api: Cygwin compatibility

wand/api.py

@@ -14,11 +14,38 @@
 import platform
 import sys
 import traceback
-if platform.system() == "Windows":
- try:
- import winreg
- except ImportError:
- import _winreg as winreg
+
+def _is_windows():
+ """Python on Windows hatch in different nests. Some are more Unix
+ than others.
+
+ :returns: A pair of ``<Bool, Maybe<str>>`` type. The first element
+ indicates Windows-ness; the second gives a string for
+ replacement "lib" prefix when the platform is Unix-y.
+ :rtype: :class:`tuple`
+ """
+ system = platform.system()
+ if system == "Windows":
+ return (True, False)
+ if system.startswith('CYGWIN_NT-'):
+ return (True, "cyg")
+ if system.startswith('MSYS_NT-'):
+ return (True, "msys-")
+ else:
+ return (False, False)
+
+is_windows = _is_windows()
+
+if is_windows[0]:
+ for winregmod in ['winreg', '_winreg', 'cygwinreg']:
+ try:
+ winreg = __import__(winregmod)
+ except ImportError:
+ pass
+ else:
+ winreg = None
+else:
+ winreg = None
 
 __all__ = ('MagickPixelPacket', 'PointInfo', 'AffineMatrix', 'c_magick_char_p',
  'library', 'libc', 'libmagick', 'load_library')
@@ -60,26 +87,31 @@ def library_paths():
  system = platform.system()
  magick_home = os.environ.get('MAGICK_HOME')
 
- if system == 'Windows':
+ if winreg:
  # ImageMagick installers normally install coder and filter DLLs in
  # subfolders, we need to add those folders to PATH, otherwise loading
  # the DLL later will fail.
+ #
+ # We prepend those paths to PATH so that ImageMagick will be sure to
+ # use those DLLs. Since ctype looks in PATH, we can save magick_home
+ # for the actual environment variable.
  try:
  with winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE,
  r"SOFTWARE\ImageMagick\Current") as reg_key:
  libPath = winreg.QueryValueEx(reg_key, "LibPath")
  coderPath = winreg.QueryValueEx(reg_key, "CoderModulesPath")
  filterPath = winreg.QueryValueEx(reg_key, "FilterModulesPath")
- magick_home = libPath[0]
- os.environ['PATH'] += (';' + libPath[0] + ";" +
-  coderPath[0] + ";" + filterPath[0])
+ pathSep = ';' if is_windows[1] == False else ':'
+ os.environ['PATH'] = (pathSep.join((libPath[0], coderPath[0], filterPath[0])) + 
+ os.environ['PATH'])
  except OSError:
- # otherwise use MAGICK_HOME, and we assume the coder and
+ # otherwise do nothing; we assume the coder and
  # filter DLLs are in the same directory
  pass
 
  def magick_path(path):
  return os.path.join(magick_home, *path)
+
  combinations = itertools.product(versions, options)
  suffixes = (version + option for version, option in combinations)
  if magick_home:
@@ -92,9 +124,20 @@ def magick_path(path):
  libwand = 'CORE_RL_wand_{0}.dll'.format(suffix),
  libmagick = 'CORE_RL_magick_{0}.dll'.format(suffix),
  yield magick_path(libwand), magick_path(libmagick)
- libwand = 'libMagickWand{0}.dll'.format(suffix),
- libmagick = 'libMagickCore{0}.dll'.format(suffix),
- yield magick_path(libwand), magick_path(libmagick)
+
+ # Prioritize the Unix-y instance
+ if is_windows[1] != False:
+ prefixes = (is_windows[1], 'lib')
+ else:
+ prefixes = ('lib',)
+
+ for prefix in prefixes:
+ libwand = '{1}MagickWand{0}.dll'.format(suffix, prefix),
+ libmagick = '{1}MagickCore{0}.dll'.format(suffix, prefix),
+ # "lib" (or other prefixes) are used for MinGW/Cygwin/MSYS
+ # builds, which may have a "bin" hierarchy over the DLLs. Add twice.
+ yield magick_path(libwand), magick_path(libmagick)
+ yield magick_path('bin', libwand), magick_path('bin', libmagick)
  elif system == 'Darwin':
  libwand = 'lib', 'libMagickWand{0}.dylib'.format(suffix),
  yield magick_path(libwand), magick_path(libwand)
@@ -107,11 +150,14 @@ def magick_path(path):
  libmagick = ctypes.util.find_library('CORE_RL_magick_' + suffix)
  yield libwand, libmagick
  libwand = ctypes.util.find_library('libMagickWand' + suffix)
- libmagick = ctypes.util.find_library('libMagickCore' + suffix)
+ libmagick = ctypes.util.find_library('libMagickCore' + suffix) or libwand
  yield libwand, libmagick
+ # On Cygwin-like systems, find_library function normally with the prefixes.
+ # But libmagick is split (totally legit), so let's do a "or" fallback instead:
  else:
  libwand = ctypes.util.find_library('MagickWand' + suffix)
- yield libwand, libwand
+ libmagick = ctypes.util.find_library('MagickCore' + suffix) or libwand
+ yield libwand, libmagick
 
 
 def load_library():
@@ -1422,10 +1468,13 @@ class AffineMatrix(ctypes.Structure):
  except OSError:
  # In case of El Capitan SIP
  libc = ctypes.cdll.LoadLibrary('/usr/lib/libc.dylib')
- elif sys.platform.startswith(('dragonfly', 'freebsd')):
- libc = ctypes.cdll.LoadLibrary(ctypes.util.find_library('c'))
  else:
- libc = ctypes.cdll.LoadLibrary('libc.so.6')
+ try:
+ # Theoretically correct for all *nix, including Darwin
+ libc = ctypes.cdll.LoadLibrary(ctypes.util.find_library('c'))
+ except OSError:
+ # Hardcode a Linux case
+ libc = ctypes.cdll.LoadLibrary('libc.so.6')
  libc.fdopen.argtypes = [ctypes.c_int, ctypes.c_char_p]
  libc.fdopen.restype = ctypes.c_void_p
  libc.fflush.argtypes = [ctypes.c_void_p]