diff mercurial/utils/procutil.py @ 37121:5be286db5fb5

procutil: move process/executable management functions to new module

std* files, pipe helpers, and findexe()s are moved as well since they are
likely to be used with sub processes.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/utils/procutil.py	Sat Mar 24 13:38:04 2018 +0900
@@ -0,0 +1,319 @@
+# procutil.py - utility for managing processes and executable environment
+#
+#  Copyright 2005 K. Thananchayan <[e-mail]>
+#  Copyright 2005-2007 Matt Mackall <[e-mail]>
+#  Copyright 2006 Vadim Gelfer <[e-mail]>
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+from __future__ import absolute_import
+
+import imp
+import io
+import os
+import signal
+import subprocess
+import sys
+import tempfile
+import time
+
+from ..i18n import _
+
+from .. import (
+    encoding,
+    error,
+    policy,
+    pycompat,
+)
+
+osutil = policy.importmod(r'osutil')
+
+stderr = pycompat.stderr
+stdin = pycompat.stdin
+stdout = pycompat.stdout
+
+def isatty(fp):
+    try:
+        return fp.isatty()
+    except AttributeError:
+        return False
+
+# glibc determines buffering on first write to stdout - if we replace a TTY
+# destined stdout with a pipe destined stdout (e.g. pager), we want line
+# buffering
+if isatty(stdout):
+    stdout = os.fdopen(stdout.fileno(), r'wb', 1)
+
+if pycompat.iswindows:
+    from .. import windows as platform
+    stdout = platform.winstdout(stdout)
+else:
+    from .. import posix as platform
+
+explainexit = platform.explainexit
+findexe = platform.findexe
+_gethgcmd = platform.gethgcmd
+getuser = platform.getuser
+getpid = os.getpid
+hidewindow = platform.hidewindow
+popen = platform.popen
+quotecommand = platform.quotecommand
+readpipe = platform.readpipe
+setbinary = platform.setbinary
+setsignalhandler = platform.setsignalhandler
+shellquote = platform.shellquote
+shellsplit = platform.shellsplit
+spawndetached = platform.spawndetached
+sshargs = platform.sshargs
+testpid = platform.testpid
+
+try:
+    setprocname = osutil.setprocname
+except AttributeError:
+    pass
+try:
+    unblocksignal = osutil.unblocksignal
+except AttributeError:
+    pass
+
+closefds = pycompat.isposix
+
+def popen2(cmd, env=None, newlines=False):
+    # Setting bufsize to -1 lets the system decide the buffer size.
+    # The default for bufsize is 0, meaning unbuffered. This leads to
+    # poor performance on Mac OS X: http://bugs.python.org/issue4194
+    p = subprocess.Popen(cmd, shell=True, bufsize=-1,
+                         close_fds=closefds,
+                         stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+                         universal_newlines=newlines,
+                         env=env)
+    return p.stdin, p.stdout
+
+def popen3(cmd, env=None, newlines=False):
+    stdin, stdout, stderr, p = popen4(cmd, env, newlines)
+    return stdin, stdout, stderr
+
+def popen4(cmd, env=None, newlines=False, bufsize=-1):
+    p = subprocess.Popen(cmd, shell=True, bufsize=bufsize,
+                         close_fds=closefds,
+                         stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+                         stderr=subprocess.PIPE,
+                         universal_newlines=newlines,
+                         env=env)
+    return p.stdin, p.stdout, p.stderr, p
+
+def pipefilter(s, cmd):
+    '''filter string S through command CMD, returning its output'''
+    p = subprocess.Popen(cmd, shell=True, close_fds=closefds,
+                         stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    pout, perr = p.communicate(s)
+    return pout
+
+def tempfilter(s, cmd):
+    '''filter string S through a pair of temporary files with CMD.
+    CMD is used as a template to create the real command to be run,
+    with the strings INFILE and OUTFILE replaced by the real names of
+    the temporary files generated.'''
+    inname, outname = None, None
+    try:
+        infd, inname = tempfile.mkstemp(prefix='hg-filter-in-')
+        fp = os.fdopen(infd, r'wb')
+        fp.write(s)
+        fp.close()
+        outfd, outname = tempfile.mkstemp(prefix='hg-filter-out-')
+        os.close(outfd)
+        cmd = cmd.replace('INFILE', inname)
+        cmd = cmd.replace('OUTFILE', outname)
+        code = os.system(cmd)
+        if pycompat.sysplatform == 'OpenVMS' and code & 1:
+            code = 0
+        if code:
+            raise error.Abort(_("command '%s' failed: %s") %
+                              (cmd, explainexit(code)))
+        with open(outname, 'rb') as fp:
+            return fp.read()
+    finally:
+        try:
+            if inname:
+                os.unlink(inname)
+        except OSError:
+            pass
+        try:
+            if outname:
+                os.unlink(outname)
+        except OSError:
+            pass
+
+_filtertable = {
+    'tempfile:': tempfilter,
+    'pipe:': pipefilter,
+}
+
+def filter(s, cmd):
+    "filter a string through a command that transforms its input to its output"
+    for name, fn in _filtertable.iteritems():
+        if cmd.startswith(name):
+            return fn(s, cmd[len(name):].lstrip())
+    return pipefilter(s, cmd)
+
+def mainfrozen():
+    """return True if we are a frozen executable.
+
+    The code supports py2exe (most common, Windows only) and tools/freeze
+    (portable, not much used).
