1#ifndef PACK_OBJECTS_H 2#define PACK_OBJECTS_H 3 4#include "object-store.h" 5 6#define OE_DFS_STATE_BITS 2 7#define OE_DEPTH_BITS 12 8#define OE_IN_PACK_BITS 10 9 10/* 11 * State flags for depth-first search used for analyzing delta cycles. 12 * 13 * The depth is measured in delta-links to the base (so if A is a delta 14 * against B, then A has a depth of 1, and B a depth of 0). 15 */ 16enum dfs_state { 17 DFS_NONE = 0, 18 DFS_ACTIVE, 19 DFS_DONE, 20 DFS_NUM_STATES 21}; 22 23/* 24 * basic object info 25 * ----------------- 26 * idx.oid is filled up before delta searching starts. idx.crc32 is 27 * only valid after the object is written out and will be used for 28 * generating the index. idx.offset will be both gradually set and 29 * used in writing phase (base objects get offset first, then deltas 30 * refer to them) 31 * 32 * "size" is the uncompressed object size. Compressed size of the raw 33 * data for an object in a pack is not stored anywhere but is computed 34 * and made available when reverse .idx is made. 35 * 36 * "hash" contains a path name hash which is used for sorting the 37 * delta list and also during delta searching. Once prepare_pack() 38 * returns it's no longer needed. 39 * 40 * source pack info 41 * ---------------- 42 * The (in_pack, in_pack_offset) tuple contains the location of the 43 * object in the source pack. in_pack_header_size allows quickly 44 * skipping the header and going straight to the zlib stream. 45 * 46 * "type" and "in_pack_type" both describe object type. in_pack_type 47 * may contain a delta type, while type is always the canonical type. 48 * 49 * deltas 50 * ------ 51 * Delta links (delta, delta_child and delta_sibling) are created to 52 * reflect that delta graph from the source pack then updated or added 53 * during delta searching phase when we find better deltas. 54 * 55 * delta_child and delta_sibling are last needed in 56 * compute_write_order(). "delta" and "delta_size" must remain valid 57 * at object writing phase in case the delta is not cached. 58 * 59 * If a delta is cached in memory and is compressed, delta_data points 60 * to the data and z_delta_size contains the compressed size. If it's 61 * uncompressed [1], z_delta_size must be zero. delta_size is always 62 * the uncompressed size and must be valid even if the delta is not 63 * cached. 64 * 65 * [1] during try_delta phase we don't bother with compressing because 66 * the delta could be quickly replaced with a better one. 67 */ 68struct object_entry { 69 struct pack_idx_entry idx; 70 unsigned long size; /* uncompressed size */ 71 unsigned in_pack_idx:OE_IN_PACK_BITS; /* already in pack */ 72 off_t in_pack_offset; 73 uint32_t delta_idx; /* delta base object */ 74 uint32_t delta_child_idx; /* deltified objects who bases me */ 75 uint32_t delta_sibling_idx; /* other deltified objects who 76 * uses the same base as me 77 */ 78 void *delta_data; /* cached delta (uncompressed) */ 79 unsigned long delta_size; /* delta data size (uncompressed) */ 80 unsigned long z_delta_size; /* delta data size (compressed) */ 81 unsigned type_:TYPE_BITS; 82 unsigned in_pack_type:TYPE_BITS; /* could be delta */ 83 unsigned type_valid:1; 84 uint32_t hash; /* name hint hash */ 85 unsigned char in_pack_header_size; 86 unsigned preferred_base:1; /* 87 * we do not pack this, but is available 88 * to be used as the base object to delta 89 * objects against. 