git-p4: do not fail in verbose mode for missing 'fileSize' key
[git] / split-index.c
1 #include "cache.h"
2 #include "split-index.h"
3 #include "ewah/ewok.h"
4
5 struct split_index *init_split_index(struct index_state *istate)
6 {
7         if (!istate->split_index) {
8                 istate->split_index = xcalloc(1, sizeof(*istate->split_index));
9                 istate->split_index->refcount = 1;
10         }
11         return istate->split_index;
12 }
13
14 int read_link_extension(struct index_state *istate,
15                          const void *data_, unsigned long sz)
16 {
17         const unsigned char *data = data_;
18         struct split_index *si;
19         int ret;
20
21         if (sz < the_hash_algo->rawsz)
22                 return error("corrupt link extension (too short)");
23         si = init_split_index(istate);
24         hashcpy(si->base_oid.hash, data);
25         data += the_hash_algo->rawsz;
26         sz -= the_hash_algo->rawsz;
27         if (!sz)
28                 return 0;
29         si->delete_bitmap = ewah_new();
30         ret = ewah_read_mmap(si->delete_bitmap, data, sz);
31         if (ret < 0)
32                 return error("corrupt delete bitmap in link extension");
33         data += ret;
34         sz -= ret;
35         si->replace_bitmap = ewah_new();
36         ret = ewah_read_mmap(si->replace_bitmap, data, sz);
37         if (ret < 0)
38                 return error("corrupt replace bitmap in link extension");
39         if (ret != sz)
40                 return error("garbage at the end of link extension");
41         return 0;
42 }
43
44 int write_link_extension(struct strbuf *sb,
45                          struct index_state *istate)
46 {
47         struct split_index *si = istate->split_index;
48         strbuf_add(sb, si->base_oid.hash, the_hash_algo->rawsz);
49         if (!si->delete_bitmap && !si->replace_bitmap)
50                 return 0;
51         ewah_serialize_strbuf(si->delete_bitmap, sb);
52         ewah_serialize_strbuf(si->replace_bitmap, sb);
53         return 0;
54 }
55
56 static void mark_base_index_entries(struct index_state *base)
57 {
58         int i;
59         /*
60          * To keep track of the shared entries between
61          * istate->base->cache[] and istate->cache[], base entry
62          * position is stored in each base entry. All positions start
63          * from 1 instead of 0, which is reserved to say "this is a new
64          * entry".
65          */
66         for (i = 0; i < base->cache_nr; i++)
67                 base->cache[i]->index = i + 1;
68 }
69
70 void move_cache_to_base_index(struct index_state *istate)
71 {
72         struct split_index *si = istate->split_index;
73         int i;
74
75         /*
76          * If there was a previous base index, then transfer ownership of allocated
77          * entries to the parent index.
78          */
79         if (si->base &&
80                 si->base->ce_mem_pool) {
81
82                 if (!istate->ce_mem_pool)
83                         mem_pool_init(&istate->ce_mem_pool, 0);
84
85                 mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
86         }
87
88         si->base = xcalloc(1, sizeof(*si->base));
89         si->base->version = istate->version;
90         /* zero timestamp disables racy test in ce_write_index() */
91         si->base->timestamp = istate->timestamp;
92         ALLOC_GROW(si->base->cache, istate->cache_nr, si->base->cache_alloc);
93         si->base->cache_nr = istate->cache_nr;
94
95         /*
96          * The mem_pool needs to move with the allocated entries.
