WIP: experiment with netman.nvim

Working proof-of-concept that has functional browsing. Remaining work:

* Figure out how the url scheme should work (esp with multiple netman providers)
* Column definitions
* Normalize buffer names
* Check if directory is modifiable
* Render actions
* Perform actions
* Perform actions across adapters

lua/oil/adapters/netman_ssh.lua

@@ -0,0 +1,148 @@
+local cache = require("oil.cache")
+local netman = require("netman")
+local pathutil = require("oil.pathutil")
+local util = require("oil.util")
+local FIELD = require("oil.constants").FIELD
+local M = {}
+
+---@param oil_url string
+---@return oil.sshUrl
+local function parse_url(oil_url)
+  local scheme, url = util.parse_url(oil_url)
+  local ret = { scheme = scheme }
+  local username, rem = url:match("^([^@%s]+)@(.*)$")
+  ret.user = username
+  url = rem or url
+  local host, port, path = url:match("^([^:]+):(%d+)//?(.*)$")
+  if host then
+    ret.host = host
+    ret.port = tonumber(port)
+    ret.path = path
+  else
+    host, path = url:match("^([^/]+)//?(.*)$")
+    ret.host = host
+    ret.path = path
+  end
+  if not ret.host or not ret.path then
+    error(string.format("Malformed SSH url: %s", oil_url))
+  end
+
+  return ret
+end
+
+---@param url oil.sshUrl
+---@return string
+local function url_to_str(url)
+  local pieces = { url.scheme }
+  if url.user then
+    table.insert(pieces, url.user)
+    table.insert(pieces, "@")
+  end
+  table.insert(pieces, url.host)
+  if url.port then
+    table.insert(pieces, string.format(":%d", url.port))
+  end
+  table.insert(pieces, "/")
+  if vim.startswith(url.path, "/") then
+    table.insert(pieces, "/")
+  end
+  table.insert(pieces, url.path)
+  return table.concat(pieces, "")
+end
+
+---@param name string
+---@return nil|oil.ColumnDefinition
+M.get_column = function(name)
+  -- TODO
+  return nil
+end
+
+---@param bufname string
+---@return string
+M.get_parent = function(bufname)
+  local res = parse_url(bufname)
+  res.path = pathutil.parent(res.path)
+  return url_to_str(res)
+end
+
+---@param url string
+---@param callback fun(url: string)
+M.normalize_url = function(url, callback)
+  -- TODO
+  callback(url)
+end
+
+local TYPE_MAP = setmetatable({
+  ["regular file"] = "file",
+}, {
+  __index = function(_, k)
+    return k
+  end,
+})
+
+---@param url string
+---@param column_defs string[]
+---@param callback fun(err: nil|string, entries: nil|oil.InternalEntry[])
+M.list = function(url, column_defs, callback)
+  local _, hostpath = util.parse_url(url)
+  local netman_url = "scp://" .. hostpath
+  cache.begin_update_url(url)
+  local res = netman.api.read(netman_url)
+  if res.success and res.type == "EXPLORE" then
+    for _, entry in ipairs(res.data) do
+      local cache_entry = cache.create_entry(url, entry.NAME, TYPE_MAP[entry.METADATA.TYPE])
+      cache_entry[FIELD.meta] = entry.METADATA
+      cache.store_entry(url, cache_entry)
+    end
+    callback()
+    cache.end_update_url(url)
+  else
+    cache.end_update_url(url)
+    callback("Unknown error")
+  end
+end
+
+---@param bufnr integer
+---@return boolean
+M.is_modifiable = function(bufnr)
+  -- TODO
+  return false
+end
+
+---@param url string
+M.url_to_buffer_name = function(url)
+  local parsed = parse_url(url)
+  local pieces = { "scp://" }
+  if parsed.user then
+    table.insert(pieces, parsed.user)
+    table.insert(pieces, "@")
+  end
+  table.insert(pieces, parsed.host)
+  if parsed.port then
+    table.insert(pieces, string.format(":%d", parsed.port))
+  end
+  table.insert(pieces, "/")
+  if vim.startswith(parsed.path, "/") then
+    table.insert(pieces, "/")
+  end
+  table.insert(pieces, parsed.path)
+  return table.concat(pieces, "")
+end
+
+---@param action oil.Action
+---@return string
+M.render_action = function(action)
+  -- TODO
+end
+
+---@param action oil.Action
+---@param cb fun(err: nil|string)
+M.perform_action = function(action, cb)
+  -- TODO
+  cb("Not implemented")
+end
+
+-- TODO
+M.supports_xfer = {}
+
+return M