opus/sys/apis/fs/ramfs.lua

local Util   = require('util')

local fs = _G.fs

local ramfs = { }

function ramfs.mount(_, nodeType)
  if nodeType == 'directory' then
    return {
      nodes = { },
      size = 0,
    }
  elseif nodeType == 'file' then
    return {
      size = 0,
    }
  end
  error('ramfs syntax: [directory, file]')
end

function ramfs.delete(node, dir)
  if node.mountPoint == dir then
    fs.unmount(node.mountPoint)
  end
end

function ramfs.exists(node, fn)
  return node.mountPoint == fn
end

function ramfs.getSize(node)
  return node.size
end

function ramfs.isReadOnly()
  return false
end

function ramfs.makeDir(_, dir)
  fs.mount(dir, 'ramfs', 'directory')
end

function ramfs.isDir(node)
  return not not node.nodes
end

function ramfs.getDrive()
  return 'ram'
end

function ramfs.list(node, dir)
  if node.nodes and node.mountPoint == dir then
    local files = { }
    for k in pairs(node.nodes) do
      table.insert(files, k)
    end
    return files
  end
  error('Not a directory')
end

function ramfs.open(node, fn, fl)

  if fl ~= 'r' and fl ~= 'w' and fl ~= 'rb' and fl ~= 'wb' then
    error('Unsupported mode')
  end

  if fl == 'r' then
    if node.mountPoint ~= fn then
      return
    end

    local ctr = 0
    local lines
    return {
      readLine = function()
        if not lines then
          lines = Util.split(node.contents)
        end
        ctr = ctr + 1
        return lines[ctr]
      end,
      readAll = function()
        return node.contents
      end,
      close = function()
        lines = nil
      end,
    }
  elseif fl == 'w' then
    node = fs.mount(fn, 'ramfs', 'file')

    local c = ''
    return {
      write = function(str)
        c = c .. str
      end,
      writeLine = function(str)
        c = c .. str .. '\n'
      end,
      flush = function()
        node.contents = c
        node.size = #c
      end,
      close = function()
        node.contents = c
        node.size = #c
        c = nil
      end,
    }
  elseif fl == 'rb' then
    if node.mountPoint ~= fn or not node.contents then
      return
    end

    local ctr = 0
    return {
      read = function()
        ctr = ctr + 1
        return node.contents[ctr]
      end,
      close = function()
      end,
    }

  elseif fl == 'wb' then
    node = fs.mount(fn, 'ramfs', 'file')

    local c = { }
    return {
      write = function(b)
        table.insert(c, b)
      end,
      flush = function()
        node.contents = c
        node.size = #c
      end,
      close = function()
        node.contents = c
        node.size = #c
        c = nil
      end,
    }
  end
end

return ramfs