CHEF-3714: New object dedicated to manipulating text

2 files changed, 244 insertions, 0 deletions

diff --git a/lib/chef/util/editor.rb b/lib/chef/util/editor.rb
new file mode 100644
index 0000000000..973cf48e30
--- /dev/null
+++ b/lib/chef/util/editor.rb
@@ -0,0 +1,92 @@
+#
+# Author:: Chris Bandy (<bandy.chris@gmail.com>)
+# Copyright:: Copyright (c) 2014 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.
+#
+
+class Chef
+  class Util
+    class Editor
+      attr_reader :lines
+
+      def initialize(lines)
+        @lines = lines.to_a.clone
+      end
+
+      def append_line_after(search, line_to_append)
+        lines = []
+
+        @lines.each do |line|
+          lines << line
+          lines << line_to_append if line.match(search)
+        end
+
+        (lines.length - @lines.length).tap { @lines = lines }
+      end
+
+      def append_line_if_missing(search, line_to_append)
+        count = 0
+
+        unless @lines.find { |line| line.match(search) }
+          count = 1
+          @lines << line_to_append
+        end
+
+        count
+      end
+
+      def remove_lines(search)
+        count = 0
+
+        @lines.delete_if do |line|
+          count += 1 if line.match(search)
+        end
+
+        count
+      end
+
+      def replace(search, replace)
+        count = 0
+
+        @lines.map! do |line|
+          if line.match(search)
+            count += 1
+            line.gsub!(search, replace)
+          else
+            line
+          end
+        end
+
+        count
+      end
+
+      def replace_lines(search, replace)
+        count = 0
+
+        @lines.map! do |line|
+          if line.match(search)
+            count += 1
+            replace
+          else
+            line
+          end
+        end
+
+        count
+      end
+    end
+  end
+end
+
diff --git a/spec/unit/util/editor_spec.rb b/spec/unit/util/editor_spec.rb
new file mode 100644
index 0000000000..06370f7de0
--- /dev/null
+++ b/spec/unit/util/editor_spec.rb
@@ -0,0 +1,152 @@
+require 'spec_helper'
+require 'chef/util/editor'
+
+describe Chef::Util::Editor do
+  describe '#initialize' do
+    it 'takes an Enumerable of lines' do
+      editor = described_class.new(File.open(__FILE__))
+      expect(editor.lines).to be == IO.readlines(__FILE__)
+    end
+
+    it 'makes a copy of an Array' do
+      array = Array.new
+      editor = described_class.new(array)
+      expect(editor.lines).to_not be(array)
+    end
+  end
+
+  subject(:editor) { described_class.new(input_lines) }
+  let(:input_lines) { ['one', 'two', 'two', 'three'] }
+
+  describe '#append_line_after' do
+    context 'when there is no match' do
+      subject(:execute) { editor.append_line_after('missing', 'new') }
+
+      it('returns the number of added lines') { should be == 0 }
+      it 'does not add any lines' do
+        expect { execute }.to_not change { editor.lines }
+      end
+    end
+
+    context 'when there is a match' do
+      subject(:execute) { editor.append_line_after('two', 'new') }
+
+      it('returns the number of added lines') { should be == 2 }
+      it 'adds a line after each match' do
+        execute
+        expect(editor.lines).to be == ['one', 'two', 'new', 'two', 'new', 'three']
+      end
+    end
+
+    it 'matches a Regexp' do
+      expect(editor.append_line_after(/^ee/, 'new')).to be == 0
+      expect(editor.append_line_after(/ee$/, 'new')).to be == 1
+    end
+  end
+
+  describe '#append_line_if_missing' do
+    context 'when there is no match' do
+      subject(:execute) { editor.append_line_if_missing('missing', 'new') }
+
+      it('returns the number of added lines') { should be == 1 }
+      it 'adds a line to the end' do
+        execute
+        expect(editor.lines).to be == ['one', 'two', 'two', 'three', 'new']
+      end
+    end
+
+    context 'when there is a match' do
+      subject(:execute) { editor.append_line_if_missing('one', 'new') }
+
+      it('returns the number of added lines') { should be == 0 }
+      it 'does not add any lines' do
+        expect { execute }.to_not change { editor.lines }
+      end
+    end
+
+    it 'matches a Regexp' do
+      expect(editor.append_line_if_missing(/ee$/, 'new')).to be == 0
+      expect(editor.append_line_if_missing(/^ee/, 'new')).to be == 1
+    end
+  end
+
+  describe '#remove_lines' do
+    context 'when there is no match' do
+      subject(:execute) { editor.remove_lines('missing') }
+
+      it('returns the number of removed lines') { should be == 0 }
+      it 'does not remove any lines' do
+        expect { execute }.to_not change { editor.lines }
+      end
+    end
+
+    context 'when there is a match' do
+      subject(:execute) { editor.remove_lines('two') }
+
+      it('returns the number of removed lines') { should be == 2 }
+      it 'removes the matching lines' do
+        execute
+        expect(editor.lines).to be == ['one', 'three']
+      end
+    end
+
+    it 'matches a Regexp' do
+      expect(editor.remove_lines(/^ee/)).to be == 0
+      expect(editor.remove_lines(/ee$/)).to be == 1
+    end
+  end
+
+  describe '#replace' do
+    context 'when there is no match' do
+      subject(:execute) { editor.replace('missing', 'new') }
+
+      it('returns the number of changed lines') { should be == 0 }
+      it 'does not change any lines' do
+        expect { execute }.to_not change { editor.lines }
+      end
+    end
+
+    context 'when there is a match' do
+      subject(:execute) { editor.replace('two', 'new') }
+
+      it('returns the number of changed lines') { should be == 2 }
+      it 'replaces the matching portions' do
+        execute
+        expect(editor.lines).to be == ['one', 'new', 'new', 'three']
+      end
+    end
+
+    it 'matches a Regexp' do
+      expect(editor.replace(/^ee/, 'new')).to be == 0
+      expect(editor.replace(/ee$/, 'new')).to be == 1
+      expect(editor.lines).to be == ['one', 'two', 'two', 'thrnew']
+    end
+  end
+
+  describe '#replace_lines' do
+    context 'when there is no match' do
+      subject(:execute) { editor.replace_lines('missing', 'new') }
+
+      it('returns the number of changed lines') { should be == 0 }
+      it 'does not change any lines' do
+        expect { execute }.to_not change { editor.lines }
+      end
+    end
+
+    context 'when there is a match' do
+      subject(:execute) { editor.replace_lines('two', 'new') }
+
+      it('returns the number of replaced lines') { should be == 2 }
+      it 'replaces the matching line' do
+        execute
+        expect(editor.lines).to be == ['one', 'new', 'new', 'three']
+      end
+    end
+
+    it 'matches a Regexp' do
+      expect(editor.replace_lines(/^ee/, 'new')).to be == 0
+      expect(editor.replace_lines(/ee$/, 'new')).to be == 1
+      expect(editor.lines).to be == ['one', 'two', 'two', 'new']
+    end
+  end
+end