[issue11258] ctypes: Speed up find_library() on Linux by 500%

[Antoine Pitrou]

Antoine Pitrou <pitrou at free.fr> added the comment:

Here is an excerpt:

	libc.so.6 (libc6,x86-64, OS ABI: Linux 2.6.9) => /lib64/libc.so.6
	libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6

The "OS ABI" thing is not always there:

	libdrm.so.2 (libc6,x86-64) => /usr/lib64/libdrm.so.2
	libdrm.so.2 (libc6) => /usr/lib/libdrm.so.2

As you see, there are two of them with the same name but in a different path. If you return the absolute path, there is a 50% possibility that you are returning the wrong one ;)

There seem to be two key differences between the original implementation and yours:
- the orig impl matches the abi_type at the beginning of the parentheses, yours simply ignores the abi_type (that should have caught my eye, but that regex looked so much like magic that I didn't try to make sense of it :-))
- the orig impl returns the file name from the beginning of the matched line, yours returns the full path from the end of the line

I guess it should be doable to retain the speed benefit while implementing a matching algorithm closer to the original one.

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue11258>
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