stream-clone: smoothly detect and handle a case were a revlog is split
This detect and handle the most common case for a race condition around stream
and revlog splitting. The one were the revlog is split between the initial
collection of data and the time were we start considering stream that data.
In such case, we repatch an inlined version of that revlog together when this
happens. This is necessary as stream-v2 promised a specific number of bytes and
a specific number of files to the client. In stream-v3, we will have the
opportunity to just send a split revlog instead.
Getting a better version of the protocol for stream-v3 is still useful, but it
is no longer a blocket to fix that race condition.
Note that another, rarer race condition exist, were the revlog is split while
we creating the revlog and extracing content from it. This can be dealt with
later.
#ifndef CONTRIB_FUZZ_FUZZUTIL_H
#define CONTRIB_FUZZ_FUZZUTIL_H
#include <iostream>
#include <memory>
#include <stdint.h>
/* Try and use std::optional, but failing that assume we'll have a
* workable https://abseil.io/ install on the include path to get
* their backport of std::optional. */
#ifdef __has_include
#if __has_include(<optional>) && __cplusplus >= 201703L
#include <optional>
#define CONTRIB_FUZZ_HAVE_STD_OPTIONAL
#endif
#endif
#ifdef CONTRIB_FUZZ_HAVE_STD_OPTIONAL
namespace contrib
{
using std::nullopt;
using std::optional;
} /* namespace contrib */
#else
#include "third_party/absl/types/optional.h"
namespace contrib
{
using absl::nullopt;
using absl::optional;
} /* namespace contrib */
#endif
/* set DEBUG to 1 for a few debugging prints, or 2 for a lot */
#define DEBUG 0
#define LOG(level) \
if (level <= DEBUG) \
std::cout
#endif /* CONTRIB_FUZZ_FUZZUTIL_H */