]> git.rkrishnan.org Git - tahoe-lafs/tahoe-lafs.git/blobdiff - src/allmydata/util/fileutil.py
Improved error handling and cosmetics for ctypes calls on Windows.
[tahoe-lafs/tahoe-lafs.git] / src / allmydata / util / fileutil.py
index 74132733169f306f8feb668f565d547f9b6f4df9..152cae0bb82860844dbbb77fe567a54d74332352 100644 (file)
@@ -4,6 +4,11 @@ Futz with files like a pro.
 
 import sys, exceptions, os, stat, tempfile, time, binascii
 
+if sys.platform == "win32":
+    from ctypes import WINFUNCTYPE, WinError, windll, POINTER, byref, c_ulonglong, \
+        create_unicode_buffer, get_last_error
+    from ctypes.wintypes import BOOL, DWORD, LPCWSTR, LPWSTR
+
 from twisted.python import log
 
 from pycryptopp.cipher.aes import AES
@@ -87,34 +92,6 @@ class ReopenableNamedTemporaryFile:
     def shutdown(self):
         remove(self.name)
 
-class NamedTemporaryDirectory:
-    """
-    This calls tempfile.mkdtemp(), stores the name of the dir in
-    self.name, and rmrf's the dir when it gets garbage collected or
-    "shutdown()".
-    """
-    def __init__(self, cleanup=True, *args, **kwargs):
-        """ If cleanup, then the directory will be rmrf'ed when the object is shutdown. """
-        self.cleanup = cleanup
-        self.name = tempfile.mkdtemp(*args, **kwargs)
-
-    def __repr__(self):
-        return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
-
-    def __str__(self):
-        return self.__repr__()
-
-    def __del__(self):
-        try:
-            self.shutdown()
-        except:
-            import traceback
-            traceback.print_exc()
-
-    def shutdown(self):
-        if self.cleanup and hasattr(self, 'name'):
-            rm_dir(self.name)
-
 class EncryptedTemporaryFile:
     # not implemented: next, readline, readlines, xreadlines, writelines
 
@@ -318,10 +295,14 @@ def abspath_expanduser_unicode(path, base=None):
     path = expanduser(path)
 
     if _getfullpathname:
-        # On Windows, os.path.isabs will return True for paths without a drive letter,
+        # On Windows, os.path.isabs will incorrectly return True
+        # for paths without a drive letter (that are not UNC paths),
         # e.g. "\\". See <http://bugs.python.org/issue1669539>.
         try:
-            path = _getfullpathname(path or u".")
+            if base is None:
+                path = _getfullpathname(path or u".")
+            else:
+                path = _getfullpathname(os.path.join(base, path))
         except OSError:
             pass
 
@@ -359,23 +340,21 @@ def to_windows_long_path(path):
 
 have_GetDiskFreeSpaceExW = False
 if sys.platform == "win32":
-    from ctypes import WINFUNCTYPE, windll, POINTER, byref, c_ulonglong, create_unicode_buffer
-    from ctypes.wintypes import BOOL, DWORD, LPCWSTR, LPWSTR
-
-    # <http://msdn.microsoft.com/en-us/library/ms679360%28v=VS.85%29.aspx>
-    GetLastError = WINFUNCTYPE(DWORD)(("GetLastError", windll.kernel32))
-
     # <http://msdn.microsoft.com/en-us/library/windows/desktop/ms683188%28v=vs.85%29.aspx>
-    GetEnvironmentVariableW = WINFUNCTYPE(DWORD, LPCWSTR, LPWSTR, DWORD)(
-        ("GetEnvironmentVariableW", windll.kernel32))
+    GetEnvironmentVariableW = WINFUNCTYPE(
+        DWORD,  LPCWSTR, LPWSTR, DWORD,
+        use_last_error=True
+    )(("GetEnvironmentVariableW", windll.kernel32))
 
     try:
         # <http://msdn.microsoft.com/en-us/library/aa383742%28v=VS.85%29.aspx>
         PULARGE_INTEGER = POINTER(c_ulonglong)
 
