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 = strlen(a->path);
  36 }
  37
  38 void update_tree_entry(struct tree_desc *desc)
  39 {
  40         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 = buf + len;
  47         desc->size = size - len;
  48 }
  49
  50 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
  51 {
  52         void *tree = desc->buf;
  53         unsigned long size = desc->size;
  54         int len = strlen(tree)+1;
  55         const unsigned char *sha1 = tree + len;
  56         const char *path = strchr(tree, ' ');
  57         unsigned int mode;
  58
  59         if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)
  60                 die("corrupt tree file");
  61         *pathp = path+1;
  62         *modep = canon_mode(mode);
  63         return sha1;
  64 }
  65
  66 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
  67 {
  68         struct name_entry *entry = xmalloc(n*sizeof(*entry));
  69
  70         for (;;) {
  71                 struct name_entry entry[3];
  72                 unsigned long mask = 0;
  73                 int i, last;
  74
  75                 last = -1;
  76                 for (i = 0; i < n; i++) {
  77                         if (!t[i].size)
  78                                 continue;
  79                         entry_extract(t+i, entry+i);
  80                         if (last >= 0) {
  81                                 int cmp = entry_compare(entry+i, entry+last);
  82
  83                                 /*
  84                                  * Is the new name bigger than the old one?
  85                                  * Ignore it
  86                                  */
  87                                 if (cmp > 0)
  88                                         continue;
  89                                 /*
  90                                  * Is the new name smaller than the old one?
  91                                  * Ignore all old ones
  92                                  */
  93                                 if (cmp < 0)
  94                                         mask = 0;
  95                         }
  96                         mask |= 1ul << i;
  97                         last = i;
  98                 }
  99                 if (!mask)
 100                         break;
 101
 102                 /*
 103                  * Update the tree entries we've walked, and clear
 104                  * all the unused name-entries.
 105                  */
 106                 for (i = 0; i < n; i++) {
 107                         if (mask & (1ul << i)) {
 108                                 update_tree_entry(t+i);
 109                                 continue;
 110                         }
 111                         entry_clear(entry + i);
 112                 }
 113                 callback(n, mask, entry, base);
 114         }
 115         free(entry);
 116 }
 117