add metadata caching to mtfs, to increase the speed of, among other things, ls

MTFS/OpenOS/usr/bin/importfs.lua

@@ -1,3 +1,4 @@
+local computer = require "computer"
 local fs = require "filesystem"
 local rpc = require "rpc"
 local tA = {...}
@@ -19,7 +20,52 @@ for k,v in pairs(px) do
  mc = mc + 1
 end
 if mc < 1 then
- error("no such remote filesystem: "..addr)
+ error("no such remote filesystem: "..rpath)
 end
+local statcache = {}
 px.address = rpath
+if px.dirstat then -- use single call for file info
+ function px.list(path)
+  local t,e = px.dirstat(path)
+  if not t then return nil,e end
+  local rt = {}
+  for k,v in pairs(t) do
+   rt[#rt+1] = k
+   statcache[fs.canonical("/"..path.."/"..k)] = {computer.uptime(),v[1],v[2],v[3]}
+  end
+  return rt
+ end
+ local oid, osize, olm = px.isDirectory, px.size, px.lastModified
+ local function cc() -- clean the cache of old entries
+  for k,v in pairs(statcache) do
+   if computer.uptime() > v[1] + 1 then
+    statcache[k] = nil
+   end
+  end
+ end
+ function px.isDirectory(path)
+  cc()
+  local ci = statcache["/"..fs.canonical(path)]
+  if ci then
+   return ci[3]
+  end
+  return oid(path)
+ end
+ function px.size(path)
+  cc()
+  local ci = statcache["/"..fs.canonical(path)]
+  if ci then
+   return ci[2]
+  end
+  return osize(path)
+ end
+ function px.lastModified(path)
+  cc()
+  local ci = statcache["/"..fs.canonical(path)]
+  if ci then
+   return ci[3]
+  end
+  return olm(path)
+ end
+end
 fs.mount(px, lpath)

MTFS/OpenOS/usr/lib/fsproxy.lua

@@ -75,6 +75,17 @@ function fsproxy.new(path,wp) -- string boolean -- table -- Returns a proxy obje
   return fs.size(cpath..sanitisePath(path))
  end
 
+ function proxy.dirstat(path) -- bundle the metadata about files into the listing to reduce round trips
+  local rt = {}
+  local dp = cpath..sanitisePath(path).."/"
+  local iter, err = fs.list(dp)
+  if not iter then return nil, err end
+  for name in iter do
+   rt[name] = {fs.isDirectory(dp..name), fs.size(dp..name), fs.lastModified(dp..name)}
+  end
+  return rt
+ end
+ 
  function proxy.open(path,mode)
   if wp and mode:find("[wa]") then return false, "read-only filesystem" end
   local h, e = fs.open(cpath..sanitisePath(path),mode)