systemd/coccinelle/take-ptr.cocci

@@
local idexpression p;
expression q;
@@
- p = q;
- q = NULL;
- return p;
+ return TAKE_PTR(q);
@@
expression p, q;
@@
- p = q;
- q = NULL;
+ p = TAKE_PTR(q);
macro: introduce TAKE_PTR() macro This macro will read a pointer of any type, return it, and set the pointer to NULL. This is useful as an explicit concept of passing ownership of a memory area between pointers. This takes inspiration from Rust: https://doc.rust-lang.org/std/option/enum.Option.html#method.take and was suggested by Alan Jenkins (@sourcejedi). It drops ~160 lines of code from our codebase, which makes me like it. Also, I think it clarifies passing of ownership, and thus helps readability a bit (at least for the initiated who know the new macro) 2018-03-22 18:53:26 +03:00			`@@`
			`local idexpression p;`
			`expression q;`
			`@@`
			`- p = q;`
			`- q = NULL;`
			`- return p;`
			`+ return TAKE_PTR(q);`
			`@@`
			`expression p, q;`
			`@@`
			`- p = q;`
			`- q = NULL;`
			`+ p = TAKE_PTR(q);`