[refactor] Cosmetic changes to core/process.py

Also add demo/jobs-builtin.sh, which reminds me of what we have to do
for 'jobs' and 'jobs -l'.

This is related to issue #360.

core/process.py

@@ -16,7 +16,7 @@
 
 from _devbuild.gen.id_kind_asdl import Id
 from _devbuild.gen.runtime_asdl import (
-    job_state_e, job_state_t,
+    job_state_e, job_state_t, job_state_str,
     wait_status, wait_status_t,
     redirect, redirect_arg_e, redirect_arg__Path, redirect_arg__CopyFd,
     redirect_arg__MoveFd, redirect_arg__HereDoc,
@@ -690,8 +690,10 @@ def DisplayLine(self):
     # type: () -> str
 
     # NOTE: These can be pieces of a pipeline, so they're arbitrary nodes.
-    # TODO: We should extract the SPIDS from each node!
-    return '[subprog] %s' % ui.CommandType(self.node)
+    # TODO: Extract SPIDS from node to display source?
+
+    thunk_str = ui.CommandType(self.node)
+    return '[subprog] %s' % thunk_str
 
   def Run(self):
     # type: () -> None
@@ -831,7 +833,8 @@ def Init_ParentPipeline(self, pi):
 
   def __repr__(self):
     # type: () -> str
-    return '<Process %s>' % self.thunk
+    s = ' %s' % self.parent_pipeline if self.parent_pipeline else ''
+    return '<Process %s%s>' % (self.thunk, s)
 
   def AddStateChange(self, s):
     # type: (ChildStateChange) -> None
@@ -966,7 +969,15 @@ def __init__(self, sigpipe_status_ok):
 
   def __repr__(self):
     # type: () -> str
-    return '<Pipeline %s>' % ' '.join(repr(p) for p in self.procs)
+    parts = ['<Pipeline\n']
+    parts.append('  procs=%s\n' % ' '.join(repr(p) for p in self.procs))
+    parts.append('  last_thunk=%s\n' % (self.last_thunk,))
+    parts.append('  pipe_status=%s\n' % self.pipe_status)
+    parts.append('>\n')
+    return ''.join(parts)
+
+  def DisplayLine(self):
+    return 'Pipeline %s\n' % self.procs
 
   def Add(self, p):
     # type: (Process) -> None
@@ -999,8 +1010,6 @@ def AddLast(self, thunk):
       return
 
     r, w = posix.pipe()
-    #log('last pipe %d %d', r, w)
-
     prev = self.procs[-1]
     prev.AddStateChange(StdoutToPipe(r, w))
 
@@ -1084,7 +1093,7 @@ def Run(self, waiter, fd_state):
     # ls | wc -l
     # echo foo | read line  # no need to fork
 
-    cmd_ev, node = self.last_thunk
+    cmd_ev, last_node = self.last_thunk
 
     #log('thunk %s', self.last_thunk)
     if self.last_pipe is not None:
@@ -1097,7 +1106,7 @@ def Run(self, waiter, fd_state):
       # exec() rather than fork/exec().
 
       try:
-        cmd_ev.ExecuteAndCatch(node)
+        cmd_ev.ExecuteAndCatch(last_node)
       finally:
         fd_state.Pop()
       # We won't read anymore.  If we don't do this, then 'cat' in 'cat
@@ -1106,9 +1115,9 @@ def Run(self, waiter, fd_state):
 
     else:
       if len(self.procs):
-        cmd_ev.ExecuteAndCatch(node)  # Background pipeline without last_pipe
+        cmd_ev.ExecuteAndCatch(last_node)  # Background pipeline without last_pipe
       else:
-        cmd_ev._Execute(node)  # singleton foreground pipeline, e.g. '! func'
+        cmd_ev._Execute(last_node)  # singleton foreground pipeline, e.g. '! func'
 
     self.pipe_status[-1] = cmd_ev.LastStatus()
     #log('pipestatus before all have finished = %s', self.pipe_status)
@@ -1142,6 +1151,11 @@ def WhenDone(self, pid, status):
       self.state = job_state_e.Done
 
 
+def _JobStateStr(i):
+  # type: (job_state_t) -> str
+  return job_state_str(i)[10:]  # remove 'job_state.'
+
+
 class JobState(object):
   """Global list of jobs, used by a few builtins."""
 
@@ -1261,14 +1275,15 @@ def List(self):
       # TODO: don't use __repr__ and so forth
 
       print('Jobs:')
-      for pid, job in iteritems(self.jobs):
+      for job_id, job in iteritems(self.jobs):
         # Use the %1 syntax
-        print('%%%d %s %s' % (pid, job.State(), job))
+        print('%%%d %7s %s' % (job_id, _JobStateStr(job.State()), job))
 
       print('')
       print('Processes:')
       for pid, proc in iteritems(self.child_procs):
-        print('%d %s %s' % (pid, proc.state, proc.thunk.DisplayLine()))
+        p = ' |' if proc.parent_pipeline else ''
+        print('%d %7s %s%s' % (pid, _JobStateStr(proc.state), proc.thunk.DisplayLine(), p))
 
   def ListRecent(self):
     # type: () -> None
@@ -1408,6 +1423,8 @@ def WaitForOne(self, eintr_retry):
       return True  # caller should keep waiting
 
     proc = self.job_state.child_procs[pid]
+    if 0:
+      self.job_state.List()
 
     if WIFSIGNALED(status):
       term_sig = WTERMSIG(status)

demo/jobs-builtin.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+#
+# Compare the output of "jobs" in different shells
+#
+# Usage:
+#   $SH demo/jobs-builtin.sh <function name>
+
+set -o nounset
+#set -o pipefail
+set -o errexit
+
+# Notes:
+# - the formats are consistent, because it's specified by POSIX
+#   - they use [1] [2] [3] 
+#   - + is the default job for 'fg' and 'bg', which is also %%
+#   - - is the job that would become the default, which is also %-
+#
+# "[%d] %c %s %s\n", <job-number>, <current>, <state>, <command>
+#
+# https://pubs.opengroup.org/onlinepubs/9699919799/utilities/jobs.html
+#
+# TODO: Oil should print this as QSN!   So you can parse it.
+#
+# - dash is the only shell that doesn't show source code; it just shows | for pipe
+# - mksh has some weird quoting, like \sleep 1
+# - mksh and zsh doesn't show trailing &, but bash does
+#
+
+show_jobs() {
+  echo ___
+
+  # all shells support this long format which shows components of a pipeline
+  jobs -l
+  #jobs
+}
+
+myfunc() {
+  sleep 0.3
+  show_jobs
+
+  sleep 0.4
+  show_jobs
+}
+
+
+demo() {
+  sleep 1 & sleep 2 & 
+  show_jobs
+
+  { echo pipe1; sleep 0.5; } | cat &
+  show_jobs
+
+  myfunc &
+
+  # only bash supports wait -n
+  if test -n "${BASH_VERSION:-}"; then
+    wait -n
+    show_jobs
+  fi
+
+  wait
+  show_jobs
+
+  ls | wc -l
+  show_jobs
+}
+
+"$@"

test/py3_parse.py

@@ -36,6 +36,9 @@ def main(argv):
 
     print('Parsed %s: %s' % (filename, module))
 
+    # TODO:
+    # - Use Python 3.10 and match statements here!
+    # - Parse type comments out of __init__() like self.field = field
     if type_comments:
       for stmt in module.body:
         if isinstance(stmt, ast.FunctionDef):