Class: Mongoose::Table

Inherits:
Object show all
Defined in:
lib/mongoose/table.rb

Overview

Table class

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*values) ⇒ Table

initialize



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# File 'lib/mongoose/table.rb', line 369

def initialize(*values)
  self.class.columns.zip(values).each { |c,v| send("#{c.name}=", v) }
end

Class Method Details

.add_column(col_name, col_def, col_class = Column) ⇒ Object

Table.add_column



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# File 'lib/mongoose/table.rb', line 204

def self.add_column(col_name, col_def, col_class=Column)
  self.init_column(col_name, col_def, col_class)

  tbl_header = self.read_header

  tbl_header[:columns] << { :name => col_name, :data_type => col_def, 
                        :class => col_class.to_s }

  self.write_header(tbl_header)
end

.add_indexed_column(col_name, col_def) ⇒ Object

Table.add_indexed



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# File 'lib/mongoose/table.rb', line 218

def self.add_indexed_column(col_name, col_def)
  self.add_column(col_name, col_def, SkipListIndexColumn)
end

.any ⇒ Object

Table.any



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# File 'lib/mongoose/table.rb', line 324

def self.any
  self.query << :any_begin
  yield
  self.query << :any_end
end

.belongs_to(kind) ⇒ Object

Table.belongs_to



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# File 'lib/mongoose/table.rb', line 97

def self.belongs_to(kind)
  table_name = kind.to_sym
  class_name = Util.us_case_to_class_case(table_name)

  define_method(kind) do
    klass = Object.const_get(class_name.to_s)
    klass.find(send("#{kind}_id".to_sym))
  end

  define_method("#{kind}=".to_sym) do |other|
    other.save
    send("#{kind}_id=".to_sym, other.id.to_i)
    save
  end
end

.close ⇒ Object

Table.close



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# File 'lib/mongoose/table.rb', line 180

def self.close
  self.columns.each { |c| c.close }
end

.column_names ⇒ Object

Table.column_names



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# File 'lib/mongoose/table.rb', line 45

def self.column_names
  self.db.tables[self][:columns].collect { |c| c.name }
end

.columns ⇒ Object

Table.columns



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# File 'lib/mongoose/table.rb', line 38

def self.columns
  self.db.tables[self][:columns]
end

.db ⇒ Object

Table.db



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# File 'lib/mongoose/table.rb', line 10

def self.db
  @@db
end

.db=(db) ⇒ Object

Table.db=



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# File 'lib/mongoose/table.rb', line 17

def self.db=(db)
  @@db = db
end

.deleted_recs_counter ⇒ Object

Table.deleted_recs_counter



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# File 'lib/mongoose/table.rb', line 123

def self.deleted_recs_counter
  self.class.read_header[:deleted_recs_counter]
end

.find(*args) ⇒ Object

Table.find



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# File 'lib/mongoose/table.rb', line 225

def self.find(*args)
  # If searching for just one id or a group of ids...
  if args[0].is_a?(Integer)
    if args.size == 1
      self.get_rec(args[0])
    else
      args.collect { |a| self.get_rec(a) }
    end
  else
    result = []
    # If passed a query block...
    if block_given?
      self.query.clear
      query_start = true
      sub_q = false
      sub_q_start = false
      sub_q_result = []

      # Grab the query block
      yield self 

      # Step through the query block...
      self.query.each_with_index do |q,i|
        # If this is the start of an #any sub-block within the main block,
        # mark it as so and start grabbing the sub-block query.
        if q == :any_begin
          sub_q = :true
          sub_q_start = true
          sub_q_result = []
          next
        end
        # If this is the end of an #any sub-block within the main block,
        # mark it as so, and add the sub-block's query results to the current
        # results of the main query.
        if q == :any_end
          sub_q = false
          if query_start
            query_start = false
            result = sub_q_result
          else
            result = result & sub_q_result
          end
          sub_q_result = nil
          next
        end

