Edit File: py_compile.py
"""Routine to "compile" a .py file to a .pyc file. This module has intimate knowledge of the format of .pyc files. """ import importlib._bootstrap_external import importlib.machinery import importlib.util import os import os.path import sys import traceback __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 def compile(file, cfile=None, dfile=None, doraise=False, optimize=-1): """Byte-compile one Python source file to Python bytecode. :param file: The source file name. :param cfile: The target byte compiled file name. When not given, this defaults to the PEP 3147/PEP 488 location. :param dfile: Purported file name, i.e. the file name that shows up in error messages. Defaults to the source file name. :param 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. :param optimize: The optimization level for the compiler. Valid values are -1, 0, 1 and 2. A value of -1 means to use the optimization level of the current interpreter, as given by -O command line options. :return: Path to the resulting byte compiled file. 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 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 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). Do note that FileExistsError is raised if cfile ends up pointing at a non-regular file or symlink. Because the compilation uses a file renaming, the resulting file would be regular and thus not the same type of file as it was previously. """ if cfile is None: if optimize >= 0: optimization = optimize if optimize >= 1 else '' cfile = importlib.util.cache_from_source(file, optimization=optimization) else: cfile = importlib.util.cache_from_source(file) if os.path.islink(cfile): msg = ('{} is a symlink and will be changed into a regular file if ' 'import writes a byte-compiled file to it') raise FileExistsError(msg.format(cfile)) elif os.path.exists(cfile) and not os.path.isfile(cfile): msg = ('{} is a non-regular file and will be changed into a regular ' 'one if import writes a byte-compiled file to it') raise FileExistsError(msg.format(cfile)) loader = importlib.machinery.SourceFileLoader('<py_compile>', file) source_bytes = loader.get_data(file) try: code = loader.source_to_code(source_bytes, dfile or file, _optimize=optimize) except Exception as err: py_exc = PyCompileError(err.__class__, err, dfile or file) if doraise: raise py_exc else: sys.stderr.write(py_exc.msg + '\n') return try: dirname = os.path.dirname(cfile) if dirname: os.makedirs(dirname) except FileExistsError: pass source_stats = loader.path_stats(file) bytecode = importlib._bootstrap_external._code_to_bytecode( code, source_stats['mtime'], source_stats['size']) mode = importlib._bootstrap_external._calc_mode(file) importlib._bootstrap_external._write_atomic(cfile, bytecode, mode) return 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 '-' is the only parameter in args, the list of files is taken from standard input. """ if args is None: args = sys.argv[1:] rv = 0 if args == ['-']: while True: filename = sys.stdin.readline() if not filename: break filename = filename.rstrip('\n') try: compile(filename, doraise=True) except PyCompileError as error: rv = 1 sys.stderr.write("%s\n" % error.msg) except OSError as error: rv = 1 sys.stderr.write("%s\n" % error) else: for filename in args: try: compile(filename, doraise=True) except PyCompileError as error: # return value to indicate at least one failure rv = 1 sys.stderr.write("%s\n" % error.msg) return rv if __name__ == "__main__": sys.exit(main())
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