Class: Chef::ChefFS::PathUtils

Inherits:
Object
  • Object
show all
Defined in:
lib/chef/chef_fs/path_utils.rb

Class Method Summary collapse

Class Method Details

.descendant_path(path, ancestor) ⇒ Object

Given two general OS-dependent file paths, determines the relative path of the child with respect to the ancestor. Both child and ancestor must exist and be fully resolved - this is strictly a lexical comparison. No trailing slashes and other shenanigans are allowed.

TODO: Move this to util/path_helper.


115
116
117
118
119
120
121
122
123
124
125
126
# File 'lib/chef/chef_fs/path_utils.rb', line 115

def self.descendant_path(path, ancestor)
  candidate_fragment = path[0, ancestor.length]
  return nil unless PathUtils.os_path_eq?(candidate_fragment, ancestor)

  if ancestor.length == path.length
    ""
  elsif /#{PathUtils.regexp_path_separator}/.match?(path[ancestor.length, 1])
    path[ancestor.length + 1..-1]
  else
    nil
  end
end

.is_absolute?(path) ⇒ Boolean

Given a server path, determines if it is absolute.

Returns:

  • (Boolean)

65
66
67
# File 'lib/chef/chef_fs/path_utils.rb', line 65

def self.is_absolute?(path)
  !!(path =~ /^#{regexp_path_separator}/)
end

.join(*parts) ⇒ Object

A Chef-FS path is a path in a chef-repository that can be used to address both files on a local file-system as well as objects on a chef server. These paths are stricter than file-system paths allowed on various OSes. Absolute Chef-FS paths begin with "/" (on windows, "\" is acceptable as well). "/" is used as the path element separator (on windows, "\" is acceptable as well). No directory/path element may contain a literal "\" character. Any such characters encountered are either dealt with as separators (on windows) or as escape characters (on POSIX systems). Relative Chef-FS paths may use ".." or "." but may never use these to back-out of the root of a Chef-FS path. Any such extraneous ".."s are ignored. Chef-FS paths are case sensitive (since the paths on the server are). On OSes with case insensitive paths, you may be unable to locally deal with two objects whose server paths only differ by case. OTOH, the case of path segments that are outside the Chef-FS root (such as when looking at a file-system absolute path to discover the Chef-FS root path) are handled in accordance to the rules of the local file-system and OS.


43
44
45
46
47
48
49
50
51
52
53
54
# File 'lib/chef/chef_fs/path_utils.rb', line 43

def self.join(*parts)
  return "" if parts.length == 0

  # Determine if it started with a slash
  absolute = parts[0].length == 0 || parts[0].length > 0 && parts[0] =~ /^#{regexp_path_separator}/
  # Remove leading and trailing slashes from each part so that the join will work (and the slash at the end will go away)
  parts = parts.map { |part| part.gsub(/^#{regexp_path_separator}+|#{regexp_path_separator}+$/, "") }
  # Don't join empty bits
  result = parts.select { |part| part != "" }.join("/")
  # Put the / back on
  absolute ? "/#{result}" : result
end

.os_path_eq?(left, right) ⇒ Boolean

Compares two path fragments according to the case-sensitivity of the host platform.

Returns:

  • (Boolean)

105
106
107
# File 'lib/chef/chef_fs/path_utils.rb', line 105

def self.os_path_eq?(left, right)
  ChefUtils.windows? ? left.casecmp(right) == 0 : left == right
end

.realest_path(path, cwd = Dir.pwd) ⇒ Object

Given a path which may only be partly real (i.e. /x/y/z when only /x exists, or /x/y/*/blah when /x/y/z/blah exists), call File.realpath on the biggest part that actually exists. The paths operated on here are not Chef-FS paths. These are OS paths that may contain symlinks but may not also fully exist.

If /x is a symlink to /foo_bar, and has no subdirectories, then: PathUtils.realest_path('/x/y/z') == '/foo_bar/y/z' PathUtils.realest_path('/x//z') == '/foo_bar//z' PathUtils.realest_path('//y/z') == '//y/z'

TODO: Move this to wherever util/path_helper is these days.


80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
# File 'lib/chef/chef_fs/path_utils.rb', line 80

def self.realest_path(path, cwd = Dir.pwd)
  path = File.expand_path(path, cwd)
  parent_path = File.dirname(path)
  suffix = []

  # File.dirname happens to return the path as its own dirname if you're
  # at the root (such as at \\foo\bar, C:\ or /)
  until parent_path == path
    # This can occur if a path such as "C:" is given.  Ruby gives the parent as "C:."
    # for reasons only it knows.
    raise ArgumentError "Invalid path segment #{path}" if parent_path.length > path.length

    begin
      path = File.realpath(path)
      break
    rescue Errno::ENOENT, Errno::EINVAL
      suffix << File.basename(path)
      path = parent_path
      parent_path = File.dirname(path)
    end
  end
  File.join(path, *suffix.reverse)
end

.regexp_path_separatorObject


60
61
62
# File 'lib/chef/chef_fs/path_utils.rb', line 60

def self.regexp_path_separator
  ChefUtils.windows? ? '[\/\\\\]' : "/"
end

.split(path) ⇒ Object


56
57
58
# File 'lib/chef/chef_fs/path_utils.rb', line 56

def self.split(path)
  path.split(Regexp.new(regexp_path_separator))
end