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Diffstat (limited to 'lib/chef/util/diff.rb')
| -rw-r--r-- | lib/chef/util/diff.rb | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/lib/chef/util/diff.rb b/lib/chef/util/diff.rb new file mode 100644 index 0000000000..72459642de --- /dev/null +++ b/lib/chef/util/diff.rb @@ -0,0 +1,103 @@ +# Author:: Lamont Granquist (<lamont@opscode.com>) +# Copyright:: Copyright (c) 2013 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 'chef/mixin/shell_out' + +class Chef + class Util + class Diff + include Chef::Mixin::ShellOut + + def for_output + # formatted output to a terminal uses arrays of strings and returns error strings + @diff.nil? ? [ @error ] : @diff + end + + def for_reporting + # caller needs to ensure that new files aren't posted to resource reporting + return nil if @diff.nil? + @diff.join("\\n") + end + + def diff(old_file, new_file) + # indicates calling code bug: caller is reponsible for making certain both + # files exist + raise "old file #{old_file} does not exist" unless File.exists?(old_file) + raise "new file #{new_file} does not exist" unless File.exists?(new_file) + @error = catch (:nodiff) do + do_diff(old_file, new_file) + end + end + + private + + def do_diff(old_file, new_file) + if Chef::Config[:diff_disabled] + throw :nodiff, "(diff output suppressed by config)" + end + + diff_filesize_threshold = Chef::Config[:diff_filesize_threshold] + diff_output_threshold = Chef::Config[:diff_output_threshold] + + if ::File.size(old_file) > diff_filesize_threshold || ::File.size(new_file) > diff_filesize_threshold + throw :nodiff, "(file sizes exceed #{diff_filesize_threshold} bytes, diff output suppressed)" + end + + # MacOSX(BSD?) diff will *sometimes* happily spit out nasty binary diffs + throw :nodiff, "(current file is binary, diff output suppressed)" if is_binary?(old_file) + throw :nodiff, "(new content is binary, diff output suppressed)" if is_binary?(new_file) + + begin + # -u: Unified diff format + result = shell_out("diff -u #{old_file} #{new_file}") + rescue Exception => e + # Should *not* receive this, but in some circumstances it seems that + # an exception can be thrown even using shell_out instead of shell_out! + throw :nodiff, "Could not determine diff. Error: #{e.message}" + end + + # diff will set a non-zero return code even when there's + # valid stdout results, if it encounters something unexpected + # So as long as we have output, we'll show it. + if not result.stdout.empty? + if result.stdout.length > diff_output_threshold + throw :nodiff, "(long diff of over #{diff_output_threshold} characters, diff output suppressed)" + else + @diff = result.stdout.split("\n") + @diff.delete("\\ No newline at end of file") + # XXX: successful return of the diff is here, we return nil as no error... ugh... + return nil + end + elsif not result.stderr.empty? + throw :nodiff, "Could not determine diff. Error: #{result.stderr}" + else + throw :nodiff, "(no diff)" + end + end + + def is_binary?(path) + ::File.open(path) do |file| + buff = file.read(Chef::Config[:diff_filesize_threshold]) + buff = "" if buff.nil? + return buff !~ /^[\r[:print:]]*$/ + end + end + + end + end +end + |