This change adds support for a OneofDef (upb_oneofdef), which represents
a 'oneof' as introduced by Protocol Buffers. This is semantically a
union type that contains fields and in turn may be added to a
MessageDef. This change does not alter parsing or the handler
abstraction in any way, because a oneof has impact only at a higher
semantic level (i.e., any sort of storage of the fields in a message
object), which is user-specific with respect to upb.
There are a number of tweaks to get this to work:
- The #include dependence graph wasn't quite complete, and I had to add
a few #includes to get the tool to work.
- I had to change a number of symbol names to avoid conflicts between
'static' definitions in different .c files. This could be avoided if
the tool were smart enough to rename static symbols to have unique
prefixes instead, but (i) this requires semantic understanding of C,
and (ii) the macro-defined static functions (e.g., handlers for
primitive types in several places) would probably trip this up.
Verified that the resulting upb.h/upb.c compiles and doesn't have any
unresolved references.
- rewritten decoder; interpreted decoder is bytecode-based,
JIT decoder no longer falls back to the interpreter.
- C++ improvements: C++11-compatible iterators, upb::reffed_ptr
for RAII refcounting, better upcast/downcast support.
- removed the gross upb_value abstraction from public upb.h.
Major changes:
- Got rid of all bytestream interfaces in favor of
using regular handlers.
- new Pipeline object represents a upb pipeline, does
bump allocation internally to manage memory.
- proto2 support now can handle extensions.
Many things have changed and been simplified.
The memory-management story for upb_def and upb_handlers
is much more robust; upb_def and upb_handlers should be
fairly stable interfaces now. There is still much work
to do for the runtime component (upb_sink).
Many improvements, too many to mention. One significant
perf regression warrants investigation:
omitfp.parsetoproto2_googlemessage1.upb_jit: 343 -> 252 (-26.53)
plain.parsetoproto2_googlemessage1.upb_jit: 334 -> 251 (-24.85)
25% regression for this benchmark is bad, but since I don't think
there's any fundamental design issue that caused it I'm going to
go ahead with the commit anyway. Can investigate and fix later.
Other benchmarks were neutral or showed slight improvement.
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.
Includes are now via upb/foo.h.
Files specific to the protobuf format are
now in upb/pb (the core library is concerned
with message definitions, handlers, and
byte streams, but knows nothing about any
particular serializationf format).
This doesn't reflect any material change in
how I will be working on upb, and I have no
problem making this change. It's still open
source under the BSD license, and I'll still
be working on it well beyond the hours that
constitute a normal job.
upb_inttable() now supports a "compact" operation that will
decide on an array size and put all entries with small enough
keys into the array part for faster lookup.
Also exposed the upb_itof_ent structure and put a few useful
values there, so they are one fewer pointer chase away.
Unfortunately this degrades hash table lookup performance by
about 8%, which affects the streaming benchmark for googlemessage1
by about 5%. We could get this back at the cost of some memory,
but it would be nice to avoid that.
Josh Haberman
Chris Fallin
Josh Haberman
Joshua Haberman