bitbake: Add codeparser for parsing shell and python functions

This commit is derived from Chris Larson's checksum work, turned into a
standalone piece of code for parsing python and shell functions.

The deindent code has been replaced with code to work around indentation
for speed. The original NodeVisitor in the ast was replaced with a faster
class walk call.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
This commit is contained in:
Richard Purdie 2010-08-02 10:20:20 +01:00
parent 13fdd4ae5d
commit 3492bff64a
2 changed files with 276 additions and 3 deletions

View File

@ -0,0 +1,273 @@
from pysh import pyshyacc, pyshlex
from itertools import chain
from bb import msg, utils
import ast
import codegen
def check_indent(codestr):
"""If the code is indented, add a top level piece of code to 'remove' the indentation"""
if codestr[0] is " " or codestr[0] is " ":
return "if 1:\n" + codestr
return codestr
pythonparsecache = {}
class PythonParser():
class ValueVisitor():
"""Visitor to traverse a python abstract syntax tree and obtain
the variables referenced via bitbake metadata APIs, and the external
functions called.
"""
getvars = ("d.getVar", "bb.data.getVar", "data.getVar")
expands = ("d.expand", "bb.data.expand", "data.expand")
execs = ("bb.build.exec_func", "bb.build.exec_task")
@classmethod
def _compare_name(cls, strparts, node):
"""Given a sequence of strings representing a python name,
where the last component is the actual Name and the prior
elements are Attribute nodes, determine if the supplied node
matches.
"""
if not strparts:
return True
current, rest = strparts[0], strparts[1:]
if isinstance(node, ast.Attribute):
if current == node.attr:
return cls._compare_name(rest, node.value)
elif isinstance(node, ast.Name):
if current == node.id:
return True
return False
@classmethod
def compare_name(cls, value, node):
"""Convenience function for the _compare_node method, which
can accept a string (which is split by '.' for you), or an
iterable of strings, in which case it checks to see if any of
them match, similar to isinstance.
"""
if isinstance(value, basestring):
return cls._compare_name(tuple(reversed(value.split("."))),
node)
else:
return any(cls.compare_name(item, node) for item in value)
def __init__(self, value):
self.var_references = set()
self.var_execs = set()
self.direct_func_calls = set()
self.var_expands = set()
self.value = value
@classmethod
def warn(cls, func, arg):
"""Warn about calls of bitbake APIs which pass a non-literal
argument for the variable name, as we're not able to track such
a reference.
"""
try:
funcstr = codegen.to_source(func)
argstr = codegen.to_source(arg)
except TypeError:
msg.debug(2, None, "Failed to convert function and argument to source form")
else:
msg.debug(1, None, "Warning: in call to '%s', argument '%s' is not a literal" %
(funcstr, argstr))
def visit_Call(self, node):
if self.compare_name(self.getvars, node.func):
if isinstance(node.args[0], ast.Str):
self.var_references.add(node.args[0].s)
else:
self.warn(node.func, node.args[0])
elif self.compare_name(self.expands, node.func):
if isinstance(node.args[0], ast.Str):
self.warn(node.func, node.args[0])
self.var_expands.update(node.args[0].s)
elif isinstance(node.args[0], ast.Call) and \
self.compare_name(self.getvars, node.args[0].func):
pass
else:
self.warn(node.func, node.args[0])
elif self.compare_name(self.execs, node.func):
if isinstance(node.args[0], ast.Str):
self.var_execs.add(node.args[0].s)
else:
self.warn(node.func, node.args[0])
elif isinstance(node.func, ast.Name):
self.direct_func_calls.add(node.func.id)
elif isinstance(node.func, ast.Attribute):
# We must have a qualified name. Therefore we need
# to walk the chain of 'Attribute' nodes to determine
# the qualification.
attr_node = node.func.value
identifier = node.func.attr
while isinstance(attr_node, ast.Attribute):
identifier = attr_node.attr + "." + identifier
attr_node = attr_node.value
if isinstance(attr_node, ast.Name):
identifier = attr_node.id + "." + identifier
self.direct_func_calls.add(identifier)
def __init__(self):
#self.funcdefs = set()
self.execs = set()
#self.external_cmds = set()
self.references = set()
def parse_python(self, node):
if node in pythonparsecache:
