lib/fast_excel.rb in fast_excel-0.2.3 vs lib/fast_excel.rb in fast_excel-0.2.5

@@ -11,20 +11,20 @@
 
   DEF_COL_WIDTH = 8.43
 
   def self.open(filename = nil, constant_memory: false, default_format: nil)
     tmp_file = false
-    unless filename
+    if filename
+      if File.exist?(filename)
+        raise ArgumentError, "File '#{filename}' already exists. FastExcel can not open existing files, only create new files"
+      end
+    else
       require 'tmpdir'
       filename = "#{Dir.mktmpdir}/fast_excel.xlsx"
       tmp_file = true
     end
 
-    unless filename
-      raise ArgumentError, "filename is required"
-    end
-
     filename = filename.to_s if defined?(Pathname) && filename.is_a?(Pathname)
 
     workbook = if constant_memory
       opt = Libxlsxwriter::WorkbookOptions.new
       opt[:constant_memory] = 1
@@ -321,10 +321,11 @@
     include AttributeHelper
     attr_accessor :tmp_file, :is_open, :filename
 
     def initialize(struct)
       @is_open = true
+      @sheet_names = Set.new
       super(struct)
     end
 
     def add_format(options = nil)
       new_format = super()
@@ -345,11 +346,26 @@
       format.set_num_format(pattern)
       format
     end
 
     def add_worksheet(sheetname = nil)
+      sheetname = nil if sheetname == ""
+
+      if !sheetname.nil? && @sheet_names.include?(sheetname)
+        raise ArgumentError, "Worksheet name '#{sheetname}' is already in use"
+      end
+      @sheet_names << sheetname
+
       sheet = super
       sheet.workbook = self
+
+      sheet
+    end
+
+    def get_worksheet_by_name(name)
+      sheet = super(name)
+      sheet.workbook = self
+
       sheet
     end
 
     def close
       @is_open = false