check_return_types Namespace Reference

Functions
	_strip_comments (text)
	_body_of (text, open_brace)
	_returns_pointer (ret)
	scan (path)
	main ()

Variables
	DEF_RE
dict	SKIP_DIRS = {'external', 'attic'}

Detailed Description

Find `return FALSE` in a function that returns a pointer, and its mirror.

The compiler cannot help here. GLib defines `FALSE` as `0`, and `0` is a valid null
pointer constant in C -- so `return FALSE;` from a `char *` function compiles silently and
means exactly `return NULL;`. It is only wrong to a reader, which is the worst kind of
wrong: it says "this function answers a yes/no question" about a function that hands back
an object.

The mirror cases are already covered by the compiler: `return TRUE;` from a pointer
function and `return NULL;` from an integer one both trip -Wint-conversion. This script
deliberately reports ONLY the FALSE-for-NULL direction, because it is the only one nothing
else catches -- and because the mirror cannot be checked textually anyway. `cmsHPROFILE`,
`cl_mem` and `gpointer` are pointers with no `*` in the spelling, so a check for
"`return NULL` in a non-pointer function" reports seventeen correct lines in this tree and
nothing else. A gate that cries wolf gets switched off.

    tools/check_return_types.py [path ...]        # default: src/

Exits non-zero if anything is found.

Function Documentation

_body_of()

check_return_types._body_of (   text,   open_brace  )

protected

Return (body, offset_of_body_start) for the block opening at `open_brace`.

Definition at line 74 of file check_return_types.py.

Referenced by scan().

_returns_pointer()

check_return_types._returns_pointer (   ret )

protected

Definition at line 93 of file check_return_types.py.

Referenced by scan().

_strip_comments()

check_return_types._strip_comments (   text )

protected

Blank out comments, preserving every byte offset and line number.

Necessary, not cosmetic: an apostrophe in a comment -- "can't", "doesn't", which this
codebase is full of -- reads as an opening character literal to the scanner below, and
everything up to the next apostrophe gets skipped, braces included. The first version
of this script reported five confident findings in mipmap_cache.c that were all that
bug swallowing a function boundary.

Definition at line 38 of file check_return_types.py.

References min.

Referenced by scan().

main()

check_return_types.main

(

void

)

Scan the given paths (default src/) and print what does not line up.

Definition at line 136 of file check_return_types.py.

References main(), and scan().

Referenced by main().

scan()

check_return_types.scan

(

path

)

Report every return-value/return-type mismatch in one file.

Definition at line 101 of file check_return_types.py.

References _body_of(), _returns_pointer(), and _strip_comments().

Referenced by main().

Variable Documentation

DEF_RE

check_return_types.DEF_RE

Initial value:

=  re.compile(
    r'^(?P<ret>[A-Za-z_][\w \t]*?[\w \t*]*?)'      # return type, possibly with * at the end
    r'(?P<name>[A-Za-z_]\w*)'                      # function name
    r'\s*\‍((?P<args>[^;]*?)\‍)\s*$',                # parameter list, no trailing semicolon
    re.M)

Definition at line 29 of file check_return_types.py.

SKIP_DIRS

dict check_return_types.SKIP_DIRS = {'external', 'attic'}

Definition at line 35 of file check_return_types.py.