        # If currently within a sub-block query, execute and add it's results
        # to the current sub-block query results.
        if sub_q
          if sub_q_start
            sub_q_start = false
            sub_q_result = q[0].send(q[1], *q[2]) 
          else        
            sub_q_result = sub_q_result | q[0].send(q[1], *q[2])
          end
          next
        end

        # If this is the beginning of the query start a new result set, 
        # otherwise, add the results of the current line of the query to
        # the existing result set.
        if query_start
          query_start = false
          result = q[0].send(q[1], *q[2]) 
        else        
          result = result & q[0].send(q[1], *q[2])
        end
      end
    # If did not pass a query block, just grab all of the ids in the table...
    else  
      result = self.id.keys
    end

    # If no matching records found, return nil.
    if result.nil?
      nil
    # If user just wants first record, return first record.
    elsif args[0] == :first 
      self.get_rec(result.first)
    # If user specified a paramaters hash, see if they specified a limit and
    # return that many records.
    elsif args[1].is_a?(Hash)
      if args[1].has_key?(:limit)
        if args[1][:limit] == 1
          self.get_rec(result.first)
        else
          result[0...args[1][:limit]].collect { |r| self.get_rec(r) }
        end
      end
    # Otherwise, just return the whole damn result set.
    else
      result.collect { |r| self.get_rec(r) }
    end
  end
end

.get_all_recs ⇒ Object

Table.get_all_recs



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# File 'lib/mongoose/table.rb', line 187

def self.get_all_recs
  self.with_table do |fptr|
    begin
      while true
        fpos = fptr.tell
        rec_arr = Marshal.load(fptr)

        yield rec_arr[1..-1], fpos unless rec_arr[0]
      end
    rescue EOFError
    end
  end
end

.get_rec(id) ⇒ Object

Table.get_rec

Raises:

  • (IndexCorruptError) 


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# File 'lib/mongoose/table.rb', line 333

def self.get_rec(id)
  fpos = self.id[id]

  return nil if fpos.nil?
  rec_arr = []

  self.with_table(File::RDONLY) do |fptr|
    fptr.seek(fpos)
    rec_arr = Marshal.load(fptr)
  end      

  raise IndexCorruptError, "Index references deleted record!", caller \
   if rec_arr[0]

  raise IndexCorruptError, "Index ID does not match table ID!", caller \
   unless rec_arr[1] == id

  rec = self.new(*rec_arr[1..-1])
  return rec
end

.has_many(kind) ⇒ Object

Table.has_many



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# File 'lib/mongoose/table.rb', line 68

def self.has_many(kind)
  table_name = Util.singularize(kind.to_s).to_sym
  class_name = Util.us_case_to_class_case(table_name)
  col = Util.col_name_for_class(self.to_s)

  define_method(kind.to_sym) do 
    klass = Object.const_get(class_name)
    Collection.new(self, klass.find { |r|
     r.send(col) == self.instance_eval { @id } })
  end
end

.has_one(kind) ⇒ Object

Table.has_one



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# File 'lib/mongoose/table.rb', line 83

def self.has_one(kind)
  table_name = kind.to_sym
  class_name = Util.us_case_to_class_case(table_name)
  col = Util.col_name_for_class(self.to_s)

  define_method(kind.to_sym) do
    klass = Object.const_get(class_name)
    klass.find(:first) { |r| r.send(col) == self.instance_eval { @id } }
  end
end

.init_column(col_name, col_def, col_class) ⇒ Object

Table.init_column



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# File 'lib/mongoose/table.rb', line 158

def self.init_column(col_name, col_def, col_class)
  col = col_class.create(self, col_name, col_def)

  self.columns << col

  meth = <<-END_OF_STRING
  def self.#{col_name}
    self.columns.detect { |c| c.name == "#{col_name}".to_sym } 
  end
  END_OF_STRING
  self.class_eval(meth)

  self.class_eval do
    attr_accessor col_name
  end

  col.init_index if col.indexed?
end

.init_table ⇒ Object

Table.init_table



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# File 'lib/mongoose/table.rb', line 146

def self.init_table
  tbl_header = self.read_header

  self.read_header[:columns].each do |c| 
    self.init_column(c[:name], c[:data_type], Object.full_const_get(c[:class])
     ) 
  end
end

