contrib/fuzz/fuzzutil.cc

changegroup: change topics during generation

Changegroup generation and consumption currently uses different sets of
topics. Generation uses "bundling" and consumption uses the name of the
thing being consumed.

This commit makes the topic and unit names consistent on both ends.

The reason I chose to change the generation side is because when
"bundling" is used for 3 different stages, it is unclear which stage
of changegroup generation we're in. By making the topics "changesets,"
"manifests," and "files," one can get a better feel for how far along
in the bundling process we are.

Differential Revision: https://phab.mercurial-scm.org/D4272

#include "fuzzutil.h"

#include <cstring>
#include <utility>

contrib::optional<two_inputs> SplitInputs(const uint8_t *Data, size_t Size)
{
	if (!Size) {
		return contrib::nullopt;
	}
	// figure out a random point in [0, Size] to split our input.
	size_t left_size = (Data[0] / 255.0) * (Size - 1);

	// Copy inputs to new allocations so if bdiff over-reads
	// AddressSanitizer can detect it.
	std::unique_ptr<char[]> left(new char[left_size]);
	std::memcpy(left.get(), Data + 1, left_size);
	// right starts at the next byte after left ends
	size_t right_size = Size - (left_size + 1);
	std::unique_ptr<char[]> right(new char[right_size]);
	std::memcpy(right.get(), Data + 1 + left_size, right_size);
	LOG(2) << "inputs are  " << left_size << " and " << right_size
	       << " bytes" << std::endl;
	two_inputs result = {std::move(right), right_size, std::move(left),
	                     left_size};
	return result;
}