1 files changed, 250 insertions, 0 deletions
diff --git a/src/include/filepath.h b/src/include/filepath.h
new file mode 100644
index 000000000..d0965ad0c
--- /dev/null
+++ b/src/include/filepath.h
@@ -0,0 +1,250 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+
+
+#ifndef CEPH_FILEPATH_H
+#define CEPH_FILEPATH_H
+
+/*
+ * BUG:  /a/b/c is equivalent to a/b/c in dentry-breakdown, but not string.
+ *   -> should it be different?  how?  should this[0] be "", with depth 4?
+ *
+ */
+
+
+#include <iosfwd>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "buffer.h"
+#include "encoding.h"
+#include "include/types.h"
+#include "include/fs_types.h"
+
+#include "common/Formatter.h"
+
+
+class filepath {
+  inodeno_t ino = 0;   // base inode.  ino=0 implies pure relative path.
+  std::string path;     // relative path.
+
+  /** bits - path segments
+   * this is ['a', 'b', 'c'] for both the aboslute and relative case.
+   *
+   * NOTE: this value is LAZILY maintained... i.e. it's a cache
+   */
+  mutable std::vector<std::string> bits;
+  bool encoded = false;
+
+  void rebuild_path() {
+    path.clear();
+    for (unsigned i=0; i<bits.size(); i++) {
+      if (i) path += "/";
+      path += bits[i];
+    }
+  }
+  void parse_bits() const {
+    bits.clear();
+    int off = 0;
+    while (off < (int)path.length()) {
+      int nextslash = path.find('/', off);
+      if (nextslash < 0) 
+        nextslash = path.length();  // no more slashes
+      if (((nextslash - off) > 0) || encoded) {
+        // skip empty components unless they were introduced deliberately
+        // see commit message for more detail
+        bits.push_back( path.substr(off,nextslash-off) );
+      }
+      off = nextslash+1;
+    }
+  }
+
+ public:
+  filepath() = default;
+  filepath(std::string_view p, inodeno_t i) : ino(i), path(p) {}
+  filepath(const filepath& o) {
+    ino = o.ino;
+    path = o.path;
+    bits = o.bits;
+    encoded = o.encoded;
+  }
+  filepath(inodeno_t i) : ino(i) {}
+  filepath& operator=(const char* path) {
+    set_path(path);
+    return *this;
+  }
+
+  /*
+   * if we are fed a relative path as a string, either set ino=0 (strictly
+   * relative) or 1 (absolute).  throw out any leading '/'.
+   */
+  filepath(std::string_view s) { set_path(s); }
+  filepath(const char* s) { set_path(s); }
+
+  void set_path(std::string_view s, inodeno_t b) {
+    path = s;
+    ino = b;
+  }
+  void set_path(std::string_view s) {
+    if (s[0] == '/') {
+      path = s.substr(1);
+      ino = 1;
+    } else {
+      ino = 0;
+      path = s;
+    }
+    bits.clear();
+  }
+
+
+  // accessors
+  inodeno_t get_ino() const { return ino; }
+  const std::string& get_path() const { return path; }
+  const char *c_str() const { return path.c_str(); }
+
+  int length() const { return path.length(); }
+  unsigned depth() const {
+    if (bits.empty() && path.length() > 0) parse_bits();
+    return bits.size();
+  }
+  bool empty() const { return path.length() == 0 && ino == 0; }
+
+  bool absolute() const { return ino == 1; }
+  bool pure_relative() const { return ino == 0; }
+  bool ino_relative() const { return ino > 0; }
+
+  const std::string& operator[](int i) const {
+    if (bits.empty() && path.length() > 0) parse_bits();
+    return bits[i];
+  }
+
+  const std::string& last_dentry() const {
+    if (bits.empty() && path.length() > 0) parse_bits();
+    ceph_assert(!bits.empty());
+    return bits[ bits.size()-1 ];
+  }
+
+  filepath prefixpath(int s) const {
+    filepath t(ino);
+    for (int i=0; i<s; i++)
+      t.push_dentry(bits[i]);
+    return t;
+  }
+  filepath postfixpath(int s) const {
+    filepath t;
+    for (unsigned i=s; i<bits.size(); i++)
+      t.push_dentry(bits[i]);
+    return t;
+  }
+
+
+  // modifiers
+  //  string can be relative "a/b/c" (ino=0) or absolute "/a/b/c" (ino=1)
+  void _set_ino(inodeno_t i) { ino = i; }
+  void clear() {
+    ino = 0;
+    path = "";
+    bits.clear();
+  }
+
+  void pop_dentry() {
+    if (bits.empty() && path.length() > 0) 
+      parse_bits();
+    bits.pop_back();
+    rebuild_path();
+  }
+  void push_dentry(std::string_view s) {
+    if (bits.empty() && path.length() > 0) 
+      parse_bits();
+    if (!bits.empty())
+      path += "/";
+    path += s;
+    bits.emplace_back(s);
+  }
+  void push_dentry(const std::string& s) {
+    push_dentry(std::string_view(s));
+  }
+  void push_dentry(const char *cs) {
+    push_dentry(std::string_view(cs, strlen(cs)));
+  }
+  void push_front_dentry(const std::string& s) {
+    bits.insert(bits.begin(), s);
+    rebuild_path();
+  }
+  void append(const filepath& a) {
+    ceph_assert(a.pure_relative());
+    for (unsigned i=0; i<a.depth(); i++) 
+      push_dentry(a[i]);
+  }
+
+  // encoding
+  void encode(ceph::buffer::list& bl) const {
+    using ceph::encode;
+    __u8 struct_v = 1;
+    encode(struct_v, bl);
+    encode(ino, bl);
+    encode(path, bl);
+  }
+  void decode(ceph::buffer::list::const_iterator& blp) {
+    using ceph::decode;
+    bits.clear();
+    __u8 struct_v;
+    decode(struct_v, blp);
+    decode(ino, blp);
+    decode(path, blp);
+    encoded = true;
+  }
+  void dump(ceph::Formatter *f) const {
+    f->dump_unsigned("base_ino", ino);
+    f->dump_string("relative_path", path);
+  }
+  static void generate_test_instances(std::list<filepath*>& o) {
+    o.push_back(new filepath);
+    o.push_back(new filepath("/usr/bin", 0));
+    o.push_back(new filepath("/usr/sbin", 1));
+    o.push_back(new filepath("var/log", 1));
+    o.push_back(new filepath("foo/bar", 101));
+  }
+
+  bool is_last_dot_or_dotdot() const {
+    if (depth() > 0) {
+      std::string dname = last_dentry();
+      if (dname == "." || dname == "..") {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  bool is_last_snap() const {
+    // walk into snapdir?
+    return depth() > 0 && bits[0].length() == 0;
+  }
+};
+
+WRITE_CLASS_ENCODER(filepath)
+
+inline std::ostream& operator<<(std::ostream& out, const filepath& path)
+{
+  if (path.get_ino()) {
+    out << '#' << path.get_ino();
+    if (path.length())
+      out << '/';
+  }
+  return out << path.get_path();
+}
+
+#endif