1 files changed, 132 insertions, 0 deletions
diff --git a/lib/chef/util/file_edit.rb b/lib/chef/util/file_edit.rb
new file mode 100644
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+++ b/lib/chef/util/file_edit.rb
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+#
+# Author:: Nuo Yan (<nuo@opscode.com>)
+# Copyright:: Copyright (c) 2009 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+require 'fileutils'
+require 'tempfile'
+
+class Chef
+  class Util
+    class FileEdit
+
+      private
+
+      attr_accessor :original_pathname, :contents, :file_edited
+
+      public
+
+      def initialize(filepath)
+        @original_pathname = filepath
+        @file_edited = false
+
+        raise ArgumentError, "File doesn't exist" unless File.exist? @original_pathname
+        raise ArgumentError, "File is blank" unless (@contents = File.new(@original_pathname).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', 1)
+      end
+
+      #search the file line by line and match each line with the given regex
+      #if not matched, insert newline at the end of the file
+      def insert_line_if_no_match(regex, newline)
+        search_match(regex, newline, 'i', 2)
+      end
+
+      #Make a copy of old_file and write new file out (only if file changed)
+      def write_file
+
+        # file_edited is false when there was no match in the whole file and thus no contents have changed.
+        if file_edited
+          backup_pathname = original_pathname + ".old"
+          FileUtils.cp(original_pathname, backup_pathname, :preserve => true)
+          File.open(original_pathname, "w") do |newfile|
+            contents.each do |line|
+              newfile.puts(line)
+            end
+            newfile.flush
+          end
+        end
+        self.file_edited = false
+      end
+
+      private
+
+      #helper method to do the match, replace, delete, and insert operations
+      #command is the switch of delete, replace, and insert ('d', 'r', 'i')
+      #method is to control operation on whole line or only the match (1 for line, 2 for match)
+      def search_match(regex, replace, command, method)
+
+        #convert regex to a Regexp object (if not already is one) and store it in exp.
+        exp = Regexp.new(regex)
+
+        #loop through contents and do the appropriate operation depending on 'command' and 'method'
+        new_contents = []
+
+        contents.each do |line|
+          if line.match(exp)
+            self.file_edited = true
+            case
+            when command == 'r'
+              new_contents << ((method == 1) ? replace : line.gsub!(exp, replace))
+            when command == 'd'
+              if method == 2
+                new_contents << line.gsub!(exp, "")
+              end
+            when command == 'i'
+              new_contents << line
+              new_contents << replace unless method == 2
+            end
+          else
+            new_contents << line
+          end
+        end
+        if command == 'i' && method == 2 && ! file_edited
+          new_contents << replace
+          self.file_edited = true
+        end
+
+        self.contents = new_contents
+      end
+    end
+  end
+end