Change getattr and statx to bespoke policies

* Provides: slight improvement in performance as it no longer will
need to find and then act on the files.
* It doesn't make sense to support all original policy types. Most
people used 'newest' or 'ff' and 'combine' is a better default which
has same runtime as 'newest' but with better output.

src/func_readlink_ff.cpp

@@ -0,0 +1,104 @@
+#include "func_readlink_ff.hpp"
+
+#include "error.hpp"
+#include "fs_readlink.hpp"
+#include "fs_lstat.hpp"
+#include "symlinkify.hpp"
+
+#include <cstring>
+
+
+std::string_view
+Func2::ReadlinkFF::name() const
+{
+  return "ff";
+}
+
+static
+int
+_readlink_symlinkify(const Branches &branches_,
+                     const fs::path &fusepath_,
+                     char           *buf_,
+                     const size_t    bufsize_,
+                     const time_t    symlinkify_timeout_)
+{
+  int rv;
+  Err err;
+  struct stat st;
+  fs::path fullpath;
+
+  for(const auto &branch : branches_)
+    {
+      fullpath = branch.path / fusepath_;
+
+      err = rv = fs::lstat(fullpath,&st);
+      if(rv < 0)
+        continue;
+
+      if(not symlinkify::can_be_symlink(st,symlinkify_timeout_))
+        {
+          err = rv = fs::readlink(fusepath_,buf_,bufsize_);
+          if(rv < 0)
+            continue;
+
+          buf_[rv] = '\0';
+
+          return 0;
+        }
+
+      strncpy(buf_,fullpath.c_str(),bufsize_);
+
+      return 0;
+    }
+
+  return err;
+}
+
+static
+int
+_readlink(const Branches &branches_,
+          const fs::path &fusepath_,
+          char           *buf_,
+          const size_t    bufsize_)
+{
+  int rv;
+  Err err;
+  fs::path fullpath;
+
+  for(const auto &branch : branches_)
+    {
+      fullpath = branch.path / fusepath_;
+
+      err = rv = fs::readlink(fusepath_,buf_,bufsize_);
+      if(rv < 0)
+        continue;
+
+      buf_[rv] = '\0';
+
+      return 0;
+    }
+
+  return err;
+}
+
+
+
+int
+Func2::ReadlinkFF::operator()(const Branches &branches_,
+                              const fs::path &fusepath_,
+                              char           *buf_,
+                              const size_t    bufsize_,
+                              const time_t    symlinkify_timeout_)
+{
+  if(symlinkify_timeout_ > 0)
+    return ::_readlink_symlinkify(branches_,
+                                  fusepath_,
+                                  buf_,
+                                  bufsize_,
+                                  symlinkify_timeout_);
+
+  return ::_readlink(branches_,
+                     fusepath_,
+                     buf_,
+                     bufsize_);
+}