From 6c3d25e6f5f09a110ad0fffaeeea6a65ee5d228b Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Thu, 18 Sep 2014 00:49:55 +0200
Subject: command: allow using ASS tags on OSD messages

We don't allow this by default, because it would be silly if random
external data (like filenames or file tags) could accidentally trigger
them.

Add a property that magically disables this ASS tag escaping.

Note that malicious input could still disable ASS tag escaping by
itself. This would be annoying but harmless.
---
 sub/osd.h        |  2 ++
 sub/osd_dummy.c  |  3 +++
 sub/osd_libass.c | 14 ++++++++++++--
 3 files changed, 17 insertions(+), 2 deletions(-)

(limited to 'sub')

diff --git a/sub/osd.h b/sub/osd.h
index 2a5bf71b05..2662e2b67f 100644
--- a/sub/osd.h
+++ b/sub/osd.h
@@ -219,6 +219,8 @@ void osd_destroy_backend(struct osd_state *osd);
 
 // doesn't need locking
 void osd_get_function_sym(char *buffer, size_t buffer_size, int osd_function);
+extern const char *osd_ass_0;
+extern const char *osd_ass_1;
 
 // defined in backend, but locks if required
 void osd_object_get_resolution(struct osd_state *osd, int obj,
diff --git a/sub/osd_dummy.c b/sub/osd_dummy.c
index 6fc78ab368..b9178e1925 100644
--- a/sub/osd_dummy.c
+++ b/sub/osd_dummy.c
@@ -6,6 +6,9 @@
 #include "talloc.h"
 #include "osd.h"
 
+const char *osd_ass_0 = "";
+const char *osd_ass_1 = "";
+
 void osd_init_backend(struct osd_state *osd)
 {
 }
diff --git a/sub/osd_libass.c b/sub/osd_libass.c
index 1fea27ced6..03d5040dbf 100644
--- a/sub/osd_libass.c
+++ b/sub/osd_libass.c
@@ -159,8 +159,13 @@ void osd_get_function_sym(char *buffer, size_t buffer_size, int osd_function)
     snprintf(buffer, buffer_size, "\xFF%c", osd_function);
 }
 
+// Same trick as above: never valid UTF-8, so we expect it's free for use.
+const char *osd_ass_0 = "\xFD";
+const char *osd_ass_1 = "\xFE";
+
 static void mangle_ass(bstr *dst, const char *in)
 {
+    bool escape_ass = true;
     while (*in) {
         // As used by osd_get_function_sym().
         if (in[0] == '\xFF' && in[1]) {
@@ -170,11 +175,16 @@ static void mangle_ass(bstr *dst, const char *in)
             in += 2;
             continue;
         }
-        if (*in == '{')
+        if (*in == '\xFD' || *in == '\xFE') {
+            escape_ass = *in == '\xFE';
+            in += 1;
+            continue;
+        }
+        if (escape_ass && *in == '{')
             bstr_xappend(NULL, dst, bstr0("\\"));
         bstr_xappend(NULL, dst, (bstr){(char *)in, 1});
         // Break ASS escapes with U+2060 WORD JOINER
-        if (*in == '\\')
+        if (escape_ass && *in == '\\')
             mp_append_utf8_bstr(NULL, dst, 0x2060);
         in++;
     }
-- 
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