class Gem::Package::TarReader::Entry

用于从 tar 文件中读取条目的类

属性

header[R]

此 tar 条目的头部

公共类方法

new(header, io) 点击切换源代码

为 header 创建一个新的 tar 条目，该条目将从 io 中读取

# File rubygems/package/tar_reader/entry.rb, line 36
def initialize(header, io)
  @closed = false
  @header = header
  @io = io
  @orig_pos = @io.pos
  @end_pos = @orig_pos + @header.size
  @read = 0
end

open(header, io) { |entry| ... } 点击切换源代码

为 header 创建一个新的 tar 条目，该条目将从 io 中读取。如果给定了代码块，则会先 yield 条目，然后关闭。

# File rubygems/package/tar_reader/entry.rb, line 18
def self.open(header, io, &block)
  entry = new header, io
  return entry unless block_given?
  begin
    yield entry
  ensure
    entry.close
  end
end

公共实例方法

bytes_read() 点击切换源代码

从 tar 条目中读取的字节数

# File rubygems/package/tar_reader/entry.rb, line 52
def bytes_read
  @read
end

close() 点击切换源代码

关闭 tar 条目

# File rubygems/package/tar_reader/entry.rb, line 59
def close
  return if closed?
  # Seek to the end of the entry if it wasn't fully read
  seek(0, IO::SEEK_END)
  # discard trailing zeros
  skip = (512 - (@header.size % 512)) % 512
  @io.read(skip)
  @closed = true
  nil
end

closed?() 点击切换源代码

tar 条目是否已关闭？

# File rubygems/package/tar_reader/entry.rb, line 73
def closed?
  @closed
end

directory?() 点击切换源代码

此 tar 条目是否为目录？

# File rubygems/package/tar_reader/entry.rb, line 112
def directory?
  @header.typeflag == "5"
end

eof?() 点击切换源代码

是否已到达 tar 条目的末尾？

# File rubygems/package/tar_reader/entry.rb, line 80
def eof?
  check_closed

  @read >= @header.size
end

file?() 点击切换源代码

此 tar 条目是否为文件？

# File rubygems/package/tar_reader/entry.rb, line 119
def file?
  @header.typeflag == "0"
end

full_name() 点击切换源代码

tar 条目的完整名称

# File rubygems/package/tar_reader/entry.rb, line 89
def full_name
  @header.full_name.force_encoding(Encoding::UTF_8)
rescue ArgumentError => e
  raise unless e.message == "string contains null byte"
  raise Gem::Package::TarInvalidError,
        "tar is corrupt, name contains null byte"
end

getc() 点击切换源代码

从 tar 条目读取一个字节

# File rubygems/package/tar_reader/entry.rb, line 100
def getc
  return nil if eof?

  ret = @io.getc
  @read += 1 if ret

  ret
end

length()

别名为：size

pos() 点击切换源代码

tar 条目中的位置

# File rubygems/package/tar_reader/entry.rb, line 133
def pos
  check_closed

  bytes_read
end

pos=(new_pos) 点击切换源代码

在 tar 条目中定位到指定位置

# File rubygems/package/tar_reader/entry.rb, line 142
def pos=(new_pos)
  seek(new_pos, IO::SEEK_SET)
end

read(maxlen = nil) 点击切换源代码

从 tar 文件条目中读取 maxlen 个字节，如果为 nil 则读取条目的剩余部分

# File rubygems/package/tar_reader/entry.rb, line 155
def read(maxlen = nil)
  if eof?
    return maxlen.to_i.zero? ? "" : nil
  end

  max_read = [maxlen, @header.size - @read].compact.min

  ret = @io.read max_read
  if ret.nil?
    return maxlen ? nil : "" # IO.read returns nil on EOF with len argument
  end
  @read += ret.size

  ret
end

readpartial(maxlen, outbuf = "".b) 点击切换源代码

# File rubygems/package/tar_reader/entry.rb, line 171
def readpartial(maxlen, outbuf = "".b)
  if eof? && maxlen > 0
    raise EOFError, "end of file reached"
  end

  max_read = [maxlen, @header.size - @read].min

  @io.readpartial(max_read, outbuf)
  @read += outbuf.size

  outbuf
end

rewind() 点击切换源代码

倒回至 tar 文件条目的开头

# File rubygems/package/tar_reader/entry.rb, line 240
def rewind
  check_closed
  seek(0, IO::SEEK_SET)
end

seek(offset, whence = IO::SEEK_SET) 点击切换源代码

在 tar 文件条目中定位到 offset 字节的位置。whence 可以是 IO::SEEK_SET、IO::SEEK_CUR 或 IO::SEEK_END

# File rubygems/package/tar_reader/entry.rb, line 188
def seek(offset, whence = IO::SEEK_SET)
  check_closed

  new_pos =
    case whence
    when IO::SEEK_SET then @orig_pos + offset
    when IO::SEEK_CUR then @io.pos + offset
    when IO::SEEK_END then @end_pos + offset
    else
      raise ArgumentError, "invalid whence"
    end

  if new_pos < @orig_pos
    new_pos = @orig_pos
  elsif new_pos > @end_pos
    new_pos = @end_pos
  end

  pending = new_pos - @io.pos

  return 0 if pending == 0

  if @io.respond_to?(:seek)
    begin
      # avoid reading if the @io supports seeking
      @io.seek new_pos, IO::SEEK_SET
      pending = 0
    rescue Errno::EINVAL
    end
  end

  # if seeking isn't supported or failed
  # negative seek requires that we rewind and read
  if pending < 0
    @io.rewind
    pending = new_pos
  end

  while pending > 0 do
    size_read = @io.read([pending, 4096].min)&.size
    raise(EOFError, "end of file reached") if size_read.nil?
    pending -= size_read
  end

  @read = @io.pos - @orig_pos

  0
end

size() 点击切换源代码

# File rubygems/package/tar_reader/entry.rb, line 146
def size
  @header.size
end

也别名为：length

symlink?() 点击切换源代码

此 tar 条目是否为符号链接？

# File rubygems/package/tar_reader/entry.rb, line 126
def symlink?
  @header.typeflag == "2"
end