         # <http://msdn.microsoft.com/en-us/library/aa364937%28VS.85%29.aspx>
-        GetDiskFreeSpaceExW = WINFUNCTYPE(BOOL, LPCWSTR, PULARGE_INTEGER, PULARGE_INTEGER, PULARGE_INTEGER)(
-            ("GetDiskFreeSpaceExW", windll.kernel32))
+        GetDiskFreeSpaceExW = WINFUNCTYPE(
+            BOOL,  LPCWSTR, PULARGE_INTEGER, PULARGE_INTEGER, PULARGE_INTEGER,
+            use_last_error=True
+        )(("GetDiskFreeSpaceExW", windll.kernel32))
 
         have_GetDiskFreeSpaceExW = True
     except Exception:
@@ -392,27 +371,39 @@ def expanduser(path):
 def windows_expanduser(path):
     if not path.startswith('~'):
         return path
-    home_drive = windows_getenv(u'HOMEDRIVE')
-    home_path = windows_getenv(u'HOMEPATH')
+
+    home_dir = windows_getenv(u'USERPROFILE')
+    if home_dir is None:
+        home_drive = windows_getenv(u'HOMEDRIVE')
+        home_path = windows_getenv(u'HOMEPATH')
+        if home_drive is None or home_path is None:
+            raise OSError("Could not find home directory: neither %USERPROFILE% nor (%HOMEDRIVE% and %HOMEPATH%) are set.")
+        home_dir = os.path.join(home_drive, home_path)
+
     if path == '~':
-        return os.path.join(home_drive, home_path)
+        return home_dir
     elif path.startswith('~/') or path.startswith('~\\'):
-        return os.path.join(home_drive, home_path, path[2 :])
+        return os.path.join(home_dir, path[2 :])
     else:
         return path
 
+# <https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382%28v=vs.85%29.aspx>
+ERROR_ENVVAR_NOT_FOUND = 203
+
 def windows_getenv(name):
     # Based on <http://stackoverflow.com/questions/2608200/problems-with-umlauts-in-python-appdata-environvent-variable/2608368#2608368>,
-    # with improved error handling.
+    # with improved error handling. Returns None if there is no enivronment variable of the given name.
     if not isinstance(name, unicode):
         raise AssertionError("name must be Unicode")
 
     n = GetEnvironmentVariableW(name, None, 0)
     # GetEnvironmentVariableW returns DWORD, so n cannot be negative.
     if n == 0:
-        err = GetLastError()
-        raise OSError("Windows error %d attempting to read size of environment variable %r"
-                      % (err, name))
+        err = get_last_error()
+        if err == ERROR_ENVVAR_NOT_FOUND:
+            return None
+        raise OSError("WinError: %s\n attempting to read size of environment variable %r"
+                      % (WinError(err), name))
     if n == 1:
         # Avoid an ambiguity between a zero-length string and an error in the return value of the
         # call to GetEnvironmentVariableW below.
@@ -421,9 +412,11 @@ def windows_getenv(name):
     buf = create_unicode_buffer(u'\0'*n)
     retval = GetEnvironmentVariableW(name, buf, n)
     if retval == 0:
-        err = GetLastError()
-        raise OSError("Windows error %d attempting to read environment variable %r"
-                      % (err, name))
+        err = get_last_error()
+        if err == ERROR_ENVVAR_NOT_FOUND:
+            return None
+        raise OSError("WinError: %s\n attempting to read environment variable %r"
+                      % (WinError(err), name))
     if retval >= n:
         raise OSError("Unexpected result %d (expected less than %d) from GetEnvironmentVariableW attempting to read environment variable %r"
                       % (retval, n, name))
@@ -465,8 +458,8 @@ def get_disk_stats(whichdir, reserved_space=0):
                                                byref(n_total),
                                                byref(n_free_for_root))
         if retval == 0:
-            raise OSError("Windows error %d attempting to get disk statistics for %r"
-                          % (GetLastError(), whichdir))
+            raise OSError("WinError: %s\n attempting to get disk statistics for %r"
+                          % (WinError(get_last_error()), whichdir))
         free_for_nonroot = n_free_for_nonroot.value
         total            = n_total.value
         free_for_root    = n_free_for_root.value