refactor parallel code

openos/ps.lua

@@ -0,0 +1,155 @@
+local process = require("process")
+local unicode = require("unicode")
+local event = require("event")
+local thread = require("thread")
+local event_mt = getmetatable(event.handlers)
+
+-- WARNING this code does not use official kernel API and is likely to change
+
+local data = {}
+local widths = {}
+local sorted = {}
+local moved_indexes = {}
+
+local elbow = unicode.char(0x2514)
+
+local function thread_id(t,p)
+  if t then
+    return tostring(t):gsub("^thread: 0x", "")
+  end
+  -- find the parent thread
+  for k,v in pairs(process.list) do
+    if v == p then
+      return thread_id(k)
+    end
+  end
+  return "-"
+end
+
+local cols =
+{
+  {"PID", thread_id},
+  {"EVENTS", function(_,p)
+    local handlers = {}
+    if event_mt.threaded then
+      handlers = rawget(p.data, "handlers") or {}
+    elseif not p.parent then
+      handlers = event.handlers
+    end
+    local count = 0
+    for _ in pairs(handlers) do
+      count = count + 1
+    end
+    return count == 0 and "-" or tostring(count)
+  end},
+  {"THREADS", function(_,p)
+    -- threads are handles with mt.close == thread.waitForAll
+    local count = 0
+    for h in pairs(p.data.handles) do
+      local mt = getmetatable(h)
+      if mt and mt.__status then
+        count = count + 1
+      end
+    end
+    return count == 0 and "-" or tostring(count)
+  end},
+  {"PARENT", function(_,p)
+    for _,process_info in pairs(process.list) do
+      for handle in pairs(process_info.data.handles) do
+        local mt = getmetatable(handle)
+        if mt and mt.__status then
+          if mt.process == p then
+            return thread_id(nil, process_info)
+          end
+        end
+      end
+    end
+    return thread_id(nil, p.parent)
+  end},
+  {"HANDLES", function(_, p)
+    local count = 0
+    for _,closure in pairs(p.data.handles) do
+      if closure then
+        count = count + 1
+      end
+    end
+    return count == 0 and "-" or tostring(count)
+  end},
+  {"CMD", function(_,p) return p.command end},
+}
+
+local function add_field(key, value)
+  if not data[key] then data[key] = {} end
+  table.insert(data[key], value)
+  widths[key] = math.max(widths[key] or 0, #value)
+end
+
+for _,key in ipairs(cols) do
+  add_field(key[1], key[1])
+end
+
+for thread_handle, process_info in pairs(process.list) do
+  for _,key in ipairs(cols) do
+    add_field(key[1], key[2](thread_handle, process_info))
+  end
+end
+
+local parent_index
+for index,set in ipairs(cols) do
+  if set[1] == "PARENT" then
+    parent_index = index
+    break
+  end
+end
+assert(parent_index, "did not find a parent column")
+
+local function move_to_sorted(index)
+  if moved_indexes[index] then
+    return false
+  end
+  local entry = {}
+  for k,v in pairs(data) do
+    entry[k] = v[index]
+  end
+  sorted[#sorted + 1] = entry
+  moved_indexes[index] = true
+  return true
+end
+
+local function make_elbow(depth)
+  return (" "):rep(depth - 1) .. (depth > 0 and elbow or "")
+end
+
+-- remove COLUMN labels to simplify sort
+move_to_sorted(1)
+
+local function update_family(parent, depth)
+  depth = depth or 0
+  parent = parent or "-"
+  for index in ipairs(data.PID) do
+    local this_parent = data[cols[parent_index][1]][index]
+    if this_parent == parent then
+      local dash_cmd = make_elbow(depth) .. data.CMD[index]
+      data.CMD[index] = dash_cmd
+      widths.CMD = math.max(widths.CMD or 0, #dash_cmd)
+      if move_to_sorted(index) then
+        update_family(data.PID[index], depth + 1)
+      end
+    end
+  end
+end
+
+update_family()
+table.remove(cols, parent_index) -- don't show parent id
+
+for _,set in ipairs(sorted) do
+  local split = ""
+  for _,key in ipairs(cols) do
+    local label = key[1]
+    local format = split .. "%-" .. tostring(widths[label]) .. "s"
+    io.write(string.format(format, set[label]))
+    split = "   "
+  end
+  print()
+end
+