From 60020d1f52d032c495785802c44226a63a217737 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sun, 7 Apr 2019 08:12:15 -0400
Subject: bftw: Don't store trailing slashes in bftw_file names

---
 bftw.c | 49 +++++++++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 26 deletions(-)

(limited to 'bftw.c')

diff --git a/bftw.c b/bftw.c
index 717ffab..aee3689 100644
--- a/bftw.c
+++ b/bftw.c
@@ -281,17 +281,19 @@ static int bftw_cache_shrink(struct bftw_cache *cache, const struct bftw_file *s
 	return ret;
 }
 
+/** Compute the name offset of a child path. */
+static size_t bftw_child_nameoff(const struct bftw_file *parent) {
+	size_t ret = parent->nameoff + parent->namelen;
+	if (parent->name[parent->namelen - 1] != '/') {
+		++ret;
+	}
+	return ret;
+}
+
 /** Create a new bftw_file. */
 static struct bftw_file *bftw_file_new(struct bftw_cache *cache, struct bftw_file *parent, const char *name) {
 	size_t namelen = strlen(name);
 	size_t size = sizeof(struct bftw_file) + namelen + 1;
-
-	bool needs_slash = false;
-	if (namelen == 0 || name[namelen - 1] != '/') {
-		needs_slash = true;
-		++size;
-	}
-
 	struct bftw_file *file = malloc(size);
 	if (!file) {
 		return NULL;
@@ -301,7 +303,7 @@ static struct bftw_file *bftw_file_new(struct bftw_cache *cache, struct bftw_fil
 
 	if (parent) {
 		file->depth = parent->depth + 1;
-		file->nameoff = parent->nameoff + parent->namelen;
+		file->nameoff = bftw_child_nameoff(parent);
 		bftw_file_incref(cache, parent);
 	} else {
 		file->depth = 0;
@@ -316,12 +318,8 @@ static struct bftw_file *bftw_file_new(struct bftw_cache *cache, struct bftw_fil
 	file->dev = -1;
 	file->ino = -1;
 
-	memcpy(file->name, name, namelen);
-	if (needs_slash) {
-		file->name[namelen++] = '/';
-	}
-	file->name[namelen] = '\0';
 	file->namelen = namelen;
+	memcpy(file->name, name, namelen + 1);
 
 	return file;
 }
@@ -338,6 +336,9 @@ static int bftw_file_path(const struct bftw_file *file, char **path) {
 
 	// Build the path backwards
 	while (file) {
+		if (file->nameoff > 0) {
+			dest[file->nameoff - 1] = '/';
+		}
 		memcpy(dest + file->nameoff, file->name, file->namelen);
 		file = file->parent;
 	}
@@ -365,7 +366,7 @@ static struct bftw_file *bftw_file_base(struct bftw_file *file, int *at_fd, cons
 
 	if (base) {
 		*at_fd = base->fd;
-		*at_path += base->nameoff + base->namelen;
+		*at_path += bftw_child_nameoff(base);
 	}
 
 	return base;
@@ -839,16 +840,7 @@ static int bftw_update_path(struct bftw_state *state) {
 	struct bftw_file *file = reader->file;
 	struct dirent *de = reader->de;
 
-	size_t length;
-	if (de) {
-		length = file->nameoff + file->namelen;
-	} else if (file->depth == 0) {
-		// Use exactly the string passed to bftw(), including any trailing slashes
-		length = strlen(state->root);
-	} else {
-		// -1 to trim the trailing slash
-		length = file->nameoff + file->namelen - 1;
-	}
+	size_t length = file->nameoff + file->namelen;
 
 	if (dstrlen(reader->path) < length) {
 		errno = reader->error;
@@ -857,6 +849,11 @@ static int bftw_update_path(struct bftw_state *state) {
 	dstresize(&reader->path, length);
 
 	if (de) {
+		if (reader->path[length - 1] != '/') {
+			if (dstrapp(&reader->path, '/') != 0) {
+				return -1;
+			}
+		}
 		if (dstrcat(&reader->path, reader->de->d_name) != 0) {
 			return -1;
 		}
@@ -920,16 +917,16 @@ static void bftw_prepare_visit(struct bftw_state *state) {
 	ftwbuf->at_flags = AT_SYMLINK_NOFOLLOW;
 
 	if (file) {
-		ftwbuf->nameoff = file->nameoff;
 		ftwbuf->depth = file->depth;
 
 		if (de) {
-			ftwbuf->nameoff += file->namelen;
+			ftwbuf->nameoff = bftw_child_nameoff(file);
 			++ftwbuf->depth;
 
 			ftwbuf->at_fd = file->fd;
 			ftwbuf->at_path += ftwbuf->nameoff;
 		} else {
+			ftwbuf->nameoff = file->nameoff;
 			bftw_file_base(file, &ftwbuf->at_fd, &ftwbuf->at_path);
 		}
 	}
-- 
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