Refinement of upb_bytesrc interface.

Added a upb_byteregion that tracks a region of
the input buffer; decoders use this instead of
using a upb_bytesrc directly.  upb_byteregion
is also used as the way of passing a string to
a upb_handlers callback.  This symmetry makes
decoders compose better; if you want to take
a parsed string and decode it as something else,
you can take the string directly from the callback
and feed it as input to another parser.

A commented-out version of a pinning interface
is present; I decline to actually implement it
(and accept its extra complexity) until/unless
it is clear that it is actually a win.  But it
is included as a proof-of-concept, to show that
it fits well with the existing interface.

1 files changed, 1 insertions, 2 deletions

diff --git a/benchmarks/parsestream.upb.c b/benchmarks/parsestream.upb.c
index 4d13e9d..19d8ccf 100644
--- a/benchmarks/parsestream.upb.c
+++ b/benchmarks/parsestream.upb.c
@@ -76,8 +76,7 @@ static size_t run(int i)
   (void)i;
   upb_status status = UPB_STATUS_INIT;
   upb_stringsrc_reset(&stringsrc, input_str, input_len);
-  upb_decoder_reset(&decoder, upb_stringsrc_bytesrc(&stringsrc),
-                    0, UPB_NONDELIMITED, NULL);
+  upb_decoder_reset(&decoder, upb_stringsrc_allbytes(&stringsrc), NULL);
   upb_decoder_decode(&decoder, &status);
   if(!upb_ok(&status)) goto err;
   return input_len;