Add e_web_view_suggest_filename().

Attempts to derive a suggested filename from the given URI for use in a
"Save As" dialog.

By default the suggested filename is the last path segment of the given
URI (the unless the given URI looks like a query), but subclasses can use
other mechanisms for custom URI schemes.  For example, "cid:" URIs in an
email message may refer to a MIME part with a suggested filename in its
Content-Disposition header.

doc/reference/evolution-util/evolution-util-sections.txt

@@ -4356,6 +4356,7 @@ e_web_view_clear
 e_web_view_load_string
 e_web_view_load_uri
 e_web_view_redirect_uri
+e_web_view_suggest_filename
 e_web_view_reload
 e_web_view_get_html
 e_web_view_get_caret_mode

e-util/e-web-view.c

@@ -1087,6 +1087,25 @@ web_view_redirect_uri (EWebView *web_view,
 	return g_strdup (uri);
 }
 
+static gchar *
+web_view_suggest_filename (EWebView *web_view,
+                           const gchar *uri)
+{
+	const gchar *cp;
+
+	/* Try to derive a filename from the last path segment. */
+
+	cp = strrchr (uri, '/');
+	if (cp != NULL) {
+		if (strchr (cp, '?') == NULL)
+			cp++;
+		else
+			cp = NULL;
+	}
+
+	return g_strdup (cp);
+}
+
 static gboolean
 web_view_popup_event (EWebView *web_view,
                       const gchar *uri)
@@ -1375,6 +1394,7 @@ e_web_view_class_init (EWebViewClass *class)
 	class->load_string = web_view_load_string;
 	class->load_uri = web_view_load_uri;
 	class->redirect_uri = web_view_redirect_uri;
+	class->suggest_filename = web_view_suggest_filename;
 	class->popup_event = web_view_popup_event;
 	class->stop_loading = web_view_stop_loading;
 	class->update_actions = web_view_update_actions;
@@ -1850,6 +1870,47 @@ e_web_view_redirect_uri (EWebView *web_view,
 	return class->redirect_uri (web_view, uri);
 }
 
+/**
+ * e_web_view_suggest_filename:
+ * @web_view: an #EWebView
+ * @uri: a URI string
+ *
+ * Attempts to derive a suggested filename from the @uri for use in a
+ * "Save As" dialog.
+ *
+ * By default the suggested filename is the last path segment of the @uri
+ * (unless @uri looks like a query), but subclasses can use other mechanisms
+ * for custom URI schemes.  For example, "cid:" URIs in an email message may
+ * refer to a MIME part with a suggested filename in its Content-Disposition
+ * header.
+ *
+ * The returned string should be freed with g_free() when finished with it,
+ * but callers should also be prepared for the function to return %NULL if
+ * a filename cannot be determined.
+ *
+ * Returns: a suggested filename, or %NULL
+ **/
+gchar *
+e_web_view_suggest_filename (EWebView *web_view,
+                             const gchar *uri)
+{
+	EWebViewClass *class;
+	gchar *filename;
+
+	g_return_val_if_fail (E_IS_WEB_VIEW (web_view), NULL);
+	g_return_val_if_fail (uri != NULL, NULL);
+
+	class = E_WEB_VIEW_GET_CLASS (web_view);
+	g_return_val_if_fail (class->suggest_filename != NULL, NULL);
+
+	filename = class->suggest_filename (web_view, uri);
+
+	if (filename != NULL)
+		e_filename_make_safe (filename);
+
+	return filename;
+}
+
 void
 e_web_view_reload (EWebView *web_view)
 {

e-util/e-web-view.h

@@ -82,6 +82,8 @@ struct _EWebViewClass {
 						 const gchar *load_uri);
 	gchar *		(*redirect_uri)		(EWebView *web_view,
 						 const gchar *uri);
+	gchar *		(*suggest_filename)	(EWebView *web_view,
+						 const gchar *uri);
 	void		(*set_fonts)		(EWebView *web_view,
 						 PangoFontDescription **monospace,
 						 PangoFontDescription **variable_width);
@@ -106,6 +108,8 @@ void		e_web_view_load_uri		(EWebView *web_view,
 						 const gchar *uri);
 gchar *		e_web_view_redirect_uri		(EWebView *web_view,
 						 const gchar *uri);
+gchar *		e_web_view_suggest_filename	(EWebView *web_view,
+						 const gchar *uri);
 void		e_web_view_reload		(EWebView *web_view);
 gchar *		e_web_view_get_html		(EWebView *web_view);
 gboolean	e_web_view_get_caret_mode	(EWebView *web_view);

mail/e-mail-display.c

@@ -1477,6 +1477,45 @@ chainup:
 		redirect_uri (web_view, uri);
 }
 
+static gchar *
+mail_display_suggest_filename (EWebView *web_view,
+                               const gchar *uri)
+{
+	if (g_str_has_prefix (uri, "cid:")) {
+		EMailDisplay *display;
+		EMailPartList *part_list;
+		CamelMimeMessage *message;
+		CamelMimePart *mime_part;
+		const gchar *filename;
+
+		/* Note, this assumes the URI comes
+		 * from the currently loaded message. */
+
+		display = E_MAIL_DISPLAY (web_view);
+
+		part_list = e_mail_display_get_part_list (display);
+		if (part_list == NULL)
+			return NULL;
+
+		message = e_mail_part_list_get_message (part_list);
+		if (message == NULL)
+			return NULL;
+
+		mime_part = camel_mime_message_get_part_by_content_id (
+			message, uri + 4);
+		if (mime_part == NULL)
+			return NULL;
+
+		filename = camel_mime_part_get_filename (mime_part);
+
+		return g_strdup (filename);
+	}
+
+	/* Chain up to parent's suggest_filename() method. */
+	return E_WEB_VIEW_CLASS (e_mail_display_parent_class)->
+		suggest_filename (web_view, uri);
+}
+
 static void
 mail_display_set_fonts (EWebView *web_view,
                         PangoFontDescription **monospace,
@@ -1531,6 +1570,7 @@ e_mail_display_class_init (EMailDisplayClass *class)
 
 	web_view_class = E_WEB_VIEW_CLASS (class);
 	web_view_class->redirect_uri = mail_display_redirect_uri;
+	web_view_class->suggest_filename = mail_display_suggest_filename;
 	web_view_class->set_fonts = mail_display_set_fonts;
 
 	g_object_class_install_property (