contrib/fuzz/xdiff.cc
author Arseniy Alekseyev <aalekseyev@janestreet.com>
Fri, 26 Apr 2024 19:10:35 +0100
changeset 51626 865efc020c33
parent 43816 d37658efbec2
permissions -rw-r--r--
dirstate: remove the python-side whitelist of allowed matchers This whitelist is too permissive because it allows matchers that contain disallowed ones deep inside, for example through `intersectionmatcher`. It is also too restrictive because it doesn't pass through some of the matchers we support, such as `patternmatcher`. It's also unnecessary because unsupported matchers raise `FallbackError` and we fall back anyway. Making this change makes more of the tests use rust code path, and therefore subtly change behavior. For example, rust status in largefiles repos seems to have strange behavior.

/*
 * 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"