parsedfile.rb in puppet-3.2.0.rc1

- old
+ new

@@ -101,10 +101,41 @@
 %{# HEADER: This file was autogenerated at #{Time.now}
 # HEADER: by puppet.  While it can still be managed manually, it
 # HEADER: is definitely not recommended.\n}
   end
 
+  # An optional regular expression matched by third party headers.
+  #
+  # For example, this can be used to filter the vixie cron headers as
+  # erronously exported by older cron versions.
+  #
+  # @api private
+  # @abstract Providers based on ParsedFile may implement this to make it
+  #   possible to identify a header maintained by a third party tool.
+  #   The provider can then allow that header to remain near the top of the
+  #   written file, or remove it after composing the file content.
+  #   If implemented, the function must return a Regexp object.
+  #   The expression must be tailored to match exactly one third party header.
+  # @see drop_native_header
+  # @note When specifying regular expressions in multiline mode, avoid
+  #   greedy repititions such as '.*' (use .*? instead). Otherwise, the
+  #   provider may drop file content between sparse headers.
+  def self.native_header_regex
+    nil
+  end
+
+  # How to handle third party headers.
+  # @api private
+  # @abstract Providers based on ParsedFile that make use of the support for
+  #   third party headers may override this method to return +true+.
+  #   When this is done, headers that are matched by the native_header_regex
+  #   are not written back to disk.
+  # @see native_header_regex
+  def self.drop_native_header
+    false
+  end
+
   # Add another type var.
   def self.initvars
     @records = []
     @target_objects = {}
 
@@ -184,41 +215,69 @@
     @records = prefetch_all_targets(resources)
 
     match_providers_with_resources(resources)
   end
 
+  # Match a list of catalog resources with provider instances
+  #
+  # @api private
+  #
+  # @param [Array<Puppet::Resource>] resources A list of resources using this class as a provider
   def self.match_providers_with_resources(resources)
     return unless resources
     matchers = resources.dup
     @records.each do |record|
       # Skip things like comments and blank lines
       next if skip_record?(record)
 
-      if name = record[:name] and resource = resources[name]
+      if (resource = resource_for_record(record, resources))
         resource.provider = new(record)
       elsif respond_to?(:match)
         if resource = match(record, matchers)
-          # Remove this resource from circulation so we don't unnecessarily try to match
           matchers.delete(resource.title)
           record[:name] = resource[:name]
           resource.provider = new(record)
         end
       end
     end
   end
 
+  # Look up a resource based on a parsed file record
+  #
+  # @api private
+  #
+  # @param [Hash<Symbol, Object>] record
+  # @param [Array<Puppet::Resource>] resources
+  #
+  # @return [Puppet::Resource, nil] The resource if found, else nil
+  def self.resource_for_record(record, resources)
+    name = record[:name]
+    if name
+      resources[name]
+    end
+  end
+
   def self.prefetch_all_targets(resources)
     records = []
     targets(resources).each do |target|
       records += prefetch_target(target)
     end
     records
   end
 
   # Prefetch an individual target.
   def self.prefetch_target(target)
-    target_records = retrieve(target).each do |r|
+
+    begin
+      target_records = retrieve(target)
+    rescue Puppet::Util::FileType::FileReadError => detail
+      puts detail.backtrace if Puppet[:trace]
+      Puppet.err "Could not prefetch #{self.resource_type.name} provider '#{self.name}' target '#{target}': #{detail}. Treating as empty"
+      target_records = []
+    end
+
+    target_records.each do |r|
       r[:on_disk] = true
       r[:target] = target
       r[:ensure] = :present
     end
 
@@ -297,11 +356,29 @@
     end
 
     targets.uniq.compact
   end
 
+  # Compose file contents from the set of records.
+  #
+  # If self.native_header_regex is not nil, possible vendor headers are
+  # identified by matching the return value against the expression.
+  # If one (or several consecutive) such headers, are found, they are
+  # either moved in front of the self.header if self.drop_native_header
+  # is false (this is the default), or removed from the return value otherwise.
+  #
+  # @api private
   def self.to_file(records)
     text = super
+    if native_header_regex and (match = text.match(native_header_regex))
+      if drop_native_header
+        # concatenate the text in front of and after the native header
+        text = match.pre_match + match.post_match
+      else
+        native_header = match[0]
+        return native_header + header + match.pre_match + match.post_match
+      end
+    end
     header + text
   end
 
   def create
     @resource.class.validproperties.each do |property|