90 */ 91 unsigned no_try_delta:1; 92 unsigned tagged:1; /* near the very tip of refs */ 93 unsigned filled:1; /* assigned write-order */ 94 unsigned dfs_state:OE_DFS_STATE_BITS; 95 unsigned depth:OE_DEPTH_BITS; 96}; 97 98struct packing_data { 99 struct object_entry *objects; 100 uint32_t nr_objects, nr_alloc; 101 102 int32_t *index; 103 uint32_t index_size; 104 105 unsigned int *in_pack_pos; 106 107 /* 108 * Only one of these can be non-NULL and they have different 109 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns 110 * the pack of an object using in_pack_idx field. If not, 111 * in_pack[] array is used the same way as in_pack_pos[] 112 */ 113 struct packed_git **in_pack_by_idx; 114 struct packed_git **in_pack; 115}; 116 117void prepare_packing_data(struct packing_data *pdata); 118struct object_entry *packlist_alloc(struct packing_data *pdata, 119 const unsigned char *sha1, 120 uint32_t index_pos); 121 122struct object_entry *packlist_find(struct packing_data *pdata, 123 const unsigned char *sha1, 124 uint32_t *index_pos); 125 126static inline uint32_t pack_name_hash(const char *name) 127{ 128 uint32_t c, hash = 0; 129 130 if (!name) 131 return 0; 132 133 /* 134 * This effectively just creates a sortable number from the 135 * last sixteen non-whitespace characters. Last characters 136 * count "most", so things that end in ".c" sort together. 137 */ 138 while ((c = *name++) != 0) { 139 if (isspace(c)) 140 continue; 141 hash = (hash >> 2) + (c << 24); 142 } 143 return hash; 144} 145 146static inline enum object_type oe_type(const struct object_entry *e) 147{ 148 return e->type_valid ? e->type_ : OBJ_BAD; 149} 150 151static inline void oe_set_type(struct object_entry *e, 152 enum object_type type) 153{ 154 if (type >= OBJ_ANY) 155 BUG("OBJ_ANY cannot be set in pack-objects code"); 156 157 e->type_valid = type >= OBJ_NONE; 158 e->type_ = (unsigned)type; 159} 160 161static inline unsigned int oe_in_pack_pos(const struct packing_data *pack, 162 const struct object_entry *e) 163{ 164 return pack->in_pack_pos[e - pack->objects]; 165} 166 167static inline void oe_set_in_pack_pos(const struct packing_data *pack, 168 const struct object_entry *e, 169 unsigned int pos) 170{ 171 pack->in_pack_pos[e - pack->objects] = pos; 172} 173 174static inline struct packed_git *oe_in_pack(const struct packing_data *pack, 175 const struct object_entry *e) 176{ 177 if (pack->in_pack_by_idx) 178 return pack->in_pack_by_idx[e->in_pack_idx]; 179 else 180 return pack->in_pack[e - pack->objects]; 181} 182 183void oe_map_new_pack(struct packing_data *pack, 184 struct packed_git *p); 185static inline void oe_set_in_pack(struct packing_data *pack, 186 struct object_entry *e, 187 struct packed_git *p) 188{ 189 if (!p->index) 190 oe_map_new_pack(pack, p); 191 if (pack->in_pack_by_idx) 192 e->in_pack_idx = p->index; 193 else 194 pack->in_pack[e - pack->objects] = p; 195} 196 197static inline struct object_entry *oe_delta( 198 const struct packing_data *pack, 199 const struct object_entry *e) 200{ 201 if (e->delta_idx) 202 return &pack->objects[e->delta_idx - 1]; 203 return NULL; 204} 205 206static inline void oe_set_delta(struct packing_data *pack, 207 struct object_entry *e, 208 struct object_entry *delta) 209{ 210 if (delta) 211 e->delta_idx = (delta - pack->objects) + 1; 212 else 213 e->delta_idx = 0; 214} 215 216static inline struct object_entry *oe_delta_child( 217 const struct packing_data *pack, 218 const struct object_entry *e) 219{ 220 if (e->delta_child_idx) 221 return &pack->objects[e->delta_child_idx - 1]; 222 return NULL; 223} 224 225static inline void oe_set_delta_child(struct packing_data *pack, 226 struct object_entry *e, 227 struct object_entry *delta) 228{ 229 if (delta) 230 e->delta_child_idx = (delta - pack->objects) + 1; 231 else 232 e->delta_child_idx = 0; 233} 234 235static inline struct object_entry *oe_delta_sibling( 236 const struct packing_data *pack, 237 const struct object_entry *e) 238{ 239 if (e->delta_sibling_idx) 240 return &pack->objects[e->delta_sibling_idx - 1]; 241 return NULL; 242} 243 244static inline void oe_set_delta_sibling(struct packing_data *pack, 245 struct object_entry *e, 246 struct object_entry *delta) 247{ 248 if (delta) 249 e->delta_sibling_idx = (delta - pack->objects) + 1; 250 else 251 e->delta_sibling_idx = 0; 252} 253 254#endif