Stop fetching inode metadata on handle open, now fetch it lazy on demand.

8 files changed, 48 insertions, 40 deletions

diff --git a/Readme.md b/Readme.md
index 11a03f00..c68d3488 100644
--- a/Readme.md
+++ b/Readme.md
@@ -16,6 +16,7 @@ Tarballs of source and prebuilt binaries for Linux x64, MacOS x64 and Windows x6
 - [ ] Add OS X support to `storage_profile`, this should complete the Mac OS port.
 - [x] Fix all known bugs in Outcome, plus reorg source code in prep for `status_code`.
 - [x] Scatter-gather buffers to use https://github.com/martinmoene/byte-lite
+- [x] Make lazy the stat fetch during file/dir open.
 - [ ] Implement SG14 `status_code` as a standalone library and test in AFIO.
 - [ ] Single include generation now we're on `status_code` and it's safe.
 - [ ] `atomic_append` isn't actually being tested in shared_fs_mutex
diff --git a/include/afio/revision.hpp b/include/afio/revision.hpp
index e7e3feb9..89a13ea0 100644
--- a/include/afio/revision.hpp
+++ b/include/afio/revision.hpp
@@ -1,4 +1,4 @@
 // Note the second line of this file must ALWAYS be the git SHA, third line ALWAYS the git SHA update time
-#define AFIO_PREVIOUS_COMMIT_REF    4e837be97c2972e11a8515ae260e4476bd6654e3
-#define AFIO_PREVIOUS_COMMIT_DATE   "2018-04-11 11:25:46 +00:00"
-#define AFIO_PREVIOUS_COMMIT_UNIQUE 4e837be9
+#define AFIO_PREVIOUS_COMMIT_REF    bb5b4123ccd90798ae4957a611c3725f5239ebd4
+#define AFIO_PREVIOUS_COMMIT_DATE   "2018-04-14 16:37:23 +00:00"
+#define AFIO_PREVIOUS_COMMIT_UNIQUE bb5b4123
diff --git a/include/afio/v2.0/detail/impl/posix/file_handle.ipp b/include/afio/v2.0/detail/impl/posix/file_handle.ipp
index 7ad66d1f..a65eabff 100644
--- a/include/afio/v2.0/detail/impl/posix/file_handle.ipp
+++ b/include/afio/v2.0/detail/impl/posix/file_handle.ipp
@@ -48,14 +48,6 @@ result<file_handle> file_handle::file(const path_handle &base, file_handle::path
   {
     return {errno, std::system_category()};
   }
-  if(!(flags & flag::disable_safety_unlinks))
-  {
-    if(!ret.value()._fetch_inode())
-    {
-      // If fetching inode failed e.g. were opening device, disable safety unlinks
-      ret.value()._flags &= ~flag::disable_safety_unlinks;
-    }
-  }
   if((flags & flag::disable_prefetching) || (flags & flag::maximum_prefetching))
   {
 #ifdef POSIX_FADV_SEQUENTIAL
@@ -98,7 +90,6 @@ result<file_handle> file_handle::temp_inode(const path_handle &dirh, mode _mode,
   if(-1 != nativeh.fd)
   {
     ret.value()._flags |= flag::anonymous_inode;
-    OUTCOME_TRYV(ret.value()._fetch_inode());      // It can be useful to know the inode of temporary inodes
     ret.value()._flags &= ~flag::unlink_on_close;  // It's already unlinked
     return ret;
   }
@@ -132,7 +123,6 @@ result<file_handle> file_handle::temp_inode(const path_handle &dirh, mode _mode,
     {
       return {errno, std::system_category()};
     }
-    OUTCOME_TRYV(ret.value()._fetch_inode());  // It can be useful to know the inode of temporary inodes
     ret.value()._flags &= ~flag::unlink_on_close;
     return ret;
   }
diff --git a/include/afio/v2.0/detail/impl/posix/fs_handle.ipp b/include/afio/v2.0/detail/impl/posix/fs_handle.ipp
index d521ce07..0856b5ea 100644
--- a/include/afio/v2.0/detail/impl/posix/fs_handle.ipp
+++ b/include/afio/v2.0/detail/impl/posix/fs_handle.ipp
@@ -31,7 +31,7 @@ Distributed under the Boost Software License, Version 1.0.
 
