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2834bc27 VM |
1 | #ifndef PACK_OBJECTS_H |
2 | #define PACK_OBJECTS_H | |
3 | ||
0c6804ab | 4 | #define OE_DFS_STATE_BITS 2 |
b5c0cbd8 | 5 | #define OE_DEPTH_BITS 12 |
0c6804ab NTND |
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 | ||
8d6ccce1 NTND |
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 | */ | |
2834bc27 VM |
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) */ | |
fd9b1bae NTND |
78 | unsigned type_:TYPE_BITS; |
79 | unsigned in_pack_type:TYPE_BITS; /* could be delta */ | |
80 | unsigned type_valid:1; | |
2834bc27 VM |
81 | uint32_t hash; /* name hint hash */ |
82 | unsigned char in_pack_header_size; | |
83 | unsigned preferred_base:1; /* | |
84 | * we do not pack this, but is available | |
85 | * to be used as the base object to delta | |
86 | * objects against. | |
87 | */ | |
88 | unsigned no_try_delta:1; | |
89 | unsigned tagged:1; /* near the very tip of refs */ | |
90 | unsigned filled:1; /* assigned write-order */ | |
0c6804ab | 91 | unsigned dfs_state:OE_DFS_STATE_BITS; |
b5c0cbd8 | 92 | unsigned depth:OE_DEPTH_BITS; |
2834bc27 VM |
93 | }; |
94 | ||
95 | struct packing_data { | |
96 | struct object_entry *objects; | |
97 | uint32_t nr_objects, nr_alloc; | |
98 | ||
99 | int32_t *index; | |
100 | uint32_t index_size; | |
06af3bba NTND |
101 | |
102 | unsigned int *in_pack_pos; | |
2834bc27 VM |
103 | }; |
104 | ||
105 | struct object_entry *packlist_alloc(struct packing_data *pdata, | |
106 | const unsigned char *sha1, | |
107 | uint32_t index_pos); | |
108 | ||
109 | struct object_entry *packlist_find(struct packing_data *pdata, | |
110 | const unsigned char *sha1, | |
111 | uint32_t *index_pos); | |
112 | ||
68fb36eb VM |
113 | static inline uint32_t pack_name_hash(const char *name) |
114 | { | |
115 | uint32_t c, hash = 0; | |
116 | ||
117 | if (!name) | |
118 | return 0; | |
119 | ||
120 | /* | |
121 | * This effectively just creates a sortable number from the | |
122 | * last sixteen non-whitespace characters. Last characters | |
123 | * count "most", so things that end in ".c" sort together. | |
124 | */ | |
125 | while ((c = *name++) != 0) { | |
126 | if (isspace(c)) | |
127 | continue; | |
128 | hash = (hash >> 2) + (c << 24); | |
129 | } | |
130 | return hash; | |
131 | } | |
132 | ||
fd9b1bae NTND |
133 | static inline enum object_type oe_type(const struct object_entry *e) |
134 | { | |
135 | return e->type_valid ? e->type_ : OBJ_BAD; | |
136 | } | |
137 | ||
138 | static inline void oe_set_type(struct object_entry *e, | |
139 | enum object_type type) | |
140 | { | |
141 | if (type >= OBJ_ANY) | |
142 | BUG("OBJ_ANY cannot be set in pack-objects code"); | |
143 | ||
144 | e->type_valid = type >= OBJ_NONE; | |
145 | e->type_ = (unsigned)type; | |
146 | } | |
147 | ||
06af3bba NTND |
148 | static inline unsigned int oe_in_pack_pos(const struct packing_data *pack, |
149 | const struct object_entry *e) | |
150 | { | |
151 | return pack->in_pack_pos[e - pack->objects]; | |
152 | } | |
153 | ||
154 | static inline void oe_set_in_pack_pos(const struct packing_data *pack, | |
155 | const struct object_entry *e, | |
156 | unsigned int pos) | |
157 | { | |
158 | pack->in_pack_pos[e - pack->objects] = pos; | |
159 | } | |
160 | ||
2834bc27 | 161 | #endif |