Reference Manual

def TreeCrawler.mymf.scan_opcodes_25	(	self,
		co,
		unpack = `struct.unpack`
	)

This is basically just the default opcode scanner from ModuleFinder, but extended to also
look for "process.load(<module>)' commands. Since the Process object might not necassarily
be called "process", it scans for a call to a "load" method with a single parameter on
*any* object. If one is found it checks if the parameter is a string that refers to a valid
python module in the local or global area. If it does, the scanner assumes this was a call
to a Process object and yields the module name.
It's not possible to scan first for Process object declarations to get the name of the
objects since often (e.g. for customisation functions) the object is passed to a function
in a different file.

The ModuleFinder.scan_opcodes_25 implementation this is based was taken from
https://hg.python.org/cpython/file/2.7/Lib/modulefinder.py#l364

Definition at line 130 of file TreeCrawler.py.

References TreeCrawler.mymf._globalarea, TreeCrawler.mymf._localarea, and timeUnitHelper.unpack().

 
     def scan_opcodes_25(self, co, unpack = struct.unpack):
         """
         This is basically just the default opcode scanner from ModuleFinder, but extended to also
         look for "process.load(<module>)' commands. Since the Process object might not necassarily
         be called "process", it scans for a call to a "load" method with a single parameter on
         *any* object. If one is found it checks if the parameter is a string that refers to a valid
         python module in the local or global area. If it does, the scanner assumes this was a call
         to a Process object and yields the module name.
         It's not possible to scan first for Process object declarations to get the name of the
         objects since often (e.g. for customisation functions) the object is passed to a function
         in a different file.
 
         The ModuleFinder.scan_opcodes_25 implementation this is based was taken from
         https://hg.python.org/cpython/file/2.7/Lib/modulefinder.py#l364
         """
         # Scan the code, and yield 'interesting' opcode combinations
         # Python 2.5 version (has absolute and relative imports)
         code = co.co_code
         names = co.co_names
         consts = co.co_consts
         LOAD_CONST = modulefinder.LOAD_CONST
         IMPORT_NAME = modulefinder.IMPORT_NAME
         STORE_OPS = modulefinder.STORE_OPS
         HAVE_ARGUMENT = modulefinder.HAVE_ARGUMENT
         LOAD_ATTR = chr(dis.opname.index('LOAD_ATTR'))
         LOAD_NAME = chr(dis.opname.index('LOAD_NAME'))
         CALL_FUNCTION = chr(dis.opname.index('CALL_FUNCTION'))
         LOAD_LOAD_AND_IMPORT = LOAD_CONST + LOAD_CONST + IMPORT_NAME
         
         try :
             indexOfLoadConst = names.index("load") # This might throw a ValueError
             # These are the opcodes required to access the "load" attribute. This might
             # not even be a function, but I check for that later.
             loadMethodOpcodes = LOAD_ATTR+struct.pack('<H',indexOfLoadConst)
         except ValueError :
             # doesn't look like "load" is used anywhere in this file
             loadMethodOpcodes=None
 
         while code:
             c = code[0]
             
