in cpp/build-support/cpplint.py [0:0]
def CheckBraces(filename, clean_lines, linenum, error):
"""Looks for misplaced braces (e.g. at the end of line).
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] # get rid of comments and strings
if Match(r'\s*{\s*$', line):
# We allow an open brace to start a line in the case where someone is using
# braces in a block to explicitly create a new scope, which is commonly used
# to control the lifetime of stack-allocated variables. Braces are also
# used for brace initializers inside function calls. We don't detect this
# perfectly: we just don't complain if the last non-whitespace character on
# the previous non-blank line is ',', ';', ':', '(', '{', or '}', or if the
# previous line starts a preprocessor block. We also allow a brace on the
# following line if it is part of an array initialization and would not fit
# within the 80 character limit of the preceding line.
prevline = GetPreviousNonBlankLine(clean_lines, linenum)[0]
if (not Search(r'[,;:}{(]\s*$', prevline) and
not Match(r'\s*#', prevline) and
not (GetLineWidth(prevline) > _line_length - 2 and '[]' in prevline)):
error(filename, linenum, 'whitespace/braces', 4,
'{ should almost always be at the end of the previous line')
# An else clause should be on the same line as the preceding closing brace.
if Match(r'\s*else\b\s*(?:if\b|\{|$)', line):
prevline = GetPreviousNonBlankLine(clean_lines, linenum)[0]
if Match(r'\s*}\s*$', prevline):
error(filename, linenum, 'whitespace/newline', 4,
'An else should appear on the same line as the preceding }')
# If braces come on one side of an else, they should be on both.
# However, we have to worry about "else if" that spans multiple lines!
if Search(r'else if\s*\(', line): # could be multi-line if
brace_on_left = bool(Search(r'}\s*else if\s*\(', line))
# find the ( after the if
pos = line.find('else if')
pos = line.find('(', pos)
if pos > 0:
(endline, _, endpos) = CloseExpression(clean_lines, linenum, pos)
brace_on_right = endline[endpos:].find('{') != -1
if brace_on_left != brace_on_right: # must be brace after if
error(filename, linenum, 'readability/braces', 5,
'If an else has a brace on one side, it should have it on both')
elif Search(r'}\s*else[^{]*$', line) or Match(r'[^}]*else\s*{', line):
error(filename, linenum, 'readability/braces', 5,
'If an else has a brace on one side, it should have it on both')
# Likewise, an else should never have the else clause on the same line
if Search(r'\belse [^\s{]', line) and not Search(r'\belse if\b', line):
error(filename, linenum, 'whitespace/newline', 4,
'Else clause should never be on same line as else (use 2 lines)')
# In the same way, a do/while should never be on one line
if Match(r'\s*do [^\s{]', line):
error(filename, linenum, 'whitespace/newline', 4,
'do/while clauses should not be on a single line')
# Check single-line if/else bodies. The style guide says 'curly braces are not
# required for single-line statements'. We additionally allow multi-line,
# single statements, but we reject anything with more than one semicolon in
# it. This means that the first semicolon after the if should be at the end of
# its line, and the line after that should have an indent level equal to or
# lower than the if. We also check for ambiguous if/else nesting without
# braces.
if_else_match = Search(r'\b(if\s*(|constexpr)\s*\(|else\b)', line)
if if_else_match and not Match(r'\s*#', line):
if_indent = GetIndentLevel(line)
endline, endlinenum, endpos = line, linenum, if_else_match.end()
if_match = Search(r'\bif\s*(|constexpr)\s*\(', line)
if if_match:
# This could be a multiline if condition, so find the end first.
pos = if_match.end() - 1
(endline, endlinenum, endpos) = CloseExpression(clean_lines, linenum, pos)
# Check for an opening brace, either directly after the if or on the next
# line. If found, this isn't a single-statement conditional.
if (not Match(r'\s*{', endline[endpos:])
and not (Match(r'\s*$', endline[endpos:])
and endlinenum < (len(clean_lines.elided) - 1)
and Match(r'\s*{', clean_lines.elided[endlinenum + 1]))):
while (endlinenum < len(clean_lines.elided)
and ';' not in clean_lines.elided[endlinenum][endpos:]):
endlinenum += 1
endpos = 0
if endlinenum < len(clean_lines.elided):
endline = clean_lines.elided[endlinenum]
# We allow a mix of whitespace and closing braces (e.g. for one-liner
# methods) and a single \ after the semicolon (for macros)
endpos = endline.find(';')
if not Match(r';[\s}]*(\\?)$', endline[endpos:]):
# Semicolon isn't the last character, there's something trailing.
# Output a warning if the semicolon is not contained inside
# a lambda expression.
if not Match(r'^[^{};]*\[[^\[\]]*\][^{}]*\{[^{}]*\}\s*\)*[;,]\s*$',
endline):
error(filename, linenum, 'readability/braces', 4,
'If/else bodies with multiple statements require braces')
elif endlinenum < len(clean_lines.elided) - 1:
# Make sure the next line is dedented
next_line = clean_lines.elided[endlinenum + 1]
next_indent = GetIndentLevel(next_line)
# With ambiguous nested if statements, this will error out on the
# if that *doesn't* match the else, regardless of whether it's the
# inner one or outer one.
if (if_match and Match(r'\s*else\b', next_line)
and next_indent != if_indent):
error(filename, linenum, 'readability/braces', 4,
'Else clause should be indented at the same level as if. '
'Ambiguous nested if/else chains require braces.')
elif next_indent > if_indent:
error(filename, linenum, 'readability/braces', 4,
'If/else bodies with multiple statements require braces')