Class: Gel::Support::Tar::TarWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/gel/support/tar/tar_writer.rb

Overview

Allows writing of tar files

Defined Under Namespace

Classes: BoundedStream, FileOverflow, RestrictedStream

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io) ⇒ TarWriter

Creates a new TarWriter that will write to io



97
98
99
100
 
# File 'lib/gel/support/tar/tar_writer.rb', line 97

def initialize(io)
  @io = io
  @closed = false
end

Class Method Details

.new(io) ⇒ Object

Creates a new TarWriter, yielding it if a block is given



80
81
82
83
84
85
86
87
88
89
90
91
92
 
# File 'lib/gel/support/tar/tar_writer.rb', line 80

def self.new(io)
  writer = super

  return writer unless block_given?

  begin
    yield writer
  ensure
    writer.close
  end

  nil
end

Instance Method Details

#add_file(name, mode) {|RestrictedStream.new(@io)| ... } ⇒ Object

Adds file name with permissions mode, and yields an IO for writing the file to

Yields:

Raises:



106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
 
# File 'lib/gel/support/tar/tar_writer.rb', line 106

def add_file(name, mode) # :yields: io
  check_closed

  raise Gel::Support::Tar::NonSeekableIO unless @io.respond_to? :pos=

  name, prefix = split_name name

  init_pos = @io.pos
  @io.write "\0" * 512 # placeholder for the header

  yield RestrictedStream.new(@io) if block_given?

  size = @io.pos - init_pos - 512

  remainder = (512 - (size % 512)) % 512
  @io.write "\0" * remainder

  final_pos = @io.pos
  @io.pos = init_pos

  header = Gel::Support::Tar::TarHeader.new :name => name, :mode => mode,
                                       :size => size, :prefix => prefix,
                                       :mtime => Time.now

  @io.write header
  @io.pos = final_pos

  self
end

#add_file_digest(name, mode, digest_algorithms) ⇒ Object

Adds name with permissions mode to the tar, yielding io for writing the file. The digest_algorithm is written to a read-only name.sum file following the given file contents containing the digest name and hexdigest separated by a tab.

The created digest object is returned.



144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
 
# File 'lib/gel/support/tar/tar_writer.rb', line 144

def add_file_digest name, mode, digest_algorithms # :yields: io
  digests = digest_algorithms.map do |digest_algorithm|
    digest = digest_algorithm.new
    digest_name =
      if digest.respond_to? :name then
        digest.name
      else
        /::([^:]+)$/ =~ digest_algorithm.name
        $1
      end

    [digest_name, digest]
  end

  digests = Hash[*digests.flatten]

  add_file name, mode do |io|
    Gel::Support::Tar::DigestIO.wrap io, digests do |digest_io|
      yield digest_io
    end
  end

  digests
end

#add_file_signed(name, mode, signer) ⇒ Object

Adds name with permissions mode to the tar, yielding io for writing the file. The signer is used to add a digest file using its digest_algorithm per add_file_digest and a cryptographic signature in name.sig. If the signer has no key only the checksum file is added.

Returns the digest.



177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
 
# File 'lib/gel/support/tar/tar_writer.rb', line 177

def add_file_signed name, mode, signer
  digest_algorithms = [
    signer.digest_algorithm,
    Digest::SHA512,
  ].compact.uniq

  digests = add_file_digest name, mode, digest_algorithms do |io|
    yield io
  end

  signature_digest = digests.values.compact.find do |digest|
    digest_name =
      if digest.respond_to? :name then
        digest.name
      else
        /::([^:]+)$/ =~ digest.class.name
        $1
      end

    digest_name == signer.digest_name
  end

  if signer.key then
    signature = signer.sign signature_digest.digest

    add_file_simple "#{name}.sig", 0444, signature.length do |io|
      io.write signature
    end
  end

  digests
end

#add_file_simple(name, mode, size) {|os| ... } ⇒ Object

Add file name with permissions mode size bytes long. Yields an IO to write the file to.

