Class: Omnizip::Formats::Zip::Writer

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

Overview

ZIP archive writer

Constant Summary

Constants included from Constants

Constants::ATTR_ARCHIVE, Constants::ATTR_DIRECTORY, Constants::CENTRAL_DIRECTORY_SIGNATURE, Constants::COMPRESSION_BZIP2, Constants::COMPRESSION_DEFLATE, Constants::COMPRESSION_DEFLATE64, Constants::COMPRESSION_IMPLODED, Constants::COMPRESSION_LZMA, Constants::COMPRESSION_PPMD, Constants::COMPRESSION_REDUCED_1, Constants::COMPRESSION_REDUCED_2, Constants::COMPRESSION_REDUCED_3, Constants::COMPRESSION_REDUCED_4, Constants::COMPRESSION_SHRUNK, Constants::COMPRESSION_STORE, Constants::COMPRESSION_ZSTANDARD, Constants::DATA_DESCRIPTOR_SIGNATURE, Constants::END_OF_CENTRAL_DIRECTORY_SIGNATURE, Constants::FLAG_DATA_DESCRIPTOR, Constants::FLAG_ENCRYPTED, Constants::FLAG_STRONG_ENCRYPTION, Constants::FLAG_UTF8, Constants::LOCAL_FILE_HEADER_SIGNATURE, Constants::MAX_COMMENT_LENGTH, Constants::UNIX_DIR_PERMISSIONS, Constants::UNIX_EXTRA_FIELD_TAG, Constants::UNIX_FILE_PERMISSIONS, Constants::UNIX_SYMLINK_PERMISSIONS, Constants::VERSION_BZIP2, Constants::VERSION_DEFAULT, Constants::VERSION_DEFLATE, Constants::VERSION_LZMA, Constants::VERSION_MADE_BY_UNIX, Constants::VERSION_MADE_BY_WINDOWS, Constants::VERSION_ZIP64, Constants::ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR_SIGNATURE, Constants::ZIP64_END_OF_CENTRAL_DIRECTORY_SIGNATURE, Constants::ZIP64_EXTRA_FIELD_TAG, Constants::ZIP64_LIMIT

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path) ⇒ Writer

Returns a new instance of Writer.



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# File 'lib/omnizip/formats/zip/writer.rb', line 14

def initialize(file_path)
  @file_path = file_path
  @entries = []
  @local_headers = []
end

Instance Attribute Details

#entries ⇒ Object (readonly)

Returns the value of attribute entries.



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# File 'lib/omnizip/formats/zip/writer.rb', line 12

def entries
  @entries
end

#file_path ⇒ Object (readonly)

Returns the value of attribute file_path.



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# File 'lib/omnizip/formats/zip/writer.rb', line 12

def file_path
  @file_path
end

Instance Method Details

#add_data(archive_path, data, stat = nil) ⇒ Object

Add data directly to the archive



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# File 'lib/omnizip/formats/zip/writer.rb', line 96

def add_data(archive_path, data, stat = nil)
  entry = create_entry(
    filename: archive_path,
    uncompressed_data: data,
    stat: stat,
  )

  @entries << entry
end

#add_directory(archive_path) ⇒ Object

Add a directory to the archive



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# File 'lib/omnizip/formats/zip/writer.rb', line 83

def add_directory(archive_path)
  archive_path = "#{archive_path}/" unless archive_path.end_with?("/")

  entry = create_entry(
    filename: archive_path,
    uncompressed_data: "",
    directory: true,
  )

  @entries << entry
end

#add_file(file_path, archive_path = nil, preserve_links: true) ⇒ Object

Add a file to the archive



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# File 'lib/omnizip/formats/zip/writer.rb', line 21

def add_file(file_path, archive_path = nil, preserve_links: true)
  archive_path ||= File.basename(file_path)

  if File.directory?(file_path)
    add_directory(archive_path)
  elsif preserve_links && LinkHandler.symlink?(file_path)
    add_symlink(archive_path, LinkHandler.read_link_target(file_path))
  elsif preserve_links && LinkHandler.hardlink?(file_path)
    # For hard links, we add as regular file but track inode
    data = File.binread(file_path)
    add_data(archive_path, data, File.stat(file_path))
  else
    data = File.binread(file_path)
    add_data(archive_path, data, File.stat(file_path))
  end
end

#add_hardlink(archive_path, target_path) ⇒ Object

Add a hard link to the archive



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# File 'lib/omnizip/formats/zip/writer.rb', line 57

def add_hardlink(archive_path, target_path)
  unless LinkHandler.hardlink_supported?
    warn "Warning: Hard links not supported on #{RUBY_PLATFORM}, storing as regular file"
    # Store the target file content instead
    if File.exist?(target_path)
      data = File.binread(target_path)
      add_data(archive_path, data, File.stat(target_path))
    else
      add_data(archive_path, "")
    end
    return
  end

  # For hard links, we store the first occurrence as a regular file
  # and subsequent ones reference the original
  entry = create_entry(
    filename: archive_path,
    uncompressed_data: "",
    hardlink: true,
    hardlink_target: target_path,
  )

  @entries << entry
end

#add_precompressed_entry(filename:, uncompressed_size:, compressed_size:, crc32:, compressed_data:, stat: nil) ⇒ Object

Add an entry whose payload is already compressed. Bypasses per-entry compression in #write, so #write_precompressed must be used instead of #write to emit the archive.

