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Refactored finding SWI-Prolog home
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@yuce
yuce committed Sep 22, 2024
1 parent 57ad6db commit d399f0d
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Showing 2 changed files with 97 additions and 176 deletions.
271 changes: 96 additions & 175 deletions src/pyswip/core.py
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,9 @@
from ctypes.util import find_library
from subprocess import Popen, PIPE

ENV_LIBSWIPL_PATH = "LIBSWIPL_PATH"
ENV_SWI_HOME_DIR = "SWI_HOME_DIR"


# To initialize the SWI-Prolog environment, two things need to be done: the
# first is to find where the SO/DLL is located and the second is to find the
Expand Down Expand Up @@ -153,14 +156,10 @@ def _findSwiplFromExec():
return (fullName, swiHome)


def _findSwiplWin():
import re

def _find_swipl_windows():
"""
This function uses several heuristics to gues where SWI-Prolog is installed
in Windows. It always returns None as the path of the resource file because,
in Windows, the way to find it is more robust so the SWI-Prolog DLL is
always able to find it.
in Windows.
:returns:
A tuple of (path to the swipl DLL, path to the resource file)
Expand All @@ -169,66 +168,31 @@ def _findSwiplWin():
({str, None}, {str, None})
"""

dllNames = ("swipl.dll", "libswipl.dll")
libswipl = "libswipl.dll"
# tru to get the SWI dir from registry
swi_dir = find_swipl_dir_from_registry()
if swi_dir:
# libswipl.dll must be in SWI_DIR/bin
libswipl_path = os.path.join(swi_dir, "bin", libswipl)
if not os.path.exists(libswipl_path):
raise FileNotFoundError(f"could not locate {libswipl}", libswipl_path)
return libswipl_path, swi_dir

# First try: check the usual installation path (this is faster but
# hardcoded)
programFiles = os.getenv("ProgramFiles")
paths = [os.path.join(programFiles, r"pl\bin", dllName) for dllName in dllNames]
for path in paths:
if os.path.exists(path):
return (path, None)

# Second try: use the find_library
path = _findSwiplPathFromFindLib()
if path is not None and os.path.exists(path):
return (path, None)
raise FileNotFoundError("could not locate SWI home directory")

# Third try: use reg.exe to find the installation path in the registry
# (reg should be installed in all Windows XPs)
try:
cmd = Popen(
["reg", "query", r"HKEY_LOCAL_MACHINE\Software\SWI\Prolog", "/v", "home"],
stdout=PIPE,
)
ret = cmd.communicate()

# Result is like:
# ! REG.EXE VERSION 3.0
#
# HKEY_LOCAL_MACHINE\Software\SWI\Prolog
# home REG_SZ C:\Program Files\pl
# (Note: spaces may be \t or spaces in the output)
ret = ret[0].splitlines()
ret = [line.decode("utf-8") for line in ret if len(line) > 0]
pattern = re.compile("[^h]*home[^R]*REG_SZ( |\t)*(.*)$")
match = pattern.match(ret[-1])
if match is not None:
path = match.group(2)

paths = [os.path.join(path, "bin", dllName) for dllName in dllNames]
for path in paths:
if os.path.exists(path):
return (path, None)

except OSError:
# reg.exe not found? Weird...
pass
def find_swipl_dir_from_registry():
import winreg

# May the exec is on path?
(path, swiHome) = _findSwiplFromExec()
if path is not None:
return (path, swiHome)

# Last try: maybe it is in the current dir
for dllName in dllNames:
if os.path.exists(dllName):
return (dllName, None)

return (None, None)
try:
with winreg.OpenKeyEx(winreg.HKEY_LOCAL_MACHINE, r"Software\SWI\Prolog") as key:
path, _ = winreg.QueryValueEx(key, "home")
return path
except FileNotFoundError:
return ""


def _findSwiplLin():
def _find_swipl_unix():
"""
This function uses several heuristics to guess where SWI-Prolog is
installed in Linuxes.
Expand Down Expand Up @@ -259,7 +223,7 @@ def _findSwiplLin():
"./lib",
"/usr/lib/swi-prolog/lib/x86_64-linux",
]
names = ["libswipl.so", "libpl.so"]
names = ["libswipl.so"]

