"""SCons.Scanner.C

This module implements the depenency scanner for C/C++ code. 

"""

#
# Copyright (c) 2001 Steven Knight
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#

__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"


import SCons.Scanner
import re
import os.path
import SCons.Util

angle_re = re.compile('^[ \t]*#[ \t]*include[ \t]+<([\\w./\\\\]+)>', re.M)
quote_re = re.compile('^[ \t]*#[ \t]*include[ \t]+"([\\w./\\\\]+)"', re.M)

def CScan():
    "Return a prototype Scanner instance for scanning C/C++ source files"
    return SCons.Scanner.Recursive(scan, "CScan",
                                   SCons.Node.FS.default_fs.File,
                                   [".c", ".C", ".cxx", ".cpp", ".c++",
                                    ".h", ".H", ".hxx", ".hpp"])

def scan(filename, env, node_factory):
    """
    scan(str, Environment) -> [str]

    the C/C++ dependency scanner function

    This function is intentionally simple. There are two rules it
    follows:
    
    1) #include <foo.h> - search for foo.h in CPPPATH followed by the
        directory 'filename' is in
    2) #include \"foo.h\" - search for foo.h in the directory 'filename' is
       in followed by CPPPATH

    These rules approximate the behaviour of most C/C++ compilers.

    This scanner also ignores #ifdef and other preprocessor conditionals, so
    it may find more depencies than there really are, but it never misses
    dependencies.
    """

    try:
        paths = env.Dictionary("CPPPATH")
    except KeyError:
        paths = []

    try:
        file = open(filename)
        contents = file.read()
        file.close()

        angle_includes = angle_re.findall(contents)
        quote_includes = quote_re.findall(contents)

        source_dir = os.path.dirname(filename)
        
        return (SCons.Util.find_files(angle_includes, paths + [source_dir],
                                      node_factory)
                + SCons.Util.find_files(quote_includes, [source_dir] + paths,
                                        node_factory))
    except OSError:
        return []