fuzzer: add a revparse fuzzer

fuzzers/corpora/revparse/head

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+HEAD

fuzzers/corpora/revparse/revat

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+xxxxxxxxxxxxxxxx@

fuzzers/revparse_fuzzer.c

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+/*
+ * libgit2 revparse fuzzer target.
+ *
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "git2.h"
+
+#include "standalone_driver.h"
+#include "fuzzer_utils.h"
+
+#define UNUSED(x) (void)(x)
+
+static git_repository *repo;
+
+int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	UNUSED(argc);
+	UNUSED(argv);
+
+	if (git_libgit2_init() < 0)
+		abort();
+
+	if (git_libgit2_opts(GIT_OPT_SET_PACK_MAX_OBJECTS, 10000000) < 0)
+		abort();
+
+	repo = fuzzer_repo_init();
+	return 0;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	git_object *obj = NULL;
+	char *c;
+
+	if ((c = calloc(1, size + 1)) == NULL)
+		abort();
+
+	memcpy(c, data, size);
+
+	git_revparse_single(&obj, repo, c);
+	git_object_free(obj);
+	free(c);
+
+	return 0;
+}