.last_id_used ⇒ Object

Table.last_id_used



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# File 'lib/mongoose/table.rb', line 116

def self.last_id_used
  self.class.read_header[:last_id_used]
end

.path ⇒ Object

Table.path



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# File 'lib/mongoose/table.rb', line 52

def self.path
  self.db.path
end

.query ⇒ Object

Table.query



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# File 'lib/mongoose/table.rb', line 24

def self.query
  self.db.tables[self][:query]
end

.read_header ⇒ Object

Table.read_header



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# File 'lib/mongoose/table.rb', line 130

def self.read_header
  YAML.load(File.open(File.join(self.path, self.table_name.to_s +
   TBL_HDR_EXT), 'r'))
end

.table_name ⇒ Object

Table.table_name



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# File 'lib/mongoose/table.rb', line 31

def self.table_name
  self.db.tables[self][:table_name]
end

.validates_presence_of(*col_names) ⇒ Object

Table.validates_presence_of



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# File 'lib/mongoose/table.rb', line 59

def self.validates_presence_of(*col_names)
  define_method(:required?) do |col_name|
    col_names.include?(col_name)
  end
end

.with_table(access = 'r') ⇒ Object

Table.with_table



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# File 'lib/mongoose/table.rb', line 357

def self.with_table(access='r')
  begin
    yield fptr = open(File.join(self.db.path, self.table_name.to_s + TBL_EXT), 
     access)
  ensure
    fptr.close
  end
end

.write_header(header) ⇒ Object

Table.write_header



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# File 'lib/mongoose/table.rb', line 138

def self.write_header(header)
  File.open(File.join(self.path, self.table_name.to_s + TBL_HDR_EXT), 'w'
   ) { |f| YAML.dump(header, f) }
end

Instance Method Details

#destroy ⇒ Object

destroy



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# File 'lib/mongoose/table.rb', line 401

def destroy
  fpos_rec_start = self.class.id[@id]

  self.class.with_table(File::RDWR) do |fptr|
    fptr.seek(fpos_rec_start)

    rec = Marshal.load(fptr)
    
    raise IndexCorruptError, "Index ID does not match table ID!", caller \
     unless rec[1] == @id

    # First array position of record is the deleted flag:  true means deleted
    rec[0] = true

    # Record is not actually deleted; it just has its deleted flag set to
    # true.
    write_record(fptr, fpos_rec_start, Marshal.dump(rec))
    increment_deleted_recs_counter
  end

  # Remove all index recs pointing to this record.
  self.class.columns.each_with_index do |c,i|
    if i == 0
      c.remove_index_rec(@id)
    elsif c.indexed?
      c.remove_index_rec(send(c.name), @id)
    end
  end

  # Don't allow any more changes to this record.
  freeze
end

#save ⇒ Object

save



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# File 'lib/mongoose/table.rb', line 376

def save
  self.class.columns.each do |c|
    # First checks to see if validates_presence_of was set in class def.
    raise "Value required for #{c.name}!" if respond_to?('required?') and \
     required?(c.name) and send(c.name).nil?
    # Next checks to see if validates_presence_of was set in #add_column.
    raise "Value required for #{c.name}!" if c.required? and send(c.name).nil?
  end

  # Add new record.
  if @id.nil?
    id = increment_last_id_used
    append_record(id, self.class.column_names[1..-1].collect { |col_name| 
     send(col_name) })
    @id = id
  # Update existing record.
  else
    update_record(@id, self.class.columns[1..-1].collect { |c| send(c.name) })
  end
  return true
end