Previously, `string-cache` defined:
* An string-like `Atom` type,
* An `atom!("foo")` macro that expands to a value of that type, for a set of strings known at compile-time,
* A `struct Namespace(Atom);` type
* A `ns!(html)` macro that maps known prefixed to `Namespace` values with the corresponding namespace URL.
Adding a string to the static set required making a change to the `string-cache` crate.
With 0.3, the `Atom` type is now generic, with a type parameter that provides a set of static strings. We can have multiple such sets, defined in different crates. The `string_cache_codegen` crate, to be used in build scripts, generates code that defines such a set, a new atom type (a type alias for `Atom<_>` with the type parameter set), and an `atom!`-like macro.
The html5ever repository has a new `html5ever_atoms` crate that defines three such types: `Prefix`, `Namespace`, and `LocalName` (with respective `namespace_prefix!`, `namespace_url!`, and `local_name!` macros). It also defines the `ns!` macro like before.
This repository has a new `servo_atoms` crate in `components/atoms` that, for now, defines a single `Atom` type (and `atom!`) macro. (`servo_atoms::Atom` is defined as something like `type Atom = string_cache::Atom<ServoStaticStringSet>;`, so overall there’s now two types named `Atom`.)
In this PR, `servo_atoms::Atom` is used for everything else that was `string_cache::Atom` before. But more atom types can be defined as needed. Two reasons to do this are to auto-generate the set of static strings (I’m planning to do this for CSS property names, which is the motivation for this change), or to have the type system help us avoid mix up unrelated things (this is why we had a `Namespace` type ever before this change).
Introducing new types helped me find a bug: when creating a new attribute `dom::Element::set_style_attr`, would pass `Some(atom!("style"))` instead of `None` (now `Option<html5ever_atoms::Prefix>` instead of `Option<string_cache::Atom>`) to the `prefix` argument of `Attr::new`. I suppose the author of that code confused it with the `local_name` argument.
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Note that Stylo is not affected by any of this. The `gecko_string_cache` module is unchanged, with a single `Atom` type. The `style` crate conditionally compiles `Prefix` and `LocalName` re-exports for that are both `gecko_string_cache::Atom` on stylo.
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Source-Repo: https://github.com/servo/servo
Source-Revision: 5b4cc9568dbd5c15e5d2fbc62719172f11566ffa
This fixes about 130 clippy lints. Let me know if i should split up the commit.
I wasn't sure about some of the changes, especially map_or instead of map(...).unwrap_or(...) and if let instead of single arm match were not always a strict improvement in my opinion, but i'll leave that decision to the reviewer :)
There are about 150 lints left which i thought were clippy bugs or i didn't know how to fix.
cc @Manishearth
Source-Repo: https://github.com/servo/servo
Source-Revision: 9da739acefc7d1776bf727c8bf782eb79f241028
Updated string_cache to 0.2, and updated the dependencies that depend on string_cache.
Removed references to string_cache_plugin.
Import atom! and ns! from string_cache.
Replaced ns!("") by ns!().
Replaced ns!(XML) and co by ns!(xml) and co.
Replaced Atom::from_slice by Atom::from.
Replaced atom.as_slice() by &*atom.
r? @SimonSapin
Source-Repo: https://github.com/servo/servo
Source-Revision: 188fa9378c103093f1f8dac24bff0d9d237fd2bc
