[util/hb-subset] Move output-file validation code into post_parse

util/hb-shape.cc

@@ -36,7 +36,7 @@
 const unsigned DEFAULT_FONT_SIZE = FONT_SIZE_UPEM;
 const unsigned SUBPIXEL_BITS = 0;
 
-struct output_buffer_t : output_options_t
+struct output_buffer_t : output_options_t<>
 {
   void add_options (option_parser_t *parser)
   {

util/hb-subset.cc

@@ -38,7 +38,7 @@
  * Command line interface to the harfbuzz font subsetter.
  */
 
-struct subset_main_t : option_parser_t, face_options_t, text_options_t, subset_options_t, output_options_t
+struct subset_main_t : option_parser_t, face_options_t, text_options_t, subset_options_t, output_options_t<false>
 {
   int operator () (int argc, char **argv)
   {
@@ -92,8 +92,7 @@ struct subset_main_t : option_parser_t, face_options_t, text_options_t, subset_o
   bool
   write_file (const char *output_file, hb_blob_t *blob)
   {
-    if (!output_file)
+    assert (out_fp);
-      fail (true, "No output file was specified");
 
     unsigned int size;
     const char* data = hb_blob_get_data (blob, &size);

util/helper-cairo.hh

@@ -426,6 +426,8 @@ static const char *helper_cairo_supported_formats[] =
   nullptr
 };
 
+template <typename view_options_t,
+	 typename output_options_t>
 static inline cairo_t *
 helper_cairo_create_context (double w, double h,
 			     view_options_t *view_opts,

util/output-options.hh

@@ -29,6 +29,7 @@
 
 #include "options.hh"
 
+template <bool default_stdout = true>
 struct output_options_t
 {
   ~output_options_t ()
@@ -40,57 +41,7 @@ struct output_options_t
   }
 
   void add_options (option_parser_t *parser,
-		    const char **supported_formats = nullptr);
+		    const char **supported_formats = nullptr)
-
-  void post_parse (GError **error G_GNUC_UNUSED);
-
-  char *output_file = nullptr;
-  char *output_format = nullptr;
-
-  bool explicit_output_format = false;
-  FILE *out_fp = nullptr;
-};
-
-void
-output_options_t::post_parse (GError **error)
-{
-  if (output_format)
-    explicit_output_format = true;
-
-  if (output_file && !output_format)
-  {
-    output_format = strrchr (output_file, '.');
-    if (output_format)
-    {
-	output_format++; /* skip the dot */
-	output_format = g_strdup (output_format);
-    }
-  }
-
-  if (output_file && 0 == strcmp (output_file, "-"))
-    output_file = nullptr; /* STDOUT */
-
-  if (output_file)
-    out_fp = fopen (output_file, "wb");
-  else
-  {
-#if defined(_WIN32) || defined(__CYGWIN__)
-    setmode (fileno (stdout), O_BINARY);
-#endif
-    out_fp = stdout;
-  }
-  if (!out_fp)
-  {
-    g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_FAILED,
-		 "Cannot open output file `%s': %s",
-		 g_filename_display_name (output_file), strerror (errno));
-    return;
-  }
-}
-
-void
-output_options_t::add_options (option_parser_t *parser,
-			       const char **supported_formats)
   {
     const char *text = nullptr;
 
@@ -116,4 +67,51 @@ output_options_t::add_options (option_parser_t *parser,
 		       this);
   }
 
+  void post_parse (GError **error)
+  {
+    if (output_format)
+      explicit_output_format = true;
+
+    if (output_file && !output_format)
+    {
+      output_format = strrchr (output_file, '.');
+      if (output_format)
+      {
+	  output_format++; /* skip the dot */
+	  output_format = g_strdup (output_format);
+      }
+    }
+
+    if (output_file && 0 != strcmp (output_file, "-"))
+      out_fp = fopen (output_file, "wb");
+    else
+    {
+      if (!default_stdout && !output_file)
+      {
+	g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_FAILED,
+		     "No output file was specified");
+        return;
+      }
+
+#if defined(_WIN32) || defined(__CYGWIN__)
+      setmode (fileno (stdout), O_BINARY);
+#endif
+      out_fp = stdout;
+    }
+    if (!out_fp)
+    {
+      g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_FAILED,
+		   "Cannot open output file `%s': %s",
+		   g_filename_display_name (output_file), strerror (errno));
+      return;
+    }
+  }
+
+  char *output_file = nullptr;
+  char *output_format = nullptr;
+
+  bool explicit_output_format = false;
+  FILE *out_fp = nullptr;
+};
+
 #endif

util/view-cairo.hh

@@ -31,7 +31,7 @@
 #include "output-options.hh"
 #include "helper-cairo.hh"
 
-struct view_cairo_t : view_options_t, output_options_t
+struct view_cairo_t : view_options_t, output_options_t<>
 {
   ~view_cairo_t ()
   {