Class: Oinky::Index

Inherits:
Object
  • Object
show all
Includes:
RowSet
Defined in:
lib/oinky.rb,
lib/oinky/query.rb

Overview

module RowSet

Defined Under Namespace

Classes: Cursor

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from RowSet

#__each_filtered, #__make_filter_proc, #__rs_filter, #cursor_each, #each, #new_cursor

Constructor Details

#initialize(table, handle) ⇒ Index

Returns a new instance of Index.



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# File 'lib/oinky.rb', line 1037

def initialize(table, handle)
  @table, @handle = table, handle
end

Instance Attribute Details

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'lib/oinky.rb', line 1041

def table
  @table
end

Instance Method Details

#column_count ⇒ Object 



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# File 'lib/oinky.rb', line 1044

def column_count
  Internal.oinky_idx_column_count(@handle)
end

#columns ⇒ Object 



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# File 'lib/oinky.rb', line 1073

def columns
  definition
  @colnames
end

#db ⇒ Object 



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# File 'lib/oinky.rb', line 1042

def db ; @table.db ; end

#definition ⇒ Object 



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# File 'lib/oinky.rb', line 1051

def definition
  return @definition if @definition

  sz = self.column_count()
  nm = FFI::MemoryPointer.new(Internal::DB_string)
  uniq = FFI::MemoryPointer.new(:char)
  defs = Internal::IndexColumnDefn::IxColumnSet.new(sz)
  Internal.wrap_oinky(Internal.oinky_index_get_definition(@handle, nm, uniq, defs, sz))

  # Unlike the table, ordering of the index column definitions is 
  # semantically important.
  @definition = { 
    :name=>Internal::DB_string.new(nm).to_s,
    :unique=>uniq.read_char != 0 ? true : false,
    :columns=> (0..sz-1).map{|i|
      defs[i].to_h
    }
  }
  @colnames = @definition[:columns].map{|c| c[:column_name] }
  return @definition
end

#filter(f) ⇒ Object

Specialize the rowset filter to add specification by array(position)



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# File 'lib/oinky/query.rb', line 151

def filter(f)
  if f.is_a? Array
    c = new_cursor().seek(f)
    rg = f
    cols = self.columns
    if f.size > cols.size
      raise ArgumentError.new("Position specification exceeds index width.")
    end
    # truncate our test width to what we were given
    cols = cols[0..f.size-1]
    # Use an array for indirection in the first parameter, so
    # the two lambdas can share state.
    result = [true]
    f = lambda {|v| 
      r = true
      cols.each_with_index{|cn,i|
        if rg[i].is_a? Proc
          r &&= rg[i].call(v[cn])
        else
          r &&= (v[cn] == rg[i])
        end
      }
      result[0] = r
      r
    }
    result[0] = c.is_valid? && f.call(c.select_all)
    # We stop on the first rejection
    done = lambda { |c| !result[0]}
  else
    c = new_cursor().seek_first()
    done = nil
  end
  e = __rs_filter(f,c,done)
  if block_given?
    e.each {|v| yield v}
    return self
  else
    return e
  end
end

#name ⇒ Object 



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# File 'lib/oinky.rb', line 1082

def name
  return @idxname if @idxname
  dbs = Internal.oinky_index_name(@handle)
  @idxname = dbs.to_s
end

#row_count ⇒ Object 



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# File 'lib/oinky.rb', line 1047

def row_count
  Internal.oinky_idx_row_count(@handle)
end

#selector ⇒ Object 



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# File 'lib/oinky.rb', line 1078

def selector
  table.select_columns(self.columns)
end