rust/library/std
bors 154f1f544d Auto merge of #77029 - ehuss:command-access, r=dtolnay
Add accessors to Command.

This adds some accessor methods to `Command` to provide a way to access the values set when building the `Command`. An example where this can be useful is to display the command to be executed. This is roughly based on the [`ProcessBuilder`](13b73cdaf7/src/cargo/util/process_builder.rs (L105-L134)) in Cargo.

Possible concerns about the API:
- Values with NULs on Unix will be returned as `"<string-with-nul>"`. I don't think it is practical to avoid this, since otherwise a whole separate copy of all the values would need to be kept in `Command`.
- Does not handle `arg0` on Unix. This can be awkward to support in `get_args` and is rarely used. I figure if someone really wants it, it can be added to `CommandExt` as a separate method.
- Does not offer a way to detect `env_clear`. I'm uncertain if it would be useful for anyone.
- Does not offer a way to get an environment variable by name (`get_env`). I figure this can be added later if anyone really wants it. I think the motivation for this is weak, though. Also, the API could be a little awkward (return a `Option<Option<&OsStr>>`?).
- `get_envs` could skip "cleared" entries and just return `&OsStr` values instead of `Option<&OsStr>`. I'm on the fence here. My use case is to display a shell command, and I only intend it to be roughly equivalent to the actual execution, and I probably won't display `None` entries. I erred on the side of providing extra information, but I suspect many situations will just filter out the `None`s.
- Could implement more iterator stuff (like `DoubleEndedIterator`).

I have not implemented new std items before, so I'm uncertain if the existing issue should be reused, or if a new tracking issue is needed.

cc #44434
2020-10-02 07:51:24 +00:00
..
benches mv std libs to library/ 2020-07-27 19:51:13 -05:00
src Auto merge of #77029 - ehuss:command-access, r=dtolnay 2020-10-02 07:51:24 +00:00
tests mv std libs to library/ 2020-07-27 19:51:13 -05:00
build.rs Remove duplicated library links between std and libc 2020-09-21 01:37:15 -07:00
Cargo.toml libary: Forward compiler-builtins "mem" feature 2020-09-27 20:31:06 -07:00