Structify more of the internals to simplify the implementation. #911

Alexhuszagh · 2022-07-05T17:03:39Z

Reduces the number of arguments to the function signatures, making the code much easier to understand, and relocates some things. For example, docker_in_docker is now associated with Engine, and now with cli::Args. Likewise, unstable doctests is now a part of Environment and not cli::Args. MessageInfo now stores mutable state (needs to clear lines) and is no longer copyable, and a single instance is created in lib and passed around everywhere as a mutable reference.

The changes with MessageInfo will allow us to erase lines in the future, both from stderr and stdout, which we currently don't use but will allow us to close #859.

This also fixes an issue where -vv+ was not recognized as a valid verbose flag: cargo can handle 1 or more v characters. Also allowed parsing of --color=value args, when we previously only accepted --color value.

Reduces the number of arguments to the function signatures, making the code much easier to understand, and relocates some things. For example, `docker_in_docker` is now associated with `Engine`, and now with `cli::Args`. Likewise, unstable doctests is now a part of `Environment` and not `cli::Args`. `MessageInfo` now stores mutable state (needs to clear lines) and is no longer copyable, and a single instance is created in lib and passed around everywhere as a mutable reference. This also fixes an issue where `-vv+` was not recognized as a valid verbose flag: `cargo` can handle 1 or more `v` characters. Also allowed parsing of `--color=value` args, when we previously only accepted `--color value`.

Alexhuszagh · 2022-07-05T17:04:51Z

Still a draft since many things changed and I need to triple check no bugs were introduced. This refactors a lot of things to try to simplify our logic internally. The only actual changes in terms of behavior for the user are bug fixes:

--color=value is now valid
-vvvvvvvvvvvv or as many arguments of v are now valid

Both are consistent with cargo.

src/bin/commands/clean.rs

Alexhuszagh · 2022-07-05T17:07:34Z

src/bin/commands/containers.rs

@@ -149,6 +149,18 @@ pub enum Volumes {
    Remove(RemoveVolume),
 }

+macro_rules! volumes_get_field {
+    ($self:ident, $field:ident $(.$cb:ident)?) => {{


To avoid a lot of redundant code, I added macros so we can extract a single field from an enumeration. The callback allows to add as_deref if needed.

src/bin/commands/containers.rs

Alexhuszagh · 2022-07-05T17:24:13Z

src/shell.rs

-        }
-    }
-}
+    fn as_verbosity<T, C: Fn(&mut MessageInfo) -> T>(&mut self, call: C, new: Verbosity) -> T {


I've added these functions so we can temporarily change the verbosity of a function call, either to silence or to be more verbose, etc. It allows us to store the old value, and return a result and ensure the old state is restored.

Alexhuszagh · 2022-07-05T17:25:02Z

src/shell.rs

-        message!(@status stream, $status, $message, $color, $msg_info)
-    }};
-}
+    /// prints a red 'error' message and terminates.


I've also moved away from free functions since we store state now.

Alexhuszagh · 2022-07-05T17:26:12Z

src/bin/cross-util.rs

+
+macro_rules! get_engine {
+    ($args:ident, $docker_in_docker:expr, $msg_info: ident) => {{
+        get_container_engine($args.engine(), $docker_in_docker, &mut $msg_info)


These macros just simplify a lot of redundant code that existed earlier, while being relatively transparent.

Alexhuszagh · 2022-07-05T17:32:16Z

src/cli.rs

        }
    }
    Ok(())
 }

+fn is_verbose(arg: &str) -> bool {


This corrects the behavior so -vvvvv and similar are accepted as arguments to get the verbosity. Previously this was passed to cargo, but not correctly processed for cross itself.

Nice, was meaning to fix this myself

Alexhuszagh · 2022-07-05T17:34:36Z

src/cli.rs

+    }
+}
+
+enum ArgKind {


Allows us to determine if the argument is the field or starts with the field in a single check, and then we can choose to process it immediately after.

Alexhuszagh · 2022-07-05T17:35:34Z

src/cli.rs

@@ -167,37 +223,17 @@ pub fn parse(target_list: &TargetList) -> Result<Args> {
        }
    }

-    let msg_info = shell::MessageInfo::create(verbose, quiet, color.as_deref())?;


This should have a single instance, so it's been moved to lib.

Alexhuszagh · 2022-07-05T17:35:49Z

src/cli.rs

@@ -167,37 +223,17 @@ pub fn parse(target_list: &TargetList) -> Result<Args> {
        }
    }

-    let msg_info = shell::MessageInfo::create(verbose, quiet, color.as_deref())?;
-    let docker_in_docker = if let Ok(value) = env::var("CROSS_CONTAINER_IN_CONTAINER") {


Not a CLI argument, so it's been moved to Engine.

