view contrib/fuzz/standalone_fuzz_target_runner.cc @ 51597:b4a6a1ff8fce

tags-cache: skip the filternode step if we are not going to use it

When warming the hgtagsfnodescache, we don't need the actual result, so we can
simply skip the part that "filter" fnode we read from the cache. So provide a
quite visible speed up to the top level `hg debugupdatecache` function.

### data-env-vars.name            = mozilla-try-2023-03-22-zstd-sparse-revlog
  # benchmark.name                = hg.debug.debug-update-cache
  # bin-env-vars.hg.flavor        = default
  # bin-env-vars.hg.py-re2-module = default
  # benchmark.variants.pre-state  = warm
before: 19.947581
after:  18.916804   (-5.17%, -1.03)

// Copyright 2017 Google Inc. All Rights Reserved.
// Licensed under the Apache License, Version 2.0 (the "License");

// Example of a standalone runner for "fuzz targets".
// It reads all files passed as parameters and feeds their contents
// one by one into the fuzz target (LLVMFuzzerTestOneInput).
// This runner does not do any fuzzing, but allows us to run the fuzz target
// on the test corpus (e.g. "do_stuff_test_data") or on a single file,
// e.g. the one that comes from a bug report.

#include <cassert>
#include <fstream>
#include <iostream>
#include <vector>

// Forward declare the "fuzz target" interface.
// We deliberately keep this inteface simple and header-free.
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv);

int main(int argc, char **argv)
{
	LLVMFuzzerInitialize(&argc, &argv);

	for (int i = 1; i < argc; i++) {
		std::ifstream in(argv[i]);
		in.seekg(0, in.end);
		size_t length = in.tellg();
		in.seekg(0, in.beg);
		std::cout << "Reading " << length << " bytes from " << argv[i]
		          << std::endl;
		// Allocate exactly length bytes so that we reliably catch
		// buffer overflows.
		std::vector<char> bytes(length);
		in.read(bytes.data(), bytes.size());
		assert(in);
		LLVMFuzzerTestOneInput(
		    reinterpret_cast<const uint8_t *>(bytes.data()),
		    bytes.size());
		std::cout << "Execution successful" << std::endl;
	}
	return 0;
}
// no-check-code since this is from a third party