[gtk/wip/otte/widgetfactory-dnd: 1/7] contentformats: Add gdk_content_formats_parse()

[Benjamin Otte <otte src gnome org>]

commit 131be5f2e8c307fd70a7b3e302564159c4d935bf
Author: Benjamin Otte <otte redhat com>
Date:   Mon Jul 26 02:33:31 2021 +0200

    contentformats: Add gdk_content_formats_parse()

 gdk/gdkcontentformats.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++---
 gdk/gdkcontentformats.h |  2 ++
 2 files changed, 76 insertions(+), 4 deletions(-)
---
diff --git a/gdk/gdkcontentformats.c b/gdk/gdkcontentformats.c
index 24ac00ad14..662ff1b825 100644
--- a/gdk/gdkcontentformats.c
+++ b/gdk/gdkcontentformats.c
@@ -179,6 +179,76 @@ gdk_content_formats_new_for_gtype (GType type)
   return gdk_content_formats_new_take (data, 1, NULL, 0);
 }
 
+/**
+ * gdk_content_formats_parse:
+ * @string: the string to parse
+ *
+ * Parses the given @string into `GdkContentFormats` and
+ * returns the formats. 
+ *
+ * Strings printed via [method@Gdk.ContentFormats.to_string]
+ * can be read in again successfully using this function.
+ *
+ * If @string does not describe valid content formats, %NULL
+ * is returned.
+ *
+ * Returns: (nullable): the content formats if @string is valid
+ *
+ * Since: 4.4
+ */
+GdkContentFormats *
+gdk_content_formats_parse (const char *string)
+{
+  GdkContentFormatsBuilder *builder;
+  char **split;
+  gsize i;
+
+  g_return_val_if_fail (string != NULL, NULL);
+
+  split = g_strsplit_set (string, "\t\n\f\r ", -1); /* same as g_ascii_isspace() */
+  builder = gdk_content_formats_builder_new ();
+
+  /* first the GTypes */
+  for (i = 0; split[i] != NULL; i++)
+    {
+      GType type;
+
+      if (split[i][0] == 0)
+        continue;
+
+      type = g_type_from_name (split[i]);
+      if (type != 0)
+        gdk_content_formats_builder_add_gtype (builder, type);
+      else
+        break;
+    }
+
+  /* then the mime types */
+  for (; split[i] != NULL; i++)
+    {
+      const char *mime_type;
+
+      if (split[i][0] == 0)
+        continue;
+
+      mime_type = gdk_intern_mime_type (split[i]);
+      if (mime_type)
+        gdk_content_formats_builder_add_mime_type (builder, mime_type);
+      else
+        break;
+    }
+
+  if (split[i] != NULL)
+    {
+      g_strfreev (split);
+      gdk_content_formats_builder_unref (builder);
+      return NULL;
+    }
+
+  g_strfreev (split);
+  return gdk_content_formats_builder_free_to_formats (builder);
+}
+
 /**
  * gdk_content_formats_ref:
  * @formats:  a `GdkContentFormats`
@@ -227,10 +297,8 @@ gdk_content_formats_unref (GdkContentFormats *formats)
  *
  * Prints the given @formats into a string for human consumption.
  *
- * This is meant for debugging and logging.
- *
- * The form of the representation may change at any time and is
- * not guaranteed to stay identical.
+ * The result of this function can later be parsed with
+ * [func@Gdk.ContentFormats.parse].
  */
 void
 gdk_content_formats_print (GdkContentFormats *formats,
@@ -261,6 +329,8 @@ gdk_content_formats_print (GdkContentFormats *formats,
  *
  * Prints the given @formats into a human-readable string.
  *
+ * The resulting string can be parsed with [func@Gdk.ContentFormats.parse].
+ *
  * This is a small wrapper around [method@Gdk.ContentFormats.print]
  * to help when debugging.
  *
diff --git a/gdk/gdkcontentformats.h b/gdk/gdkcontentformats.h
index 1798c48284..143a669340 100644
--- a/gdk/gdkcontentformats.h
+++ b/gdk/gdkcontentformats.h
@@ -40,6 +40,8 @@ GdkContentFormats *     gdk_content_formats_new                 (const char
                                                                  guint                           
n_mime_types);
 GDK_AVAILABLE_IN_ALL
 GdkContentFormats *     gdk_content_formats_new_for_gtype       (GType                           type);
+GDK_AVAILABLE_IN_4_4
+GdkContentFormats *     gdk_content_formats_parse               (const char                     *string);
 GDK_AVAILABLE_IN_ALL
 GdkContentFormats *     gdk_content_formats_ref                 (GdkContentFormats              *formats);
 GDK_AVAILABLE_IN_ALL