Yields:

  • (os) 


214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
 
# File 'lib/gel/support/tar/tar_writer.rb', line 214

def add_file_simple(name, mode, size) # :yields: io
  check_closed

  name, prefix = split_name name

  header = Gel::Support::Tar::TarHeader.new(:name => name, :mode => mode,
                                       :size => size, :prefix => prefix,
                                       :mtime => Time.now).to_s

  @io.write header
  os = BoundedStream.new @io, size

  yield os if block_given?

  min_padding = size - os.written
  @io.write("\0" * min_padding)

  remainder = (512 - (size % 512)) % 512
  @io.write("\0" * remainder)

  self
end

#add_symlink(name, target, mode) ⇒ Object

Adds symlink name with permissions mode, linking to target.



240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
 
# File 'lib/gel/support/tar/tar_writer.rb', line 240

def add_symlink(name, target, mode)
  check_closed

  name, prefix = split_name name

  header = Gel::Support::Tar::TarHeader.new(:name => name, :mode => mode,
                                       :size => 0, :typeflag => "2",
                                       :linkname => target,
                                       :prefix => prefix,
                                       :mtime => Time.now).to_s

  @io.write header

  self
end

#check_closed ⇒ Object

Raises IOError if the TarWriter is closed

Raises:

  • (IOError) 


259
260
261
 
# File 'lib/gel/support/tar/tar_writer.rb', line 259

def check_closed
  raise IOError, "closed #{self.class}" if closed?
end

#close ⇒ Object

Closes the TarWriter



266
267
268
269
270
271
272
273
 
# File 'lib/gel/support/tar/tar_writer.rb', line 266

def close
  check_closed

  @io.write "\0" * 1024
  flush

  @closed = true
end

#closed? ⇒ Boolean

Is the TarWriter closed?

Returns:

  • (Boolean) 


278
279
280
 
# File 'lib/gel/support/tar/tar_writer.rb', line 278

def closed?
  @closed
end

#flush ⇒ Object

Flushes the TarWriter’s IO



285
286
287
288
289
 
# File 'lib/gel/support/tar/tar_writer.rb', line 285

def flush
  check_closed

  @io.flush if @io.respond_to? :flush
end

#mkdir(name, mode) ⇒ Object

Creates a new directory in the tar file name with mode



294
295
296
297
298
299
300
301
302
303
304
305
306
307
 
# File 'lib/gel/support/tar/tar_writer.rb', line 294

def mkdir(name, mode)
  check_closed

  name, prefix = split_name(name)

  header = Gel::Support::Tar::TarHeader.new :name => name, :mode => mode,
                                       :typeflag => "5", :size => 0,
                                       :prefix => prefix,
                                       :mtime => Time.now

  @io.write header

  self
end

#split_name(name) ⇒ Object

Splits name into a name and prefix that can fit in the TarHeader



312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
 
# File 'lib/gel/support/tar/tar_writer.rb', line 312

def split_name(name) # :nodoc:
  if name.bytesize > 256 then
    raise Gel::Support::Tar::TooLongFileName.new("File \"#{name}\" has a too long path (should be 256 or less)")
  end

  prefix = ''
  if name.bytesize > 100 then
    parts = name.split('/', -1) # parts are never empty here
    name = parts.pop            # initially empty for names with a trailing slash ("foo/.../bar/")
    prefix = parts.join('/')    # if empty, then it's impossible to split (parts is empty too)
    while !parts.empty? && (prefix.bytesize > 155 || name.empty?)
      name = parts.pop + '/' + name
      prefix = parts.join('/')
    end

    if name.bytesize > 100 or prefix.empty? then
      raise Gel::Support::Tar::TooLongFileName.new("File \"#{prefix}/#{name}\" has a too long name (should be 100 or less)")
    end

    if prefix.bytesize > 155 then
      raise Gel::Support::Tar::TooLongFileName.new("File \"#{prefix}/#{name}\" has a too long base path (should be 155 or less)")
    end
  end

  return name, prefix
end