Class: Rumai::IXP::Agent::FidStream

Inherits:
Object
  • Object
show all
Defined in:
lib/rumai/ixp/transport.rb

Overview

Note:

this class is NOT thread safe!

Encapsulates I/O access over a file handle (fid).

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(agent, path_fid, message_size) ⇒ FidStream

Returns a new instance of FidStream.



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# File 'lib/rumai/ixp/transport.rb', line 243

def initialize agent, path_fid, message_size
  @agent  = agent
  @fid    = path_fid
  @msize  = message_size
  @stat   = @agent.stat_fid(@fid)
  @closed = false
  rewind
end

Instance Attribute Details

#eof ⇒ Object (readonly) Also known as: eof?

Returns the value of attribute eof.



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# File 'lib/rumai/ixp/transport.rb', line 237

def eof
  @eof
end

#fid ⇒ Object (readonly)

Returns the value of attribute fid.



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# File 'lib/rumai/ixp/transport.rb', line 235

def fid
  @fid
end

#pos ⇒ Object Also known as: tell

Returns the value of attribute pos.



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# File 'lib/rumai/ixp/transport.rb', line 240

def pos
  @pos
end

#stat ⇒ Object (readonly)

Returns the value of attribute stat.



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# File 'lib/rumai/ixp/transport.rb', line 235

def stat
  @stat
end

Instance Method Details

#close ⇒ Object

Closes this stream.



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# File 'lib/rumai/ixp/transport.rb', line 263

def close
  unless @closed
    @agent.clunk @fid
    @closed = true
    @eof = true
  end
end

#closed? ⇒ Boolean

Returns true if this stream is closed.

Returns:

  • (Boolean) 


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# File 'lib/rumai/ixp/transport.rb', line 274

def closed?
  @closed
end

#read(partial = false) ⇒ Object

Reads some data from this stream at the current position. If this stream corresponds to a directory, then an Array of Stat (one for each file in the directory) will be returned.

Parameters:

  • partial (Boolean) (defaults to: false) —

    When false, the entire content of this stream is read and returned.

    When true, the maximum amount of content that can fit inside a single 9P2000 message is read and returned.



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# File 'lib/rumai/ixp/transport.rb', line 291

def read partial = false
  raise 'cannot read from a closed stream' if @closed

  content = ''
  begin
    req = Tread.new(
      :fid    => @fid,
      :offset => @pos,
      :count  => @msize
    )
    rsp = @agent.talk(req)

    content << rsp.data
    count = rsp.count
    @pos += count
  end until @eof = count.zero? or partial

  # the content of a directory is a sequence
  # of Stat for all files in that directory
  if @stat.directory?
    buffer = StringIO.new(content)
    content = []

    until buffer.eof?
      content << Stat.from_9p(buffer)
    end
  end

  content
end

#rewind ⇒ Object

Rewinds the stream to the beginning.



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# File 'lib/rumai/ixp/transport.rb', line 255

def rewind
  @pos = 0
  @eof = false
end

#write(content) ⇒ Object Also known as: <<

Writes the given content at the current position in this stream.



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# File 'lib/rumai/ixp/transport.rb', line 325

def write content
  raise 'cannot write to a closed stream' if @closed
  raise 'cannot write to a directory' if @stat.directory?

  data = content.to_s
  limit = data.bytesize + @pos

  while @pos < limit
    chunk = data.byteslice(@pos, @msize)

    req = Twrite.new(
      :fid    => @fid,
      :offset => @pos,
      :count  => chunk.bytesize,
      :data   => chunk
    )
    rsp = @agent.talk(req)

    @pos += rsp.count
  end
end