self.references = pythonparsecache[node].references
self.execs = pythonparsecache[node].execs
return
code = compile(check_indent(str(node)), "<string>", "exec",
ast.PyCF_ONLY_AST)
visitor = self.ValueVisitor(code)
for n in ast.walk(code):
if n.__class__.__name__ == "Call":
visitor.visit_Call(n)
self.references.update(visitor.var_references)
self.references.update(visitor.var_execs)
self.execs = visitor.direct_func_calls
pythonparsecache[node] = self
shellparsecache = {}
class ShellParser():
def __init__(self):
self.funcdefs = set()
self.allexecs = set()
self.execs = set()
def parse_shell(self, value):
"""Parse the supplied shell code in a string, returning the external
commands it executes.
"""
if value in pythonparsecache:
self.execs = shellparsecache[value].execs
return
try:
tokens, _ = pyshyacc.parse(value, eof=True, debug=False)
except pyshlex.NeedMore:
raise ShellSyntaxError("Unexpected EOF")
for token in tokens:
self.process_tokens(token)
self.execs = set(cmd for cmd in self.allexecs if cmd not in self.funcdefs)
shellparsecache[value] = self
return self.execs
def process_tokens(self, tokens):
"""Process a supplied portion of the syntax tree as returned by
pyshyacc.parse.
"""
def function_definition(value):
self.funcdefs.add(value.name)
return [value.body], None
def case_clause(value):
# Element 0 of each item in the case is the list of patterns, and
# Element 1 of each item in the case is the list of commands to be
# executed when that pattern matches.
words = chain(*[item[0] for item in value.items])
cmds = chain(*[item[1] for item in value.items])
return cmds, words
def if_clause(value):
main = chain(value.cond, value.if_cmds)
rest = value.else_cmds
if isinstance(rest, tuple) and rest[0] == "elif":
return chain(main, if_clause(rest[1]))
else:
return chain(main, rest)
def simple_command(value):
return None, chain(value.words, (assign[1] for assign in value.assigns))
token_handlers = {
"and_or": lambda x: ((x.left, x.right), None),
"async": lambda x: ([x], None),
"brace_group": lambda x: (x.cmds, None),
"for_clause": lambda x: (x.cmds, x.items),
"function_definition": function_definition,
"if_clause": lambda x: (if_clause(x), None),
"pipeline": lambda x: (x.commands, None),
"redirect_list": lambda x: ([x.cmd], None),
"subshell": lambda x: (x.cmds, None),
"while_clause": lambda x: (chain(x.condition, x.cmds), None),
"until_clause": lambda x: (chain(x.condition, x.cmds), None),
"simple_command": simple_command,
"case_clause": case_clause,
}
for token in tokens:
name, value = token
try:
more_tokens, words = token_handlers[name](value)
except KeyError:
raise NotImplementedError("Unsupported token type " + name)
if more_tokens:
self.process_tokens(more_tokens)
if words:
self.process_words(words)
def process_words(self, words):
"""Process a set of 'words' in pyshyacc parlance, which includes
extraction of executed commands from $() blocks, as well as grabbing
the command name argument.
"""
words = list(words)
for word in list(words):
wtree = pyshlex.make_wordtree(word[1])
for part in wtree:
if not isinstance(part, list):
continue
if part[0] in ('`', '$('):
command = pyshlex.wordtree_as_string(part[1:-1])
self.parse_shell(command)
if word[0] in ("cmd_name", "cmd_word"):
if word in words:
words.remove(word)
usetoken = False
for word in words:
if word[0] in ("cmd_name", "cmd_word") or \
(usetoken and word[0] == "TOKEN"):
if "=" in word[1]:
usetoken = True
continue
cmd = word[1]
if cmd.startswith("$"):
msg.debug(1, None, "Warning: execution of non-literal command '%s'" % cmd)
elif cmd == "eval":
command = " ".join(word for _, word in words[1:])
self.parse_shell(command)
else:
self.allexecs.add(cmd)
break

View File

@ -46,7 +46,7 @@ class VariableParse:
self.value = val
self.references = set()
self.funcrefs = set()
self.execs = set()
def var_sub(self, match):
key = match.group()[2:-1]
@ -64,10 +64,10 @@ class VariableParse:
code = match.group()[3:-1]
codeobj = compile(code.strip(), self.varname or "<expansion>", "eval")
parser = bb.rptest.PythonParser()
parser = bb.codeparser.PythonParser()
parser.parse_python(code)
self.references |= parser.references
self.funcrefs |= parser.execs
self.execs |= parser.execs
value = utils.better_eval(codeobj, {"d": self.d})
return str(value)