Method: Spider::Model::Storage::BaseStorage#sequence_next

Defined in:
lib/spiderfw/model/storage/base_storage.rb

#sequence_next(name, newval = nil, increment = 1) ⇒ Fixnum

Increments a named sequence and returns the new value

Parameters:

  • name (String) —

    Sequence name

  • newval (Fixnum) (defaults to: nil) —

    New value for the sequence

  • increment (Fixnum) (defaults to: 1)

Returns:

  • (Fixnum) —

    New value for the sequence



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# File 'lib/spiderfw/model/storage/base_storage.rb', line 445

def sequence_next(name, newval=nil, increment=1)
    path = sequence_file_path(name)
    FileUtils.mkpath(File.dirname(path))
    self.class.sequence_sync.lock(::Sync::EX)
    if newval
        seq = newval
    else
        seq = 0
        File.open(path, 'a+') do |f|
            f.rewind
            f.flock File::LOCK_EX
            cur = f.gets
            if (cur)
                seq, increment_str = cur.split('|')
            else
                seq, increment_str = 0, 1
            end
            seq = seq.to_i
            increment = increment_str.to_i if increment_str
            f.close
        end
        seq += increment
    end
    File.open(path, 'w+') do |f|
        f.print(seq)
        f.print("|#{increment}") if (increment != 1)
        f.flock File::LOCK_UN
        f.close
    end
    self.class.sequence_sync.lock(::Sync::UN)
    return seq
end