# Check for a module in a set of extension directories.
# An extension directory should contain a Setup file
# and one or more .o files or a lib.a file.

import os
import parsesetup

def checkextensions(unknown, extensions):
 files = []
 modules = []
 edict = {}
 for e in extensions:
 setup = os.path.join(e, 'Setup')
 liba = os.path.join(e, 'lib.a')
 if not os.path.isfile(liba):
 liba = None
 edict[e] = parsesetup.getsetupinfo(setup), liba
 for mod in unknown:
 for e in extensions:
 (mods, vars), liba = edict[e]
 if mod not in mods:
 continue
 modules.append(mod)
 if liba:
 # If we find a lib.a, use it, ignore the
 # .o files, and use *all* libraries for
 # *all* modules in the Setup file
 if liba in files:
 break
 files.append(liba)
 for m in list(mods.keys()):
 files = files + select(e, mods, vars,
 m, 1)
 break
 files = files + select(e, mods, vars, mod, 0)
 break
 return files, modules

def select(e, mods, vars, mod, skipofiles):
 files = []
 for w in mods[mod]:
 w = treatword(w)
 if not w:
 continue
 w = expandvars(w, vars)
 for w in w.split():
 if skipofiles and w[-2:] == '.o':
 continue
 # Assume $var expands to absolute pathname
 if w[0] not in ('-', '$') and w[-2:] in ('.o', '.a'):
 w = os.path.join(e, w)
 if w[:2] in ('-L', '-R') and w[2:3] != '$':
 w = w[:2] + os.path.join(e, w[2:])
 files.append(w)
 return files

cc_flags = ['-I', '-D', '-U']
cc_exts = ['.c', '.C', '.cc', '.c++']

def treatword(w):
 if w[:2] in cc_flags:
 return None
 if w[:1] == '-':
 return w # Assume loader flag
 head, tail = os.path.split(w)
 base, ext = os.path.splitext(tail)
 if ext in cc_exts:
 tail = base + '.o'
 w = os.path.join(head, tail)
 return w

def expandvars(str, vars):
 i = 0
 while i < len(str):
 i = k = str.find('$', i)
 if i < 0:
 break
 i = i+1
 var = str[i:i+1]
 i = i+1
 if var == '(':
 j = str.find(')', i)
 if j < 0:
 break
 var = str[i:j]
 i = j+1
 if var in vars:
 str = str[:k] + vars[var] + str[i:]
 i = k
 return str