Module: Oinky::RowSet

Included in:
Index, Table
Defined in:
lib/oinky/query.rb,
lib/oinky.rb

Overview

Add dataset filtering to the rowset (applies to both tables and indices) The indexes are not used autmatically. An index is only used if the filter is applied to an index using positional specification.

Instance Method Summary collapse

Instance Method Details

#__each_filtered(c, terminate, filter) ⇒ Object 



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# File 'lib/oinky/query.rb', line 90

def __each_filtered(c,terminate,filter)
  Enumerator.new {|blk|
    if c.is_valid?
      v = c.select_all
      while true
        blk.yield v if filter.call(v)
        c.seek_next
        break unless c.is_valid?
        v = c.select_all
        break if terminate and terminate.call(v)
      end
    end
  }
end

#__make_filter_proc(f) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/oinky/query.rb', line 104

def __make_filter_proc(f)
  if [String,Integer,Fixnum,Float,DateTime].find_index(f.class)
    return lambda{|v| v == f}
  end
  if f.is_a? Proc
    return f
  end
  raise ArgumentError.new("Hash value must be proc or value.")
end

#__rs_filter(f, c, t) ⇒ Object 



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# File 'lib/oinky/query.rb', line 113

def __rs_filter(f,c,t)
  if f.is_a? Hash
    p = {}
    cols = @table.columns
    f.each{|k,kf|
      unless cols[k]
        raise ArgumentError.new("Unknown column name in hash filter.")
      end
      p[k] = __make_filter_proc(kf)
    }
    f = lambda {|v|
      r = true
      p.each{|k,kf|
        r &&= kf.call(v[k])
      }
    }
  end
  unless f.is_a? Proc
    raise ArgumentError.new("Invalid argument to filter.  Need Proc or Hash.")
  end

  seq = __each_filtered(c,t,f)
  if block_given?
    seq.each {|v|
      yield v
    }
    return self
  else
    return seq
  end
end

#cursor_each ⇒ Object 



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# File 'lib/oinky.rb', line 744

def cursor_each
  e = Enumerator.new {|blk|
    c = self.new_cursor
    while c.is_valid?
      blk.yield c
      c.seek_next
    end
  }
  if block_given?
    e.each{|k| yield k}
  else
    return e
  end
end

#each(cs = nil) ⇒ Object 



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# File 'lib/oinky.rb', line 759

def each(cs = nil)
  # Making the selector first will be most efficient
  cs = @table.select_columns(cs)

  e = ValuesEnumerator.new {|blk|
    self.cursor_each { |c| blk.yield c.select(cs) }
  }
  if block_given?
    e.each{|k| yield k}
  else
    return e
  end
end

#filter(f) ⇒ Object 



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# File 'lib/oinky/query.rb', line 144

def filter(f)
  __rs_filter(f,new_cursor(),nil)
end

#new_cursor(*a) ⇒ Object 



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# File 'lib/oinky.rb', line 773

def new_cursor(*a)
  self.class::Cursor.new(self, *a)
end