Class: Omnizip::Formats::Xar::Toc

Inherits:
Object
  • Object
show all
Includes:
Constants
Defined in:
lib/omnizip/formats/xar/toc.rb

Overview

XAR Table of Contents (TOC) parser and builder

The TOC is a GZIP-compressed XML document that contains:

  • Archive metadata (creation time, checksum info)
  • File hierarchy with metadata for each entry
  • Data offsets and sizes in the heap
  • Extended attributes

Constant Summary

Constants included from Constants

Constants::CHECKSUM_ALGORITHMS, Constants::CHECKSUM_NAMES, Constants::CHECKSUM_SIZES, Constants::CKSUM_MD5, Constants::CKSUM_NONE, Constants::CKSUM_OTHER, Constants::CKSUM_SHA1, Constants::COMPRESSION_BZIP2, Constants::COMPRESSION_GZIP, Constants::COMPRESSION_LZMA, Constants::COMPRESSION_MIME_TYPES, Constants::COMPRESSION_NONE, Constants::COMPRESSION_XZ, Constants::DEFAULT_COMPRESSION, Constants::DEFAULT_COMPRESSION_LEVEL, Constants::DEFAULT_FILE_CHECKSUM, Constants::DEFAULT_TOC_CHECKSUM, Constants::HEADER_CKSUM_ALG_OFFSET, Constants::HEADER_MAGIC_OFFSET, Constants::HEADER_SIZE, Constants::HEADER_SIZE_EX, Constants::HEADER_SIZE_OFFSET, Constants::HEADER_TOC_COMPRESSED_OFFSET, Constants::HEADER_TOC_UNCOMPRESSED_OFFSET, Constants::HEADER_VERSION_OFFSET, Constants::MAGIC, Constants::MAGIC_BYTES, Constants::MAX_PATH_LENGTH, Constants::MIME_TYPE_TO_COMPRESSION, Constants::TOC_XML_DECLARATION, Constants::TYPE_BLOCK, Constants::TYPE_CHAR, Constants::TYPE_DIRECTORY, Constants::TYPE_FIFO, Constants::TYPE_FILE, Constants::TYPE_HARDLINK, Constants::TYPE_SOCKET, Constants::TYPE_SYMLINK, Constants::XAR_VERSION

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Toc

Initialize TOC



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# File 'lib/omnizip/formats/xar/toc.rb', line 98

def initialize
  @creation_time = Time.now
  @entries = []
  @checksum_offset = 0
  @checksum_size = 0
  @checksum_style = DEFAULT_TOC_CHECKSUM
  @next_id = 1
end

Instance Attribute Details

#checksum_offset ⇒ Object

Returns the value of attribute checksum_offset.



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# File 'lib/omnizip/formats/xar/toc.rb', line 21

def checksum_offset
  @checksum_offset
end

#checksum_size ⇒ Object

Returns the value of attribute checksum_size.



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# File 'lib/omnizip/formats/xar/toc.rb', line 21

def checksum_size
  @checksum_size
end

#checksum_style ⇒ Object

Returns the value of attribute checksum_style.



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# File 'lib/omnizip/formats/xar/toc.rb', line 21

def checksum_style
  @checksum_style
end

#creation_time ⇒ Object

Returns the value of attribute creation_time.



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# File 'lib/omnizip/formats/xar/toc.rb', line 21

def creation_time
  @creation_time
end

#entries ⇒ Object (readonly)

Returns the value of attribute entries.



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# File 'lib/omnizip/formats/xar/toc.rb', line 23

def entries
  @entries
end

Class Method Details

.decompress(compressed_data, expected_size = nil) ⇒ String

Decompress TOC data

Parameters:

  • compressed_data (String) —

    Zlib-compressed data

  • expected_size (Integer, nil) (defaults to: nil) —

    Expected size for validation

Returns:

  • (String) —

    Decompressed XML



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# File 'lib/omnizip/formats/xar/toc.rb', line 41

def self.decompress(compressed_data, expected_size = nil)
  # XAR TOC is zlib compressed (with zlib headers, 0x78xx)
  # Try zlib format first (most common), then fall back to raw deflate
  result = begin
    # Try standard zlib format (with header)
    Zlib::Inflate.inflate(compressed_data)
  rescue Zlib::DataError
    # Fall back to raw deflate for non-conforming implementations
    Zlib::Inflate.new(-Zlib::MAX_WBITS).inflate(compressed_data)
  end

  if expected_size && result.bytesize != expected_size
    raise ArgumentError,
          "TOC size mismatch: #{result.bytesize} != #{expected_size}"
  end

  result
end

.from_xml(xml_doc) ⇒ Toc

Parse TOC from XML document

Parameters:

  • xml_doc (REXML::Document) —

    Parsed XML document

Returns:

