annotate contrib/fuzz/xdiff.cc @ 36747:4c71a26a4009

sslutil: some more forcebytes() on some exception messages

At this point, test-https.t no longer dumps tracebacks
everywhere. Instead, we get some results that look like we're not
adequately finding things in hg's configuration, which should be
manageable (if somewhat annoying to find and fix.)

Differential Revision: https://phab.mercurial-scm.org/D2690

/*
 * 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>

extern "C" {

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)
{
	if (!Size) {
		return 0;
	}
	// figure out a random point in [0, Size] to split our input.
	size_t split = Data[0] / 255.0 * Size;

	mmfile_t a, b;

	// `a` input to diff is data[1:split]
	a.ptr = (char *)Data + 1;
	// which has len split-1
	a.size = split - 1;
	// `b` starts at the next byte after `a` ends
	b.ptr = a.ptr + a.size;
	b.size = Size - split;
	xpparam_t xpp = {
	    XDF_INDENT_HEURISTIC, /* flags */
	    NULL,                 /* anchors */
	    0,                    /* anchors_nr */
	};
	xdemitconf_t xecfg = {
	    0,                  /* ctxlen */
	    0,                  /* interhunkctxlen */
	    XDL_EMIT_BDIFFHUNK, /* flags */
	    NULL,               /* find_func */
	    NULL,               /* find_func_priv */
	    hunk_consumer,      /* hunk_consume_func */
	};
	xdemitcb_t ecb = {
	    NULL, /* priv */
	    NULL, /* outf */
	};
	xdl_diff(&a, &b, &xpp, &xecfg, &ecb);
	return 0; // Non-zero return values are reserved for future use.
}

#ifdef HG_FUZZER_INCLUDE_MAIN
int main(int argc, char **argv)
{
	const char data[] = "asdf";
	return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);
}
#endif

} // extern "C"