Class: Rubyfocus::Patch

Inherits:
Object
  • Object
show all
Defined in:
lib/rubyfocus/patch.rb

Overview

The patch class represents a text-file patch, storing update, delete, and creation operations. It should also be able to apply itself to an existing document.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fetcher = nil, file = nil) ⇒ Patch

By default we initialize patches from a file. To initialize from a string, use the .from_string method. This class will lazily load data from the file proper



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# File 'lib/rubyfocus/patch.rb', line 21

def initialize(fetcher=nil, file=nil)
	@fetcher = fetcher
	@file = file
	@update = []
	@create = []
	@delete = []

	if file 
		if File.basename(file) =~ /^(\d+)=(.*)\./
			time_string = $1
			self.time = if (time_string == "00000000000000")
				Time.at(0)
			else
				Time.parse(time_string)
			end

			ids 					= $2.split("+")
			self.to_id 		= ids.pop
			self.from_ids = ids
		else
			raise ArgumentError, "Constructed patch from a malformed patch file: #{file}."
		end
	end
end

Instance Attribute Details

#create ⇒ Object

Operations to be performed on a document



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# File 'lib/rubyfocus/patch.rb', line 8

def create
  @create
end

#delete ⇒ Object

Operations to be performed on a document



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# File 'lib/rubyfocus/patch.rb', line 8

def delete
  @delete
end

#fetcher ⇒ Object

The fetcher this patch belongs to. We mainly use this to work out how to fetch content for the patch proper



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# File 'lib/rubyfocus/patch.rb', line 5

def fetcher
  @fetcher
end

#file ⇒ Object

The file the patch loads from



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# File 'lib/rubyfocus/patch.rb', line 11

def file
  @file
end

#from_ids ⇒ Object

These record the transformation in terms of patch ID values.



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# File 'lib/rubyfocus/patch.rb', line 14

def from_ids
  @from_ids
end

#time ⇒ Object

The time the file was submitted



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# File 'lib/rubyfocus/patch.rb', line 17

def time
  @time
end

#to_id ⇒ Object

These record the transformation in terms of patch ID values.



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# File 'lib/rubyfocus/patch.rb', line 14

def to_id
  @to_id
end

#update ⇒ Object

Update, delete and create methods



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# File 'lib/rubyfocus/patch.rb', line 8

def update
  @update
end

Class Method Details

.from_string(fetcher, str) ⇒ Object

Load from a string.



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# File 'lib/rubyfocus/patch.rb', line 47

def self.from_string(fetcher, str)
	n = new(fetcher)
	n.load_data(str)
	n
end

Instance Method Details

#apply_to(document) ⇒ Object

Apply this patch to a document. Check to make sure ids match



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# File 'lib/rubyfocus/patch.rb', line 87

def apply_to(document)
	if can_patch?(document)
		apply_to!(document)
	else
		raise RuntimeError, "Patch ID mismatch (patch from_ids: [#{self.from_ids.join(", ")}], document.patch_id: #{document.patch_id}"
	end
end

#apply_to!(document) ⇒ Object

Apply this patch to a document. Who needs error checking amirite?



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# File 'lib/rubyfocus/patch.rb', line 96

def apply_to!(document)
	# Updates modify elements
	self.update.each do |node|
		elem = document[node["id"]]

		# Tasks can become projects and v.v.: check this.
		if [Rubyfocus::Task, Rubyfocus::Project].include?(elem.class)
			should_be_project = (node.at_xpath("xmlns:project") != nil)
			if (elem.class == Rubyfocus::Project) && !should_be_project
				elem.document = nil # Remove this from current document
				elem = elem.to_task # Convert to task
				elem.document = document # Insert again!
			elsif (elem.class == Rubyfocus::Task) && should_be_project
				elem.document = nil # Remove this from current document
				elem = elem.to_project # Convert to task
				elem.document = document # Insert again!
			end
		end

		elem.apply_xml(node) if elem
	end

	# Deletes remove elements
	self.delete.each do |node|
		document.remove_element(node["id"])
	end

	# Creates make new elements
	self.create.each do |node|
		if Rubyfocus::Parser.parse(document, node).nil?
			raise RuntimeError, "Encountered unparsable XML during patch reading: #{node}."
		end
	end

	# Modify current patch_id to show new value
	document.patch_id = self.to_id
end

#can_patch?(document) ⇒ Boolean

Can we apply this patch to a given document?

Returns:

  • (Boolean) 


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# File 'lib/rubyfocus/patch.rb', line 82

def can_patch?(document)
	self.from_ids.include?(document.patch_id)
end

#load_data(str = nil) ⇒ Object

Loads data from the file. Optional argument str if you want to supply your own data, otherwise will load file data



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# File 'lib/rubyfocus/patch.rb', line 55

def load_data(str=nil)
	return if @data_loaded
	@data_loaded = true

	str ||= fetcher.patch(self.file)
  doc = Nokogiri::XML(str)
  doc.root.children.select{ |n| !n.text?}.each do |child|
  	case child["op"]
  	when "update"
  		@update << child
  	when "delete"
  		@delete << child
  	when "reference" # Ignore!
  	when nil
  		@create << child
  	else
  		raise RuntimeError, "Rubyfocus::Patch encountered unknown operation type #{child["op"]}."
  	end
  end
end

#to_s ⇒ Object

String representation



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# File 'lib/rubyfocus/patch.rb', line 135

def to_s
	if from_ids.size == 1
		"(#{from_ids.first} -> #{to_id})"
	else
		"([#{from_ids.join(", ")}] -> #{to_id})"
	end
end