qapi: Simplify inclusion cycle detection

We maintain a stack of filenames in include_hist for convenient cycle
detection.

As error_path() demonstrates, the same information is readily
available in the expr_info, so just use that, and drop include_hist.

Backports commit a1366087270b312d94ff8c4031395a4218f160d4 from qemu
This commit is contained in:
Markus Armbruster 2018-02-19 15:40:42 -05:00 committed by Lioncash
parent b387a62f73
commit de88f40dfd
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@ -101,15 +101,10 @@ class QAPIExprError(Exception):
class QAPISchema:
def __init__(self, fp, include_hist = [],
previously_included = [], incl_info = None):
""" include_hist is a stack used to detect inclusion cycles
previously_included is a global state used to avoid multiple
inclusions of the same file"""
def __init__(self, fp, previously_included = [], incl_info = None):
abs_fname = os.path.abspath(fp.name)
fname = fp.name
self.fname = fname
self.include_hist = include_hist + [(fname, abs_fname)]
previously_included.append(abs_fname)
self.incl_info = incl_info
self.src = fp.read()
@ -135,10 +130,13 @@ class QAPISchema:
% include)
incl_abs_fname = os.path.join(os.path.dirname(abs_fname),
include)
for elem in self.include_hist:
if incl_abs_fname == elem[1]:
# catch inclusion cycle
inf = expr_info
while inf:
if incl_abs_fname == os.path.abspath(inf['file']):
raise QAPIExprError(expr_info, "Inclusion loop for %s"
% include)
inf = inf['parent']
# skip multiple include of the same file
if incl_abs_fname in previously_included:
continue
@ -147,8 +145,8 @@ class QAPISchema:
except IOError, e:
raise QAPIExprError(expr_info,
'%s: %s' % (e.strerror, include))
exprs_include = QAPISchema(fobj, self.include_hist,
previously_included, expr_info)
exprs_include = QAPISchema(fobj, previously_included,
expr_info)
self.exprs.extend(exprs_include.exprs)
else:
expr_elem = {'expr': expr,