erubi.rb in erubi-1.1.0

- old
+ new

@@ -1,21 +1,25 @@
 # frozen_string_literal: true
 
 module Erubi
   ESCAPE_TABLE = {'&' => '&amp;'.freeze, '<' => '&lt;'.freeze, '>' => '&gt;'.freeze, '"' => '&quot;'.freeze, "'" => '&#039;'.freeze}.freeze
-  RANGE_FIRST = 0..0
   RANGE_ALL = 0..-1
-  RANGE_LAST = -1..-1
 
   if RUBY_VERSION >= '1.9'
+    RANGE_FIRST = 0
+    RANGE_LAST = -1
+
     # Escape the following characters with their HTML/XML
     # equivalents.
     def self.h(value)
       value.to_s.gsub(/[&<>"']/, ESCAPE_TABLE)
     end
   else
     # :nocov:
+    RANGE_FIRST = 0..0
+    RANGE_LAST = -1..-1
+
     def self.h(value)
       value.to_s.gsub(/[&<>"']/){|s| ESCAPE_TABLE[s]}
     end
     # :nocov:
   end
@@ -29,30 +33,37 @@
 
     # The variable name used for the buffer variable.
     attr_reader :bufvar
 
     # Initialize a new Erubi::Engine.  Options:
+    # :bufval :: The value to use for the buffer variable, as a string.
     # :bufvar :: The variable name to use for the buffer variable, as a string.
+    # :ensure :: Wrap the template in a begin/ensure block restoring the previous value of bufvar.
     # :escapefunc :: The function to use for escaping, as a string (default: ::Erubi.h).
     # :escape :: Whether to make <%= escape by default, and <%== not escape by default.
     # :escape_html :: Same as :escape, with lower priority.
     # :filename :: The filename for the template.
     # :freeze :: Whether to enable frozen string literals in the resulting source code.
     # :outvar :: Same as bufvar, with lower priority.
-    # :postable :: the postamble for the template, by default returns the resulting source code.
+    # :postamble :: The postamble for the template, by default returns the resulting source code.
     # :preamble :: The preamble for the template, by default initializes up the buffer variable.
+    # :regexp :: The regexp to use for scanning.
+    # :src :: The initial value to use for the source code
     # :trim :: Whether to trim leading and trailing whitespace, true by default.
     def initialize(input, properties={})
       escape     = properties.fetch(:escape){properties.fetch(:escape_html, false)}
       trim       = properties[:trim] != false
       @filename  = properties[:filename]
       @bufvar = bufvar = properties[:bufvar] || properties[:outvar] || "_buf"
-      preamble   = properties[:preamble] || "#{bufvar} = String.new;"
+      bufval = properties[:bufval] || 'String.new'
+      regexp = properties[:regexp] || /<%(={1,2}|-|\#|%)?(.*?)([-=])?%>([ \t]*\r?\n)?/m
+      preamble   = properties[:preamble] || "#{bufvar} = #{bufval};"
       postamble  = properties[:postamble] || "#{bufvar}.to_s\n"
 
-      @src = src = String.new
+      @src = src = properties[:src] || String.new
       src << "# frozen_string_literal: true\n" if properties[:freeze]
+      src << "begin; __original_outvar = #{bufvar} if defined?(#{bufvar}); " if properties[:ensure]
 
       unless escapefunc = properties[:escapefunc]
         if escape
           escapefunc = '__erubi.h'
           src << "__erubi = ::Erubi;"
@@ -63,16 +74,17 @@
 
       src << preamble
 
       pos = 0
       is_bol = true
-      input.scan(/<%(={1,2}|-|\#|%)?(.*?)([-=])?%>([ \t]*\r?\n)?/m) do |indicator, code, tailch, rspace|
+      input.scan(regexp) do |indicator, code, tailch, rspace|
         match = Regexp.last_match
         len  = match.begin(0) - pos
         text = input[pos, len]
         pos  = match.end(0)
         ch   = indicator ? indicator[RANGE_FIRST] : nil
+
         lspace = nil
 
         unless ch == '='
           if text.empty?
             lspace = "" if is_bol
@@ -96,45 +108,49 @@
           end
         end
 
         is_bol = rspace ? true : false
         add_text(text) if text && !text.empty?
-        if ch == '='
+        case ch
+        when '='
           rspace = nil if tailch && !tailch.empty?
           add_text(lspace) if lspace
           if ((indicator == '=') ^ escape)
             src << " #{bufvar} << (" << code << ').to_s;'
           else
             src << " #{bufvar} << #{escapefunc}((" << code << '));'
           end
           add_text(rspace) if rspace
-        elsif ch == '#'
+        when '#'
           n = code.count("\n") + (rspace ? 1 : 0)
           if trim
             add_code("\n" * n)
           else
             add_text(lspace) if lspace
             add_code("\n" * n)
             add_text(rspace) if rspace
           end
-        elsif ch == '%'
+        when '%'
           add_text("#{lspace}#{prefix||='<%'}#{code}#{tailch}#{postfix||='%>'}#{rspace}")
-        else
+        when nil, '-'
           if trim
             add_code("#{lspace}#{code}#{rspace}")
           else
             add_text(lspace) if lspace
             add_code(code)
             add_text(rspace) if rspace
           end
+        else
+          handle(indicator, code, tailch, rspace, lspace)
         end
       end
       rest = pos == 0 ? input : input[pos..-1]
       add_text(rest)
 
       src << "\n" unless src[RANGE_LAST] == "\n"
       src << postamble
+      src << "; ensure\n  #{bufvar} = __original_outvar\nend\n" if properties[:ensure]
       freeze
     end
 
     private
 
@@ -145,8 +161,13 @@
 
     # Add ruby code to the template
     def add_code(code)
       @src << code
       @src << ';' unless code[RANGE_LAST] == "\n"
+    end
+
+    # Raise an exception, as the base engine class does not support handling other indicators.
+    def handle(indicator, code, tailch, rspace, lspace)
+      raise ArgumentError, "Invalid indicator: #{indicator}"
     end
   end
 end