97          */
98         si->base->ce_mem_pool = istate->ce_mem_pool;
99         istate->ce_mem_pool = NULL;
100
101         COPY_ARRAY(si->base->cache, istate->cache, istate->cache_nr);
102         mark_base_index_entries(si->base);
103         for (i = 0; i < si->base->cache_nr; i++)
104                 si->base->cache[i]->ce_flags &= ~CE_UPDATE_IN_BASE;
105 }
106
107 static void mark_entry_for_delete(size_t pos, void *data)
108 {
109         struct index_state *istate = data;
110         if (pos >= istate->cache_nr)
111                 die("position for delete %d exceeds base index size %d",
112                     (int)pos, istate->cache_nr);
113         istate->cache[pos]->ce_flags |= CE_REMOVE;
114         istate->split_index->nr_deletions = 1;
115 }
116
117 static void replace_entry(size_t pos, void *data)
118 {
119         struct index_state *istate = data;
120         struct split_index *si = istate->split_index;
121         struct cache_entry *dst, *src;
122
123         if (pos >= istate->cache_nr)
124                 die("position for replacement %d exceeds base index size %d",
125                     (int)pos, istate->cache_nr);
126         if (si->nr_replacements >= si->saved_cache_nr)
127                 die("too many replacements (%d vs %d)",
128                     si->nr_replacements, si->saved_cache_nr);
129         dst = istate->cache[pos];
130         if (dst->ce_flags & CE_REMOVE)
131                 die("entry %d is marked as both replaced and deleted",
132                     (int)pos);
133         src = si->saved_cache[si->nr_replacements];
134         if (ce_namelen(src))
135                 die("corrupt link extension, entry %d should have "
136                     "zero length name", (int)pos);
137         src->index = pos + 1;
138         src->ce_flags |= CE_UPDATE_IN_BASE;
139         src->ce_namelen = dst->ce_namelen;
140         copy_cache_entry(dst, src);
141         discard_cache_entry(src);
142         si->nr_replacements++;
143 }
144
145 void merge_base_index(struct index_state *istate)
146 {
147         struct split_index *si = istate->split_index;
148         unsigned int i;
149
150         mark_base_index_entries(si->base);
151
152         si->saved_cache     = istate->cache;
153         si->saved_cache_nr  = istate->cache_nr;
154         istate->cache_nr    = si->base->cache_nr;
155         istate->cache       = NULL;
156         istate->cache_alloc = 0;
157         ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
158         COPY_ARRAY(istate->cache, si->base->cache, istate->cache_nr);
159
160         si->nr_deletions = 0;
161         si->nr_replacements = 0;
162         ewah_each_bit(si->replace_bitmap, replace_entry, istate);
163         ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
164         if (si->nr_deletions)
165                 remove_marked_cache_entries(istate);
166
167         for (i = si->nr_replacements; i < si->saved_cache_nr; i++) {
168                 if (!ce_namelen(si->saved_cache[i]))
169                         die("corrupt link extension, entry %d should "
170                             "have non-zero length name", i);
171                 add_index_entry(istate, si->saved_cache[i],
172                                 ADD_CACHE_OK_TO_ADD |
173                                 ADD_CACHE_KEEP_CACHE_TREE |
174                                 /*
175                                  * we may have to replay what
176                                  * merge-recursive.c:update_stages()
177                                  * does, which has this flag on
178                                  */
179                                 ADD_CACHE_SKIP_DFCHECK);
180                 si->saved_cache[i] = NULL;
181         }
182
183         ewah_free(si->delete_bitmap);
184         ewah_free(si->replace_bitmap);
185         FREE_AND_NULL(si->saved_cache);
186         si->delete_bitmap  = NULL;
187         si->replace_bitmap = NULL;
188         si->saved_cache_nr = 0;
189 }
190
191 void prepare_to_write_split_index(struct index_state *istate)
192 {
193         struct split_index *si = init_split_index(istate);
194         struct cache_entry **entries = NULL, *ce;
195         int i, nr_entries = 0, nr_alloc = 0;
196
197         si->delete_bitmap = ewah_new();
198         si->replace_bitmap = ewah_new();
199
200         if (si->base) {
201                 /* Go through istate->cache[] and mark CE_MATCHED to
202                  * entry with positive index. We'll go through
203                  * base->cache[] later to delete all entries in base
204                  * that are not marked with either CE_MATCHED or
205                  * CE_UPDATE_IN_BASE. If istate->cache[i] is a
206                  * duplicate, deduplicate it.
207                  */
208                 for (i = 0; i < istate->cache_nr; i++) {
209                         struct cache_entry *base;
210                         /* namelen is checked separately */
211                         const unsigned int ondisk_flags =
212                                 CE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;
213                         unsigned int ce_flags, base_flags, ret;
214                         ce = istate->cache[i];
215                         if (!ce->index)
216                                 continue;
217                         if (ce->index > si->base->cache_nr) {
218                                 ce->index = 0;
219                                 continue;
220                         }
221                         ce->ce_flags |= CE_MATCHED; /* or "shared" */
222                         base = si->base->cache[ce->index - 1];
223                         if (ce == base)
224                                 continue;
225                         if (ce->ce_namelen != base->ce_namelen ||
226                             strcmp(ce->name, base->name)) {
227                                 ce->index = 0;
228                                 continue;
229                         }
230                         ce_flags = ce->ce_flags;
231                         base_flags = base->ce_flags;
232                         /* only on-disk flags matter */
