Class: ActiveDocument::Database

Inherits:
Object
  • Object
show all
Defined in:
lib/active_document/database.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ Database

Returns a new instance of Database.



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# File 'lib/active_document/database.rb', line 2

def initialize(opts)
  @model_class = opts[:model_class]
  @field       = opts[:field]
  @unique      = opts[:unique]
  @suffix      = opts[:suffix] || (@field ? "by_#{@field}" : nil)
end

Instance Attribute Details

#db ⇒ Object

Returns the value of attribute db.



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# File 'lib/active_document/database.rb', line 9

def db
  @db
end

#field ⇒ Object

Returns the value of attribute field.



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# File 'lib/active_document/database.rb', line 9

def field
  @field
end

#model_class ⇒ Object

Returns the value of attribute model_class.



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# File 'lib/active_document/database.rb', line 9

def model_class
  @model_class
end

#suffix ⇒ Object

Returns the value of attribute suffix.



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# File 'lib/active_document/database.rb', line 9

def suffix
  @suffix
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/active_document/database.rb', line 150

def close
  if @db
    @db.close(0)
    @db = nil
  end
end

#delete(model) ⇒ Object 



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# File 'lib/active_document/database.rb', line 119

def delete(model)
  key = Tuple.dump(model.primary_key)
  db.del(transaction, key, 0)
end

#environment ⇒ Object 



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# File 'lib/active_document/database.rb', line 15

def environment
  model_class.environment
end

#find(keys, opts = {}, &block) ⇒ Object 



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# File 'lib/active_document/database.rb', line 31

def find(keys, opts = {}, &block)
  models = block_given? ? BlockArray.new(block) : []
  flags  = opts[:modify] ? Bdb::DB_RMW : 0

  keys.uniq.each do |key|
    if opts[:partial] and not key.kind_of?(Range)
      first = [*key]
      last  = first + [true]
      key = first..last
    end

    if key == :all
      cursor = db.cursor(transaction, 0)
      if opts[:reverse]
        k,v  = cursor.get(nil, nil, Bdb::DB_LAST | flags)          # Start at the last item.
        iter = lambda {cursor.get(nil, nil, Bdb::DB_PREV | flags)} # Move backward.
      else
        k,v  = cursor.get(nil, nil, Bdb::DB_FIRST | flags)         # Start at the first item.
        iter = lambda {cursor.get(nil, nil, Bdb::DB_NEXT | flags)} # Move forward.
      end

      while k
        models << Marshal.load(v)
        break if opts[:limit] and models.size == opts[:limit]
        k,v = iter.call
      end
      cursor.close
    elsif key.kind_of?(Range)
      # Fetch a range of keys.
      cursor = db.cursor(transaction, 0)
      first = Tuple.dump(key.first)
      last  = Tuple.dump(key.last)        

      # Return false once we pass the end of the range.
      cond = key.exclude_end? ? lambda {|k| k < last} : lambda {|k| k <= last}

      if opts[:reverse]
        # Position the cursor at the end of the range.
        k,v = cursor.get(last, nil, Bdb::DB_SET_RANGE | flags)
        while k and not cond.call(k)
          k,v = iter.call
        end

        iter = lambda {cursor.get(nil, nil, Bdb::DB_PREV | flags)} # Move backward.
        cond = lambda {|k| k >= first} # Change the condition to stop when we move past the start.
      else
        k,v  = cursor.get(first, nil, Bdb::DB_SET_RANGE | flags)   # Start at the beginning of the range.
        iter = lambda {cursor.get(nil, nil, Bdb::DB_NEXT | flags)} # Move forward.
      end

      while k and cond.call(k)
        models << Marshal.load(v)
        break if opts[:limit] and models.size == opts[:limit]
        k,v = iter.call
      end
      cursor.close
    else
      if unique?
        # There can only be one item for each key.
        data = db.get(transaction, Tuple.dump(key), nil, flags)
        models << Marshal.load(data) if data
      else
        # Have to use a cursor because there may be multiple items with each key.
        cursor = db.cursor(transaction, 0)
        k,v = cursor.get(Tuple.dump(key), nil, Bdb::DB_SET | flags)
        while k
          models << Marshal.load(v)
          break if opts[:limit] and models.size == opts[:limit]
          k,v = cursor.get(nil, nil, Bdb::DB_NEXT_DUP | flags)
        end
        cursor.close
      end
    end
    break if opts[:limit] and models.size == opts[:limit]
  end

  block_given? ? nil : models
end

#name ⇒ Object 



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# File 'lib/active_document/database.rb', line 23

def name
  @name ||= [model_class.database_name, suffix].compact.join('_')
end

#open ⇒ Object 



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# File 'lib/active_document/database.rb', line 124

def open
  if @db.nil?
    @db = environment.db
    @db.flags = Bdb::DB_DUPSORT unless unique?
    @db.open(nil, name, nil, Bdb::Db::BTREE, Bdb::DB_CREATE | Bdb::DB_AUTO_COMMIT, 0)
    
    if primary_db
      index_callback = lambda do |db, key, data|
        model = Marshal.load(data)
        return unless model.kind_of?(model_class)
        
        index_key = model.send(field)
        if index_key.kind_of?(Array)
          # Index multiple keys. If the key is an array, you must wrap it with an outer array.
          index_key.collect {|k| Tuple.dump(k)}
        elsif index_key
          # Index a single key.
          Tuple.dump(index_key)
        end
      end
      
      primary_db.associate(nil, @db, 0, index_callback)
    end
  end
end

#primary_db ⇒ Object 



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# File 'lib/active_document/database.rb', line 19

def primary_db
  model_class.database.db if field
end

#save(model, opts = {}) ⇒ Object 



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# File 'lib/active_document/database.rb', line 110

def save(model, opts = {})
  key   = Tuple.dump(model.primary_key)
  data  = Marshal.dump(model)
  flags = opts[:create] ? Bdb::DB_NOOVERWRITE : 0
  db.put(transaction, key, data, flags)
rescue Bdb::DbError => e
  raise ActiveDocument::DuplicatePrimaryKey, "primary key #{model.primary_key.inspect} already exists"
end

#transaction ⇒ Object 



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# File 'lib/active_document/database.rb', line 27

def transaction
  environment.transaction
end

#unique? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_document/database.rb', line 11

def unique?
  @unique
end