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