in cpp/misc/cpplint.py [0:0]
def CheckForNonConstReference(filename, clean_lines, linenum,
nesting_state, error):
"""Check for non-const references.
Separate from CheckLanguage since it scans backwards from current
line, instead of scanning forward.
Args:
filename: The name of the current file.
clean_lines: A CleansedLines instance containing the file.
linenum: The number of the line to check.
nesting_state: A NestingState instance which maintains information about
the current stack of nested blocks being parsed.
error: The function to call with any errors found.
"""
# Do nothing if there is no '&' on current line.
line = clean_lines.elided[linenum]
if '&' not in line:
return
# If a function is inherited, current function doesn't have much of
# a choice, so any non-const references should not be blamed on
# derived function.
if IsDerivedFunction(clean_lines, linenum):
return
# Don't warn on out-of-line method definitions, as we would warn on the
# in-line declaration, if it isn't marked with 'override'.
if IsOutOfLineMethodDefinition(clean_lines, linenum):
return
# Long type names may be broken across multiple lines, usually in one
# of these forms:
# LongType
# ::LongTypeContinued &identifier
# LongType::
# LongTypeContinued &identifier
# LongType<
# ...>::LongTypeContinued &identifier
#
# If we detected a type split across two lines, join the previous
# line to current line so that we can match const references
# accordingly.
#
# Note that this only scans back one line, since scanning back
# arbitrary number of lines would be expensive. If you have a type
# that spans more than 2 lines, please use a typedef.
if linenum > 1:
previous = None
if Match(r'\s*::(?:[\w<>]|::)+\s*&\s*\S', line):
# previous_line\n + ::current_line
previous = Search(r'\b((?:const\s*)?(?:[\w<>]|::)+[\w<>])\s*$',
clean_lines.elided[linenum - 1])
elif Match(r'\s*[a-zA-Z_]([\w<>]|::)+\s*&\s*\S', line):
# previous_line::\n + current_line
previous = Search(r'\b((?:const\s*)?(?:[\w<>]|::)+::)\s*$',
clean_lines.elided[linenum - 1])
if previous:
line = previous.group(1) + line.lstrip()
else:
# Check for templated parameter that is split across multiple lines
endpos = line.rfind('>')
if endpos > -1:
(_, startline, startpos) = ReverseCloseExpression(
clean_lines, linenum, endpos)
if startpos > -1 and startline < linenum:
# Found the matching < on an earlier line, collect all
# pieces up to current line.
line = ''
for i in xrange(startline, linenum + 1):
line += clean_lines.elided[i].strip()
# Check for non-const references in function parameters. A single '&' may
# found in the following places:
# inside expression: binary & for bitwise AND
# inside expression: unary & for taking the address of something
# inside declarators: reference parameter
# We will exclude the first two cases by checking that we are not inside a
# function body, including one that was just introduced by a trailing '{'.
# TODO(unknown): Doesn't account for 'catch(Exception& e)' [rare].
if (nesting_state.previous_stack_top and
not (isinstance(nesting_state.previous_stack_top, _ClassInfo) or
isinstance(nesting_state.previous_stack_top, _NamespaceInfo))):
# Not at toplevel, not within a class, and not within a namespace
return
# Avoid initializer lists. We only need to scan back from the
# current line for something that starts with ':'.
#
# We don't need to check the current line, since the '&' would
# appear inside the second set of parentheses on the current line as
# opposed to the first set.
if linenum > 0:
for i in xrange(linenum - 1, max(0, linenum - 10), -1):
previous_line = clean_lines.elided[i]
if not Search(r'[),]\s*$', previous_line):
break
if Match(r'^\s*:\s+\S', previous_line):
return
# Avoid preprocessors
if Search(r'\\\s*$', line):
return
# Avoid constructor initializer lists
if IsInitializerList(clean_lines, linenum):
return
# We allow non-const references in a few standard places, like functions
# called "swap()" or iostream operators like "<<" or ">>". Do not check
# those function parameters.
#
# We also accept & in static_assert, which looks like a function but
# it's actually a declaration expression.
allowed_functions = (r'(?:[sS]wap(?:<\w:+>)?|'
r'operator\s*[<>][<>]|'
r'static_assert|COMPILE_ASSERT'
r')\s*\(')
if Search(allowed_functions, line):
return
elif not Search(r'\S+\([^)]*$', line):
# Don't see an allowed function on this line. Actually we
# didn't see any function name on this line, so this is likely a
# multi-line parameter list. Try a bit harder to catch this case.
for i in xrange(2):
if (linenum > i and
Search(allowed_functions, clean_lines.elided[linenum - i - 1])):
return
decls = ReplaceAll(r'{[^}]*}', ' ', line) # exclude function body
for parameter in re.findall(_RE_PATTERN_REF_PARAM, decls):
if (not Match(_RE_PATTERN_CONST_REF_PARAM, parameter) and
not Match(_RE_PATTERN_REF_STREAM_PARAM, parameter)):
error(filename, linenum, 'runtime/references', 2,
'Is this a non-const reference? '
'If so, make const or use a pointer: ' +
ReplaceAll(' *<', '<', parameter))