Alexhuszagh · 2022-07-05T17:36:07Z

src/cli.rs

-        false
-    };
-
-    let enable_doctests = env::var("CROSS_UNSTABLE_ENABLE_DOCTESTS")


Not a CLI argument, so this has been moved to config.

Alexhuszagh · 2022-07-05T17:36:53Z

src/config.rs

+            .ok()
+    }
+
+    fn custom_toolchain(&self) -> bool {


I think it's better we don't process all our config options for environment variables in lib itself, since variables like this are part of the configuration.

Alexhuszagh · 2022-07-05T17:38:09Z

src/docker/engine.rs

@@ -22,27 +22,38 @@ pub enum EngineType {
 pub struct Engine {
    pub kind: EngineType,
    pub path: PathBuf,
+    pub in_docker: bool,


docker_in_docker is natural here, since it's part of the behavior of the engine. We also only need it to determine the mount finder, so it's a good place.

Emilgardis · 2022-07-05T17:38:34Z

Great! looks like a straightforward interface improvement

Alexhuszagh · 2022-07-05T17:38:58Z

src/docker/local.rs

 pub(crate) fn run(
-    engine: &Engine,
-    target: &Target,
+    options: DockerOptions,


Restructuring into 2 logical structs simplifies our function signatures a lot, especially in docker::run and the like.

Alexhuszagh · 2022-07-05T17:40:04Z

src/docker/local.rs

-        .wrap_err("when copying seccomp profile")?;
-    docker_user_id(&mut docker, engine.kind);
+    docker_seccomp(
+        &mut docker,


I've tried not to overly rely on just having the structs passed: if there's any question of if the logic could need to be accessed outside and the logic does not rely on most of the members or it would require a lot of work to create those members, I've avoided passing the struct itself.

Alexhuszagh · 2022-07-05T17:41:51Z

src/docker/remote.rs

-struct DeleteVolume<'a>(&'a Engine, &'a VolumeId, MessageInfo);
+// it's unlikely that we ever need to erase a line in the destructors,
+// and it's better than keep global state everywhere, or keeping a ref
+// cell which could have already deleted a line


The deleters are the only location we don't have a single instance of MessageInfo, but I think this is fine since it avoids having to pass a RefCell everywhere, worrying about avoiding multiple mutable borrows, etc., and the chance we delete a line when invoking the deleters is near 0.

src/docker/shared.rs

Alexhuszagh · 2022-07-05T17:44:18Z

src/extensions.rs

-    fn print(&self, msg_info: MessageInfo) -> Result<()> {
-        shell::print(&self.fmt_message(msg_info), msg_info)
+    fn print(&self, msg_info: &mut MessageInfo) -> Result<()> {
+        let msg = self.fmt_message(msg_info);


This needs to be in 2 steps to avoid multiple mutable borrows.

Alexhuszagh · 2022-07-05T17:45:01Z

src/lib.rs

@@ -338,7 +338,7 @@ impl From<Host> for Target {
            Host::Aarch64UnknownLinuxMusl => Target::new_built_in("aarch64-unknown-linux-musl"),
            Host::Other(s) => Target::from(
                s.as_str(),
-                &rustc::target_list(Verbosity::Quiet.into()).unwrap(),
+                &rustc::target_list(&mut Verbosity::Quiet.into()).unwrap(),


Once again, we will never need to delete a line from the output here, so this isn't an issue.

Emilgardis

bors r+

bors · 2022-07-06T11:42:18Z

Build succeeded:

conclusion

Alexhuszagh added meta issues/PRs related to the maintenance of the crate. no changelog A valid PR without changelog (no-changelog) labels Jul 5, 2022

Alexhuszagh commented Jul 5, 2022

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src/bin/commands/clean.rs Show resolved Hide resolved

Alexhuszagh commented Jul 5, 2022

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src/bin/commands/containers.rs Outdated Show resolved Hide resolved

Move MessageInfo outwards.

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Alexhuszagh commented Jul 5, 2022

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src/docker/shared.rs Show resolved Hide resolved

Alexhuszagh commented Jul 5, 2022

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Remove redundant getters.

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Alexhuszagh marked this pull request as ready for review July 6, 2022 00:08

Alexhuszagh requested a review from a team as a code owner July 6, 2022 00:08

Emilgardis approved these changes Jul 6, 2022

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bors bot merged commit 3dc0d1f into cross-rs:main Jul 6, 2022

Alexhuszagh deleted the structify branch July 7, 2022 21:27

Alexhuszagh mentioned this pull request Jul 14, 2022

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Structify more of the internals to simplify the implementation. #911

Structify more of the internals to simplify the implementation. #911

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Structify more of the internals to simplify the implementation. #911

Structify more of the internals to simplify the implementation. #911

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Alexhuszagh commented Jul 5, 2022 • edited

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Alexhuszagh Jul 5, 2022 • edited

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bors bot commented Jul 6, 2022

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