Parameters:

  • filename (String) —

    Entry name in the archive

  • uncompressed_size (Integer) —

    Size before compression

  • compressed_size (Integer) —

    Size of compressed_data

  • crc32 (Integer) —

    CRC32 of the uncompressed data

  • compressed_data (String) —

    Pre-compressed payload

  • stat (File::Stat, nil) (defaults to: nil) —

    Optional stat for the source file



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# File 'lib/omnizip/formats/zip/writer.rb', line 124

def add_precompressed_entry(filename:, uncompressed_size:,
                            compressed_size:, crc32:,
                            compressed_data:, stat: nil)
  entry = create_entry(
    filename: filename,
    uncompressed_data: "",
    stat: stat,
  )
  entry[:compressed_size] = compressed_size
  entry[:uncompressed_size] = uncompressed_size
  entry[:crc32] = crc32
  entry[:compressed_data] = compressed_data
  @entries << entry
  entry
end

#add_symlink(archive_path, target) ⇒ Object

Add a symbolic link to the archive



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# File 'lib/omnizip/formats/zip/writer.rb', line 39

def add_symlink(archive_path, target)
  unless LinkHandler.symlink_supported?
    warn "Warning: Symbolic links not supported on #{RUBY_PLATFORM}, storing as regular file"
    add_data(archive_path, target)
    return
  end

  entry = create_entry(
    filename: archive_path,
    uncompressed_data: target,
    symlink: true,
    symlink_target: target,
  )

  @entries << entry
end

#write(compression_method: COMPRESSION_DEFLATE, level: 6) ⇒ Object

Write the archive to disk



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# File 'lib/omnizip/formats/zip/writer.rb', line 107

def write(compression_method: COMPRESSION_DEFLATE, level: 6)
  File.open(file_path, "wb") do |io|
    write_to_io(io, compression_method: compression_method,
                    level: level)
  end
end

#write_precompressed(compression_method: COMPRESSION_DEFLATE) ⇒ Object

Write the archive using pre-compressed entry payloads (set via #add_precompressed_entry).

Parameters:

  • compression_method (Integer) (defaults to: COMPRESSION_DEFLATE) —

    ZIP compression method code recorded in the headers



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# File 'lib/omnizip/formats/zip/writer.rb', line 145

def write_precompressed(compression_method: COMPRESSION_DEFLATE)
  File.open(file_path, "wb") do |io|
    write_precompressed_to_io(io, compression_method: compression_method)
  end
end

#write_precompressed_to_io(io, compression_method: COMPRESSION_DEFLATE) ⇒ Object 



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# File 'lib/omnizip/formats/zip/writer.rb', line 151

def write_precompressed_to_io(io, compression_method: COMPRESSION_DEFLATE)
  local_header_offsets = []

  entries.each do |entry|
    offset = io.pos
    local_header_offsets << offset

    local_header = create_local_header(entry, compression_method)
    local_header.compressed_size = entry[:compressed_size]
    local_header.uncompressed_size = entry[:uncompressed_size]
    local_header.crc32 = entry[:crc32]
    io.write(local_header.to_binary)
    io.write(entry[:compressed_data]) unless entry[:directory]
  end

  central_directory_offset = io.pos

  entries.each_with_index do |entry, index|
    central_header = create_central_header(
      entry,
      compression_method,
      local_header_offsets[index],
    )
    io.write(central_header.to_binary)
  end

  central_directory_size = io.pos - central_directory_offset

  eocd = create_eocd(
    total_entries: entries.size,
    central_directory_size: central_directory_size,
    central_directory_offset: central_directory_offset,
  )
  io.write(eocd.to_binary)
end

#write_to_io(io, compression_method: COMPRESSION_DEFLATE, level: 6) ⇒ Object

Write to an IO object



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# File 'lib/omnizip/formats/zip/writer.rb', line 188

def write_to_io(io, compression_method: COMPRESSION_DEFLATE, level: 6)
  local_header_offsets = []

  # Write local file headers and data
  entries.each do |entry|
    offset = io.pos
    local_header_offsets << offset

    # Create local file header
    local_header = create_local_header(entry, compression_method)

    # Compress data if not a directory
    if entry[:directory]
      compressed_data = ""
      entry[:compressed_size] = 0
      entry[:uncompressed_size] = 0
      entry[:crc32] = 0
    else
      compressed_data = compress_data(
        entry[:uncompressed_data],
        compression_method,
        level,
      )
      entry[:compressed_size] = compressed_data.bytesize
      entry[:uncompressed_size] = entry[:uncompressed_data].bytesize
      entry[:crc32] = calculate_crc32(entry[:uncompressed_data])
    end

    # Update local header with compressed sizes
    local_header.compressed_size = entry[:compressed_size]
    local_header.uncompressed_size = entry[:uncompressed_size]
    local_header.crc32 = entry[:crc32]

    # Write local header
    io.write(local_header.to_binary)

    # Write compressed data
    io.write(compressed_data) unless entry[:directory]
  end

  # Record start of central directory
  central_directory_offset = io.pos

  # Write central directory headers
  entries.each_with_index do |entry, index|
    central_header = create_central_header(
      entry,
      compression_method,
      local_header_offsets[index],
    )
    io.write(central_header.to_binary)
  end

  # Calculate central directory size
  central_directory_size = io.pos - central_directory_offset

  # Write end of central directory record
  eocd = create_eocd(
    total_entries: entries.size,
    central_directory_size: central_directory_size,
    central_directory_offset: central_directory_offset,
  )
  io.write(eocd.to_binary)
end