86d86a85e4
The casting functions in `unsafe.rs` were unsound (i.e., they allowed
safe code to cause undefined behavior). While they did appear to be used
in a way that wouldn't cause UB the fact that there exists unsound
functions is unsettling.
This commit removes those functions and replaces it with a macro that
performs the same reification - the difference is that the macro call
will also include the checks which are required to prevent UB. A macro
was chosen instead of a function for two reasons:
1. A macro can keep the same code generation whereas a function would
require going through an `Option` which has negative impacts on code
generation (niche values cause poor DCE).
2. There exist other `unsafe` code blocks in the crate and an attempt to
make Rhai 100% safe is completely out-of-scope for this merge
request, so we may as well use `unsafe` in the macro.
Regarding (2) above, I may come back at a later date with a 100% safe
`reify` function but only once the other `unsafe` blocks are removed.
For posterity, said function would look something like:
```rust
fn reify<A: Any, C>(value: A) -> Option<C> {
let mut v = Some(value);
let v: &mut dyn Any = &mut v;
v.downcast_mut::<Option<C>>().map(Option::take)
}
```
32 lines
1.8 KiB
Markdown
32 lines
1.8 KiB
Markdown
Source Structure
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Root Sources
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| Source file | Description |
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| -------------- | ------------------------------------------------------------------------------- |
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| `lib.rs` | Crate root |
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| `engine.rs` | The scripting engine, defines the `Engine` type |
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| `tokenizer.rs` | Script tokenizer/lexer |
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| `parser.rs` | Script parser |
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| `optimizer.rs` | Script optimizer |
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| `reify.rs` | Utilities for making generic types concrete |
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| `tests.rs` | Unit tests (not integration tests, which are in the `rhai/tests` sub-directory) |
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Sub-Directories
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---------------
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| Sub-directory | Description |
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| ------------- | ----------------------------------------------------- |
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| `types` | Common data types (e.g. `Dynamic`, errors) |
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| `api` | Public API for the scripting engine |
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| `ast` | AST definition |
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| `module` | Support for modules |
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| `packages` | Pre-defined packages |
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| `func` | Support for function calls |
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| `eval` | Evaluation engine |
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| `serde` | Support for [`serde`](https://crates.io/crates/serde) |
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| `bin` | Pre-built CLI binaries (e.g. `rhai-run`, `rhai-repl`) |
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