Initial Prototype for Cygwin support module (take 2)

.gitignore

@@ -12,6 +12,7 @@ syntax: glob
 *.so
 *.swp
 .failed-tests.txt
+*.dll
 .cache/
 .idea/
 .tox/

psutil/__init__.py

@@ -16,6 +16,7 @@
  - NetBSD
  - Sun Solaris
  - AIX
+ - Cygwin (experimental)
 
 Works with Python versions from 2.6 to 3.4+.
 """
@@ -77,6 +78,7 @@
 
 from ._common import AIX
 from ._common import BSD
+from ._common import CYGWIN
 from ._common import FREEBSD  # NOQA
 from ._common import LINUX
 from ._common import MACOS
@@ -173,6 +175,10 @@
     # via sys.modules.
     PROCFS_PATH = "/proc"
 
+elif CYGWIN:
+    PROCFS_PATH = "/proc"
+    from . import _pscygwin as _psplatform
+
 else:  # pragma: no cover
     raise NotImplementedError('platform %s is not supported' % sys.platform)
 
@@ -201,7 +207,7 @@
     "POWER_TIME_UNKNOWN", "POWER_TIME_UNLIMITED",
 
     "BSD", "FREEBSD", "LINUX", "NETBSD", "OPENBSD", "MACOS", "OSX", "POSIX",
-    "SUNOS", "WINDOWS", "AIX",
+    "SUNOS", "WINDOWS", "AIX", "CYGWIN",
 
     # classes
     "Process", "Popen",
@@ -357,6 +363,12 @@ def __init__(self, seconds, pid=None, name=None):
 if POSIX:
     from . import _psposix
     _psposix.TimeoutExpired = TimeoutExpired
+if CYGWIN:
+    from . import _pslinux
+    _pslinux.NoSuchProcess = NoSuchProcess
+    _pslinux.ZombieProcess = ZombieProcess
+    _pslinux.AccessDenied = AccessDenied
+    _pslinux.TimeoutExpired = TimeoutExpired
 
 
 # =====================================================================
@@ -657,11 +669,16 @@ def parent(self):
         if self.pid == lowest_pid:
             return None
         ppid = self.ppid()
+        if CYGWIN:
+            # See note for Process.create_time in _pscygwin.py
+            rounding_error = 1
+        else:
+            rounding_error = 0
         if ppid is not None:
             ctime = self.create_time()
             try:
                 parent = Process(ppid)
-                if parent.create_time() <= ctime:
+                if parent.create_time() <= (ctime + rounding_error):
                     return parent
                 # ...else ppid has been reused by another process
             except NoSuchProcess:
@@ -1490,7 +1507,15 @@ def pids():
     """Return a list of current running PIDs."""
     global _LOWEST_PID
     ret = sorted(_psplatform.pids())
-    _LOWEST_PID = ret[0]
+
+    if CYGWIN:
+        # Note: The _LOWEST_PID concept is not very meaningful since every
+        # "top-level" process has a non-1 PID; they do have PPID of 1 but that
+        # does not correspend to an actual process that shows up in the pids()
+        # list
+        _LOWEST_PID = 1
+    else:
+        _LOWEST_PID = ret[0]
     return ret
 
 
@@ -2462,7 +2487,7 @@ def test():  # pragma: no cover
         else:
             cputime = ''
 
-        user = p.info['username']
+        user = p.info['username'] or ''
         if not user and POSIX:
             try:
                 user = p.uids()[0]

psutil/_common.py

@@ -38,12 +38,13 @@
     enum = None
 
 # can't take it from _common.py as this script is imported by setup.py
+PY2 = sys.version_info[0] == 2
 PY3 = sys.version_info[0] == 3
 
