Add readdir policies

src/fuse_readdir_factory.cpp

@@ -0,0 +1,75 @@
+/*
+  ISC License
+
+  Copyright (c) 2023, Antonio SJ Musumeci <trapexit@spawn.link>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "fuse_readdir_factory.hpp"
+
+#include "fuse_readdir_cor.hpp"
+#include "fuse_readdir_cosr.hpp"
+#include "fuse_readdir_seq.hpp"
+
+#include <cassert>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+
+
+namespace l
+{
+  static
+  void
+  read_cfg(std::string const  cfgstr_,
+           std::string       &type_,
+           int               &concurrency_)
+  {
+    char type[16];
+    int concurrency;
+
+    concurrency = 0;
+    std::sscanf(cfgstr_.c_str(),"%15[a-z]:%u",type,&concurrency);
+
+    if(concurrency == 0)
+      concurrency = std::thread::hardware_concurrency();
+    else if(concurrency < 0)
+      concurrency = (std::thread::hardware_concurrency() / std::abs(concurrency));
+
+    if(concurrency == 0)
+      concurrency = 1;
+
+    type_        = type;
+    concurrency_ = concurrency;
+  }
+}
+
+std::shared_ptr<FUSE::ReadDirBase>
+FUSE::ReadDirFactory::make(std::string const cfgstr_)
+{
+  int concurrency;
+  std::string type;
+
+  l::read_cfg(cfgstr_,type,concurrency);
+  assert(concurrency);
+
+  if(type == "seq")
+    return std::make_shared<FUSE::ReadDirSeq>();
+  if(type == "cosr")
+    return std::make_shared<FUSE::ReadDirCOSR>(concurrency);
+  if(type == "cor")
+    return std::make_shared<FUSE::ReadDirCOR>(concurrency);
+
+  return {};
+}