233                         ce->ce_flags   &= ondisk_flags;
234                         base->ce_flags &= ondisk_flags;
235                         ret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,
236                                      offsetof(struct cache_entry, name) -
237                                      offsetof(struct cache_entry, ce_stat_data));
238                         ce->ce_flags = ce_flags;
239                         base->ce_flags = base_flags;
240                         if (ret)
241                                 ce->ce_flags |= CE_UPDATE_IN_BASE;
242                         discard_cache_entry(base);
243                         si->base->cache[ce->index - 1] = ce;
244                 }
245                 for (i = 0; i < si->base->cache_nr; i++) {
246                         ce = si->base->cache[i];
247                         if ((ce->ce_flags & CE_REMOVE) ||
248                             !(ce->ce_flags & CE_MATCHED))
249                                 ewah_set(si->delete_bitmap, i);
250                         else if (ce->ce_flags & CE_UPDATE_IN_BASE) {
251                                 ewah_set(si->replace_bitmap, i);
252                                 ce->ce_flags |= CE_STRIP_NAME;
253                                 ALLOC_GROW(entries, nr_entries+1, nr_alloc);
254                                 entries[nr_entries++] = ce;
255                         }
256                         if (is_null_oid(&ce->oid))
257                                 istate->drop_cache_tree = 1;
258                 }
259         }
260
261         for (i = 0; i < istate->cache_nr; i++) {
262                 ce = istate->cache[i];
263                 if ((!si->base || !ce->index) && !(ce->ce_flags & CE_REMOVE)) {
264                         assert(!(ce->ce_flags & CE_STRIP_NAME));
265                         ALLOC_GROW(entries, nr_entries+1, nr_alloc);
266                         entries[nr_entries++] = ce;
267                 }
268                 ce->ce_flags &= ~CE_MATCHED;
269         }
270
271         /*
272          * take cache[] out temporarily, put entries[] in its place
273          * for writing
274          */
275         si->saved_cache = istate->cache;
276         si->saved_cache_nr = istate->cache_nr;
277         istate->cache = entries;
278         istate->cache_nr = nr_entries;
279 }
280
281 void finish_writing_split_index(struct index_state *istate)
282 {
283         struct split_index *si = init_split_index(istate);
284
285         ewah_free(si->delete_bitmap);
286         ewah_free(si->replace_bitmap);
287         si->delete_bitmap = NULL;
288         si->replace_bitmap = NULL;
289         free(istate->cache);
290         istate->cache = si->saved_cache;
291         istate->cache_nr = si->saved_cache_nr;
292 }
293
294 void discard_split_index(struct index_state *istate)
295 {
296         struct split_index *si = istate->split_index;
297         if (!si)
298                 return;
299         istate->split_index = NULL;
300         si->refcount--;
301         if (si->refcount)
302                 return;
303         if (si->base) {
304                 discard_index(si->base);
305                 free(si->base);
306         }
307         free(si);
308 }
309
310 void save_or_free_index_entry(struct index_state *istate, struct cache_entry *ce)
311 {
312         if (ce->index &&
313             istate->split_index &&
314             istate->split_index->base &&
315             ce->index <= istate->split_index->base->cache_nr &&
316             ce == istate->split_index->base->cache[ce->index - 1])
317                 ce->ce_flags |= CE_REMOVE;
318         else
319                 discard_cache_entry(ce);
320 }
321
322 void replace_index_entry_in_base(struct index_state *istate,
323                                  struct cache_entry *old_entry,
324                                  struct cache_entry *new_entry)
325 {
326         if (old_entry->index &&
327             istate->split_index &&
328             istate->split_index->base &&
329             old_entry->index <= istate->split_index->base->cache_nr) {
330                 new_entry->index = old_entry->index;
331                 if (old_entry != istate->split_index->base->cache[new_entry->index - 1])
332                         discard_cache_entry(istate->split_index->base->cache[new_entry->index - 1]);
333                 istate->split_index->base->cache[new_entry->index - 1] = new_entry;
334         }
335 }
336
337 void add_split_index(struct index_state *istate)
338 {
339         if (!istate->split_index) {
340                 init_split_index(istate);
341                 istate->cache_changed |= SPLIT_INDEX_ORDERED;
342         }
343 }
344
345 void remove_split_index(struct index_state *istate)
346 {
347         if (istate->split_index) {
348                 /*
349                  * When removing the split index, we need to move
350                  * ownership of the mem_pool associated with the
351                  * base index to the main index. There may be cache entries
352                  * allocated from the base's memory pool that are shared with
353                  * the_index.cache[].
354                  */
355                 mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
356
357                 /*
358                  * The split index no longer owns the mem_pool backing
359                  * its cache array. As we are discarding this index,
360                  * mark the index as having no cache entries, so it
361                  * will not attempt to clean up the cache entries or
362                  * validate them.
363                  */
364                 if (istate->split_index->base)
365                         istate->split_index->base->cache_nr = 0;
366
367                 /*
368                  * We can discard the split index because its
369                  * memory pool has been incorporated into the
370                  * memory pool associated with the the_index.
371                  */
372                 discard_split_index(istate);
373
374                 istate->cache_changed |= SOMETHING_CHANGED;
375         }
376 }