initial work chef-78

Author: Nuo Yan

chef/lib/chef/util/FileEdit.rb

@@ -0,0 +1,113 @@
+class FileEdit
+  
+  require 'ftools'
+
+  private
+  attr_accessor :filename, :contents, :match
+
+  public
+  
+  def initialize(filepath)
+    @filename = filepath
+    @contents = Array.new
+    @match = false
+    
+
+    raise ArgumentError, "File doesn't exist" unless (ret = File.exist? @filename)
+
+    f = File.new(@filename)
+    raise ArgumentError, "File is blank" unless (@contents = f.readlines).length > 0
+    
+  end
+  
+
+  #search the file line by line and match each line with the given regex
+  #if matched, replace the whole line with newline.
+  def search_file_replace_line(regex, newline)
+    search_match(regex, newline, 'r', 1)
+  end
+
+  #search the file line by line and match each line with the given regex
+  #if matched, replace the match (all occurances)  with the replace parameter
+  def search_file_replace(regex, replace)
+    search_match(regex, replace, 'r', 2)
+  end
+  
+  #search the file line by line and match each line with the given regex
+  #if matched, delete the line
+  def search_file_delete_line(regex)
+    search_match(regex, " ", 'd', 1)
+  end
+  
+  #search the file line by line and match each line with the given regex
+  #if matched, delete the match (all occurances) from the line
+  def search_file_delete(regex)
+    search_match(regex, " ", 'd', 2)
+  end
+
+  #search the file line by line and match each line with the given regex
+  #if matched, insert newline after each matching line
+  def insert_line_after_match(regex, newline)
+    search_match(regex, newline, 'i', 0)
+  end
+   
+  #Make a copy of old_file and write new file out (only if file changed)
+  def write_file
+    # @match is false when there is no match in the whole file. Nothing need to be done.
+    if @match == true
+      File.copy(@filename, @filename + ".old")
+      newfile = File.new("temp", "w")
+      @contents.each() do |line|
+        newfile.puts(line)
+      end
+      newfile.close
+      File.rename("temp", @filename)
+    end
+    @match = false
+  end
+
+    #helper method to search_file_replace_delete_line, search_file_replace_delete, and insert_line_after_match
+  def search_match(regex, replace, command, method)
+
+    raise ArgumentError, "command should be 'r' or 'd'" unless (command == 'r' or command == 'd' or command == 'i')
+  
+    #check if regex is Regexp object or simple string and store the Regexp object in exp.
+    (regex.kind_of? Regexp)? exp = regex : exp = Regexp.new(regex)
+    
+    i = 0
+    begin
+      line = @contents[i]
+      if line =~ exp
+        @match = true
+        case
+        when command == 'r'
+          (method == 1)? @contents[i] = replace: @contents[i].gsub!(exp, replace)
+        when command == 'd'
+          if method == 1
+            @contents.delete_at(i)
+            i = i - 1
+          else
+            @contents[i].gsub!(exp, "")
+          end
+        when command == 'i'
+          @contents.insert(i+1, replace)
+        end
+      end
+      i = i+1
+    end until i == @contents.length
+  end
+
+  
+end
+
+#test
+if __FILE__ == $0
+  fedit = FileEdit.new("test")
+  
+  fedit.insert_line_after_match(/test/, "new Line Inserted")
+  fedit.search_file_replace(/test/, "replace")
+  fedit.search_file_replace_line(/replace/, "this line is replaced")
+  fedit.search_file_delete(/this/)
+  fedit.search_file_delete_line(/new/)
+  fedit.write_file()
+end