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, 81 insertions, 0 deletions

diff --git a/third_party/git/shallow.h b/third_party/git/shallow.h
new file mode 100644
index 000000000000..5b4a96dcd69a
--- /dev/null
+++ b/third_party/git/shallow.h
@@ -0,0 +1,81 @@
+#ifndef SHALLOW_H
+#define SHALLOW_H
+
+#include "lockfile.h"
+#include "object.h"
+#include "repository.h"
+#include "strbuf.h"
+
+void set_alternate_shallow_file(struct repository *r, const char *path, int override);
+int register_shallow(struct repository *r, const struct object_id *oid);
+int unregister_shallow(const struct object_id *oid);
+int is_repository_shallow(struct repository *r);
+
+/*
+ * Lock for updating the $GIT_DIR/shallow file.
+ *
+ * Use `commit_shallow_file()` to commit an update, or
+ * `rollback_shallow_file()` to roll it back. In either case, any
+ * in-memory cached information about which commits are shallow will be
+ * appropriately invalidated so that future operations reflect the new
+ * state.
+ */
+struct shallow_lock {
+	struct lock_file lock;
+};
+#define SHALLOW_LOCK_INIT { LOCK_INIT }
+
+/* commit $GIT_DIR/shallow and reset stat-validity checks */
+int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
+/* rollback $GIT_DIR/shallow and reset stat-validity checks */
+void rollback_shallow_file(struct repository *r, struct shallow_lock *lk);
+
+struct commit_list *get_shallow_commits(struct object_array *heads,
+					int depth, int shallow_flag, int not_shallow_flag);
+struct commit_list *get_shallow_commits_by_rev_list(
+		int ac, const char **av, int shallow_flag, int not_shallow_flag);
+int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
+			  const struct oid_array *extra);
+
+void setup_alternate_shallow(struct shallow_lock *shallow_lock,
+			     const char **alternate_shallow_file,
+			     const struct oid_array *extra);
+
+const char *setup_temporary_shallow(const struct oid_array *extra);
+
+void advertise_shallow_grafts(int);
+
+#define PRUNE_SHOW_ONLY 1
+#define PRUNE_QUICK 2
+void prune_shallow(unsigned options);
+
+/*
+ * Initialize with prepare_shallow_info() or zero-initialize (equivalent to
+ * prepare_shallow_info with a NULL oid_array).
+ */
+struct shallow_info {
+	struct oid_array *shallow;
+	int *ours, nr_ours;
+	int *theirs, nr_theirs;
+	struct oid_array *ref;
+
+	/* for receive-pack */
+	uint32_t **used_shallow;
+	int *need_reachability_test;
+	int *reachable;
+	int *shallow_ref;
+	struct commit **commits;
+	int nr_commits;
+};
+
+void prepare_shallow_info(struct shallow_info *, struct oid_array *);
+void clear_shallow_info(struct shallow_info *);
+void remove_nonexistent_theirs_shallow(struct shallow_info *);
+void assign_shallow_commits_to_refs(struct shallow_info *info,
+				    uint32_t **used,
+				    int *ref_status);
+int delayed_reachability_test(struct shallow_info *si, int c);
+
+extern struct trace_key trace_shallow;
+
+#endif /* SHALLOW_H */