merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/commit-graph.h

@@ -0,0 +1,105 @@
+#ifndef COMMIT_GRAPH_H
+#define COMMIT_GRAPH_H
+
+#include "git-compat-util.h"
+#include "repository.h"
+#include "string-list.h"
+#include "cache.h"
+
+#define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH"
+#define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD"
+
+struct commit;
+
+char *get_commit_graph_filename(const char *obj_dir);
+int open_commit_graph(const char *graph_file, int *fd, struct stat *st);
+
+/*
+ * Given a commit struct, try to fill the commit struct info, including:
+ *  1. tree object
+ *  2. date
+ *  3. parents.
+ *
+ * Returns 1 if and only if the commit was found in the packed graph.
+ *
+ * See parse_commit_buffer() for the fallback after this call.
+ */
+int parse_commit_in_graph(struct repository *r, struct commit *item);
+
+/*
+ * It is possible that we loaded commit contents from the commit buffer,
+ * but we also want to ensure the commit-graph content is correctly
+ * checked and filled. Fill the graph_pos and generation members of
+ * the given commit.
+ */
+void load_commit_graph_info(struct repository *r, struct commit *item);
+
+struct tree *get_commit_tree_in_graph(struct repository *r,
+				      const struct commit *c);
+
+struct commit_graph {
+	int graph_fd;
+
+	const unsigned char *data;
+	size_t data_len;
+
+	unsigned char hash_len;
+	unsigned char num_chunks;
+	uint32_t num_commits;
+	struct object_id oid;
+	char *filename;
+	const char *obj_dir;
+
+	uint32_t num_commits_in_base;
+	struct commit_graph *base_graph;
+
+	const uint32_t *chunk_oid_fanout;
+	const unsigned char *chunk_oid_lookup;
+	const unsigned char *chunk_commit_data;
+	const unsigned char *chunk_extra_edges;
+	const unsigned char *chunk_base_graphs;
+};
+
+struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st);
+struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir);
+struct commit_graph *parse_commit_graph(void *graph_map, int fd,
+					size_t graph_size);
+
+/*
+ * Return 1 if and only if the repository has a commit-graph
+ * file and generation numbers are computed in that file.
+ */
+int generation_numbers_enabled(struct repository *r);
+
+#define COMMIT_GRAPH_APPEND     (1 << 0)
+#define COMMIT_GRAPH_PROGRESS   (1 << 1)
+#define COMMIT_GRAPH_SPLIT      (1 << 2)
+
+struct split_commit_graph_opts {
+	int size_multiple;
+	int max_commits;
+	timestamp_t expire_time;
+};
+
+/*
+ * The write_commit_graph* methods return zero on success
+ * and a negative value on failure. Note that if the repository
+ * is not compatible with the commit-graph feature, then the
+ * methods will return 0 without writing a commit-graph.
+ */
+int write_commit_graph_reachable(const char *obj_dir, unsigned int flags,
+				 const struct split_commit_graph_opts *split_opts);
+int write_commit_graph(const char *obj_dir,
+		       struct string_list *pack_indexes,
+		       struct string_list *commit_hex,
+		       unsigned int flags,
+		       const struct split_commit_graph_opts *split_opts);
+
+#define COMMIT_GRAPH_VERIFY_SHALLOW	(1 << 0)
+
+int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags);
+
+void close_commit_graph(struct raw_object_store *);
+void free_commit_graph(struct commit_graph *);
+
+#endif