tests/readlink.py

dirstate: use a presized dict for the dirstate

This uses a simple heuristic to avoid expensive resizes.

On a real-world repo with around 400,000 files, perfdirstate:

before: ! wall 0.155562 comb 0.160000 user 0.150000 sys 0.010000 (best of 64)
after:  ! wall 0.132638 comb 0.130000 user 0.120000 sys 0.010000 (best of 75)

On another real-world repo with around 250,000 files:

before: ! wall 0.098459 comb 0.100000 user 0.090000 sys 0.010000 (best of 100)
after:  ! wall 0.089084 comb 0.090000 user 0.080000 sys 0.010000 (best of 100)

#!/usr/bin/env python

import errno, os, sys

for f in sys.argv[1:]:
    try:
        print f, '->', os.readlink(f)
    except OSError, err:
        if err.errno != errno.EINVAL:
            raise
        print f, 'not a symlink'

sys.exit(0)