[gtk/wip/otte/css: 9/10] easevalue: Use gtk_css_parser_consume_function()

[Benjamin Otte <otte src gnome org>]

commit 913349d116d3ef1593d1192a1f0773d3203e99ce
Author: Benjamin Otte <otte redhat com>
Date:   Sun Mar 31 14:41:45 2019 +0200

    easevalue: Use gtk_css_parser_consume_function()

 gtk/gtkcsseasevalue.c | 117 ++++++++++++++++++++++++++------------------------
 1 file changed, 62 insertions(+), 55 deletions(-)
---
diff --git a/gtk/gtkcsseasevalue.c b/gtk/gtkcsseasevalue.c
index 319adee729..1a1e66c92a 100644
--- a/gtk/gtkcsseasevalue.c
+++ b/gtk/gtkcsseasevalue.c
@@ -216,86 +216,93 @@ _gtk_css_ease_value_can_parse (GtkCssParser *parser)
   return FALSE;
 }
 
-static GtkCssValue *
-gtk_css_ease_value_parse_cubic_bezier (GtkCssParser *parser)
+static guint
+gtk_css_ease_value_parse_cubic_bezier_arg (GtkCssParser *parser,
+                                           guint         arg,
+                                           gpointer      data)
 {
-  double values[4];
-  guint i;
+  double *values = data;
+
+  if (!gtk_css_parser_consume_number (parser, &values[arg]))
+    return 0;
 
-  for (i = 0; i < 4; i++)
+  if (arg % 2 == 0)
     {
-      if (!_gtk_css_parser_try (parser, i ? "," : "cubic-bezier(", TRUE))
+      if (values[arg] < 0 || values[arg] > 1.0)
         {
-          _gtk_css_parser_error (parser, "Expected '%s'", i ? "," : "(");
-          return NULL;
-        }
-      if (!_gtk_css_parser_try_double (parser, &values[i]))
-        {
-          _gtk_css_parser_error (parser, "Expected a number");
-          return NULL;
-        }
-      if ((i == 0 || i == 2) &&
-          (values[i] < 0 || values[i] > 1.0))
-        {
-          _gtk_css_parser_error (parser, "value %g out of range. Must be from 0.0 to 1.0", values[i]);
-          return NULL;
+          _gtk_css_parser_error (parser, "value %g out of range. Must be from 0.0 to 1.0", values[arg]);
+          return 0;
         }
     }
 
-  if (!_gtk_css_parser_try (parser, ")", TRUE))
-    {
-      _gtk_css_parser_error (parser, "Missing closing ')' for cubic-bezier");
-      return NULL;
-    }
+  return 1;
+}
+
+static GtkCssValue *
+gtk_css_ease_value_parse_cubic_bezier (GtkCssParser *parser)
+{
+  double values[4];
+
+  if (!gtk_css_parser_consume_function (parser, 4, 4, gtk_css_ease_value_parse_cubic_bezier_arg, values))
+    return NULL;
 
   return _gtk_css_ease_value_new_cubic_bezier (values[0], values[1], values[2], values[3]);
 }
 
-static GtkCssValue *
-gtk_css_ease_value_parse_steps (GtkCssParser *parser)
+typedef struct 
 {
   int n_steps;
   gboolean start;
+} ParseStepsData;
 
-  if (!_gtk_css_parser_try (parser, "steps(", TRUE))
-    {
-      _gtk_css_parser_error (parser, "Expected '('");
-      return NULL;
-    }
+static guint
+gtk_css_ease_value_parse_steps_arg (GtkCssParser *parser,
+                                    guint         arg,
+                                    gpointer      data_)
+{
+  ParseStepsData *data = data_;
 
-  if (!_gtk_css_parser_try_int (parser, &n_steps))
-    {
-      _gtk_css_parser_error (parser, "Expected number of steps");
-      return NULL;
-    }
-  else if (n_steps < 1)
-    {
-      _gtk_css_parser_error (parser, "Number of steps must be > 0");
-      return NULL;
-    }
+  switch (arg)
+  {
+    case 0:
+      if (!_gtk_css_parser_try_int (parser, &data->n_steps))
+        {
+          _gtk_css_parser_error (parser, "Expected number of steps");
+          return 0;
+        }
+      else if (data->n_steps < 1)
+        {
+          _gtk_css_parser_error (parser, "Number of steps must be > 0");
+          return 0;
+        }
+      return 1;
 
-  if (_gtk_css_parser_try (parser, ",", TRUE))
-    {
+    case 1:
       if (gtk_css_parser_try_ident (parser, "start"))
-        start = TRUE;
+        data->start = TRUE;
       else if (gtk_css_parser_try_ident (parser, "end"))
-        start = FALSE;
+        data->start = FALSE;
       else
         {
           _gtk_css_parser_error (parser, "Only allowed values are 'start' and 'end'");
-          return NULL;
+          return 0;
         }
-    }
-  else
-    start = FALSE;
+      return 1;
 
-  if (!_gtk_css_parser_try (parser, ")", TRUE))
-    {
-      _gtk_css_parser_error (parser, "Missing closing ')' for steps");
-      return NULL;
-    }
+    default:
+      g_return_val_if_reached (0);
+  }
+}
+
+static GtkCssValue *
+gtk_css_ease_value_parse_steps (GtkCssParser *parser)
+{
+  ParseStepsData data = { 0, FALSE };  
+
+  if (!gtk_css_parser_consume_function (parser, 1, 2, gtk_css_ease_value_parse_steps_arg, &data))
+    return NULL;
 
-  return _gtk_css_ease_value_new_steps (n_steps, start);
+  return _gtk_css_ease_value_new_steps (data.n_steps, data.start);
 }
 
 GtkCssValue *