path = None
for name in names:
Expand All @@ -275,39 +239,7 @@ def _findSwiplLin():
return (None, None)


def walk(path, name):
"""
This function is a 2-time recursive func,
that findin file in dirs
:parameters:
- `path` (str) - Directory path
- `name` (str) - Name of file, that we lookin for
:returns:
Path to the swipl so, path to the resource file
:returns type:
(str)
"""
back_path = path[:]
path = os.path.join(path, name)

if os.path.exists(path):
return path
else:
for dir_ in os.listdir(back_path):
path = os.path.join(back_path, dir_)

if os.path.isdir(path):
res_path = walk(path, name)
if res_path is not None:
return (res_path, back_path)

return None


def _findSwiplMacOSHome():
def find_swipl_macos_home():
"""
This function is guesing where SWI-Prolog is
installed in MacOS via .app.
Expand All @@ -322,32 +254,27 @@ def _findSwiplMacOSHome():
({str, None}, {str, None})
"""

# Need more help with MacOS
# That way works, but need more work
names = ["libswipl.dylib", "libpl.dylib"]
swi_home = os.environ.get("SWI_HOME_DIR")
if not swi_home:
swi_home = "/Applications/SWI-Prolog.app/Contents/swipl"
if os.path.exists(swi_home):
swi_base = os.path.split(swi_home)[0]
lib = find_swipl_dylib(swi_base)
if lib:
lib_path = os.path.join(swi_base, "Frameworks", lib)
return lib_path, swi_home

path = os.environ.get("SWI_HOME_DIR")
if path is None:
path = os.environ.get("SWI_LIB_DIR")
if path is None:
path = os.environ.get("PLBASE")
if path is None:
path = "/Applications/SWI-Prolog.app/Contents/"
raise FileNotFoundError("SWI-Prolog home was not found")

paths = [path]

for name in names:
for path in paths:
(path_res, back_path) = walk(path, name)
def find_swipl_dylib(root) -> str:
for item in os.listdir(root):
if item.startswith("libswipl") and item.endswith(".dylib"):
return item
return ""

if path_res is not None:
os.environ["SWI_LIB_DIR"] = back_path
return (path_res, None)

return (None, None)


def _findSwiplDar():
def _find_swipl_darwin() -> (str, str):
"""
This function uses several heuristics to guess where SWI-Prolog is
installed in MacOS.
Expand All @@ -360,29 +287,44 @@ def _findSwiplDar():
"""

# If the exec is in path
(path, swiHome) = _findSwiplFromExec()
if path is not None:
return (path, swiHome)
path, swi_home = _findSwiplFromExec()
if path:
return path, swi_home

# If it is not, use find_library
path = _findSwiplPathFromFindLib()
if path is not None:
return (path, swiHome)

# Last guess, searching for the file
paths = [".", "./lib", "/usr/lib/", "/usr/local/lib", "/opt/local/lib"]
names = ["libswipl.dylib", "libpl.dylib"]

for name in names:
for path in paths:
path = os.path.join(path, name)
if os.path.exists(path):
return (path, None)

return (None, None)


def _findSwipl():
if path:
swi_home = find_swi_home(os.path.dirname(path))
return path, swi_home

# Check the standard install path
swi_home = os.environ.get("SWI_HOME_DIR")
if not swi_home:
swi_home = "/Applications/SWI-Prolog.app/Contents/swipl"
if os.path.exists(swi_home):
swi_base = os.path.split(swi_home)[0]
lib = find_swipl_dylib(swi_base)
if lib:
lib_path = os.path.join(swi_base, "Frameworks", lib)
return lib_path, swi_home

raise FileNotFoundError("SWI-Prolog was not found")


def find_swi_home(path) -> str:
while True:
swi_home = os.path.join(path, "swipl.home")
if os.path.exists(swi_home):
with open(swi_home) as f:
sub_path = f.read().strip()
return os.path.join(path, sub_path)
path, leaf = os.path.split(path)
if not leaf:
break
return ""


def _findSwipl() -> (str, str):
"""
This function makes a big effort to find the path to the SWI-Prolog shared
library. Since this is both OS dependent and installation dependent, we may
Expand All @@ -395,41 +337,30 @@ def _findSwipl():
:rtype: Tuple of strings
:raises ImportError: If we cannot guess the name of the library
"""
# check environment
if "LIBSWIPL_PATH" in os.environ:
return (os.environ["LIBSWIPL_PATH"], os.environ.get("SWI_HOME_DIR"))
# Check the environment first
libswipl_path = os.environ.get(ENV_LIBSWIPL_PATH)
swi_home_dir = os.environ.get(ENV_SWI_HOME_DIR)
if libswipl_path and swi_home_dir:
return libswipl_path, swi_home_dir

