Merge branch 'rs/fix-alt-odb-path-comparison' into maint
[git.git] / name-hash.c
blob97444d02010e13de1eab9abe6f1fc71287658faf
1 /*
2 * name-hash.c
4 * Hashing names in the index state
6 * Copyright (C) 2008 Linus Torvalds
7 */
8 #define NO_THE_INDEX_COMPATIBILITY_MACROS
9 #include "cache.h"
11 struct dir_entry {
12 struct hashmap_entry ent;
13 struct dir_entry *parent;
14 struct cache_entry *ce;
15 int nr;
16 unsigned int namelen;
19 static int dir_entry_cmp(const struct dir_entry *e1,
20 const struct dir_entry *e2, const char *name)
22 return e1->namelen != e2->namelen || strncasecmp(e1->ce->name,
23 name ? name : e2->ce->name, e1->namelen);
26 static struct dir_entry *find_dir_entry(struct index_state *istate,
27 const char *name, unsigned int namelen)
29 struct dir_entry key;
30 hashmap_entry_init(&key, memihash(name, namelen));
31 key.namelen = namelen;
32 return hashmap_get(&istate->dir_hash, &key, name);
35 static struct dir_entry *hash_dir_entry(struct index_state *istate,
36 struct cache_entry *ce, int namelen)
39 * Throw each directory component in the hash for quick lookup
40 * during a git status. Directory components are stored without their
41 * closing slash. Despite submodules being a directory, they never
42 * reach this point, because they are stored
43 * in index_state.name_hash (as ordinary cache_entries).
45 * Note that the cache_entry stored with the dir_entry merely
46 * supplies the name of the directory (up to dir_entry.namelen). We
47 * track the number of 'active' files in a directory in dir_entry.nr,
48 * so we can tell if the directory is still relevant, e.g. for git
49 * status. However, if cache_entries are removed, we cannot pinpoint
50 * an exact cache_entry that's still active. It is very possible that
51 * multiple dir_entries point to the same cache_entry.
53 struct dir_entry *dir;
55 /* get length of parent directory */
56 while (namelen > 0 && !is_dir_sep(ce->name[namelen - 1]))
57 namelen--;
58 if (namelen <= 0)
59 return NULL;
60 namelen--;
62 /* lookup existing entry for that directory */
63 dir = find_dir_entry(istate, ce->name, namelen);
64 if (!dir) {
65 /* not found, create it and add to hash table */
66 dir = xcalloc(1, sizeof(struct dir_entry));
67 hashmap_entry_init(dir, memihash(ce->name, namelen));
68 dir->namelen = namelen;
69 dir->ce = ce;
70 hashmap_add(&istate->dir_hash, dir);
72 /* recursively add missing parent directories */
73 dir->parent = hash_dir_entry(istate, ce, namelen);
75 return dir;
78 static void add_dir_entry(struct index_state *istate, struct cache_entry *ce)
80 /* Add reference to the directory entry (and parents if 0). */
81 struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
82 while (dir && !(dir->nr++))
83 dir = dir->parent;
86 static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
89 * Release reference to the directory entry. If 0, remove and continue
90 * with parent directory.
92 struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
93 while (dir && !(--dir->nr)) {
94 struct dir_entry *parent = dir->parent;
95 hashmap_remove(&istate->dir_hash, dir, NULL);
96 free(dir);
97 dir = parent;
101 static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
103 if (ce->ce_flags & CE_HASHED)
104 return;
105 ce->ce_flags |= CE_HASHED;
106 hashmap_entry_init(ce, memihash(ce->name, ce_namelen(ce)));
107 hashmap_add(&istate->name_hash, ce);
109 if (ignore_case)
110 add_dir_entry(istate, ce);
113 static int cache_entry_cmp(const struct cache_entry *ce1,
114 const struct cache_entry *ce2, const void *remove)
117 * For remove_name_hash, find the exact entry (pointer equality); for
118 * index_file_exists, find all entries with matching hash code and
119 * decide whether the entry matches in same_name.
121 return remove ? !(ce1 == ce2) : 0;
124 static void lazy_init_name_hash(struct index_state *istate)
126 int nr;
128 if (istate->name_hash_initialized)
129 return;
130 hashmap_init(&istate->name_hash, (hashmap_cmp_fn) cache_entry_cmp,
131 istate->cache_nr);
132 hashmap_init(&istate->dir_hash, (hashmap_cmp_fn) dir_entry_cmp, 0);
133 for (nr = 0; nr < istate->cache_nr; nr++)
134 hash_index_entry(istate, istate->cache[nr]);
135 istate->name_hash_initialized = 1;
138 void add_name_hash(struct index_state *istate, struct cache_entry *ce)
140 if (istate->name_hash_initialized)
141 hash_index_entry(istate, ce);
144 void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
146 if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
147 return;
148 ce->ce_flags &= ~CE_HASHED;
149 hashmap_remove(&istate->name_hash, ce, ce);
151 if (ignore_case)
152 remove_dir_entry(istate, ce);
155 static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
157 if (len1 != len2)
158 return 0;
160 while (len1) {
161 unsigned char c1 = *name1++;
162 unsigned char c2 = *name2++;
163 len1--;
164 if (c1 != c2) {
165 c1 = toupper(c1);
166 c2 = toupper(c2);
167 if (c1 != c2)
168 return 0;
171 return 1;
174 static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
176 int len = ce_namelen(ce);
179 * Always do exact compare, even if we want a case-ignoring comparison;
180 * we do the quick exact one first, because it will be the common case.
182 if (len == namelen && !cache_name_compare(name, namelen, ce->name, len))
183 return 1;
185 if (!icase)
186 return 0;
188 return slow_same_name(name, namelen, ce->name, len);
191 struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen)
193 struct cache_entry *ce;
194 struct dir_entry *dir;
196 lazy_init_name_hash(istate);
197 dir = find_dir_entry(istate, name, namelen);
198 if (dir && dir->nr)
199 return dir->ce;
202 * It might be a submodule. Unlike plain directories, which are stored
203 * in the dir-hash, submodules are stored in the name-hash, so check
204 * there, as well.
206 ce = index_file_exists(istate, name, namelen, 1);
207 if (ce && S_ISGITLINK(ce->ce_mode))
208 return ce;
210 return NULL;
213 struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
215 struct cache_entry *ce;
216 struct hashmap_entry key;
218 lazy_init_name_hash(istate);
220 hashmap_entry_init(&key, memihash(name, namelen));
221 ce = hashmap_get(&istate->name_hash, &key, NULL);
222 while (ce) {
223 if (same_name(ce, name, namelen, icase))
224 return ce;
225 ce = hashmap_get_next(&istate->name_hash, ce);
227 return NULL;
230 void free_name_hash(struct index_state *istate)
232 if (!istate->name_hash_initialized)
233 return;
234 istate->name_hash_initialized = 0;
236 hashmap_free(&istate->name_hash, 0);
237 hashmap_free(&istate->dir_hash, 1);