rust: switch hg-core and hg-cpython to rust 2018 edition
Many interesting changes have happened in Rust since the Oxidation Plan was
introduced, like the 2018 edition and procedural macros:
- Opting in to the 2018 edition is a clear benefit in terms of future
proofing, new (nice to have) syntactical sugar notwithstanding. It
also has a new non-lexical, non-AST based borrow checker that has
fewer bugs(!) and allows us to write correct code that in some cases
would have been rejected by the old one.
- Procedural macros allow us to use the PyO3 crate which maintainers have
expressed the clear goal of compiling on stable, which would help in
code maintainability compared to rust-cpython.
In this patch are the following changes:
- Removing most `extern crate` uses
- Updating `use` clauses (`crate` keyword, nested `use`)
- Removing `mod.rs` in favor of an aptly named module file
Like discussed in the mailing list (
https://www.mercurial-scm.org/pipermail/mercurial-devel/2019-July/132316.html
), until Rust integration in Mercurial is considered to be out of the
experimental phase, the maximum version of Rust allowed is whatever the latest
version Debian packages.
Differential Revision: https://phab.mercurial-scm.org/D6597
/*
* 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 "fuzzutil.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)
{
// Don't allow fuzzer inputs larger than 100k, since we'll just bog
// down and not accomplish much.
if (Size > 100000) {
return 0;
}
auto maybe_inputs = SplitInputs(Data, Size);
if (!maybe_inputs) {
return 0;
}
auto inputs = std::move(maybe_inputs.value());
mmfile_t a, b;
a.ptr = inputs.left.get();
a.size = inputs.left_size;
b.ptr = inputs.right.get();
b.size = inputs.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.
}
#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"