 3. This notice may not be removed or altered from any source distribution.

class Filescan
   include Enumerable

   @@dotDir = /^\.\.?$/

   def initialize(dir='.', recursive=true, verbose=false)
      @startDir = dir
      @recursive = recursive
      @verbose = verbose

      yield self if block_given?
   end

   attr_accessor :startDir, :recursive, :verbose

   def each(startDir=@startDir, &block)
      puts startDir if @verbose
      begin
         Dir.open(startDir) do |dir|
            dir.each do |entry|
               next if entry =~ @@dotDir
               yield (fullPath = File.expand_path(entry, startDir))
               self.each(fullPath, &block) if @recursive and File.directory?(fullPath)
            end
         end
      rescue Errno::EINVAL, Errno::ENOENT
         $stderr.puts "Can't open dir: #{startDir}"
         return
      end
   end # def each

   # Executes a block for each directory name
   def each_dirname(pattern=//)
      self.each { |dirName| yield dirName if (dirName =~ pattern) and File.directory?(dirName) }
   end

   # Executes a block for each directory
   def each_dir(pattern=//)
      each_dirname(pattern) do |dirName|
         Dir.open(dirName) { |dirHandle| yield dirHandle, dirName }
      end
   end

   # Execute a block for each filename
   def each_filename(pattern=//)
      self.each { |fileName| yield fileName if (fileName =~ pattern) and File.file?(fileName) }
   end

   # Execute a block for each file
   def each_file(mode='r', pattern=//)
      self.each_filename(pattern) do |filename|
         File.open(filename, mode) { |file| yield file, filename }
      end
   end

   # Executes a block for each line of each file.
   # If the files are opened in writable mode, then the block must return the
   # no of changes that were made to the line.
   # Files are not written back to the disk if no lines are altered.
   def each_line(writable=false, pattern=//)
      self.each_file(writable ? 'r+' : 'r', pattern) do |file, filename|
         fileChanges = lineChanges = len = 0
         text = file.readlines

         # Yield the block for each line in the file
         text.each do |line|
            lineChanges = yield(line, filename)
            fileChanges += lineChanges if writable
         end

         # Write the file back to disk
         if writable and (fileChanges > 0)
            puts "#{filename} - #{fileChanges} changes made"
            file.rewind
            file.syswrite(text)
            file.truncate(file.pos)
         end
      end # self.eachfile
   end # def each_line

end # class Filescan
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