| | 1 | #ifndef PACK_OBJECTS_H |
| | 2 | #define PACK_OBJECTS_H |
| | 3 | |
| | 4 | #define OE_DFS_STATE_BITS 2 |
| | 5 | #define OE_DEPTH_BITS 12 |
| | 6 | |
| | 7 | /* |
| | 8 | * State flags for depth-first search used for analyzing delta cycles. |
| | 9 | * |
| | 10 | * The depth is measured in delta-links to the base (so if A is a delta |
| | 11 | * against B, then A has a depth of 1, and B a depth of 0). |
| | 12 | */ |
| | 13 | enum dfs_state { |
| | 14 | DFS_NONE = 0, |
| | 15 | DFS_ACTIVE, |
| | 16 | DFS_DONE, |
| | 17 | DFS_NUM_STATES |
| | 18 | }; |
| | 19 | |
| | 20 | /* |
| | 21 | * basic object info |
| | 22 | * ----------------- |
| | 23 | * idx.oid is filled up before delta searching starts. idx.crc32 is |
| | 24 | * only valid after the object is written out and will be used for |
| | 25 | * generating the index. idx.offset will be both gradually set and |
| | 26 | * used in writing phase (base objects get offset first, then deltas |
| | 27 | * refer to them) |
| | 28 | * |
| | 29 | * "size" is the uncompressed object size. Compressed size of the raw |
| | 30 | * data for an object in a pack is not stored anywhere but is computed |
| | 31 | * and made available when reverse .idx is made. |
| | 32 | * |
| | 33 | * "hash" contains a path name hash which is used for sorting the |
| | 34 | * delta list and also during delta searching. Once prepare_pack() |
| | 35 | * returns it's no longer needed. |
| | 36 | * |
| | 37 | * source pack info |
| | 38 | * ---------------- |
| | 39 | * The (in_pack, in_pack_offset) tuple contains the location of the |
| | 40 | * object in the source pack. in_pack_header_size allows quickly |
| | 41 | * skipping the header and going straight to the zlib stream. |
| | 42 | * |
| | 43 | * "type" and "in_pack_type" both describe object type. in_pack_type |
| | 44 | * may contain a delta type, while type is always the canonical type. |
| | 45 | * |
| | 46 | * deltas |
| | 47 | * ------ |
| | 48 | * Delta links (delta, delta_child and delta_sibling) are created to |
| | 49 | * reflect that delta graph from the source pack then updated or added |
| | 50 | * during delta searching phase when we find better deltas. |
| | 51 | * |
| | 52 | * delta_child and delta_sibling are last needed in |
| | 53 | * compute_write_order(). "delta" and "delta_size" must remain valid |
| | 54 | * at object writing phase in case the delta is not cached. |
| | 55 | * |
| | 56 | * If a delta is cached in memory and is compressed, delta_data points |
| | 57 | * to the data and z_delta_size contains the compressed size. If it's |
| | 58 | * uncompressed [1], z_delta_size must be zero. delta_size is always |
| | 59 | * the uncompressed size and must be valid even if the delta is not |
| | 60 | * cached. |
| | 61 | * |
| | 62 | * [1] during try_delta phase we don't bother with compressing because |
| | 63 | * the delta could be quickly replaced with a better one. |
| | 64 | */ |
| | 65 | struct object_entry { |
| | 66 | struct pack_idx_entry idx; |
| | 67 | unsigned long size; /* uncompressed size */ |
| | 68 | struct packed_git *in_pack; /* already in pack */ |
| | 69 | off_t in_pack_offset; |
| | 70 | struct object_entry *delta; /* delta base object */ |
| | 71 | struct object_entry *delta_child; /* deltified objects who bases me */ |
| | 72 | struct object_entry *delta_sibling; /* other deltified objects who |
| | 73 | * uses the same base as me |
| | 74 | */ |
| | 75 | void *delta_data; /* cached delta (uncompressed) */ |
| | 76 | unsigned long delta_size; /* delta data size (uncompressed) */ |
| | 77 | unsigned long z_delta_size; /* delta data size (compressed) */ |
| | 78 | unsigned type_:TYPE_BITS; |
| | 79 | unsigned in_pack_type:TYPE_BITS; /* could be delta */ |
| | 80 | unsigned type_valid:1; |
| | 81 | uint32_t hash; /* name hint hash */ |
| | 82 | unsigned int in_pack_pos; |
| | 83 | unsigned char in_pack_header_size; |
| | 84 | unsigned preferred_base:1; /* |
| | 85 | * we do not pack this, but is available |
| | 86 | * to be used as the base object to delta |
| | 87 | * objects against. |
| | 88 | */ |
| | 89 | unsigned no_try_delta:1; |
| | 90 | unsigned tagged:1; /* near the very tip of refs */ |
| | 91 | unsigned filled:1; /* assigned write-order */ |
| | 92 | unsigned dfs_state:OE_DFS_STATE_BITS; |
| | 93 | unsigned depth:OE_DEPTH_BITS; |
| | 94 | }; |
| | 95 | |
| | 96 | struct packing_data { |
| | 97 | struct object_entry *objects; |
| | 98 | uint32_t nr_objects, nr_alloc; |
| | 99 | |
| | 100 | int32_t *index; |
| | 101 | uint32_t index_size; |
| | 102 | }; |
| | 103 | |
| | 104 | struct object_entry *packlist_alloc(struct packing_data *pdata, |
| | 105 | const unsigned char *sha1, |
| | 106 | uint32_t index_pos); |
| | 107 | |
| | 108 | struct object_entry *packlist_find(struct packing_data *pdata, |
| | 109 | const unsigned char *sha1, |
| | 110 | uint32_t *index_pos); |
| | 111 | |
| | 112 | static inline uint32_t pack_name_hash(const char *name) |
| | 113 | { |
| | 114 | uint32_t c, hash = 0; |
| | 115 | |
| | 116 | if (!name) |
| | 117 | return 0; |
| | 118 | |
| | 119 | /* |
| | 120 | * This effectively just creates a sortable number from the |
| | 121 | * last sixteen non-whitespace characters. Last characters |
| | 122 | * count "most", so things that end in ".c" sort together. |
| | 123 | */ |
| | 124 | while ((c = *name++) != 0) { |
| | 125 | if (isspace(c)) |
| | 126 | continue; |
| | 127 | hash = (hash >> 2) + (c << 24); |
| | 128 | } |
| | 129 | return hash; |
| | 130 | } |
| | 131 | |
| | 132 | static inline enum object_type oe_type(const struct object_entry *e) |
| | 133 | { |
| | 134 | return e->type_valid ? e->type_ : OBJ_BAD; |
| | 135 | } |
| | 136 | |
| | 137 | static inline void oe_set_type(struct object_entry *e, |
| | 138 | enum object_type type) |
| | 139 | { |
| | 140 | if (type >= OBJ_ANY) |
| | 141 | BUG("OBJ_ANY cannot be set in pack-objects code"); |
| | 142 | |
| | 143 | e->type_valid = type >= OBJ_NONE; |
| | 144 | e->type_ = (unsigned)type; |
| | 145 | } |
| | 146 | |
| | 147 | #endif |
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