Class: Rubyfocus::Patch

Inherits:
Object
  • Object
show all
Includes:
Comparable
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 22

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 9

def create
  @create
end

#delete ⇒ Object

Operations to be performed on a document



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# File 'lib/rubyfocus/patch.rb', line 9

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 6

def fetcher
  @fetcher
end

#file ⇒ Object

The file the patch loads from



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# File 'lib/rubyfocus/patch.rb', line 12

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 15

def from_ids
  @from_ids
end

#time ⇒ Object

The time the file was submitted



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# File 'lib/rubyfocus/patch.rb', line 18

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 15

def to_id
  @to_id
end

#update ⇒ Object

Update, delete and create methods



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# File 'lib/rubyfocus/patch.rb', line 9

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 48

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

Instance Method Details

#<=>(o) ⇒ Object 



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# File 'lib/rubyfocus/patch.rb', line 129

def <=> o
  if self.time.nil?
    if o.time.nil?
      0
    else
      -1
    end
  else
    if o.time.nil?
      1
    else
      self.time <=> o.time
    end
  end
end

#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 88

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.



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# File 'lib/rubyfocus/patch.rb', line 97

def apply_to!(document)
  # Updates modify elements
  self.update.each{ |node| update_node(document, node) }
  
  # Deletes remove elements
  self.delete.each{ |node| document.remove_element(node["id"]) }

  # Creates make new elements
  self.create.each{ |node| update_node(document, node) }

  # 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 83

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 56

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 121

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

#update_node(document, node) ⇒ Object

Atomic node update code



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# File 'lib/rubyfocus/patch.rb', line 112

def update_node(document, node)
  # Create new element with correct ID. Then add to document, overwriting previous element(s)
  new_node = Rubyfocus::Parser.parse(nil, node)
  if new_node
    document.add_element(new_node, overwrite: true)
  end
end