+    """
+    return (pycompat.safehasattr(sys, "frozen") or # new py2exe
+            pycompat.safehasattr(sys, "importers") or # old py2exe
+            imp.is_frozen(u"__main__")) # tools/freeze
+
+_hgexecutable = None
+
+def hgexecutable():
+    """return location of the 'hg' executable.
+
+    Defaults to $HG or 'hg' in the search path.
+    """
+    if _hgexecutable is None:
+        hg = encoding.environ.get('HG')
+        mainmod = sys.modules[r'__main__']
+        if hg:
+            _sethgexecutable(hg)
+        elif mainfrozen():
+            if getattr(sys, 'frozen', None) == 'macosx_app':
+                # Env variable set by py2app
+                _sethgexecutable(encoding.environ['EXECUTABLEPATH'])
+            else:
+                _sethgexecutable(pycompat.sysexecutable)
+        elif (os.path.basename(
+            pycompat.fsencode(getattr(mainmod, '__file__', ''))) == 'hg'):
+            _sethgexecutable(pycompat.fsencode(mainmod.__file__))
+        else:
+            exe = findexe('hg') or os.path.basename(sys.argv[0])
+            _sethgexecutable(exe)
+    return _hgexecutable
+
+def _sethgexecutable(path):
+    """set location of the 'hg' executable"""
+    global _hgexecutable
+    _hgexecutable = path
+
+def _testfileno(f, stdf):
+    fileno = getattr(f, 'fileno', None)
+    try:
+        return fileno and fileno() == stdf.fileno()
+    except io.UnsupportedOperation:
+        return False # fileno() raised UnsupportedOperation
+
+def isstdin(f):
+    return _testfileno(f, sys.__stdin__)
+
+def isstdout(f):
+    return _testfileno(f, sys.__stdout__)
+
+def shellenviron(environ=None):
+    """return environ with optional override, useful for shelling out"""
+    def py2shell(val):
+        'convert python object into string that is useful to shell'
+        if val is None or val is False:
+            return '0'
+        if val is True:
+            return '1'
+        return pycompat.bytestr(val)
+    env = dict(encoding.environ)
+    if environ:
+        env.update((k, py2shell(v)) for k, v in environ.iteritems())
+    env['HG'] = hgexecutable()
+    return env
+
+def system(cmd, environ=None, cwd=None, out=None):
+    '''enhanced shell command execution.
+    run with environment maybe modified, maybe in different dir.
+
+    if out is specified, it is assumed to be a file-like object that has a
+    write() method. stdout and stderr will be redirected to out.'''
+    try:
+        stdout.flush()
+    except Exception:
+        pass
+    cmd = quotecommand(cmd)
+    env = shellenviron(environ)
+    if out is None or isstdout(out):
+        rc = subprocess.call(cmd, shell=True, close_fds=closefds,
+                             env=env, cwd=cwd)
+    else:
+        proc = subprocess.Popen(cmd, shell=True, close_fds=closefds,
+                                env=env, cwd=cwd, stdout=subprocess.PIPE,
+                                stderr=subprocess.STDOUT)
+        for line in iter(proc.stdout.readline, ''):
+            out.write(line)
+        proc.wait()
+        rc = proc.returncode
+    if pycompat.sysplatform == 'OpenVMS' and rc & 1:
+        rc = 0
+    return rc
+
+def gui():
+    '''Are we running in a GUI?'''
+    if pycompat.isdarwin:
+        if 'SSH_CONNECTION' in encoding.environ:
+            # handle SSH access to a box where the user is logged in
+            return False
+        elif getattr(osutil, 'isgui', None):
+            # check if a CoreGraphics session is available
+            return osutil.isgui()
+        else:
+            # pure build; use a safe default
+            return True
+    else:
+        return pycompat.iswindows or encoding.environ.get("DISPLAY")
+
+def hgcmd():
+    """Return the command used to execute current hg
+
+    This is different from hgexecutable() because on Windows we want
+    to avoid things opening new shell windows like batch files, so we
+    get either the python call or current executable.
+    """
+    if mainfrozen():
+        if getattr(sys, 'frozen', None) == 'macosx_app':
+            # Env variable set by py2app
+            return [encoding.environ['EXECUTABLEPATH']]
+        else:
+            return [pycompat.sysexecutable]
+    return _gethgcmd()
+
+def rundetached(args, condfn):
+    """Execute the argument list in a detached process.
+
+    condfn is a callable which is called repeatedly and should return
+    True once the child process is known to have started successfully.
+    At this point, the child process PID is returned. If the child
+    process fails to start or finishes before condfn() evaluates to
+    True, return -1.
+    """
+    # Windows case is easier because the child process is either
+    # successfully starting and validating the condition or exiting
+    # on failure. We just poll on its PID. On Unix, if the child
+    # process fails to start, it will be left in a zombie state until
+    # the parent wait on it, which we cannot do since we expect a long
+    # running process on success. Instead we listen for SIGCHLD telling
+    # us our child process terminated.
+    terminated = set()
+    def handler(signum, frame):
+        terminated.add(os.wait())
+    prevhandler = None
+    SIGCHLD = getattr(signal, 'SIGCHLD', None)
+    if SIGCHLD is not None:
+        prevhandler = signal.signal(SIGCHLD, handler)
+    try:
+        pid = spawndetached(args)
+        while not condfn():
+            if ((pid in terminated or not testpid(pid))
+                and not condfn()):
+                return -1
+            time.sleep(0.1)
+        return pid
+    finally:
+        if prevhandler is not None:
+            signal.signal(signal.SIGCHLD, prevhandler)