             # Check to see if this is a call to a "load" method
             if loadMethodOpcodes!=None and len(code)>=9 : # Need at least 9 codes for the full call
                 if code[:3]==loadMethodOpcodes :
                     # The attribute "load" is being accessed, need to make sure this is a function call.
                     # I'll look ahead and see if the CALL_FUNCTION code is used - this could be in a different
                     # place depending on the number of arguments, but I'm only interested in methods with a
                     # single argument so I know exactly where CALL_FUNCTION should be.
                     if code[6]==CALL_FUNCTION :
                         # I know this is calling a method called "load" with one argument. I need
                         # to find out what the argument is. Note that I still don't know if this is
                         # on a cms.Process object.
                         indexInTable=unpack('<H',code[4:6])[0]
                         if code[3]==LOAD_CONST :
                             # The argument is a constant, so retrieve that from the table
                             loadMethodArgument=consts[indexInTable]
                             # I know a load method with one argument has been called on *something*, but I don't
                             # know if it was a cms.Process object. All I can do is check to see if the argument is
                             # a string, and if so if it refers to a python file in the user or global areas.
                             try :
                                 loadMethodArgument = loadMethodArgument.replace("/",".")
                                 # I can only use imp.find_module on submodules (i.e. each bit between a "."), so try
                                 # that on each submodule in turn using the previously found filename. Note that I have
                                 # to try this twice, because if the first pass traverses into a package in the local
                                 # area but the subpackage has not been checked out it will report that the subpackage
                                 # doesn't exist, even though it is available in the global area.
                                 try :
                                     parentFilename=[self._localarea+"/python"]
                                     for subModule in loadMethodArgument.split(".") :
                                         moduleInfo=imp.find_module( subModule, parentFilename )
                                         parentFilename=[moduleInfo[1]]
                                     # If control got this far without raising an exception, then it must be a valid python module
                                     yield "import", (None, loadMethodArgument)
                                 except ImportError :
                                     # Didn't work in the local area, try in the global area.
                                     parentFilename=[self._globalarea+"/python"]
                                     for subModule in loadMethodArgument.split(".") :
                                         moduleInfo=imp.find_module( subModule, parentFilename )
                                         parentFilename=[moduleInfo[1]]
                                     # If control got this far without raising an exception, then it must be a valid python module
                                     yield "import", (None, loadMethodArgument)
                             except Exception as error:
                                 # Either there was an import error (not a python module) or there was a string
                                 # manipulaton error (argument not a string). Assume this wasn't a call on a
                                 # cms.Process object and move on silently.
                                 pass
                         
                         elif code[3]==LOAD_NAME :
                             # The argument is a variable. I can get the name of the variable quite easily but
                             # not the value, unless I execute all of the opcodes. Not sure what to do here,
                             # guess I'll just print a warning so that the user knows?
                             print "Unable to determine the value of variable '"+names[indexInTable]+"' to see if it is a proces.load(...) statement in file "+co.co_filename
                         
                         code=code[9:]
                         continue
 
             if c in STORE_OPS:
                 oparg, = unpack('<H', code[1:3])
                 yield "store", (names[oparg],)
                 code = code[3:]
                 continue
             if code[:9:3] == LOAD_LOAD_AND_IMPORT:
                 oparg_1, oparg_2, oparg_3 = unpack('<xHxHxH', code[:9])
                 level = consts[oparg_1]
                 if level == -1: # normal import
                     yield "import", (consts[oparg_2], names[oparg_3])
                 elif level == 0: # absolute import
                     yield "absolute_import", (consts[oparg_2], names[oparg_3])
                 else: # relative import
                     yield "relative_import", (level, consts[oparg_2], names[oparg_3])
                 code = code[9:]
                 continue
             if c >= HAVE_ARGUMENT:
                 code = code[3:]
             else:
                 code = code[1:]

timeUnitHelper.unpack

def unpack

Definition: timeUnitHelper.py:17

TreeCrawler.mymf._globalarea

_globalarea

Definition: TreeCrawler.py:98

TreeCrawler.mymf._localarea

_localarea

Definition: TreeCrawler.py:97

TreeCrawler.mymf.scan_opcodes_25

def scan_opcodes_25

Definition: TreeCrawler.py:130

Private Attributes
	_depgraph

	_globalarea

	_last_caller

	_localarea

	_types

def TreeCrawler.mymf.__init__	(	self,
		args,
		kwargs
	)

def TreeCrawler.mymf.import_hook	(	self,
		name,
		caller = `None`,
		fromlist = `None`,
		level = `-1`
	)

def TreeCrawler.mymf.import_module	(	self,
		partnam,
		fqname,
		parent
	)

def TreeCrawler.mymf.load_module	(	self,
		fqname,
		fp,
		pathname,
		aux_info
	)

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Public Member Functions
def	__init__

def	import_hook

def	import_module

def	load_module

def	scan_opcodes_25