Added a path helper to determine the home directory.

1 files changed, 76 insertions, 0 deletions

diff --git a/lib/chef/util/path_helper.rb b/lib/chef/util/path_helper.rb
index 1ae489598d..17c7175331 100644
--- a/lib/chef/util/path_helper.rb
+++ b/lib/chef/util/path_helper.rb
@@ -142,6 +142,82 @@ class Chef
       def self.relative_path_from(from, to)
         pathname = Pathname.new(Chef::Util::PathHelper.cleanpath(to)).relative_path_from(Pathname.new(Chef::Util::PathHelper.cleanpath(from)))
       end
+
+      # Retrieves the "home directory" of the current user while trying to ascertain the existence
+      # of said directory.  The path returned uses / for all separators (the ruby standard format).
+      # If the home directory doesn't exist or an error is otherwise encountered, nil is returned.
+      # 
+      # If a set of path elements is provided, they are appended as-is to the home path if the
+      # homepath exists. 
+      # 
+      # If an optional block is provided, the joined path is passed to that block if the home path is
+      # valid and the result of the block is returned instead.
+      #
+      # Home-path discovery is performed once.  If a path is discovered, that value is memoized so
+      # that subsequent calls to home_dir don't bounce around.
+      #
+      # See self.all_homes.
+      def self.home(*args)
+        @@home_dir ||= self.all_homes { |p| break p }
+        if @@home_dir
+          path = File.join(@@home_dir, *args)
+          block_given? ? (yield path) : path
+        end
+      end
+
+      # See self.home.  This method performs a similar operation except that it yields all the different
+      # possible values of 'HOME' that one could have on this platform.  Hence, on windows, if
+      # HOMEDRIVE\HOMEPATH and USERPROFILE are different, the provided block will be called twice.
+      # This method goes out and checks the existence of each location at the time of the call.
+      #
+      # The return is a list of all the returned values from each block invocation or a list of paths
+      # if no block is provided.
+      def self.all_homes(*args)
+        paths = []
+        if Chef::Platform.windows?
+          # By default, Ruby uses the the following environment variables to determine Dir.home:
+          # HOME
+          # HOMEDRIVE HOMEPATH
+          # USERPROFILE
+          # Ruby only checks to see if the variable is specified - not if the directory actually exists.
+          # On Windows, HOMEDRIVE HOMEPATH can point to a different location (such as an unavailable network mounted drive)
+          # while USERPROFILE points to the location where the user application settings and profile are stored.  HOME
+          # is not defined as an environment variable (usually).  If the home path actually uses UNC, then the prefix is
+          # HOMESHARE instead of HOMEDRIVE.
+          #
+          # We instead walk down the following and only include paths that actually exist.
+          # HOME
+          # HOMEDRIVE HOMEPATH
+          # HOMESHARE HOMEPATH
+          # USERPROFILE
+
+          paths << ENV['HOME']
+          paths << ENV['HOMEDRIVE'] + ENV['HOMEPATH'] if ENV['HOMEDRIVE'] && ENV['HOMEPATH']
+          paths << ENV['HOMESHARE'] + ENV['HOMEPATH'] if ENV['HOMESHARE'] && ENV['HOMEPATH']
+          paths << ENV['USERPROFILE']
+        end
+        paths << Dir.home
+
+        # Depending on what environment variables we're using, the slashes can go in any which way.
+        # Just change them all to / to keep things consistent.
+        # Note: Maybe this is a bad idea on some unixy systems where \ might be a valid character depending on
+        # the particular brand of kool-aid you consume.  This code assumes that \ and / are both
+        # path separators on any system being used.
+        paths = paths.map { |home_path| home_path.gsub(path_separator, ::File::SEPARATOR) if home_path }
+        
+        # Filter out duplicate paths and paths that don't exist.
+        valid_paths = paths.select { |home_path| home_path && Dir.exists?(home_path) }
+        valid_paths = valid_paths.uniq
+        
+        # Join all optional path elements at the end.
+        # If a block is provided, invoke it - otherwise just return what we've got.
+        joined_paths = valid_paths.map { |home_path| File.join(home_path, *args) }
+        if block_given?
+          joined_paths.each { |p| yield p }
+        else
+          joined_paths
+        end
+      end
     end
   end
 end