# Now begins the guesswork
platform = sys.platform[:3]
if platform == "win": # In Windows, we have the default installer
# path and the registry to look
(path, swiHome) = _findSwiplWin()

elif platform in ("lin", "cyg"):
(path, swiHome) = _findSwiplLin()

elif platform == "dar": # Help with MacOS is welcome!!
(path, swiHome) = _findSwiplDar()

if path is None:
(path, swiHome) = _findSwiplMacOSHome()
platform = sys.platform
if platform == "win32":
libswipl_path, swi_home_dir = _find_swipl_windows()
fix_windows_path(libswipl_path)
return libswipl_path, swi_home_dir
elif platform == "darwin":
libswipl_path, swi_home_dir = _find_swipl_darwin()
if not libswipl_path:
libswipl_path, swi_home_dir = find_swipl_macos_home()
return libswipl_path, swi_home_dir

else:
# This should work for other UNIX
(path, swiHome) = _findSwiplLin()

# This is a catch all raise
if path is None:
raise ImportError(
"Could not find the SWI-Prolog library in this "
"platform. If you are sure it is installed, please "
"open an issue."
)
else:
return (path, swiHome)
# This should work for other Linux and BSD
return _find_swipl_unix()


def _fixWindowsPath(dll):
def fix_windows_path(dll):
"""
When the path to the DLL is not in Windows search path, Windows will not be
able to find other DLLs on the same directory, so we have to add it to the
Expand All @@ -439,9 +370,6 @@ def _fixWindowsPath(dll):
- `dll` (str) - File name of the DLL
"""

if sys.platform[:3] != "win":
return # Nothing to do here

pathToDll = os.path.dirname(dll)
currentWindowsPath = os.getenv("PATH")

Expand Down Expand Up @@ -574,9 +502,7 @@ def check_and_call(*args):

# Find the path and resource file. SWI_HOME_DIR shall be treated as a constant
# by users of this module
(_path, SWI_HOME_DIR) = _findSwipl()
_fixWindowsPath(_path)

_path, SWI_HOME_DIR = _findSwipl()

# Load the library
_lib = CDLL(_path, mode=RTLD_GLOBAL)
Expand All @@ -593,7 +519,6 @@ def check_and_call(*args):
PL_VERSION_VM = 6 # VM signature
PL_VERSION_BUILT_IN = 7 # Built-in predicate signature


# After SWI-Prolog 8.5.2, PL_version was renamed to PL_version_info
# to avoid a conflict with Perl. For more details, see the following:
# https://github.com/SWI-Prolog/swipl-devel/issues/900
Expand All @@ -612,15 +537,13 @@ def check_and_call(*args):
except AttributeError:
raise Exception("swi-prolog version number could not be determined")


# PySwip constants
PYSWIP_MAXSTR = 1024
c_int_p = c_void_p
c_long_p = c_void_p
c_double_p = c_void_p
c_uint_p = c_void_p


#
# constants (from SWI-Prolog.h)
# /* PL_unify_term( arguments */
Expand Down Expand Up @@ -815,7 +738,6 @@ def check_and_call(*args):

CVT_EXCEPTION = 0x00001000 # throw exception on error


argv = list_to_bytes_list(sys.argv + [None])
argc = len(sys.argv)

Expand Down Expand Up @@ -1346,7 +1268,6 @@ class IOSTREAM(Structure):
[("tee", IOSTREAM), ("mbstate", POINTER(mbstate_t)), ("reserved", intptr_t * 6)]
)


Sopen_string = _lib.Sopen_string
Sopen_string.argtypes = [POINTER(IOSTREAM), c_char_p, c_size_t, c_char_p]
Sopen_string.restype = POINTER(IOSTREAM)
Expand Down
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