branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
/*
* bdiff.cc - fuzzer harness for bdiff.c
*
* 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 <memory>
#include <stdlib.h>
#include "FuzzedDataProvider.h"
extern "C" {
#include "bdiff.h"
extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
return 0;
}
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
FuzzedDataProvider provider(Data, Size);
std::string left = provider.ConsumeRandomLengthString(Size);
std::string right = provider.ConsumeRemainingBytesAsString();
struct bdiff_line *a, *b;
int an = bdiff_splitlines(left.c_str(), left.size(), &a);
int bn = bdiff_splitlines(right.c_str(), right.size(), &b);
struct bdiff_hunk l;
bdiff_diff(a, an, b, bn, &l);
free(a);
free(b);
bdiff_freehunks(l.next);
return 0; // Non-zero return values are reserved for future use.
}
} // extern "C"