Class: RobustExcelOle::BookStore

Inherits:
Object
  • Object
show all
Defined in:
lib/robust_excel_ole/book_store.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ BookStore

Returns a new instance of BookStore.



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# File 'lib/robust_excel_ole/book_store.rb', line 8

def initialize
  @filename2books = Hash.new {|hash, key| hash[key] = [] }
  @hidden_excel_instance = nil
end

Instance Method Details

#fetch(filename, options = {:prefer_writable => true }) ⇒ Object

returns a book with the given filename, if it was open once prefers open books to closed books, and among them, prefers more recently opened books excludes hidden Excel instance options: :prefer_writable return the writable book, if it is open (default: true)

                   otherwise return the book according to the preference order mentioned above
:prefer_excel      return the book in the given excel instance, if it exists,
                   otherwise proceed according to prefer_writable



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# File 'lib/robust_excel_ole/book_store.rb', line 20

def fetch(filename, options = {:prefer_writable => true })
  filename_key = RobustExcelOle::canonize(filename)
  weakref_books = @filename2books[filename_key]
  return nil unless weakref_books
  result = open_book = closed_book = nil      
  weakref_books.each do |wr_book|
    if (not wr_book.weakref_alive?)
      begin 
        @filename2books[filename_key].delete(wr_book)
      rescue
        puts "Warning: deleting dead reference failed! (file: #{filename})"
      end
    else
      book = wr_book.__getobj__
      next if book.excel == try_hidden_excel
      if options[:prefer_excel] && book.excel == options[:prefer_excel]
        result = book
        break 
      end
      if book.alive?
        open_book = book
        break if (book.writable && options[:prefer_writable])
      else
        closed_book = book
      end
    end
  end
  result = result ? result : (open_book ? open_book : closed_book)
  result if result
end

#hidden_excel ⇒ Object

creates and returns a separate Excel instance with Visible and DisplayAlerts false



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# File 'lib/robust_excel_ole/book_store.rb', line 64

def hidden_excel
  unless (@hidden_excel_instance &&  @hidden_excel_instance.weakref_alive? && @hidden_excel_instance.__getobj__.alive?)       
    @hidden_excel_instance = WeakRef.new(Excel.create) 
  end
  @hidden_excel_instance.__getobj__
end

#store(book) ⇒ Object

stores a book



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# File 'lib/robust_excel_ole/book_store.rb', line 52

def store(book)
  filename_key = RobustExcelOle::canonize(book.filename)      
  if book.stored_filename
    old_filename_key = RobustExcelOle::canonize(book.stored_filename)
    # deletes the weak reference to the book
    @filename2books[old_filename_key].delete(book)
  end
  @filename2books[filename_key] |= [WeakRef.new(book)]
  book.stored_filename = book.filename
end