git/pack-objects.h

#ifndef PACK_OBJECTS_H
#define PACK_OBJECTS_H

#include "object-store-ll.h"
#include "thread-utils.h"
#include "pack.h"

struct repository;

#define DEFAULT_DELTA_CACHE_SIZE …

#define OE_DFS_STATE_BITS …
#define OE_DEPTH_BITS …
#define OE_IN_PACK_BITS …
#define OE_Z_DELTA_BITS …
/*
 * Note that oe_set_size() becomes expensive when the given size is
 * above this limit. Don't lower it too much.
 */
#define OE_SIZE_BITS …
#define OE_DELTA_SIZE_BITS …

/*
 * State flags for depth-first search used for analyzing delta cycles.
 *
 * The depth is measured in delta-links to the base (so if A is a delta
 * against B, then A has a depth of 1, and B a depth of 0).
 */
enum dfs_state { … };

/*
 * The size of struct nearly determines pack-objects's memory
 * consumption. This struct is packed tight for that reason. When you
 * add or reorder something in this struct, think a bit about this.
 *
 * basic object info
 * -----------------
 * idx.oid is filled up before delta searching starts. idx.crc32 is
 * only valid after the object is written out and will be used for
 * generating the index. idx.offset will be both gradually set and
 * used in writing phase (base objects get offset first, then deltas
 * refer to them)
 *
 * "size" is the uncompressed object size. Compressed size of the raw
 * data for an object in a pack is not stored anywhere but is computed
 * and made available when reverse .idx is made. Note that when a
 * delta is reused, "size" is the uncompressed _delta_ size, not the
 * canonical one after the delta has been applied.
 *
 * "hash" contains a path name hash which is used for sorting the
 * delta list and also during delta searching. Once prepare_pack()
 * returns it's no longer needed.
 *
 * source pack info
 * ----------------
 * The (in_pack, in_pack_offset) tuple contains the location of the
 * object in the source pack. in_pack_header_size allows quickly
 * skipping the header and going straight to the zlib stream.
 *
 * "type" and "in_pack_type" both describe object type. in_pack_type
 * may contain a delta type, while type is always the canonical type.
 *
 * deltas
 * ------
 * Delta links (delta, delta_child and delta_sibling) are created to
 * reflect that delta graph from the source pack then updated or added
 * during delta searching phase when we find better deltas.
 *
 * delta_child and delta_sibling are last needed in
 * compute_write_order(). "delta" and "delta_size" must remain valid
 * at object writing phase in case the delta is not cached.
 *
 * If a delta is cached in memory and is compressed, delta_data points
 * to the data and z_delta_size contains the compressed size. If it's
 * uncompressed [1], z_delta_size must be zero. delta_size is always
 * the uncompressed size and must be valid even if the delta is not
 * cached.
 *
 * [1] during try_delta phase we don't bother with compressing because
 * the delta could be quickly replaced with a better one.
 */
struct object_entry { … };

struct packing_data { … };

void prepare_packing_data(struct repository *r, struct packing_data *pdata);
void clear_packing_data(struct packing_data *pdata);

/* Protect access to object database */
static inline void packing_data_lock(struct packing_data *pdata)
{ … }
static inline void packing_data_unlock(struct packing_data *pdata)
{ … }

struct object_entry *packlist_alloc(struct packing_data *pdata,
				    const struct object_id *oid);

struct object_entry *packlist_find(struct packing_data *pdata,
				   const struct object_id *oid);

static inline uint32_t pack_name_hash(const char *name)
{ … }

static inline enum object_type oe_type(const struct object_entry *e)
{ … }

static inline void oe_set_type(struct object_entry *e,
			       enum object_type type)
{ … }

static inline unsigned int oe_in_pack_pos(const struct packing_data *pack,
					  const struct object_entry *e)
{ … }

static inline void oe_set_in_pack_pos(const struct packing_data *pack,
				      const struct object_entry *e,
				      unsigned int pos)
{ … }

static inline struct packed_git *oe_in_pack(const struct packing_data *pack,
					    const struct object_entry *e)
{ … }

void oe_map_new_pack(struct packing_data *pack);

static inline void oe_set_in_pack(struct packing_data *pack,
				  struct object_entry *e,
				  struct packed_git *p)
{ … }

void oe_set_delta_ext(struct packing_data *pack,
		      struct object_entry *e,
		      const struct object_id *oid);

static inline unsigned int oe_tree_depth(struct packing_data *pack,
					 struct object_entry *e)
{ … }

static inline void oe_set_layer(struct packing_data *pack,
				struct object_entry *e,
				unsigned char layer)
{ … }

static inline uint32_t oe_cruft_mtime(struct packing_data *pack,
				      struct object_entry *e)
{ … }

static inline void oe_set_cruft_mtime(struct packing_data *pack,
				      struct object_entry *e,
				      uint32_t mtime)
{ … }

#endif