contrib/fuzz/xdiff.cc
author Pierre-Yves David <pierre-yves.david@octobus.net>
Wed, 17 Nov 2021 23:37:47 +0100
changeset 48429 41f40f35278a
parent 43834 d37658efbec2
permissions -rw-r--r--
status: gather fixup info at comparison time This is still racy, but on a much small windows. In addition, the API now make it possible for it to not be racy. This also unlock other cleanups that we are about to do regarding mtime ambiguity at gathering time. Differential Revision: https://phab.mercurial-scm.org/D11785

/*
 * xdiff.cc - fuzzer harness for thirdparty/xdiff
 *
 * Copyright 2018, Google Inc.
 *
 * This software may be used and distributed according to the terms of
 * the GNU General Public License, incorporated herein by reference.
 */
#include "thirdparty/xdiff/xdiff.h"
#include <inttypes.h>
#include <stdlib.h>

#include "FuzzedDataProvider.h"

extern "C" {

int LLVMFuzzerInitialize(int *argc, char ***argv)
{
	return 0;
}

int hunk_consumer(long a1, long a2, long b1, long b2, void *priv)
{
	// TODO: probably also test returning -1 from this when things break?
	return 0;
}

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
	// Don't allow fuzzer inputs larger than 100k, since we'll just bog
	// down and not accomplish much.
	if (Size > 100000) {
		return 0;
	}
	FuzzedDataProvider provider(Data, Size);
	std::string left = provider.ConsumeRandomLengthString(Size);
	std::string right = provider.ConsumeRemainingBytesAsString();
	mmfile_t a, b;

	a.ptr = (char *)left.c_str();
	a.size = left.size();
	b.ptr = (char *)right.c_str();
	b.size = right.size();
	xpparam_t xpp = {
	    XDF_INDENT_HEURISTIC, /* flags */
	};
	xdemitconf_t xecfg = {
	    XDL_EMIT_BDIFFHUNK, /* flags */
	    hunk_consumer,      /* hunk_consume_func */
	};
	xdemitcb_t ecb = {
	    NULL, /* priv */
	};
	xdl_diff(&a, &b, &xpp, &xecfg, &ecb);
	return 0; // Non-zero return values are reserved for future use.
}

} // extern "C"