Consolidate some of the logic for removals of folders

This routine checks that the folder is empty before removing and is
found in two places.  We can consolidate this for changes to the logic.

Author: tim-nordell-nimbelink

lfs.c

@@ -3894,6 +3894,63 @@ struct lfs_remove_state
 };
 #endif
 
+#ifndef LFS_READONLY
+static int lfs_dir_prep_removal(lfs_t *lfs, struct lfs_remove_state *p) {
+    lfs_stag_t res = lfs_dir_get(lfs, &p->cwd, LFS_MKTAG(0x700, 0x3ff, 0),
+            LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(p->tag), 8), p->dir_head);
+    if (res < 0) {
+        return (int)res;
+    }
+    lfs_pair_fromle32(p->dir_head);
+
+    int err = lfs_dir_fetch(lfs, &p->dir.m, p->dir_head);
+    if (err) {
+        return err;
+    }
+
+    if (p->dir.m.count > 0 || p->dir.m.split) {
+        return LFS_ERR_NOTEMPTY;
+    }
+
+    // mark fs as orphaned
+    err = lfs_fs_preporphans(lfs, +1);
+    if (err) {
+        return err;
+    }
+
+    // I know it's crazy but yes, dir can be changed by our parent's
+    // commit (if predecessor is child)
+    p->dir.type = 0;
+    p->dir.id = 0;
+    lfs->mlist = &p->dir;
+
+    return 0;
+}
+#endif
+
+#ifndef LFS_READONLY
+static int lfs_dir_finish_removal(lfs_t *lfs, struct lfs_remove_state *p)
+{
+    // fix orphan
+    int err = lfs_fs_preporphans(lfs, -1);
+    if (err) {
+        return err;
+    }
+
+    err = lfs_fs_pred(lfs, p->dir.m.pair, &p->cwd);
+    if (err) {
+        return err;
+    }
+
+    err = lfs_dir_drop(lfs, &p->cwd, &p->dir.m);
+    if (err) {
+        return err;
+    }
+
+    return 0;
+}
+#endif
+
 #ifndef LFS_READONLY
 static int lfs_remove_(lfs_t *lfs, const char *path) {
     // deorphan if we haven't yet, needed at most once after poweron
@@ -3910,34 +3967,10 @@ static int lfs_remove_(lfs_t *lfs, const char *path) {
 
     s.dir.next = lfs->mlist;
     if (lfs_tag_type3(s.tag) == LFS_TYPE_DIR) {
-        // must be empty before removal
-        lfs_stag_t res = lfs_dir_get(lfs, &s.cwd, LFS_MKTAG(0x700, 0x3ff, 0),
-                LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(s.tag), 8), s.dir_head);
-        if (res < 0) {
-            return (int)res;
-        }
-        lfs_pair_fromle32(s.dir_head);
-
-        err = lfs_dir_fetch(lfs, &s.dir.m, s.dir_head);
-        if (err) {
-            return err;
-        }
-
-        if (s.dir.m.count > 0 || s.dir.m.split) {
-            return LFS_ERR_NOTEMPTY;
-        }
-
-        // mark fs as orphaned
-        err = lfs_fs_preporphans(lfs, +1);
-        if (err) {
+        err = lfs_dir_prep_removal(lfs, &s);
+        if (err < 0) {
             return err;
         }
-
-        // I know it's crazy but yes, dir can be changed by our parent's
-        // commit (if predecessor is child)
-        s.dir.type = 0;
-        s.dir.id = 0;
-        lfs->mlist = &s.dir;
     }
 
     // delete the entry
@@ -3950,18 +3983,7 @@ static int lfs_remove_(lfs_t *lfs, const char *path) {
 
     lfs->mlist = s.dir.next;
     if (lfs_tag_type3(s.tag) == LFS_TYPE_DIR) {
-        // fix orphan
-        err = lfs_fs_preporphans(lfs, -1);
-        if (err) {
-            return err;
-        }
-
-        err = lfs_fs_pred(lfs, s.dir.m.pair, &s.cwd);
-        if (err) {
-            return err;
-        }
-
-        err = lfs_dir_drop(lfs, &s.cwd, &s.dir.m);
+        err = lfs_dir_finish_removal(lfs, &s);
         if (err) {
             return err;
         }
@@ -4027,34 +4049,10 @@ static int lfs_rename_(lfs_t *lfs, const char *oldpath, const char *newpath) {
         // we're renaming to ourselves??
         return 0;
     } else if (lfs_tag_type3(n.tag) == LFS_TYPE_DIR) {
-        lfs_stag_t res = lfs_dir_get(lfs, &n.cwd, LFS_MKTAG(0x700, 0x3ff, 0),
-                LFS_MKTAG(LFS_TYPE_STRUCT, newid, 8), n.dir_head);
-        if (res < 0) {
-            return (int)res;
-        }
-        lfs_pair_fromle32(n.dir_head);
-
-        // must be empty before removal
-        err = lfs_dir_fetch(lfs, &n.dir.m, n.dir_head);
-        if (err) {
-            return err;
-        }
-
-        if (n.dir.m.count > 0 || n.dir.m.split) {
-            return LFS_ERR_NOTEMPTY;
-        }
-
-        // mark fs as orphaned
-        err = lfs_fs_preporphans(lfs, +1);
+        err = lfs_dir_prep_removal(lfs, &n);
         if (err) {
             return err;
         }
-
-        // I know it's crazy but yes, dir can be changed by our parent's
-        // commit (if predecessor is child)
-        n.dir.type = 0;
-        n.dir.id = 0;
-        lfs->mlist = &n.dir;
     }
 
     if (!samepair) {
@@ -4092,18 +4090,7 @@ static int lfs_rename_(lfs_t *lfs, const char *oldpath, const char *newpath) {
     lfs->mlist = n.dir.next;
     if (n.tag != LFS_ERR_NOENT
             && lfs_tag_type3(n.tag) == LFS_TYPE_DIR) {
-        // fix orphan
-        err = lfs_fs_preporphans(lfs, -1);
-        if (err) {
-            return err;
-        }
-
-        err = lfs_fs_pred(lfs, n.dir.m.pair, &n.cwd);
-        if (err) {
-            return err;
-        }
-
-        err = lfs_dir_drop(lfs, &n.cwd, &n.dir.m);
+        err = lfs_dir_finish_removal(lfs, &n);
         if (err) {
             return err;
         }