From eb4d5668011bb26443add0ed8582291544c10c75 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Sun, 3 Apr 2022 11:11:28 +0900
Subject: [PATCH] [vkparse] Add support for inheriting objects

It simply parses the referenced plist dictionary (via @inherit =
plist.path;) into the current data block, then allows the data to be
overwritten by the current plist dictionary. This may be a bit iffy for
any allocated resources, so some care must be taken, but it seems to
work nicely.
---
 libs/video/renderer/vulkan/vkgen/vkstruct.r |  3 +++
 libs/video/renderer/vulkan/vkparse.c        | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/libs/video/renderer/vulkan/vkgen/vkstruct.r b/libs/video/renderer/vulkan/vkgen/vkstruct.r
index 500659bc0..cd580849b 100644
--- a/libs/video/renderer/vulkan/vkgen/vkstruct.r
+++ b/libs/video/renderer/vulkan/vkgen/vkstruct.r
@@ -130,6 +130,9 @@
 		[field_def writeParseData];
 	}
 	fprintf (output_file, "static plfield_t %s_fields[] = {\n", [self outname]);
+	fprintf (output_file,
+			 "\t{\"@inherit\", 0, QFString, parse_inherit, &%s_fields},\n",
+			 [self outname]);
 	for (int i = [field_defs count]; i-- > 0; ) {
 		FieldDef   *field_def = [field_defs objectAtIndex:i];
 		[field_def writeField];
diff --git a/libs/video/renderer/vulkan/vkparse.c b/libs/video/renderer/vulkan/vkparse.c
index 97fdd813d..e6c084672 100644
--- a/libs/video/renderer/vulkan/vkparse.c
+++ b/libs/video/renderer/vulkan/vkparse.c
@@ -376,6 +376,24 @@ parse_custom (const plfield_t *field, const plitem_t *item,
 	return custom->parse (item, offsets, messages, context);
 }
 
+static int
+parse_inherit (const plfield_t *field, const plitem_t *item,
+			   void *data, plitem_t *messages, void *context)
+{
+	exprctx_t   ectx = *((parsectx_t *)context)->ectx;
+	plitem_t   *inheritItem = 0;
+	exprval_t   result = { &cexpr_plitem, &inheritItem };
+	ectx.result = &result;
+	const char *inheritstr = PL_String (item);
+	Sys_MaskPrintf (SYS_vulkan_parse, "parse_inherit: %s\n", inheritstr);
+	int         ret = !cexpr_eval_string (inheritstr, &ectx);
+	if (ret) {
+		ret = PL_ParseStruct (field->data, inheritItem, data, messages,
+							  context);
+	}
+	return ret;
+}
+
 static int
 parse_RGBA (const plitem_t *item, void **data,
 			plitem_t *messages, parsectx_t *context)