From 733e7b58aadbaad83ecd61e2f4d8f971ad3f235d Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Mon, 23 Jan 2023 09:36:10 -0600
Subject: [PATCH] Implement DIRTREE_BREADTH.

---
 lib/dirtree.c   | 47 +++++++++++++++++++++++++++++++----------------
 toys/posix/ls.c |  2 +-
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/lib/dirtree.c b/lib/dirtree.c
index 63ba16ab..32788d38 100644
--- a/lib/dirtree.c
+++ b/lib/dirtree.c
@@ -72,6 +72,7 @@ error:
   }
   if (parent) parent->symlink = (char *)1;
   free(dt);
+
   return 0;
 }
 
@@ -116,15 +117,23 @@ int dirtree_parentfd(struct dirtree *node)
 static struct dirtree *dirtree_handle_callback(struct dirtree *new,
   int (*callback)(struct dirtree *node))
 {
-  int flags;
+  int flags, df = DIRTREE_RECURSE|DIRTREE_COMEAGAIN|DIRTREE_BREADTH,
+      fd = AT_FDCWD;
 
   if (!new) return DIRTREE_ABORTVAL;
   if (!callback) return new;
   flags = callback(new);
 
-  if (S_ISDIR(new->st.st_mode) && (flags & (DIRTREE_RECURSE|DIRTREE_COMEAGAIN)))
-    flags = dirtree_recurse(new, callback, !*new->name ? AT_FDCWD :
-      openat(dirtree_parentfd(new), new->name, O_CLOEXEC), flags);
+  if (S_ISDIR(new->st.st_mode) && (flags & df)) {
+    if (*new->name) fd = openat(dirtree_parentfd(new), new->name, O_CLOEXEC);
+    if (flags&DIRTREE_BREADTH) {
+      new->again |= DIRTREE_BREADTH;
+      if ((DIRTREE_ABORT & dirtree_recurse(new, 0, fd, flags)) ||
+          (DIRTREE_ABORT & (flags = callback(new))))
+        return DIRTREE_ABORTVAL;
+    }
+    flags = dirtree_recurse(new, callback, fd, flags);
+  }
 
   // Free node that didn't request saving and has no saved children.
   if (!new->child && !(flags & DIRTREE_SAVE)) {
@@ -141,50 +150,56 @@ static struct dirtree *dirtree_handle_callback(struct dirtree *new,
 int dirtree_recurse(struct dirtree *node,
           int (*callback)(struct dirtree *node), int dirfd, int flags)
 {
-  struct dirtree *new, **ddt = &(node->child);
+  struct dirtree *new = 0, **ddt = &(node->child);
   struct dirent *entry;
   DIR *dir = 0;
 
-  // Why doesn't fdopendir() support AT_FDCWD?
+  // fdopendir() doesn't support AT_FDCWD, closedir() closes fd from opendir()
   if (AT_FDCWD == (node->dirfd = dirfd)) dir = opendir(".");
-  else if (node->dirfd != -1) dir = fdopendir(node->dirfd);
+  else if (node->dirfd != -1) dir = fdopendir(xdup(node->dirfd));
+
   if (!dir) {
     if (!(flags & DIRTREE_SHUTUP)) {
       char *path = dirtree_path(node, 0);
       perror_msg_raw(path);
       free(path);
     }
-    close(node->dirfd);
-
-    return flags;
+    goto done;
   }
 
+  // Iterate through stored entries, if any
+  if (callback && *ddt) while (*ddt) {
+    if (!(new = dirtree_handle_callback(*ddt, callback))) {
+      new = *ddt;
+      ddt = &((*ddt)->next);
+      free(new);
+    } else if (new == DIRTREE_ABORTVAL) goto done;
+
   // according to the fddir() man page, the filehandle in the DIR * can still
   // be externally used by things that don't lseek() it.
-
-  while ((entry = readdir(dir))) {
+  } else while ((entry = readdir(dir))) {
     if ((flags&DIRTREE_PROC) && !isdigit(*entry->d_name)) continue;
     if (!(new = dirtree_add_node(node, entry->d_name, flags))) continue;
     if (!new->st.st_blksize && !new->st.st_mode)
       new->st.st_mode = entry->d_type<<12;
     new = dirtree_handle_callback(new, callback);
-    if (new == DIRTREE_ABORTVAL) break;
+    if (new == DIRTREE_ABORTVAL) goto done;
     if (new) {
       *ddt = new;
       ddt = &((*ddt)->next);
     }
   }
 
-  if (flags & DIRTREE_COMEAGAIN) {
+  if (callback && (flags & DIRTREE_COMEAGAIN)) {
     node->again |= DIRTREE_COMEAGAIN;
     flags = callback(node);
   }
 
-  // This closes filehandle as well, so note it
+done:
   closedir(dir);
   node->dirfd = -1;
 
-  return flags;
+  return (new == DIRTREE_ABORTVAL) ? DIRTREE_ABORT : flags;
 }
 
 // Create dirtree from path, using callback to filter nodes. If !callback
diff --git a/toys/posix/ls.c b/toys/posix/ls.c
index 6e100963..aa722cbb 100644
--- a/toys/posix/ls.c
+++ b/toys/posix/ls.c
@@ -290,7 +290,7 @@ static void listfiles(int dirfd, struct dirtree *indir)
     if (toys.optflags == (FLAG_1|FLAG_f)) return;
   // Read directory contents. We dup() the fd because this will close it.
   // This reads/saves contents to display later, except for in "ls -1f" mode.
-  } else dirtree_recurse(indir, filter, dup(dirfd),
+  } else dirtree_recurse(indir, filter, dirfd,
       DIRTREE_STATLESS|DIRTREE_SYMFOLLOW*!!FLAG(L));
 
   // Copy linked list to array and sort it. Directories go in array because
-- 
2.39.2