stream_lavf: escape disallowed characters in http URLs

In my opinion, libavformat should be doing this. But a patch handling a
very safe case rejected, so I suppose we have to do it manually. (This
patch was only escaping spaces, which can never work because they break
the basic syntax of the HTTP protocol.)

This commit attempts to do 2 things:
- Try to guess whether libavformat will use the URL for http. This is
  not always trivial, because some protocols will recursively pass part
  of the user URL to http in some way.
- Try to fix invalid URLs. We fix only the simplest case: only
  characters that are never valid are escaped. This excludes invalid
  escape codes, which happen with freestanding '%' characters.

Fixes #1495.

1 files changed, 2 insertions, 2 deletions

diff --git a/stream/stream.c b/stream/stream.c
index de362a6ee1..1e1c5eee4e 100644
--- a/stream/stream.c
+++ b/stream/stream.c
@@ -157,7 +157,7 @@ void mp_url_unescape_inplace(char *buf)
 //      ok[0] != '~': additional characters that are not escaped
 //      ok[0] == '~': do not escape anything but these characters
 //                    (can't override the unreserved characters, which are
-//                     never escaped, and '%', which is always escaped)
+//                     never escaped)
 char *mp_url_escape(void *talloc_ctx, const char *s, const char *ok)
 {
     int len = strlen(s);
@@ -167,7 +167,7 @@ char *mp_url_escape(void *talloc_ctx, const char *s, const char *ok)
         unsigned char c = s[i];
         if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
             (c >= '0' && c <= '9') || strchr("-._~", c) ||
-            (ok && ((ok[0] != '~') == !!strchr(ok, c)) && c != '%'))
+            (ok && ((ok[0] != '~') == !!strchr(ok, c))))
         {
             buf[o++] = c;
         } else {