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, 5 insertions, 5 deletions

diff --git a/upb/handlers.h b/upb/handlers.h
index 2945d8c..e17a726 100644
--- a/upb/handlers.h
+++ b/upb/handlers.h
@@ -324,13 +324,13 @@ typedef struct {
   uint16_t fieldindex;
 
   bool is_sequence;   // frame represents seq or submsg? (f might be both).
-  bool is_packed;     // !upb_issubmsg(f) && end_ofs != UINT64_MAX (strings aren't pushed)
+  bool is_packed;     // !upb_issubmsg(f) && end_ofs != UINT64_MAX
+                      // (strings aren't pushed).
 } upb_dispatcher_frame;
 
-// Called when some of the input needs to be skipped.  All frames from
-// top to bottom, inclusive, should be skipped.
-typedef void upb_skip_handler(void *, upb_dispatcher_frame *top,
-                              upb_dispatcher_frame *bottom);
+// Called when some of the input needs to be skipped.  All frames from the
+// current top to "bottom", inclusive, should be skipped.
+typedef void upb_skip_handler(void *, upb_dispatcher_frame *bottom);
 typedef void upb_exit_handler(void *);
 
 typedef struct {