in cpp/misc/cpplint.py [0:0]
def CheckCasts(filename, clean_lines, linenum, error):
"""Various cast related checks.
Args:
filename: The name of the current file.
clean_lines: A CleansedLines instance containing the file.
linenum: The number of the line to check.
error: The function to call with any errors found.
"""
line = clean_lines.elided[linenum]
# Check to see if they're using an conversion function cast.
# I just try to capture the most common basic types, though there are more.
# Parameterless conversion functions, such as bool(), are allowed as they are
# probably a member operator declaration or default constructor.
match = Search(
r'(\bnew\s+(?:const\s+)?|\S<\s*(?:const\s+)?)?\b'
r'(int|float|double|bool|char|int32|uint32|int64|uint64)'
r'(\([^)].*)', line)
expecting_function = ExpectingFunctionArgs(clean_lines, linenum)
if match and not expecting_function:
matched_type = match.group(2)
# matched_new_or_template is used to silence two false positives:
# - New operators
# - Template arguments with function types
#
# For template arguments, we match on types immediately following
# an opening bracket without any spaces. This is a fast way to
# silence the common case where the function type is the first
# template argument. False negative with less-than comparison is
# avoided because those operators are usually followed by a space.
#
# function<double(double)> // bracket + no space = false positive
# value < double(42) // bracket + space = true positive
matched_new_or_template = match.group(1)
# Avoid arrays by looking for brackets that come after the closing
# parenthesis.
if Match(r'\([^()]+\)\s*\[', match.group(3)):
return
# Other things to ignore:
# - Function pointers
# - Casts to pointer types
# - Placement new
# - Alias declarations
matched_funcptr = match.group(3)
if (matched_new_or_template is None and
not (matched_funcptr and
(Match(r'\((?:[^() ]+::\s*\*\s*)?[^() ]+\)\s*\(',
matched_funcptr) or
matched_funcptr.startswith('(*)'))) and
not Match(r'\s*using\s+\S+\s*=\s*' + matched_type, line) and
not Search(r'new\(\S+\)\s*' + matched_type, line)):
error(filename, linenum, 'readability/casting', 4,
'Using deprecated casting style. '
'Use static_cast<%s>(...) instead' %
matched_type)
if not expecting_function:
CheckCStyleCast(filename, clean_lines, linenum, 'static_cast',
r'\((int|float|double|bool|char|u?int(16|32|64))\)', error)
# This doesn't catch all cases. Consider (const char * const)"hello".
#
# (char *) "foo" should always be a const_cast (reinterpret_cast won't
# compile).
if CheckCStyleCast(filename, clean_lines, linenum, 'const_cast',
r'\((char\s?\*+\s?)\)\s*"', error):
pass
else:
# Check pointer casts for other than string constants
CheckCStyleCast(filename, clean_lines, linenum, 'reinterpret_cast',
r'\((\w+\s?\*+\s?)\)', error)
# In addition, we look for people taking the address of a cast. This
# is dangerous -- casts can assign to temporaries, so the pointer doesn't
# point where you think.
#
# Some non-identifier character is required before the '&' for the
# expression to be recognized as a cast. These are casts:
# expression = &static_cast<int*>(temporary());
# function(&(int*)(temporary()));
#
# This is not a cast:
# reference_type&(int* function_param);
match = Search(
r'(?:[^\w]&\(([^)*][^)]*)\)[\w(])|'
r'(?:[^\w]&(static|dynamic|down|reinterpret)_cast\b)', line)
if match:
# Try a better error message when the & is bound to something
# dereferenced by the casted pointer, as opposed to the casted
# pointer itself.
parenthesis_error = False
match = Match(r'^(.*&(?:static|dynamic|down|reinterpret)_cast\b)<', line)
if match:
_, y1, x1 = CloseExpression(clean_lines, linenum, len(match.group(1)))
if x1 >= 0 and clean_lines.elided[y1][x1] == '(':
_, y2, x2 = CloseExpression(clean_lines, y1, x1)
if x2 >= 0:
extended_line = clean_lines.elided[y2][x2:]
if y2 < clean_lines.NumLines() - 1:
extended_line += clean_lines.elided[y2 + 1]
if Match(r'\s*(?:->|\[)', extended_line):
parenthesis_error = True
if parenthesis_error:
error(filename, linenum, 'readability/casting', 4,
('Are you taking an address of something dereferenced '
'from a cast? Wrapping the dereferenced expression in '
'parentheses will make the binding more obvious'))
else:
error(filename, linenum, 'runtime/casting', 4,
('Are you taking an address of a cast? '
'This is dangerous: could be a temp var. '
'Take the address before doing the cast, rather than after'))