"""Routine to "compile" a .py file to a .pyc (or .pyo) file.

This module has intimate knowledge of the format of .pyc files.

"""

import __builtin__

import imp

import marshal

import os

import sys

import traceback

MAGIC = imp.get_magic()

__all__ = ["compile", "main", "PyCompileError"]

class PyCompileError(Exception):

    """Exception raised when an error occurs while attempting to

    compile the file.

    To raise this exception, use

        raise PyCompileError(exc_type,exc_value,file[,msg])

    where

        exc_type:   exception type to be used in error message

                    type name can be accesses as class variable

                    'exc_type_name'

        exc_value:  exception value to be used in error message

                    can be accesses as class variable 'exc_value'

        file:       name of file being compiled to be used in error message

                    can be accesses as class variable 'file'

        msg:        string message to be written as error message

                    If no value is given, a default exception message will be given,

                    consistent with 'standard' py_compile output.

                    message (or default) can be accesses as class variable 'msg'

    """

    def __init__(self, exc_type, exc_value, file, msg=''):

        exc_type_name = exc_type.__name__

        if exc_type is SyntaxError:

            tbtext = ''.join(traceback.format_exception_only(exc_type, exc_value))

            errmsg = tbtext.replace('File "<string>"', 'File "%s"' % file)

        else:

            errmsg = "Sorry: %s: %s" % (exc_type_name,exc_value)

        Exception.__init__(self,msg or errmsg,exc_type_name,exc_value,file)

        self.exc_type_name = exc_type_name

        self.exc_value = exc_value

        self.file = file

        self.msg = msg or errmsg

    def __str__(self):

        return self.msg

# Define an internal helper according to the platform

if os.name == "mac":

    import MacOS

    def set_creator_type(file):

        MacOS.SetCreatorAndType(file, 'Pyth', 'PYC ')

else:

    def set_creator_type(file):

        pass

def wr_long(f, x):

    """Internal; write a 32-bit int to a file in little-endian order."""

    f.write(chr( x        & 0xff))

    f.write(chr((x >> 8)  & 0xff))

    f.write(chr((x >> 16) & 0xff))

    f.write(chr((x >> 24) & 0xff))

def compile(file, cfile=None, dfile=None, doraise=False):

    """Byte-compile one Python source file to Python bytecode.

    Arguments:

    file:    source filename

    cfile:   target filename; defaults to source with 'c' or 'o' appended

             ('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)

    dfile:   purported filename; defaults to source (this is the filename

             that will show up in error messages)

    doraise: flag indicating whether or not an exception should be

             raised when a compile error is found. If an exception

             occurs and this flag is set to False, a string

             indicating the nature of the exception will be printed,

             and the function will return to the caller. If an

             exception occurs and this flag is set to True, a

             PyCompileError exception will be raised.

    Note that it isn't necessary to byte-compile Python modules for

    execution efficiency -- Python itself byte-compiles a module when

    it is loaded, and if it can, writes out the bytecode to the

    corresponding .pyc (or .pyo) file.

    However, if a Python installation is shared between users, it is a

    good idea to byte-compile all modules upon installation, since

    other users may not be able to write in the source directories,

    and thus they won't be able to write the .pyc/.pyo file, and then

    they would be byte-compiling every module each time it is loaded.

    This can slow down program start-up considerably.

    See compileall.py for a script/module that uses this module to

    byte-compile all installed files (or all files in selected

    directories).

    """

    f = open(file, 'U')

    try:

        timestamp = long(os.fstat(f.fileno()).st_mtime)

    except AttributeError:

        timestamp = long(os.stat(file).st_mtime)

    codestring = f.read()

    f.close()

    if codestring and codestring[-1] != '\n':

        codestring = codestring + '\n'

    try:

        codeobject = __builtin__.compile(codestring, dfile or file,'exec')

    except Exception,err:

        py_exc = PyCompileError(err.__class__,err.args,dfile or file)

        if doraise:

            raise py_exc

        else:

            sys.stderr.write(py_exc.msg + '\n')

            return

    if cfile is None:

        cfile = file + (__debug__ and 'c' or 'o')

    fc = open(cfile, 'wb')

    fc.write('\0\0\0\0')

    wr_long(fc, timestamp)

    marshal.dump(codeobject, fc)

    fc.flush()

    fc.seek(0, 0)

    fc.write(MAGIC)

    fc.close()

    set_creator_type(cfile)

def main(args=None):

    """Compile several source files.

    The files named in 'args' (or on the command line, if 'args' is

    not specified) are compiled and the resulting bytecode is cached

    in the normal manner.  This function does not search a directory

    structure to locate source files; it only compiles files named

    explicitly.

    """

    if args is None:

        args = sys.argv[1:]

    for filename in args:

        try:

            compile(filename, doraise=True)

        except PyCompileError,err:

            sys.stderr.write(err.msg)

if __name__ == "__main__":

    main()