branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
// 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