tree-walk.c

   1 #include "cache.h"
   2 #include "tree-walk.h"
   3 #include "tree.h"
   4
   5 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
   6 {
   7         unsigned long size = 0;
   8         void *buf = NULL;
   9
  10         if (sha1) {
  11                 buf = read_object_with_reference(sha1, tree_type, &size, NULL);
  12                 if (!buf)
  13                         die("unable to read tree %s", sha1_to_hex(sha1));
  14         }
  15         desc->size = size;
  16         desc->buf = buf;
  17         return buf;
  18 }
  19
  20 static int entry_compare(struct name_entry *a, struct name_entry *b)
  21 {
  22         return base_name_compare(
  23                         a->path, a->pathlen, a->mode,
  24                         b->path, b->pathlen, b->mode);
  25 }
  26
  27 static void entry_clear(struct name_entry *a)
  28 {
  29         memset(a, 0, sizeof(*a));
  30 }
  31
  32 static void entry_extract(struct tree_desc *t, struct name_entry *a)
  33 {
  34         a->sha1 = tree_entry_extract(t, &a->path, &a->mode);
  35         a->pathlen = tree_entry_len(a->path, a->sha1);
  36 }
  37
  38 void update_tree_entry(struct tree_desc *desc)
  39 {
  40         const void *buf = desc->buf;
  41         unsigned long size = desc->size;
  42         int len = strlen(buf) + 1 + 20;
  43
  44         if (size < len)
  45                 die("corrupt tree file");
  46         desc->buf = (char *) buf + len;
  47         desc->size = size - len;
  48 }
  49
  50 static const char *get_mode(const char *str, unsigned int *modep)
  51 {
  52         unsigned char c;
  53         unsigned int mode = 0;
  54
  55         while ((c = *str++) != ' ') {
  56                 if (c < '0' || c > '7')
  57                         return NULL;
  58                 mode = (mode << 3) + (c - '0');
  59         }
  60         *modep = mode;
  61         return str;
  62 }
  63
  64 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
  65 {
  66         const void *tree = desc->buf;
  67         unsigned long size = desc->size;
  68         int len = strlen(tree)+1;
  69         const unsigned char *sha1 = (unsigned char *) tree + len;
  70         const char *path;
  71         unsigned int mode;
  72
  73         path = get_mode(tree, &mode);
  74         if (!path || size < len + 20)
  75                 die("corrupt tree file");
  76         *pathp = path;
  77         *modep = canon_mode(mode);
  78         return sha1;
  79 }
  80
  81 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
  82 {
  83         const void *tree = desc->buf;
  84         const char *path;
  85         unsigned long len, size = desc->size;
  86
  87         if (!size)
  88                 return 0;
  89
  90         path = get_mode(tree, &entry->mode);
  91         if (!path)
  92                 die("corrupt tree file");
  93
  94         entry->path = path;
  95         len = strlen(path);
  96         entry->pathlen = len;
  97
  98         path += len + 1;
  99         entry->sha1 = (const unsigned char *) path;
 100
 101         path += 20;
 102         len = path - (char *) tree;
 103         if (len > size)
 104                 die("corrupt tree file");
 105
 106         desc->buf = path;
 107         desc->size = size - len;
 108         return 1;
 109 }
 110
 111 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
 112 {
 113         struct name_entry *entry = xmalloc(n*sizeof(*entry));
 114
 115         for (;;) {
 116                 unsigned long mask = 0;
 117                 int i, last;
 118
 119                 last = -1;
 120                 for (i = 0; i < n; i++) {
 121                         if (!t[i].size)
 122                                 continue;
 123                         entry_extract(t+i, entry+i);
 124                         if (last >= 0) {
 125                                 int cmp = entry_compare(entry+i, entry+last);
 126
 127                                 /*
 128                                  * Is the new name bigger than the old one?
 129                                  * Ignore it
 130                                  */
 131                                 if (cmp > 0)
 132                                         continue;
 133                                 /*
 134                                  * Is the new name smaller than the old one?
 135                                  * Ignore all old ones
 136                                  */
 137                                 if (cmp < 0)
 138                                         mask = 0;
 139                         }
 140                         mask |= 1ul << i;
 141                         last = i;
 142                 }
 143                 if (!mask)
 144                         break;
 145
 146                 /*
 147                  * Update the tree entries we've walked, and clear
 148                  * all the unused name-entries.
 149                  */
 150                 for (i = 0; i < n; i++) {
 151                         if (mask & (1ul << i)) {
 152                                 update_tree_entry(t+i);
 153                                 continue;
 154                         }
 155                         entry_clear(entry + i);
 156                 }
 157                 callback(n, mask, entry, base);
 158         }
 159         free(entry);
 160 }
 161
 162 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 163 {
 164         int namelen = strlen(name);
 165         while (t->size) {
 166                 const char *entry;
 167                 const unsigned char *sha1;
 168                 int entrylen, cmp;
 169
 170                 sha1 = tree_entry_extract(t, &entry, mode);
 171                 update_tree_entry(t);
 172                 entrylen = tree_entry_len(entry, sha1);
 173                 if (entrylen > namelen)
 174                         continue;
 175                 cmp = memcmp(name, entry, entrylen);
 176                 if (cmp > 0)
 177                         continue;
 178                 if (cmp < 0)
 179                         break;
 180                 if (entrylen == namelen) {
 181                         hashcpy(result, sha1);
 182                         return 0;
 183                 }
 184                 if (name[entrylen] != '/')
 185                         continue;
 186                 if (!S_ISDIR(*mode))
 187                         break;
 188                 if (++entrylen == namelen) {
 189                         hashcpy(result, sha1);
 190                         return 0;
 191                 }
 192                 return get_tree_entry(sha1, name + entrylen, result, mode);
 193         }
 194         return -1;
 195 }
 196
 197 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 198 {
 199         int retval;
 200         void *tree;
 201         struct tree_desc t;
 202         unsigned char root[20];
 203
 204         tree = read_object_with_reference(tree_sha1, tree_type, &t.size, root);
 205         if (!tree)
 206                 return -1;
 207
 208         if (name[0] == '\0') {
 209                 hashcpy(sha1, root);
 210                 return 0;
 211         }
 212
 213         t.buf = tree;
 214         retval = find_tree_entry(&t, name, sha1, mode);
 215         free(tree);
 216         return retval;
 217 }
 218