When I originally wrote the read_u32v_be() and write_u32_be() functions, I didn't consider memory alignment requirements of various architectures. Unfortunately, the current implementations may result in unaligned reads and writes. This doesn't impact x86 / x86_64, but it can cause a compiler crash on ARM. This pull requests rewrites those functions to make sure that all memory access is always correctly aligned.
This fix is a little bit academic - due to the way that LLVM aligns the structures that are passed as arguments to these functions, I believe that the end result is that all memory access happens to be aligned anyway. However, there is nothing in that code that actually enforces that, at least not explicitly. The new implementations are definitely slower than the existing ones. However, I don't believe that these functions are all that significant when looking at the overall performance of the compiler. I think getting rid of some unsafe code and removing a potential portability landmine justifies a very slight decrease in raw performance.
<strike>Adds a simple/detailed toggle to api doc pages.
Detailed mode is the current behaviour, simple mode hides all doccomment details leaving only signatures for quick browsing.
</strike>
Adds [expand all] and [collapse all] "links" to all api doc pages. All doccomments are collapsed, leaving only signatures for quick browsing.
In addition, clicking on a <strike>function name</strike> function's [toggle details] link now toggles the visibility of the associated doccomment.
--------
# [Live Build Here](http://cg.scs.carleton.ca/~abeinges/doc/std/vec/struct.Vec.html)
This is something that's been bothering me, and I've seen some people mention in IRC before. The docs are *great* if you want a full in-depth look at an API, but *awful* if you want to scan them. This provides the ability to toggle complexity freely. Interacts perfectly well with noscript, since the static page is effectively unchanged. Collapsing is just hiding divs with css.
I'm not much of a designer, so design input welcome on the actual UX for toggling.
The actual javascript is *a bit* brittle to layout changes, but it always will be without adding lots of extra junk to the actual markup, which didn't seem worth it.
All doccomments are now collapsable via a nearby [-] button
Adds [collapse all] and [expand all] buttons to the top of all api pages
Tweaks some layout to accomadate this
This is the next section of the guide, and it's on pointers. It's not done yet, as I need to write the section on ownership and borrowing, but I figured I'd share the rest now, to get feedback on the rest of it while I take some time to get that right.
The current spsc implementation doesn't enforce single-producer
single-consumer usage and also allows unsafe memory use through
peek & pop.
For safer usage, `new` now returns a pair of owned objects which
only allow consumer or producer behaviors through an `Arc`.
Through restricting the mutability of the receiver to `mut` the
peek and pop behavior becomes safe again, with the compiler
complaining about usage which could lead to problems.
To fix code broken from this, update:
Queue::new(x) -> unsafe { Queue::unchecked_new(x) }
[breaking-change]
For an example of broken behavior, check the added test which uses the unchecked constructor.
The start of a testing guide. This PR relies on the crates and modules one because I shuffled some stuff around, so sorry about that.
I got stuck with how to import this name with cargo. @wycats and @alexcrichton , any ideas?
The current spsc implementation doesn't enforce single-producer
single-consumer usage and also allows unsafe memory use through
peek & pop.
For safer usage, `spsc_queue::queue` now returns a pair of owned objects which
only allow consumer or producer behaviours through an `Arc`.
Through restricting the mutability of the receiver to `mut` the
peek and pop behaviour becomes safe again, with the compiler
complaining about usage which could lead to problems.
To fix code broken from this, update:
Queue::new(x) -> unsafe { Queue::new(x) }
[breaking-change]
This is an alternative to upgrading the way rvalues are handled in the
borrow check. Making rvalues handled more like lvalues in the borrow
check caused numerous problems related to double mutable borrows and
rvalue scopes. Rather than come up with more borrow check rules to try
to solve these problems, I decided to just forbid pattern bindings after
`@`. This affected fewer than 10 lines of code in the compiler and
libraries.
This breaks code like:
match x {
y @ z => { ... }
}
match a {
b @ Some(c) => { ... }
}
Change this code to use nested `match` or `let` expressions. For
example:
match x {
y => {
let z = y;
...
}
}
match a {
Some(c) => {
let b = Some(c);
...
}
}
Closes#14587.
[breaking-change]
May need discussion at the meeting, but r? @nikomatsakis anyway
This is an alternative to upgrading the way rvalues are handled in the
borrow check. Making rvalues handled more like lvalues in the borrow
check caused numerous problems related to double mutable borrows and
rvalue scopes. Rather than come up with more borrow check rules to try
to solve these problems, I decided to just forbid pattern bindings after
`@`. This affected fewer than 10 lines of code in the compiler and
libraries.
This breaks code like:
match x {
y @ z => { ... }
}
match a {
b @ Some(c) => { ... }
}
Change this code to use nested `match` or `let` expressions. For
example:
match x {
y => {
let z = y;
...
}
}
match a {
Some(c) => {
let b = Some(c);
...
}
}
Closes#14587.
[breaking-change]
This ensures that the name of the crate is set from the command line for tests
so the auto-injection of `extern crate <name>` in doc tests works correctly.
When generating a unique symbol for things like closures or glue_drop,
we call token::gensym() to create a crate-unique Name. Recently, Name
changed its Show impl so it no longer prints as a number. This caused
symbols like glue_drop:1542 to become glue_drop:"glue_drop"(1542), or in
mangled form, glue_drop.$x22glue_drop$x22$LP$1542$RP$.
Add a few new free functions to alloc::rc for manipulating
uniquely-owned Rc values. is_unique() can be used to test if the Rc is
uniquely-owned, try_unwrap() can remove the value from a uniquely-owned
Rc, and get_mut() can return a &mut for a uniquely-owned Rc.
These are all free functions, because smart pointers should avoid having
methods when possible. They can't be static methods because UFCS will
remove that distinction. I think we should probably change downgrade()
and make_unique() into free functions as well, but that's out of scope.
Add a few new free functions to alloc::rc for manipulating
uniquely-owned Rc values. is_unique() can be used to test if the Rc is
uniquely-owned, try_unwrap() can remove the value from a uniquely-owned
Rc, and get_mut() can return a &mut for a uniquely-owned Rc.
These are all free functions, because smart pointers should avoid having
methods when possible. They can't be static methods because UFCS will
remove that distinction. I think we should probably change downgrade()
and make_unique() into free functions as well, but that's out of scope.
This ensures that the name of the crate is set from the command line for tests
so the auto-injection of `extern crate <name>` in doc tests works correctly.
A quick and dirty fix for #15036 until we get serious decoder reform.
Right now it is impossible for a `Decodable` to signal a decode error, for example if it has only finitely many allowed values, is a string which must be encoded a certain way, needs a valid checksum, etc. For example in the `libuuid` implementation of `Decodable` an `Option` is unwrapped, meaning that a decode of a malformed UUID will cause the task to fail.
A quick and dirty fix for #15036 until we get serious decoder reform.
Right now it is impossible for a Decodable to signal a decode error,
for example if it has only finitely many allowed values, is a string
which must be encoded a certain way, needs a valid checksum, etc. For
example in the libuuid implementation of Decodable an Option is
unwrapped, meaning that a decode of a malformed UUID will cause the
task to fail.
Since this adds a method to the `Decoder` trait, all users will need
to update their implementations to add it. The strategy used for the
current implementations for JSON and EBML is to add a new entry to
the error enum `ApplicationError(String)` which stores the string
provided to `.error()`.
[breaking-change]
