file system back-end: map references to symlinks

1 files changed, 23 insertions, 4 deletions

diff --git a/acf/persistence/backends/files.lua b/acf/persistence/backends/files.lua
index e123e21..813dca5 100644
--- a/acf/persistence/backends/files.lua
+++ b/acf/persistence/backends/files.lua
@@ -9,6 +9,7 @@ local pth = require('acf.path')
 local util = require('acf.persistence.util')
 
 require 'posix'
+require 'stringy'
 
 
 backend = require('acf.object').class()
@@ -26,6 +27,19 @@ function backend:get(path, tpe)
       if t == 'regular' then
 	 self.cache[name] = util.read_file(name)
 
+      elseif t == 'link' then
+	 -- TODO handle relative symlinks
+	 local target = posix.readlink(name)
+	 assert(target)
+	 if not tpe then return target end
+
+	 assert(stringy.startswith(tpe, 'reference/files/'))
+	 local scope = string.sub(tpe, 16, -1)..'/'
+
+	 local slen = string.len(scope)
+	 assert(string.sub(target, 1, slen) == scope)
+	 return string.sub(target, slen + 1, -1)
+
       elseif t == 'directory' then
 	 local res = {}
 	 for _, fname in ipairs(posix.dir(name)) do
@@ -36,8 +50,6 @@ function backend:get(path, tpe)
 	 return res
 
       else error('Unsupported file type: '..name) end
-
-      -- TODO present symlinks as references
    end
 
    return self.cache[name]
@@ -48,8 +60,6 @@ function backend:set(mods)
       local path, t, value = unpack(mod)
       local name = pth.join('/', unpack(path))
 
-      -- TODO save references (t == 'reference') as symlinks
-
       if not t then
 	 -- TODO del files & dirs
 	 print('DEL', name)
@@ -57,6 +67,15 @@ function backend:set(mods)
       elseif t == 'table' then
 	 assert(posix.mkdir(name))
 
+      elseif stringy.startswith(t, 'reference/files/') then
+	 -- TODO use relative symlink
+	 os.remove(name)
+	 assert(
+	    posix.link(
+	       pth.to_absolute(value, string.sub(t, 16, -1)), name, true
+	    )
+	 )
+
       else
 	 local file = util.open_file(name, 'w')
 	 file:write(tostring(value))