options: change [...] to balanced quotes

Useful for dealing with libavfilter's terrible graph syntax.

Not strictly backwards compatible (for example "[a[b]" fails now - the
"[" within the quote is interpreted now). But hopefully it's obscure
enough not to warrant any kind of compatibility hacks.

2 files changed, 15 insertions, 2 deletions

diff --git a/DOCS/man/mpv.rst b/DOCS/man/mpv.rst
index a2e47a1a6e..ec25d720ff 100644
--- a/DOCS/man/mpv.rst
+++ b/DOCS/man/mpv.rst
@@ -278,7 +278,9 @@ quotes.
 
 The ``[...]`` from of quotes wraps everything between ``[`` and ``]``. It's
 useful with shells that don't interpret these characters in the middle of
-an argument (like bash).
+an argument (like bash). These quotes are balanced (since mpv 0.9.0): the ``[``
+and ``]`` nest, and the quote terminates on the last ``]`` that has no matching
+``[`` within the string. (For example, ``[a[b]c]`` results in ``a[b]c``.)
 
 The fixed-length quoting syntax is intended for use with external
 scripts and programs.
diff --git a/options/m_option.c b/options/m_option.c
index b5c865b8b4..bd8e3357b9 100644
--- a/options/m_option.c
+++ b/options/m_option.c
@@ -1736,11 +1736,22 @@ static int read_subparam(struct mp_log *log, bstr optname,
         }
         p = bstr_cut(p, 1);
     } else if (bstr_eatstart0(&p, "[")) {
-        if (!bstr_split_tok(p, "]", &subparam, &p)) {
+        bstr s = p;
+        int balance = 1;
+        while (p.len && balance > 0) {
+            if (p.start[0] == '[') {
+                balance++;
+            } else if (p.start[0] == ']') {
+                balance--;
+            }
+            p = bstr_cut(p, 1);
+        }
+        if (balance != 0) {
             mp_err(log, "Terminating ']' missing for '%.*s'\n",
                    BSTR_P(optname));
             return M_OPT_INVALID;
         }
+        subparam = bstr_splice(s, 0, s.len - p.len - 1);
     } else if (bstr_eatstart0(&p, "%")) {
         int optlen = bstrtoll(p, &p, 0);
         if (!bstr_startswith0(p, "%") || (optlen > p.len - 1)) {