 __all__ = [
     # constants
     'FREEBSD', 'BSD', 'LINUX', 'NETBSD', 'OPENBSD', 'MACOS', 'OSX', 'POSIX',
-    'SUNOS', 'WINDOWS',
+    'SUNOS', 'WINDOWS', 'CYGWIN',
     'ENCODING', 'ENCODING_ERRS', 'AF_INET6',
     # connection constants
     'CONN_CLOSE', 'CONN_CLOSE_WAIT', 'CONN_CLOSING', 'CONN_ESTABLISHED',
@@ -61,8 +62,9 @@
     'pthread', 'puids', 'sconn', 'scpustats', 'sdiskio', 'sdiskpart',
     'sdiskusage', 'snetio', 'snicaddr', 'snicstats', 'sswap', 'suser',
     # utility functions
-    'conn_tmap', 'deprecated_method', 'isfile_strict', 'memoize',
-    'parse_environ_block', 'path_exists_strict', 'usage_percent',
+    'str2bytes', 'bytes2str', 'unicode2str',
+    'conn_tmap', 'deprecated_method', 'get_procfs_path', 'isfile_strict',
+    'memoize', 'parse_environ_block', 'path_exists_strict', 'usage_percent',
     'supports_ipv6', 'sockfam_to_enum', 'socktype_to_enum', "wrap_numbers",
     'bytes2human',
 ]
@@ -84,6 +86,7 @@
 BSD = FREEBSD or OPENBSD or NETBSD
 SUNOS = sys.platform.startswith(("sunos", "solaris"))
 AIX = sys.platform.startswith("aix")
+CYGWIN = sys.platform.startswith("cygwin")
 
 
 # ===================================================================
@@ -264,6 +267,61 @@ class BatteryTime(enum.IntEnum):
 # --- utils
 # ===================================================================
 
+if PY2:
+    def bytes2str(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given bytes, return a str.
+
+        On Python 2 this is a no-op since bytes is str; on Python 3 the bytes
+        are decoded using the optional encoding/errors arguments, or the
+        constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s
+
+    def str2bytes(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given a str, return bytes.
+
+        On Python 2 this is a no-op since str is bytes; on Python 3 the
+        bytes are encoding using the optional encoding/errors arguments, or
+        the constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s
+
+    def unicode2str(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given a Python 3 str or Python 2 unicode, return a str.
+
+        On Python 3 this is a no-op since str is unicode, but on Python 2
+        the unicode is encoded using the optional encoding/errors arguments,
+        or the constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s.encode(encoding, errors)
+else:
+    def bytes2str(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given bytes, return a str.
+
+        On Python 2 this is a no-op since bytes is str; on Python 3 the bytes
+        are decoded using the optional encoding/errors arguments, or the
+        constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s.decode(encoding, errors)
+
+    def str2bytes(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given a str, return bytes.
+
+        On Python 2 this is a no-op since str is bytes; on Python 3 the
+        bytes are encoding using the optional encoding/errors arguments, or
+        the constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s.encode(encoding, errors)
+
+    def unicode2str(s, encoding=ENCODING, errors=ENCODING_ERRS):
+        """Given a Python 3 str or Python 2 unicode, return a str.
+
+        On Python 3 this is a no-op since str is unicode, but on Python 2
+        the unicode is encoded using the optional encoding/errors arguments,
+        or the constants ENCODING/ENCODING_ERRS by default.
+        """
+        return s
+
 
 def usage_percent(used, total, round_=None):
     """Calculate percentage usage of 'used' against 'total'."""
@@ -366,6 +424,14 @@ def cache_deactivate(proc):
     return wrapper
 
 
+def get_procfs_path():
+    """Return updted psutil.PROCFS_PATH constant."""
+    try:
+        return sys.modules['psutil'].PROCFS_PATH
+    except AttributeError:
+        raise RuntimeError("This platform does not have a proc filesystem.")
+
+
 def isfile_strict(path):
     """Same as os.path.isfile() but does not swallow EACCES / EPERM
     exceptions, see:

psutil/_psaix.py

@@ -20,6 +20,7 @@
 from . import _psutil_aix as cext
 from . import _psutil_posix as cext_posix
 from ._common import AF_INET6
+from ._common import get_procfs_path
 from ._common import memoize_when_activated
 from ._common import NIC_DUPLEX_FULL
 from ._common import NIC_DUPLEX_HALF
@@ -101,16 +102,6 @@
 svmem = namedtuple('svmem', ['total', 'available', 'percent', 'used', 'free'])
 
 
-# =====================================================================
-# --- utils
-# =====================================================================
-
-
-def get_procfs_path():
-    """Return updated psutil.PROCFS_PATH constant."""
-    return sys.modules['psutil'].PROCFS_PATH
-
-
 # =====================================================================
 # --- memory
 # =====================================================================