Highlighting of text parts and source codes

This adds 'Format as' submenu to the preview pane context menu.
The submenu is available only for text/plain parts or parts
with a source code (we support about 40 various types). Using
the 'highlight' utility, the formatter processes the part and
highlights the source code it contains.

(discussion in bug #680026)

1 files changed, 159 insertions, 0 deletions

diff --git a/modules/text-highlight/e-mail-parser-text-highlight.c b/modules/text-highlight/e-mail-parser-text-highlight.c
new file mode 100644
index 0000000000..328e590f6d
--- /dev/null
+++ b/modules/text-highlight/e-mail-parser-text-highlight.c
@@ -0,0 +1,159 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with the program; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <gtk/gtk.h>
+#include <glib/gi18n.h>
+#include <camel/camel.h>
+
+#include "e-mail-parser-text-highlight.h"
+#include "languages.h"
+
+#include <em-format/e-mail-extension-registry.h>
+#include <em-format/e-mail-parser-extension.h>
+#include <em-format/e-mail-part.h>
+#include <em-format/e-mail-part-utils.h>
+
+#include <libebackend/libebackend.h>
+
+#define d(x)
+
+typedef struct _EMailParserTextHighlight {
+	EExtension parent;
+} EMailParserTextHighlight;
+
+typedef struct _EMailParserTextHighlightClass {
+	EExtensionClass parent_class;
+} EMailParserTextHighlightClass;
+
+GType e_mail_parser_text_highlight_get_type (void);
+static void e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface);
+static void e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface);
+
+G_DEFINE_DYNAMIC_TYPE_EXTENDED (
+	EMailParserTextHighlight,
+	e_mail_parser_text_highlight,
+	E_TYPE_EXTENSION,
+	0,
+	G_IMPLEMENT_INTERFACE_DYNAMIC (
+		E_TYPE_MAIL_EXTENSION,
+		e_mail_parser_mail_extension_interface_init)
+	G_IMPLEMENT_INTERFACE_DYNAMIC (
+		E_TYPE_MAIL_PARSER_EXTENSION,
+		e_mail_parser_parser_extension_interface_init));
+
+static GSList *
+empe_text_highlight_parse (EMailParserExtension *extension,
+			   EMailParser *parser,
+			   CamelMimePart *part,
+			   GString *part_id,
+			   GCancellable *cancellable)
+{
+	GSList *parts;
+	gint len;
+	CamelContentType *ct;
+
+	/* Prevent recursion */
+	if (strstr (part_id->str, ".text-highlight") != NULL) {
+		return NULL;
+	}
+
+	/* Don't parse text/html if it's not an attachment */
+	ct = camel_mime_part_get_content_type (part);
+	if (camel_content_type_is (ct, "text", "html")) {
+		const CamelContentDisposition *disp;
+
+		disp = camel_mime_part_get_content_disposition (part);
+		if (!disp || (g_strcmp0 (disp->disposition, "attachment") != 0)) {
+			return NULL;
+		}
+	}
+
+	len = part_id->len;
+	g_string_append (part_id, ".text-highlight");
+
+	/* All source codes and scripts are in general plain texts,
+	 * so let text/plain parser handle it. */
+	parts = e_mail_parser_parse_part_as (
+			parser, part, part_id, "text/plain", cancellable);
+
+	g_string_truncate (part_id, len);
+
+	return parts;
+}
+
+static const gchar **
+empe_mime_types (EMailExtension *extension)
+{
+	return get_mime_types ();
+}
+
+void
+e_mail_parser_text_highlight_type_register (GTypeModule *type_module)
+{
+	e_mail_parser_text_highlight_register_type (type_module);
+}
+
+static void
+e_mail_parser_mail_extension_interface_init (EMailExtensionInterface *iface)
+{
+	iface->mime_types = empe_mime_types;
+}
+
+static void
+e_mail_parser_parser_extension_interface_init (EMailParserExtensionInterface *iface)
+{
+	iface->parse = empe_text_highlight_parse;
+}
+
+static void
+e_mail_parser_text_highlight_constructed (GObject *object)
+{
+	EExtensible *extensible;
+	EMailExtensionRegistry *reg;
+
+	extensible = e_extension_get_extensible (E_EXTENSION (object));
+	reg = E_MAIL_EXTENSION_REGISTRY (extensible);
+
+	e_mail_extension_registry_add_extension (reg, E_MAIL_EXTENSION (object));
+}
+
+static void
+e_mail_parser_text_highlight_class_init (EMailParserTextHighlightClass *class)
+{
+	GObjectClass *object_class;
+	EExtensionClass *extension_class;
+
+	object_class = G_OBJECT_CLASS (class);
+	object_class->constructed = e_mail_parser_text_highlight_constructed;
+
+	extension_class = E_EXTENSION_CLASS (class);
+	extension_class->extensible_type = E_TYPE_MAIL_PARSER_EXTENSION_REGISTRY;
+}
+
+void
+e_mail_parser_text_highlight_class_finalize (EMailParserTextHighlightClass *class)
+{
+}
+
+static void
+e_mail_parser_text_highlight_init (EMailParserTextHighlight *parser)
+{
+
+}