1"""Routine to "compile" a .py file to a .pyc (or .pyo) file.
2
3This module has intimate knowledge of the format of .pyc files.
4"""
5
6import _py_compile
7import os
8import sys
9import traceback
10
11__all__ = ["compile", "main", "PyCompileError"]
12
13
14class PyCompileError(Exception):
15    """Exception raised when an error occurs while attempting to
16    compile the file.
17
18    To raise this exception, use
19
20        raise PyCompileError(exc_type,exc_value,file[,msg])
21
22    where
23
24        exc_type:   exception type to be used in error message
25                    type name can be accesses as class variable
26                    'exc_type_name'
27
28        exc_value:  exception value to be used in error message
29                    can be accesses as class variable 'exc_value'
30
31        file:       name of file being compiled to be used in error message
32                    can be accesses as class variable 'file'
33
34        msg:        string message to be written as error message
35                    If no value is given, a default exception message will be given,
36                    consistent with 'standard' py_compile output.
37                    message (or default) can be accesses as class variable 'msg'
38
39    """
40
41    def __init__(self, exc_type, exc_value, file, msg=''):
42        exc_type_name = exc_type.__name__
43        if exc_type is SyntaxError:
44            tbtext = ''.join(traceback.format_exception_only(exc_type, exc_value))
45            errmsg = tbtext.replace('File "<string>"', 'File "%s"' % file)
46        else:
47            errmsg = "Sorry: %s: %s" % (exc_type_name,exc_value)
48
49        Exception.__init__(self,msg or errmsg,exc_type_name,exc_value,file)
50
51        self.exc_type_name = exc_type_name
52        self.exc_value = exc_value
53        self.file = file
54        self.msg = msg or errmsg
55
56    def __str__(self):
57        return self.msg
58
59
60def compile(file, cfile=None, dfile=None, doraise=False):
61    """Byte-compile one Python source file to Python bytecode.
62
63    Arguments:
64
65    file:    source filename
66    cfile:   target filename; defaults to source with 'c' or 'o' appended
67             ('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)
68    dfile:   purported filename; defaults to source (this is the filename
69             that will show up in error messages)
70    doraise: flag indicating whether or not an exception should be
71             raised when a compile error is found. If an exception
72             occurs and this flag is set to False, a string
73             indicating the nature of the exception will be printed,
74             and the function will return to the caller. If an
75             exception occurs and this flag is set to True, a
76             PyCompileError exception will be raised.
77
78    Note that it isn't necessary to byte-compile Python modules for
79    execution efficiency -- Python itself byte-compiles a module when
80    it is loaded, and if it can, writes out the bytecode to the
81    corresponding .pyc (or .pyo) file.
82
83    However, if a Python installation is shared between users, it is a
84    good idea to byte-compile all modules upon installation, since
85    other users may not be able to write in the source directories,
86    and thus they won't be able to write the .pyc/.pyo file, and then
87    they would be byte-compiling every module each time it is loaded.
88    This can slow down program start-up considerably.
89
90    See compileall.py for a script/module that uses this module to
91    byte-compile all installed files (or all files in selected
92    directories).
93
94    """
95    try:
96        _py_compile.compile(file, cfile, dfile)
97    except Exception,err:
98        py_exc = PyCompileError(err.__class__,err.args,dfile or file)
99        if doraise:
100            raise py_exc
101        else:
102            sys.stderr.write(py_exc.msg + '\n')
103            return
104
105def main(args=None):
106    """Compile several source files.
107
108    The files named in 'args' (or on the command line, if 'args' is
109    not specified) are compiled and the resulting bytecode is cached
110    in the normal manner.  This function does not search a directory
111    structure to locate source files; it only compiles files named
112    explicitly.
113
114    """
115    if args is None:
116        args = sys.argv[1:]
117    rv = 0
118    for filename in args:
119        try:
120            compile(filename, doraise=True)
121        except PyCompileError, err:
122            # return value to indicate at least one failure
123            rv = 1
124            sys.stderr.write(err.msg)
125    return rv
126
127if __name__ == "__main__":
128    sys.exit(main())
129