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-rw-r--r--name-hash.c238
1 files changed, 238 insertions, 0 deletions
diff --git a/name-hash.c b/name-hash.c
new file mode 100644
index 0000000..6d9f23e
--- /dev/null
+++ b/name-hash.c
@@ -0,0 +1,238 @@
+/*
+ * name-hash.c
+ *
+ * Hashing names in the index state
+ *
+ * Copyright (C) 2008 Linus Torvalds
+ */
+#define NO_THE_INDEX_COMPATIBILITY_MACROS
+#include "cache.h"
+
+struct dir_entry {
+ struct hashmap_entry ent;
+ struct dir_entry *parent;
+ int nr;
+ unsigned int namelen;
+ char name[FLEX_ARRAY];
+};
+
+static int dir_entry_cmp(const struct dir_entry *e1,
+ const struct dir_entry *e2, const char *name)
+{
+ return e1->namelen != e2->namelen || strncasecmp(e1->name,
+ name ? name : e2->name, e1->namelen);
+}
+
+static struct dir_entry *find_dir_entry(struct index_state *istate,
+ const char *name, unsigned int namelen)
+{
+ struct dir_entry key;
+ hashmap_entry_init(&key, memihash(name, namelen));
+ key.namelen = namelen;
+ return hashmap_get(&istate->dir_hash, &key, name);
+}
+
+static struct dir_entry *hash_dir_entry(struct index_state *istate,
+ struct cache_entry *ce, int namelen)
+{
+ /*
+ * Throw each directory component in the hash for quick lookup
+ * during a git status. Directory components are stored without their
+ * closing slash. Despite submodules being a directory, they never
+ * reach this point, because they are stored
+ * in index_state.name_hash (as ordinary cache_entries).
+ */
+ struct dir_entry *dir;
+
+ /* get length of parent directory */
+ while (namelen > 0 && !is_dir_sep(ce->name[namelen - 1]))
+ namelen--;
+ if (namelen <= 0)
+ return NULL;
+ namelen--;
+
+ /* lookup existing entry for that directory */
+ dir = find_dir_entry(istate, ce->name, namelen);
+ if (!dir) {
+ /* not found, create it and add to hash table */
+ FLEX_ALLOC_MEM(dir, name, ce->name, namelen);
+ hashmap_entry_init(dir, memihash(ce->name, namelen));
+ dir->namelen = namelen;
+ hashmap_add(&istate->dir_hash, dir);
+
+ /* recursively add missing parent directories */
+ dir->parent = hash_dir_entry(istate, ce, namelen);
+ }
+ return dir;
+}
+
+static void add_dir_entry(struct index_state *istate, struct cache_entry *ce)
+{
+ /* Add reference to the directory entry (and parents if 0). */
+ struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
+ while (dir && !(dir->nr++))
+ dir = dir->parent;
+}
+
+static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
+{
+ /*
+ * Release reference to the directory entry. If 0, remove and continue
+ * with parent directory.
+ */
+ struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
+ while (dir && !(--dir->nr)) {
+ struct dir_entry *parent = dir->parent;
+ hashmap_remove(&istate->dir_hash, dir, NULL);
+ free(dir);
+ dir = parent;
+ }
+}
+
+static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
+{
+ if (ce->ce_flags & CE_HASHED)
+ return;
+ ce->ce_flags |= CE_HASHED;
+ hashmap_entry_init(ce, memihash(ce->name, ce_namelen(ce)));
+ hashmap_add(&istate->name_hash, ce);
+
+ if (ignore_case)
+ add_dir_entry(istate, ce);
+}
+
+static int cache_entry_cmp(const struct cache_entry *ce1,
+ const struct cache_entry *ce2, const void *remove)
+{
+ /*
+ * For remove_name_hash, find the exact entry (pointer equality); for
+ * index_file_exists, find all entries with matching hash code and
+ * decide whether the entry matches in same_name.
+ */
+ return remove ? !(ce1 == ce2) : 0;
+}
+
+static void lazy_init_name_hash(struct index_state *istate)
+{
+ int nr;
+
+ if (istate->name_hash_initialized)
+ return;
+ hashmap_init(&istate->name_hash, (hashmap_cmp_fn) cache_entry_cmp,
+ istate->cache_nr);
+ hashmap_init(&istate->dir_hash, (hashmap_cmp_fn) dir_entry_cmp, 0);
+ for (nr = 0; nr < istate->cache_nr; nr++)
+ hash_index_entry(istate, istate->cache[nr]);
+ istate->name_hash_initialized = 1;
+}
+
+void add_name_hash(struct index_state *istate, struct cache_entry *ce)
+{
+ if (istate->name_hash_initialized)
+ hash_index_entry(istate, ce);
+}
+
+void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
+{
+ if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
+ return;
+ ce->ce_flags &= ~CE_HASHED;
+ hashmap_remove(&istate->name_hash, ce, ce);
+
+ if (ignore_case)
+ remove_dir_entry(istate, ce);
+}
+
+static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
+{
+ if (len1 != len2)
+ return 0;
+
+ while (len1) {
+ unsigned char c1 = *name1++;
+ unsigned char c2 = *name2++;
+ len1--;
+ if (c1 != c2) {
+ c1 = toupper(c1);
+ c2 = toupper(c2);
+ if (c1 != c2)
+ return 0;
+ }
+ }
+ return 1;
+}
+
+static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
+{
+ int len = ce_namelen(ce);
+
+ /*
+ * Always do exact compare, even if we want a case-ignoring comparison;
+ * we do the quick exact one first, because it will be the common case.
+ */
+ if (len == namelen && !memcmp(name, ce->name, len))
+ return 1;
+
+ if (!icase)
+ return 0;
+
+ return slow_same_name(name, namelen, ce->name, len);
+}
+
+int index_dir_exists(struct index_state *istate, const char *name, int namelen)
+{
+ struct dir_entry *dir;
+
+ lazy_init_name_hash(istate);
+ dir = find_dir_entry(istate, name, namelen);
+ return dir && dir->nr;
+}
+
+void adjust_dirname_case(struct index_state *istate, char *name)
+{
+ const char *startPtr = name;
+ const char *ptr = startPtr;
+
+ lazy_init_name_hash(istate);
+ while (*ptr) {
+ while (*ptr && *ptr != '/')
+ ptr++;
+
+ if (*ptr == '/') {
+ struct dir_entry *dir;
+
+ ptr++;
+ dir = find_dir_entry(istate, name, ptr - name + 1);
+ if (dir) {
+ memcpy((void *)startPtr, dir->name + (startPtr - name), ptr - startPtr);
+ startPtr = ptr;
+ }
+ }
+ }
+}
+
+struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
+{
+ struct cache_entry *ce;
+
+ lazy_init_name_hash(istate);
+
+ ce = hashmap_get_from_hash(&istate->name_hash,
+ memihash(name, namelen), NULL);
+ while (ce) {
+ if (same_name(ce, name, namelen, icase))
+ return ce;
+ ce = hashmap_get_next(&istate->name_hash, ce);
+ }
+ return NULL;
+}
+
+void free_name_hash(struct index_state *istate)
+{
+ if (!istate->name_hash_initialized)
+ return;
+ istate->name_hash_initialized = 0;
+
+ hashmap_free(&istate->name_hash, 0);
+ hashmap_free(&istate->dir_hash, 1);
+}