ccDocker's cext fs implementation in the works!

cext.lua

--[[
  A lightweight ext-like FS implemented in pure lua.

  Specs: <insert link here>

  @author Jared Allard <[email protected]>
  @license MIT
  @notice uses JSDoc like insource documention.
]]

-- intial declearation of the FS table.
cext = {
  ["version"] = 001,
  ["date"]    = 20150530,
  ["inodeAllocations"] = 500, -- amount of lines to save for inodes untill dynamic.
  ["print"] = function(msg)
    print(tostring(msg))
  end,
  ["fs"] = nil, -- assurance.
}

-- temporary.

-- split a string
function string:split(delimiter)
  local result = { }
  local from  = 1
  local delim_from, delim_to = string.find( self, delimiter, from  )
  while delim_from do
    table.insert( result, string.sub( self, from , delim_from-1 ) )
    from  = delim_to + 1
    delim_from, delim_to = string.find( self, delimiter, from  )
  end
  table.insert( result, string.sub( self, from  ) )
  return result
end


--[[
  Create a filesystem.

  @return {boolean} - success or failure
]]
cext.createFS = function(this, location, size)
  -- this.checkArgs(this, size)

  -- superblockHeader.
  local superblockHeader = this.version..",0,"..size..",2"
  local inodeAllocation = ""

  -- generate whitespace.
  this.print("generating lines of whitespace.")
  for i = 1,this.inodeAllocations do
   inodeAllocation = inodeAllocation.."\n"
  end

  -- remove a stale filesystem.
  if fs.exists(location) then
    this.print("removing stale fs")
    fs.delete(location)
  end

  -- open a io file handle and inject the superblockHeader & inodeAllocation ws.
  this.print("writing fs")
  local iohandle = io.open(location, "w")
  iohandle:write(superblockHeader..inodeAllocation)
  iohandle:close()
  this.print("done")

  -- return true since we probably had no issues.
  return true
end

--[[
  Open the file system (essentially load it into memory)

  @return {boolean} - success or fail.
]]
cext.open = function(this, fs)
  -- give the fs object an initial start.
  this.fs = {
    ["superblock"] = nil,
    ["raw"]        = nil,
  }

  -- load the raw filesystem.
  local iohandle = io.open(fs)
  this.fs.superblock = iohandle.read("*line")
  this.fs.raw = this.fs.superblock.."\n"..iohandle.read("*all")
  iohandle:close()

  -- look at the superblock for the next available inode line.
  local superblockSplit = string.split(this.fs.superblock, ",")

  -- assign it to the table.
  this.fs.superblock = {}
  this.fs.superblock.version = superblockSplit[1]
  this.fs.superblock.inodes = superblockSplit[2]
  this.fs.superblock.size = superblockSplit[3]
  this.fs.superblock.nextInode = superblockSplit[4]

  print('opened cext filesystem version: '..this.fs.superblock.version)

  -- return true as we probably had no issues.
  return true
end

--[[
  Write to the filesystem

  @return {boolean} - success or fail, if fail then error message
    on second param return.
]]
cext.write = function(this, filename, data)
  if this.fs == nil then
    error("fs isn't loaded. load with this:open(fs)")
  end

  local fileLocation = fs.getDir(filename)
  local fileName     = fs.getName(filename)

  -- generate the object.
  this.print("generating inode for '"..tostring(filename).."'")
  local inodeObject = fileLocation..","..fileName

  print(inodeObject)

  return true
end


-- TESTING
cext:createFS("test.fs", 1000)
cext:open("test.fs")
cext:write("file", "data\nmoredata\ndata")