From 508d5a99101097948b6de342295eec0d5c8cbe72 Mon Sep 17 00:00:00 2001
From: Pierre-Marie Pédrot
Date: Thu, 3 Mar 2016 18:59:51 +0100
Subject: Fixing bug #4105: poor escaping in the protocol between CoqIDE and
 coqtop.

Printing invalid UTF-8 string startled GTK too much, leading to CoqIDE dying
improperly. We now check that all strings outputed by Coq are proper UTF-8.
This is not perfect, as CoqIDE will sometimes truncate strings which contains
the null character, but at least it should not crash.
---
 lib/unicode.ml  | 7 +++++++
 lib/unicode.mli | 3 +++
 2 files changed, 10 insertions(+)

(limited to 'lib')

diff --git a/lib/unicode.ml b/lib/unicode.ml
index 1765e93dcd..cfaa73cc11 100644
--- a/lib/unicode.ml
+++ b/lib/unicode.ml
@@ -168,6 +168,13 @@ let next_utf8 s i =
        (c land 0x3F) lsl 6 + (d land 0x3F)
   else err ()
 
+let is_utf8 s =
+  let rec check i =
+    let (off, _) = next_utf8 s i in
+    check (i + off)
+  in
+  try check 0 with End_of_input -> true | Invalid_argument _ -> false
+
 (* Check the well-formedness of an identifier *)
 
 let initial_refutation j n s =
diff --git a/lib/unicode.mli b/lib/unicode.mli
index 520203d435..65e75a20d6 100644
--- a/lib/unicode.mli
+++ b/lib/unicode.mli
@@ -26,3 +26,6 @@ val lowercase_first_char : string -> string
 (** For extraction, turn a unicode string into an ascii-only one *)
 val is_basic_ascii : string -> bool
 val ascii_of_ident : string -> string
+
+(** Validate an UTF-8 string *)
+val is_utf8 : string -> bool
-- 
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