gh-114099 - Add iOS framework loading machinery.

Doc/library/importlib.rst

@@ -1241,6 +1241,74 @@ find and load modules.
     and how the module's :attr:`__file__` is populated.
 
 
+.. class:: AppleFrameworkLoader(fullname, dylib_path, parent_paths=None)
+
+   A specialization of :class:`importlib.machinery.ExtensionFileLoader` that
+   is able to load extension modules in Framework format.
+
+   For compatibility with the iOS App Store, *all* binary modules in an iOS app
+   must be ``.dylib objects``, contained in a framework with appropriate
+   metadata, stored in the ``Frameworks`` folder of the packaged app. There can
+   be only a single binary per framework, and there can be no executable binary
+   material outside the Frameworks folder.
+
+   If you're trying to run ``from foo.bar import _whiz``, and ``_whiz`` is
+   implemented with the binary module ``foo/bar/_whiz.abi3.dylib`` (or any
+   other ABI .dylib extension), this loader will look for
+   ``{sys.executable}/Frameworks/foo.bar._whiz.framework/_whiz.abi3.dylib``
+   (forming the package name by taking the full import path of the library,
+   and replacing ``/`` with ``.``).
+
+   However, this loader will re-write the ``__file__`` attribute of the
+   ``_whiz`` module will report as the original location inside the ``foo/bar``
+   subdirectory. This so that code that depends on walking directory trees will
+   continue to work as expected based on the *original* file location.
+
+   The *fullname* argument specifies the name of the module the loader is to
+   support. The *dylib_path* argument is the path to the framework's ``.dylib``
+   file. The ``parent_paths`` is the path or paths that was searched to find
+   the extension module.
+
+   .. versionadded:: 3.13
+
+   .. availability:: iOS.
+
+   .. attribute:: fullname
+
+      Name of the module the loader supports.
+
+   .. attribute:: dylib_path
+
+      Path to the ``.dylib`` file in the framework.
+
+   .. attribute:: parent_paths
+
+      The parent paths that were originally searched to find the module.
+
+.. class:: AppleFrameworkFinder(framework_path)
+
+   An extension module finder which is able to load extension modules packaged
+   as frameworks in an iOS app.
+
+   See the documentation for :class:`AppleFrameworkLoader` for details on the
+   requirements of binary extension modules on iOS.
+
+   The *framework_path* argument is the Frameworks directory for the app.
+
+   .. versionadded:: 3.13
+
+   .. availability:: iOS.
+
+   .. attribute:: framework_path
+
+      The path the finder will search for frameworks.
+
+   .. method:: find_spec(fullname, paths, target=None)
+
+      Attempt to find the spec to handle ``fullname``, imported from one
+      of the filesystem locations described by ``paths``.
+
+
 :mod:`importlib.util` -- Utility code for importers
 ---------------------------------------------------
 

Doc/tools/extensions/pyspecific.py

@@ -133,7 +133,7 @@ class Availability(SphinxDirective):
     known_platforms = frozenset({
         "AIX", "Android", "BSD", "DragonFlyBSD", "Emscripten", "FreeBSD",
         "GNU/kFreeBSD", "Linux", "NetBSD", "OpenBSD", "POSIX", "Solaris",
-        "Unix", "VxWorks", "WASI", "Windows", "macOS",
+        "Unix", "VxWorks", "WASI", "Windows", "macOS", "iOS",
         # libc
         "BSD libc", "glibc", "musl",
         # POSIX platforms with pthreads

Lib/importlib/_bootstrap_external.py

@@ -1713,12 +1713,13 @@ def __repr__(self):
 
 class AppleFrameworkLoader(ExtensionFileLoader):
     """A loader for modules that have been packaged as frameworks for
-    compatibility with Apple's App Store policies.
+    compatibility with Apple's iOS App Store policies.
 
-    For compatibility with the App Store, *all* binary modules must be .dylib
-    objects, contained in a framework, stored in the ``Frameworks`` folder of
-    the packaged app. There can be only a single binary per framework, and
-    there can be no executable binary material outside the Frameworks folder.
+    For compatibility with the iOS App Store, *all* binary modules in an iOS
+    app must be .dylib objects, contained in a framework with appropriate
+    metadata, stored in the ``Frameworks`` folder of the packaged app. There
+    can be only a single binary per framework, and there can be no executable
+    binary material outside the Frameworks folder.
 
     If you're trying to run ``from foo.bar import _whiz``, and ``_whiz`` is
     implemented with the binary module ``foo/bar/_whiz.abi3.dylib`` (or any
@@ -1739,9 +1740,9 @@ class AppleFrameworkLoader(ExtensionFileLoader):
     be done with a build step in the Xcode project; see the iOS documentation
     for details on how to construct this build step.
     """
-    def __init__(self, fullname, dylib_file, path=None):
+    def __init__(self, fullname, dylib_file, parent_paths=None):
         super().__init__(fullname, dylib_file)
-        self.parent_paths = path
+        self.parent_paths = parent_paths
 
     def create_module(self, spec):
         mod = super().create_module(spec)
@@ -1752,7 +1753,7 @@ def create_module(self, spec):
                         parent_path,
                         _path_split(self.path)[-1],
                     )
-                    continue
+                    break
         return mod
 
 
@@ -1762,23 +1763,23 @@ class AppleFrameworkFinder:
 
     See AppleFrameworkLoader for details.
     """
-    def __init__(self, path):
-        self.frameworks_path = path
+    def __init__(self, frameworks_path):
+        self.frameworks_path = frameworks_path
 
-    def find_spec(self, fullname, path, target=None):
+    def find_spec(self, fullname, paths, target=None):
         name = fullname.split(".")[-1]
 
         for extension in EXTENSION_SUFFIXES:
-            dylib_file = _path_join(self.frameworks_path, f"{fullname}.framework", f"{name}{extension}")
+            dylib_file = _path_join(
+                self.frameworks_path,
+                f"{fullname}.framework", f"{name}{extension}"
+            )
             _bootstrap._verbose_message("Looking for Apple Framework dylib {}", dylib_file)
-            try:
-                dylib_exists = _path_isfile(dylib_file)
-            except ValueError:
-                pass
-            else:
-                if dylib_exists:
-                    loader = AppleFrameworkLoader(fullname, dylib_file, path)
-                    return _bootstrap.spec_from_loader(fullname, loader)
+
+            dylib_exists = _path_isfile(dylib_file)
+            if dylib_exists:
+                loader = AppleFrameworkLoader(fullname, dylib_file, paths)
+                return _bootstrap.spec_from_loader(fullname, loader)
 
         return None
 

Python/dynload_shlib.c

@@ -42,13 +42,9 @@ const char *_PyImport_DynLoadFiletab[] = {
 #ifdef __CYGWIN__
     ".dll",
 #else  /* !__CYGWIN__ */
-#  ifdef __APPLE__
-//   TARGET_OS_IPHONE covers any non-macOS Apple platform.
-#    if TARGET_OS_IPHONE
-#      define SHLIB_SUFFIX ".dylib"
-#    else
-#      define SHLIB_SUFFIX ".so"
-#    endif
+// TARGET_OS_IPHONE covers any non-macOS Apple platform.
+#  if defined(__APPLE__) && TARGET_OS_IPHONE
+#    define SHLIB_SUFFIX ".dylib"
 #  else
 #    define SHLIB_SUFFIX ".so"
 #  endif