  • (Toc) —

    Parsed TOC object



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# File 'lib/omnizip/formats/xar/toc.rb', line 64

def self.from_xml(xml_doc)
  toc = new
  root = xml_doc.root

  return toc unless root&.name == "xar"

  toc_element = root.elements["toc"]
  return toc unless toc_element

  # Parse creation time
  if (ctime = toc_element.elements["creation-time"]&.text)
    toc.creation_time = parse_timestamp(ctime)
  end

  # Parse checksum info
  if (checksum = toc_element.elements["checksum"])
    toc.checksum_style = checksum.attributes["style"] || "sha1"
    toc.checksum_offset = checksum.elements["offset"]&.text.to_i
    toc.checksum_size = checksum.elements["size"]&.text.to_i
  end

  # Parse file entries
  toc_element.elements.each("file") do |file_elem|
    entry = parse_file_element(file_elem)
    toc.add_entry(entry)

    # Parse nested files (subdirectories)
    parse_nested_files(file_elem, entry, toc)
  end

  toc
end

.parse(compressed_data, uncompressed_size = nil) ⇒ Toc

Parse TOC from compressed data

Parameters:

  • compressed_data (String) —

    GZIP-compressed TOC XML

  • uncompressed_size (Integer) (defaults to: nil) —

    Expected uncompressed size

Returns:

  • (Toc) —

    Parsed TOC object



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# File 'lib/omnizip/formats/xar/toc.rb', line 30

def self.parse(compressed_data, uncompressed_size = nil)
  uncompressed = decompress(compressed_data, uncompressed_size)
  xml_doc = REXML::Document.new(uncompressed)
  from_xml(xml_doc)
end

Instance Method Details

#add_entry(entry) ⇒ Entry

Add entry to TOC

Parameters:

  • entry (Entry) —

    Entry to add

Returns:

  • (Entry) —

    The added entry



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# File 'lib/omnizip/formats/xar/toc.rb', line 113

def add_entry(entry)
  entry.id ||= @next_id
  @next_id = [@next_id, entry.id + 1].max
  @entries << entry
  entry
end

#compress ⇒ String

Compress TOC XML

Returns:

  • (String) —

    GZIP-compressed XML



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# File 'lib/omnizip/formats/xar/toc.rb', line 184

def compress
  xml = to_xml_string

  zlib = Zlib::Deflate.new(Zlib::DEFAULT_COMPRESSION, -Zlib::MAX_WBITS)
  result = zlib.deflate(xml, Zlib::FINISH)
  zlib.close
  result
end

#find_entry(name) ⇒ Entry?

Find entry by name

Parameters:

  • name (String) —

    Entry name

Returns:

  • (Entry, nil) —

    Found entry or nil



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# File 'lib/omnizip/formats/xar/toc.rb', line 131

def find_entry(name)
  @entries.find { |e| e.name == name }
end

#find_entry_by_id(id) ⇒ Entry?

Find entry by ID

Parameters:

  • id (Integer) —

    Entry ID

Returns:

  • (Entry, nil) —

    Found entry or nil



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# File 'lib/omnizip/formats/xar/toc.rb', line 139

def find_entry_by_id(id)
  @entries.find { |e| e.id == id }
end

#next_id ⇒ Integer

Get next available ID

Returns:

  • (Integer) —

    Next ID



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# File 'lib/omnizip/formats/xar/toc.rb', line 123

def next_id
  @next_id
end

#to_xml ⇒ REML::Document

Generate XML document

Returns:

  • (REML::Document) —

    XML document



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# File 'lib/omnizip/formats/xar/toc.rb', line 146

def to_xml
  doc = REXML::Document.new
  doc.add(REXML::XMLDecl.new("1.0", "UTF-8"))

  root = doc.add_element("xar")
  toc_element = root.add_element("toc")

  # Add creation time
  ctime_elem = toc_element.add_element("creation-time")
  ctime_elem.add_text(@creation_time.to_f.to_s)

  # Add checksum info
  checksum_elem = toc_element.add_element("checksum")
  checksum_elem.add_attribute("style", @checksum_style)
  offset_elem = checksum_elem.add_element("offset")
  offset_elem.add_text(@checksum_offset.to_s)
  size_elem = checksum_elem.add_element("size")
  size_elem.add_text(@checksum_size.to_s)

  # Add file entries
  build_file_tree(toc_element)

  doc
end

#to_xml_string ⇒ String

Generate XML string

Returns:

  • (String) —

    XML string



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# File 'lib/omnizip/formats/xar/toc.rb', line 174

def to_xml_string
  output = +""
  doc = to_xml
  doc.write(output: output, indent: 2)
  output
end

#uncompressed_size ⇒ Integer

Get uncompressed size

Returns:

  • (Integer) —

    Uncompressed XML size



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# File 'lib/omnizip/formats/xar/toc.rb', line 196

def uncompressed_size
  to_xml_string.bytesize
end