opus/sys/apis/fs/urlfs.lua

local synchronized = require('sync')

local urlfs = { }

function urlfs.mount(dir, url)
  if not url then
    error('URL is required')
  end
  return {
    url = url,
  }
end

function urlfs.delete(node, dir)
  fs.unmount(dir)
end

function urlfs.exists()
  return true
end

function urlfs.getSize(node)
  return node.size or 0
end

function urlfs.isReadOnly()
  return true
end

function urlfs.isDir()
  return false
end

function urlfs.getDrive()
  return 'url'
end

function urlfs.open(node, fn, fl)

  if fl ~= 'r' then
    error('Unsupported mode')
  end

  local c = node.cache
  if not c then
    synchronized(node.url, function()
      c = Util.download(node.url)
    end)
    if c then
      node.cache = c
      node.size = #c
    end
  end

  if not c then
    return
  end

  local ctr = 0
  local lines
  return {
    readLine = function()
      if not lines then
        lines = Util.split(c)
      end
      ctr = ctr + 1
      return lines[ctr]
    end,
    readAll = function()
      return c
    end,
    close = function()
      lines = nil
    end,
  }
end

return urlfs