 AFIO_V2_NAMESPACE_BEGIN
 
-result<void> fs_handle::_fetch_inode() noexcept
+result<void> fs_handle::_fetch_inode() const noexcept
 {
   stat_t s(nullptr);
   OUTCOME_TRYV(s.fill(_get_handle(), stat_t::want::dev | stat_t::want::ino));
@@ -145,6 +145,10 @@ result<path_handle> fs_handle::parent_path_handle(deadline d) const noexcept
 {
   AFIO_LOG_FUNCTION_CALL(this);
   auto &h = _get_handle();
+  if(_devid == 0 && _inode == 0)
+  {
+    OUTCOME_TRY(_fetch_inode());
+  }
   return containing_directory({}, h, *this, d);
 }
 
@@ -165,7 +169,7 @@ result<void> fs_handle::relink(const path_handle &base, path_view_type path, boo
     snprintf(_path, PATH_MAX, "/proc/self/fd/%d", h.native_handle().fd);
     if(-1 == ::linkat(AT_FDCWD, _path, base.is_valid() ? base.native_handle().fd : AT_FDCWD, zpath.buffer, AT_SYMLINK_FOLLOW))
     {
-      return { errno, std::system_category() };
+      return {errno, std::system_category()};
     }
     h._flags &= ~handle::flag::anonymous_inode;
     return success();
@@ -173,6 +177,10 @@ result<void> fs_handle::relink(const path_handle &base, path_view_type path, boo
 #endif
   // Open our containing directory
   filesystem::path filename;
+  if(_devid == 0 && _inode == 0)
+  {
+    OUTCOME_TRY(_fetch_inode());
+  }
   OUTCOME_TRY(dirh, containing_directory(std::ref(filename), h, *this, d));
   if(!atomic_replace)
   {
@@ -186,12 +194,12 @@ result<void> fs_handle::relink(const path_handle &base, path_view_type path, boo
     // Otherwise we need to use linkat followed by renameat (non-atomic)
     if(-1 == ::linkat(dirh.native_handle().fd, filename.c_str(), base.is_valid() ? base.native_handle().fd : AT_FDCWD, zpath.buffer, 0))
     {
-      return { errno, std::system_category() };
+      return {errno, std::system_category()};
     }
   }
   if(-1 == ::renameat(dirh.native_handle().fd, filename.c_str(), base.is_valid() ? base.native_handle().fd : AT_FDCWD, zpath.buffer))
   {
-    return { errno, std::system_category() };
+    return {errno, std::system_category()};
   }
   return success();
 }
@@ -202,6 +210,10 @@ result<void> fs_handle::unlink(deadline d) noexcept
   auto &h = _get_handle();
   // Open our containing directory
   filesystem::path filename;
+  if(_devid == 0 && _inode == 0)
+  {
+    OUTCOME_TRY(_fetch_inode());
+  }
   OUTCOME_TRY(dirh, containing_directory(std::ref(filename), h, *this, d));
   if(-1 == ::unlinkat(dirh.native_handle().fd, filename.c_str(), h.is_directory() ? AT_REMOVEDIR : 0))
   {
diff --git a/include/afio/v2.0/detail/impl/windows/directory_handle.ipp b/include/afio/v2.0/detail/impl/windows/directory_handle.ipp
index 1c2e2e2f..a60f9e0a 100644
--- a/include/afio/v2.0/detail/impl/windows/directory_handle.ipp
+++ b/include/afio/v2.0/detail/impl/windows/directory_handle.ipp
@@ -132,14 +132,6 @@ result<directory_handle> directory_handle::directory(const path_handle &base, pa
       return {static_cast<int>(errcode), std::system_category()};
     }
   }
-  if(!(flags & flag::disable_safety_unlinks))
-  {
-    if(!ret.value()._fetch_inode())
-    {
-      // If fetching inode failed e.g. were opening device, disable safety unlinks
-      ret.value()._flags &= ~flag::disable_safety_unlinks;
-    }
-  }
   return ret;
 }
 
