merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 97 insertions, 0 deletions

diff --git a/third_party/git/t/helper/test-bloom.c b/third_party/git/t/helper/test-bloom.c
new file mode 100644
index 000000000000..46e97b04eb83
--- /dev/null
+++ b/third_party/git/t/helper/test-bloom.c
@@ -0,0 +1,97 @@
+#include "git-compat-util.h"
+#include "bloom.h"
+#include "test-tool.h"
+#include "commit.h"
+
+static struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
+
+static void add_string_to_filter(const char *data, struct bloom_filter *filter) {
+		struct bloom_key key;
+		int i;
+
+		fill_bloom_key(data, strlen(data), &key, &settings);
+		printf("Hashes:");
+		for (i = 0; i < settings.num_hashes; i++){
+			printf("0x%08x|", key.hashes[i]);
+		}
+		printf("\n");
+		add_key_to_filter(&key, filter, &settings);
+}
+
+static void print_bloom_filter(struct bloom_filter *filter) {
+	int i;
+
+	if (!filter) {
+		printf("No filter.\n");
+		return;
+	}
+	printf("Filter_Length:%d\n", (int)filter->len);
+	printf("Filter_Data:");
+	for (i = 0; i < filter->len; i++) {
+		printf("%02x|", filter->data[i]);
+	}
+	printf("\n");
+}
+
+static void get_bloom_filter_for_commit(const struct object_id *commit_oid)
+{
+	struct commit *c;
+	struct bloom_filter *filter;
+	setup_git_directory();
+	c = lookup_commit(the_repository, commit_oid);
+	filter = get_or_compute_bloom_filter(the_repository, c, 1,
+					     &settings,
+					     NULL);
+	print_bloom_filter(filter);
+}
+
+static const char *bloom_usage = "\n"
+"  test-tool bloom get_murmur3 <string>\n"
+"  test-tool bloom generate_filter <string> [<string>...]\n"
+"  test-tool get_filter_for_commit <commit-hex>\n";
+
+int cmd__bloom(int argc, const char **argv)
+{
+	setup_git_directory();
+
+	if (argc < 2)
+		usage(bloom_usage);
+
+	if (!strcmp(argv[1], "get_murmur3")) {
+		uint32_t hashed;
+		if (argc < 3)
+			usage(bloom_usage);
+		hashed = murmur3_seeded(0, argv[2], strlen(argv[2]));
+		printf("Murmur3 Hash with seed=0:0x%08x\n", hashed);
+	}
+
+	if (!strcmp(argv[1], "generate_filter")) {
+		struct bloom_filter filter;
+		int i = 2;
+		filter.len =  (settings.bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD;
+		filter.data = xcalloc(filter.len, sizeof(unsigned char));
+
+		if (argc - 1 < i)
+			usage(bloom_usage);
+
+		while (argv[i]) {
+			add_string_to_filter(argv[i], &filter);
+			i++;
+		}
+
+		print_bloom_filter(&filter);
+	}
+
+	if (!strcmp(argv[1], "get_filter_for_commit")) {
+		struct object_id oid;
+		const char *end;
+		if (argc < 3)
+			usage(bloom_usage);
+		if (parse_oid_hex(argv[2], &oid, &end))
+			die("cannot parse oid '%s'", argv[2]);
+		init_bloom_filters();
+		get_bloom_filter_for_commit(&oid);
+	}
+
+	return 0;
+}