[PATCH 0 of 2] Pure python fallback for base85

[Brendan Cully]

On Tuesday, 30 December 2008 at 19:00, Brendan Cully wrote:
> This set of patches includes a pure python base85 implementation as
> well as a simple mechanism for allowing pure python fallbacks for C
> extensions. Fallbacks should call util.allowfallbacks before doing
> anything else. This function checks whether the environment variable
> HGALLOWFALLBACKS is 1, y, yes, or true and aborts with a warning if
> not.
> 
> I looked into setting up fallbacks at install time instead of checking
> at run time but it seemed to require some trickier distutils hacking,
> so I'm posting this simple approach for posterity. The advantage of
> doing things at install time is no environment variable would be
> needed. On the other hand, it makes it easier for a clueless sysadmin
> to set up a slow hg without making it obvious to her users.

Here's a hack to setup.py to build fallbacks when called with a --pure
argument. I wouldn't be surprised if it missed some corner cases
though.

-------------- next part --------------
# HG changeset patch
# User Brendan Cully <brendan at kublai.com>
# Date 1230705272 28800
# Node ID 075491b14c8a1d0e44c54229a26c45a477b3be6c
# Parent  acaa1a660c60aee940e749a6497b763e70d0640d
setup: install pure python when --pure is specified

diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -14,6 +14,7 @@
 import tempfile
 from distutils.core import setup, Extension
 from distutils.command.install_data import install_data
+from distutils.command.build_py import build_py
 from distutils.ccompiler import new_compiler
 
 import mercurial.version
@@ -23,6 +24,12 @@
 if os.name == 'nt':
     scripts.append('contrib/win32/hg.bat')
 
+if sys.argv[1] == '--pure':
+    sys.argv.pop(1)
+    pureinstall = True
+else:
+    pureinstall = False
+
 # simplified version of distutils.ccompiler.CCompiler.has_function
 # that actually removes its temporary files.
 def has_function(cc, funcname):
@@ -97,7 +104,7 @@
     Extension('mercurial.mpatch', ['mercurial/mpatch.c']),
     Extension('mercurial.parsers', ['mercurial/parsers.c']),
     ]
-
+py_modules=[]
 packages = ['mercurial', 'mercurial.hgweb', 'hgext', 'hgext.convert',
             'hgext.highlight', 'hgext.zeroconf', ]
 
@@ -111,7 +118,7 @@
     import posix
     ext_modules.append(Extension('mercurial.osutil', ['mercurial/osutil.c']))
 
-    if sys.platform == 'linux2' and os.uname()[2] > '2.6':
+    if sys.platform == 'linux2' and os.uname()[2] > '2.6' and not pureinstall:
         # The inotify extension is only usable with Linux 2.6 kernels.
         # You also need a reasonably recent C library.
         cc = new_compiler()
@@ -122,6 +129,25 @@
 except ImportError:
     pass
 
+if pureinstall:
+    class hg_build_py(build_py):
+        def find_modules(self):
+            modules = build_py.find_modules(self)
+            newmods = []
+            for mod in modules:
+                if not mod[0].startswith('fallbacks.'):
+                    newmods.append(mod)
+                    continue
+                if mod[1] == '__init__':
+                    continue
+                # strip 'fallbacks.' prefix
+                newmods.append((mod[0][10:], mod[1], mod[2]))
+            return newmods
+
+    cmdclass['build_py'] = hg_build_py
+    py_modules.extend(['fallbacks.' + ext.name for ext in ext_modules])
+    ext_modules = []
+
 setup(name='mercurial',
       version=mercurial.version.get_version(),
       author='Matt Mackall',
@@ -131,6 +157,7 @@
       license='GNU GPL',
       scripts=scripts,
       packages=packages,
+      py_modules=py_modules,
       ext_modules=ext_modules,
       data_files=[(os.path.join('mercurial', root),
                    [os.path.join(root, file_) for file_ in files])