1 files changed, 119 insertions, 0 deletions
diff --git a/src/base/fs/walk.c b/src/base/fs/walk.c
new file mode 100644
index 0000000..d528896
--- /dev/null
+++ b/src/base/fs/walk.c
@@ -0,0 +1,119 @@
+#include "internal.h"
+
+#define hash(k) ((int32)k.ino ^ (int32)k.dev)
+#define equal(k1, k2) (k1.ino == k2.ino && k1.dev == k2.dev)
+
+static
+int
+morehistory(fs·History *h, int n)
+{
+    SET_GROW(h, struct Key, n, hash, sys·Memory, nil);
+}
+
+static
+int
+addentry(fs·History *h, struct Key key, int *err)
+{
+    SET_PUT(h, key, hash, equal, morehistory, err);
+}
+
+static
+void
+forget(fs·History *h)
+{
+    if (!h)
+        return;
+
+    SET_RESET(h);
+}
+
+void
+fs·walk(fs·Walker *fs)
+{
+    char *e, *b;
+    DIR *dir;
+    int new, fd, ofd, flags;
+    fs·History *h;
+    struct dirent *d;
+    io·Stat cwd;
+    struct fs·Entry *it;
+
+    flags = 0;
+    if(fs->flags & fs·nolinks)
+        flags |= AT_SYMLINK_NOFOLLOW;
+
+    /* get info for base relative to current fd */
+    if(fstatat(fs->fd, fs->base, &cwd, flags) < 0){
+        if(fs->flags & fs·verbose)
+            errorf("stat: %s", fs->path);
+        return;
+    }
+
+    /* if we hit a file, finish! */
+    if(!S_ISDIR(cwd.st_mode)) {
+        fs->func(fs->data, fs->base, fs->path, &cwd);
+        return;
+    }
+
+    /* have we been here before? (cycle detection) */
+    /* if not, add to our path history */
+    if (!(fs->flags & fs·nolinks)) {
+        addentry(fs->hist, (struct Key){.dev=cwd.st_dev, .ino=cwd.st_ino}, &new);
+        if (!new)
+            return;
+    }
+
+    /* 
+     * operate on directory first if preorder traversal 
+     * truncate recursion if callback returns an error code
+     */ 
+    if (fs->flags & fs·preorder) {
+        if (fs->func(fs->data, fs->base, fs->path, &cwd))
+            return;
+    }
+
+    /* open directory */
+    if(!fs->max || fs->lev + 1 < fs->max) {
+        fd = openat(fs->fd, fs->base, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
+        if (fd < 0)
+            errorf("open %s:", fs->path);
+
+        if (!(dir=fdopendir(fd))) {
+            if(fs->flags & fs·verbose)
+                errorf("fdopendir: %s", fs->path);
+            return;
+        }
+
+        ofd = fs->fd, fs->fd = fd;
+
+        /* traverse children */
+        e = fs->end, b = fs->base;
+        if (fs->end[-1] != '/')
+            *fs->end++ = '/';
+
+        fs->base = fs->end;
+        while((d = readdir(dir))) {
+            if(*d->d_name == '.')
+            if(d->d_name[1] == 0 ||                       /* . */ 
+               (d->d_name[1] == '.' && d->d_name[2] == 0)) /* .. */ 
+                continue;
+
+            fs->end = str·copyn(fs->base, d->d_name, arrend(fs->path) - fs->base);
+
+            fs->lev++;
+            fs·walk(fs);
+            fs->lev--;
+        }
+        *e      = 0;
+        fs->fd  = ofd;
+        fs->end = e, fs->base = b;
+        closedir(dir);
+    }
+
+    /* operate on directory if postorder (default) traversal */
+    if (!(fs->flags & fs·preorder))
+        fs->func(fs->data, fs->base, fs->path, &cwd);
+
+    if (!fs->lev)
+        forget(fs->hist);
+}