Add "noclobber_cssfile" (#396) option to HTML formatter.

1 files changed, 17 insertions, 6 deletions

diff --git a/pygments/formatters/html.py b/pygments/formatters/html.py
index 6e263a12..b99fdea2 100644
--- a/pygments/formatters/html.py
+++ b/pygments/formatters/html.py
@@ -186,7 +186,9 @@ class HtmlFormatter(Formatter):
 
     `style`
         The style to use, can be a string or a Style subclass (default:
-        ``'default'``).
+        ``'default'``). This option has no effect if the `cssfile`
+        and `noclobber_cssfile` option are given and the file specified in
+        `cssfile` exists.
 
     `noclasses`
         If set to true, token ``<span>`` tags will not use CSS classes, but
@@ -223,6 +225,12 @@ class HtmlFormatter(Formatter):
         file's path, if the latter can be found. The stylesheet is then written
         to this file instead of the HTML file. *New in Pygments 0.6.*
 
+    `noclobber_cssfile'
+        If `cssfile` is given and the specified file exists, the css file will
+        not be overwritten. This allows the use of the `full` option in
+        combination with a user specified css file. Default is ``False``.
+        *New in Pygments 1.1.*
+
     `linenos`
         If set to ``'table'``, output line numbers as a table with two cells,
         one containing the line numbers, the other the whole code.  This is
@@ -342,6 +350,8 @@ class HtmlFormatter(Formatter):
         self.cssstyles = self._encodeifneeded(options.get('cssstyles', ''))
         self.prestyles = self._encodeifneeded(options.get('prestyles', ''))
         self.cssfile = self._encodeifneeded(options.get('cssfile', ''))
+        self.noclobber_cssfile = get_bool_opt(options, 'noclobber_cssfile', False)
+
         linenos = options.get('linenos', False)
         if linenos == 'inline':
             self.linenos = 2
@@ -460,12 +470,13 @@ class HtmlFormatter(Formatter):
                     print >>sys.stderr, 'Note: Cannot determine output file name, ' \
                           'using current directory as base for the CSS file name'
                     cssfilename = self.cssfile
-            # write CSS file
+            # write CSS file only if noclobber_cssfile isn't given as an option.
             try:
-                cf = open(cssfilename, "w")
-                cf.write(CSSFILE_TEMPLATE %
-                         {'styledefs': self.get_style_defs('body')})
-                cf.close()
+                if not os.path.exists(cssfilename) or not self.noclobber_cssfile:
+                    cf = open(cssfilename, "w")
+                    cf.write(CSSFILE_TEMPLATE %
+                            {'styledefs': self.get_style_defs('body')})
+                    cf.close()
             except IOError, err:
                 err.strerror = 'Error writing CSS file: ' + err.strerror
                 raise