Improved flist_find()'s empty-entry handling to deal with the case

where more entries may have been removed since the last find.

diff --git a/flist.c b/flist.c
index dc283a1..851e306 100644 (file)
--- a/flist.c
+++ b/flist.c
@@ -1445,26 +1445,29 @@ int flist_find(struct file_list *flist, struct file_struct *f)
                mid = (low + high) / 2;
                if (flist->files[mid]->basename)
                        mid_up = mid;
-               else if (flist->files[mid]->dir.depth) {
-                       mid_up = mid + flist->files[mid]->dir.depth;
-                       if (mid_up < mid) {
-                               high = mid_up;
-                               continue;
+               else {
+                       /* Scan for the next non-empty entry using the cached
+                        * distance values.  If the value isn't fully up-to-
+                        * date, update it. */
+                       while (1) {
+                               mid_up = mid + flist->files[mid]->dir.depth;
+                               if (flist->files[mid_up]->basename)
+                                       break;
+                               flist->files[mid]->dir.depth
+                                       += flist->files[mid_up]->dir.depth;
                        }
-               } else {
-                       /* Scan for the next non-empty entry and cache
-                        * the distance so we never do this again. */
-                       mid_up = mid;
-                       while (++mid_up <= high
-                           && !flist->files[mid_up]->basename) {}
                        if (mid_up > high) {
-                               high = mid;
-                               while (--high >= low
-                                   && !flist->files[high]->basename) {}
-                               flist->files[mid]->dir.depth = high - mid;
+                               /* If there's nothing left above us, set high to
+                                * a non-empty entry below us and continue. */
+                               while (1) {
+                                       high = mid - flist->files[mid]->length;
+                                       if (flist->files[high]->basename)
+                                               break;
+                                       flist->files[mid]->length
+                                               += flist->files[high]->length;
+                               }
                                continue;
                        }
-                       flist->files[mid]->dir.depth = mid_up - mid;
                }
                ret = f_name_cmp(flist->files[mid_up], f);
                if (ret == 0) {
@@ -1488,9 +1491,15 @@ int flist_find(struct file_list *flist, struct file_struct *f)
  */
 void clear_file(int i, struct file_list *flist)
 {
-       if (flist->hlink_pool && flist->files[i]->link_u.idev)
-               pool_free(flist->hlink_pool, 0, flist->files[i]->link_u.idev);
-       memset(flist->files[i], 0, file_struct_len);
+       struct file_struct *file = flist->files[i];
+       if (flist->hlink_pool && file->link_u.idev)
+               pool_free(flist->hlink_pool, 0, file->link_u.idev);
+       memset(file, 0, file_struct_len);
+       /* In an empty entry, dir.depth is an offset to the next non-empty
+        * entry.  Likewise for length in the opposite direction.  We assume
+        * that we're alone for now since flist_find() will collate adjacent
+        * items for any entries that are encountered during the find. */
+       file->length = file->dir.depth = 1;
 }
 
 /*