attr.c: read attributes in a sparse directory

[thirdparty/git.git] / attr.c

diff --git a/attr.c b/attr.c
index e5785c55dbcc9793d06725b23640c64659d33974..d85fd6d2edee4817acabaa1d71dd69563eb5e662 100644 (file)
--- a/attr.c
+++ b/attr.c
@@ -808,35 +808,56 @@ static struct attr_stack *read_attr_from_blob(struct index_state *istate,
 static struct attr_stack *read_attr_from_index(struct index_state *istate,
                                               const char *path, unsigned flags)
 {
+       struct attr_stack *stack = NULL;
        char *buf;
        unsigned long size;
+       int sparse_dir_pos = -1;
 
        if (!istate)
                return NULL;
 
        /*
-        * The .gitattributes file only applies to files within its
-        * parent directory. In the case of cone-mode sparse-checkout,
-        * the .gitattributes file is sparse if and only if all paths
-        * within that directory are also sparse. Thus, don't load the
-        * .gitattributes file since it will not matter.
-        *
-        * In the case of a sparse index, it is critical that we don't go
-        * looking for a .gitattributes file, as doing so would cause the
-        * index to expand.
+        * When handling sparse-checkouts, .gitattributes files
+        * may reside within a sparse directory. We distinguish
+        * whether a path exists directly in the index or not by
+        * evaluating if 'pos' is negative.
+        * If 'pos' is negative, the path is not directly present
+        * in the index and is likely within a sparse directory.
+        * For paths not in the index, The absolute value of 'pos'
+        * minus 1 gives us the position where the path would be
+        * inserted in lexicographic order within the index.
+        * We then subtract another 1 from this value
+        * (sparse_dir_pos = -pos - 2) to find the position of the
+        * last index entry which is lexicographically smaller than
+        * the path. This would be the sparse directory containing
+        * the path. By identifying the sparse directory containing
+        * the path, we can correctly read the attributes specified
+        * in the .gitattributes file from the tree object of the
+        * sparse directory.
         */
-       if (!path_in_cone_mode_sparse_checkout(path, istate))
-               return NULL;
+       if (!path_in_cone_mode_sparse_checkout(path, istate)) {
+               int pos = index_name_pos_sparse(istate, path, strlen(path));
 
-       buf = read_blob_data_from_index(istate, path, &size);
-       if (!buf)
-               return NULL;
-       if (size >= ATTR_MAX_FILE_SIZE) {
-               warning(_("ignoring overly large gitattributes blob '%s'"), path);
-               return NULL;
+               if (pos < 0)
+                       sparse_dir_pos = -pos - 2;
        }
 
-       return read_attr_from_buf(buf, path, flags);
+       if (sparse_dir_pos >= 0 &&
+           S_ISSPARSEDIR(istate->cache[sparse_dir_pos]->ce_mode) &&
+           !strncmp(istate->cache[sparse_dir_pos]->name, path, ce_namelen(istate->cache[sparse_dir_pos]))) {
+               const char *relative_path = path + ce_namelen(istate->cache[sparse_dir_pos]);
+               stack = read_attr_from_blob(istate, &istate->cache[sparse_dir_pos]->oid, relative_path, flags);
+       } else {
+               buf = read_blob_data_from_index(istate, path, &size);
+               if (!buf)
+                       return NULL;
+               if (size >= ATTR_MAX_FILE_SIZE) {
+                       warning(_("ignoring overly large gitattributes blob '%s'"), path);
+                       return NULL;
+               }
+               stack = read_attr_from_buf(buf, path, flags);
+       }
+       return stack;
 }
 
 static struct attr_stack *read_attr(struct index_state *istate,