auto import from //depot/cupcake/@135843
diff --git a/tools/atree/fs.cpp b/tools/atree/fs.cpp
new file mode 100644
index 0000000..022bd8c
--- /dev/null
+++ b/tools/atree/fs.cpp
@@ -0,0 +1,143 @@
+#include "fs.h"
+#include "files.h"
+#include <unistd.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <string>
+#include <vector>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <host/CopyFile.h>
+
+using namespace std;
+
+static bool
+is_dir(const string& path)
+{
+ int err;
+ struct stat st;
+ err = stat(path.c_str(), &st);
+ return err != 0 || S_ISDIR(st.st_mode);
+}
+
+static int
+remove_file(const string& path)
+{
+ int err = unlink(path.c_str());
+ if (err != 0) {
+ fprintf(stderr, "error deleting file %s (%s)\n", path.c_str(),
+ strerror(errno));
+ return errno;
+ }
+ return 0;
+}
+
+int
+remove_recursively(const string& path)
+{
+ int err;
+
+ if (is_dir(path)) {
+ DIR *d = opendir(path.c_str());
+ if (d == NULL) {
+ fprintf(stderr, "error getting directory contents %s (%s)\n",
+ path.c_str(), strerror(errno));
+ return errno;
+ }
+
+ vector<string> files;
+ vector<string> dirs;
+
+ struct dirent *ent;
+ while (NULL != (ent = readdir(d))) {
+ if (0 == strcmp(".", ent->d_name)
+ || 0 == strcmp("..", ent->d_name)) {
+ continue;
+ }
+ string full = path;
+ full += '/';
+ full += ent->d_name;
+#ifdef HAVE_DIRENT_D_TYPE
+ bool is_directory = (ent->d_type == DT_DIR);
+#else
+ // If dirent.d_type is missing, then use stat instead
+ struct stat stat_buf;
+ stat(full.c_str(), &stat_buf);
+ bool is_directory = S_ISDIR(stat_buf.st_mode);
+#endif
+ if (is_directory) {
+ dirs.push_back(full);
+ } else {
+ files.push_back(full);
+ }
+ }
+ closedir(d);
+
+ for (vector<string>::iterator it=files.begin(); it!=files.end(); it++) {
+ err = remove_file(*it);
+ if (err != 0) {
+ return err;
+ }
+ }
+
+ for (vector<string>::iterator it=dirs.begin(); it!=dirs.end(); it++) {
+ err = remove_recursively(*it);
+ if (err != 0) {
+ return err;
+ }
+ }
+
+ err = rmdir(path.c_str());
+ if (err != 0) {
+ fprintf(stderr, "error deleting directory %s (%s)\n", path.c_str(),
+ strerror(errno));
+ return errno;
+ }
+ return 0;
+ } else {
+ return remove_file(path);
+ }
+}
+
+int
+mkdir_recursively(const string& path)
+{
+ int err;
+ size_t pos = 0;
+ while (true) {
+ pos = path.find('/', pos);
+ string p = path.substr(0, pos);
+ struct stat st;
+ err = stat(p.c_str(), &st);
+ if (err != 0) {
+ err = mkdir(p.c_str(), 0770);
+ if (err != 0) {
+ fprintf(stderr, "can't create directory %s (%s)\n",
+ path.c_str(), strerror(errno));
+ return errno;
+ }
+ }
+ else if (!S_ISDIR(st.st_mode)) {
+ fprintf(stderr, "can't create directory %s because %s is a file.\n",
+ path.c_str(), p.c_str());
+ return 1;
+ }
+ pos++;
+ if (p == path) {
+ return 0;
+ }
+ }
+}
+
+int
+copy_file(const string& src, const string& dst)
+{
+ int err;
+
+ err = copyFile(src.c_str(), dst.c_str(),
+ COPY_NO_DEREFERENCE | COPY_FORCE | COPY_PERMISSIONS);
+ return err;
+}