It turns out, we don't need capabilities of MuCell (or even RefCell).
We don't to have sophisticated interior mutability. We don't ever lend
out references that may be mutated later. Instead, if there is no value
to lend, then we generate the value, require interior mutability to save
the value internally, and then we return a reference. We never ever
change a value once it's been generated. It can be changed, but only via
&mut self methods, where we can safely reason about mutability.
This means we don't need keep borrow checking code at runtime, which
helps performance. We also are able to reduce the amount of unsafe
transmutes. The internal API more safely constrains the usage of unsafe,
enforcing our invariants, instead of shotgunning unsafe usage with Refs
and promising we're doing it correctly.
On a machine with lower memory (1GB):
Before:
test bench_mock_hyper ... bench: 251772 ns/iter (+/- 128445)
After:
test bench_mock_hyper ... bench: 152603 ns/iter (+/- 25928)
On a machine with more memory, weaker CPU:
Before:
test bench_mock_hyper ... bench: 129398 ns/iter (+/- 51740)
After:
test bench_mock_hyper ... bench: 115935 ns/iter (+/- 28555)
Closes#252
It is no longer required, as we can use `<H as Header>::header_name()`.
BREAKING CHANGE: Implementations of Header will need to adjust the
header_name method. It no longer takes any arguments.
Currently headers are exported at many places. For example you can access
`Transfer-Encoding` header at `header`, `header::common` and
`header::common::transfer_encoding`. Per discussion on IRC with
@seanmonstar and @reem, all contents of headers will be exposed at `header`
directly. Parsing utilities will be exposed at `header::parsing`. Header
macros can now be used from other crates.
This breaks much code using headers. It should use everything it needs
directly from `header::`, encodings are exposed at `header::Encoding::`,
connection options are exposed at `header::ConnectionOption`.
- Some stray deriving -> derive changes
- use::{mod} -> use::{self}
- fmt.write -> fmt.write_str
This does not catch the last case of fmt.write_str in the
Show impl of a Header Item. This will need to be changed
separately.
- Includes ergonomic traits like IntoUrl and IntoBody, allowing easy
usage.
- Client can have a RedirectPolicy.
- Client can have a SslVerifier.
Updated benchmarks for client. (Disabled rust-http client bench since it
hangs.)
Previously, iter() returned (&str, HeaderView), which wasn't too useful
other than to write out to a stream. Checking for a certain header is
painful since header names are case-insensitive, but &str isn't. And
once found, you still couldn't do anything with a HeaderView other
format it.
Now, iter() returns a HeaderView, with methods is(), name(), and
value(). You can do `view.is::<ContentType>()` to check what header it
is. And you get the typed value out by calling
`view.value::<ContentType>()`, which will return an
`Option<ContentType>`, similar to `headers.get()`.
Headers also now implement Extend and FromIterator, so it's easier to
build new Headers objects by filtering out a few headers.
Because this changes .iter() to return HeaderView instead of a tuple,
this is a:
[breaking-change]