diff --git a/include/afio/v2.0/detail/impl/windows/file_handle.ipp b/include/afio/v2.0/detail/impl/windows/file_handle.ipp
index 4b9fbd19..a80ddad7 100644
--- a/include/afio/v2.0/detail/impl/windows/file_handle.ipp
+++ b/include/afio/v2.0/detail/impl/windows/file_handle.ipp
@@ -149,14 +149,6 @@ result<file_handle> file_handle::file(const path_handle &base, file_handle::path
       break;
     }
   }
-  if(!(flags & flag::disable_safety_unlinks))
-  {
-    if(!ret.value()._fetch_inode())
-    {
-      // If fetching inode failed e.g. were opening device, disable safety unlinks
-      ret.value()._flags &= ~flag::disable_safety_unlinks;
-    }
-  }
   if(need_to_set_sparse && !(flags & flag::win_disable_sparse_file_creation))
   {
     DWORD bytesout = 0;
@@ -251,7 +243,6 @@ result<file_handle> file_handle::temp_inode(const path_handle &dirh, mode _mode,
       }
     }
     // std::cerr << random << std::endl;
-    OUTCOME_TRYV(ret.value()._fetch_inode());  // It can be useful to know the inode of temporary inodes
     if(nativeh.h != nullptr)
     {
       // Hide this item
diff --git a/include/afio/v2.0/detail/impl/windows/fs_handle.ipp b/include/afio/v2.0/detail/impl/windows/fs_handle.ipp
index fc1fdaba..29ce00da 100644
--- a/include/afio/v2.0/detail/impl/windows/fs_handle.ipp
+++ b/include/afio/v2.0/detail/impl/windows/fs_handle.ipp
@@ -29,7 +29,7 @@ Distributed under the Boost Software License, Version 1.0.
 
 AFIO_V2_NAMESPACE_BEGIN
 
-result<void> fs_handle::_fetch_inode() noexcept
+result<void> fs_handle::_fetch_inode() const noexcept
 {
   stat_t s;
   OUTCOME_TRYV(s.fill(_get_handle(), stat_t::want::dev | stat_t::want::ino));
@@ -45,6 +45,10 @@ result<path_handle> fs_handle::parent_path_handle(deadline d) const noexcept
   AFIO_LOG_FUNCTION_CALL(this);
   auto &h = _get_handle();
   AFIO_WIN_DEADLINE_TO_SLEEP_INIT(d);
+  if(_devid == 0 && _inode == 0)
+  {
+    OUTCOME_TRY(_fetch_inode());
+  }
   try
   {
     for(;;)
diff --git a/include/afio/v2.0/fs_handle.hpp b/include/afio/v2.0/fs_handle.hpp
index a9659647..45e1a7c7 100644
--- a/include/afio/v2.0/fs_handle.hpp
+++ b/include/afio/v2.0/fs_handle.hpp
@@ -55,11 +55,11 @@ public:
   using unique_id_type = QUICKCPPLIB_NAMESPACE::integers128::uint128;
 
 protected:
-  dev_t _devid{0};
-  ino_t _inode{0};
+  mutable dev_t _devid{0};
+  mutable ino_t _inode{0};
 
   //! Fill in _devid and _inode from the handle via fstat()
-  AFIO_HEADERS_ONLY_MEMFUNC_SPEC result<void> _fetch_inode() noexcept;
+  AFIO_HEADERS_ONLY_MEMFUNC_SPEC result<void> _fetch_inode() const noexcept;
 
   virtual const handle &_get_handle() const noexcept = 0;
 
@@ -96,12 +96,30 @@ public:
   fs_handle &operator=(const fs_handle &o) = delete;
 
   //! Unless `flag::disable_safety_unlinks` is set, the device id of the file when opened
-  dev_t st_dev() const noexcept { return _devid; }
+  dev_t st_dev() const noexcept
+  {
+    if(_devid == 0 && _inode == 0)
+    {
+      (void) _fetch_inode();
+    }
+    return _devid;
+  }
   //! Unless `flag::disable_safety_unlinks` is set, the inode of the file when opened. When combined with st_dev(), forms a unique identifer on this system
-  ino_t st_ino() const noexcept { return _inode; }
+  ino_t st_ino() const noexcept
+  {
+    if(_devid == 0 && _inode == 0)
+    {
+      (void) _fetch_inode();
+    }
+    return _inode;
+  }
   //! A unique identifier for this handle across the entire system. Can be used in hash tables etc.
   unique_id_type unique_id() const noexcept
   {
+    if(_devid == 0 && _inode == 0)
+    {
+      (void) _fetch_inode();
+    }
     unique_id_type ret;
     ret.as_longlongs[0] = _devid;
     ret.as_longlongs[1] = _inode;