Update VM import for VirtualBox 6 driver

The dry run import with VirtualBox 6 no longer provides full paths
for disks. Extract base path from suggested settings file location
and use that to generate full path name using provided disk base
name.

plugins/providers/virtualbox/driver/version_6_0.rb

@@ -10,6 +10,95 @@ module VagrantPlugins
 
           @logger = Log4r::Logger.new("vagrant::provider::virtualbox_6_0")
         end
+
+        def import(ovf)
+          ovf = Vagrant::Util::Platform.windows_path(ovf)
+
+          output = ""
+          total = ""
+          last  = 0
+
+          # Dry-run the import to get the suggested name and path
+          @logger.debug("Doing dry-run import to determine parallel-safe name...")
+          output = execute("import", "-n", ovf)
+          result = /Suggested VM name "(.+?)"/.match(output)
+          if !result
+            raise Vagrant::Errors::VirtualBoxNoName, output: output
+          end
+          suggested_name = result[1].to_s
+
+          # Append millisecond plus a random to the path in case we're
+          # importing the same box elsewhere.
+          specified_name = "#{suggested_name}_#{(Time.now.to_f * 1000.0).to_i}_#{rand(100000)}"
+          @logger.debug("-- Parallel safe name: #{specified_name}")
+
+          # Build the specified name param list
+          name_params = [
+            "--vsys", "0",
+            "--vmname", specified_name,
+          ]
+
+          # Target path for disks is no longer a full path. Extract the path for the
+          # settings file to determine the base directory which we can then use to
+          # build the disk paths
+          result = /Suggested VM settings file name "(?<settings_path>.+?)"/.match(output)
+          if !result
+            @logger.warn("Failed to locate base path for disks. Using current working directory.")
+            base_path = "."
+          else
+            base_path = File.dirname(result[:settings_path])
+          end
+
+          @logger.info("Base path for disk import: #{base_path}")
+
+          # Extract the disks list and build the disk target params
+          disk_params = []
+          disks = output.scan(/(\d+): Hard disk image: source image=.+, target path=(.+),/)
+          disks.each do |unit_num, path|
+            path = File.join(base_path, File.basename(path))
+            disk_params << "--vsys"
+            disk_params << "0"
+            disk_params << "--unit"
+            disk_params << unit_num
+            disk_params << "--disk"
+            if Vagrant::Util::Platform.windows?
+              # we use the block form of sub here to ensure that if the specified_name happens to end with a number (which is fairly likely) then
+              # we won't end up having the character sequence of a \ followed by a number be interpreted as a back reference.  For example, if
+              # specified_name were "abc123", then "\\abc123\\".reverse would be "\\321cba\\", and the \3 would be treated as a back reference by the sub
+              disk_params << path.reverse.sub("\\#{suggested_name}\\".reverse) { "\\#{specified_name}\\".reverse }.reverse # Replace only last occurrence
+            else
+              disk_params << path.reverse.sub("/#{suggested_name}/".reverse, "/#{specified_name}/".reverse).reverse # Replace only last occurrence
+            end
+          end
+
+          execute("import", ovf , *name_params, *disk_params, retryable: true) do |type, data|
+            if type == :stdout
+              # Keep track of the stdout so that we can get the VM name
+              output << data
+            elsif type == :stderr
+              # Append the data so we can see the full view
+              total << data.gsub("\r", "")
+
+              # Break up the lines. We can't get the progress until we see an "OK"
+              lines = total.split("\n")
+              if lines.include?("OK.")
+                # The progress of the import will be in the last line. Do a greedy
+                # regular expression to find what we're looking for.
+                match = /.+(\d{2})%/.match(lines.last)
+                if match
+                  current = match[1].to_i
+                  if current > last
+                    last = current
+                    yield current if block_given?
+                  end
+                end
+              end
+            end
+          end
+
+          return get_machine_id specified_name
+        end
+
       end
     end
   end