This makes using the `PreferredRuntime` the first-class option inside
`arti-client`, freeing users who don't want to think about runtimes from
having to do so.
`TorClient::create_unbootstrapped` and `builder` now automatically
use this runtime, leaving only `builder_custom` for users who wish to
manually specify a runtime.
This lets us clean up the docs a lot: mentions of using custom runtimes
are now relegated to nearer the end of the crate-level documentation,
and we mostly just link to `tor_rtcompat`'s docs to explain more there.
Instead, we take some more time to explain how you use the builder API
to create clients synchronously.
Other doc cleanups included getting rid of the explanation of `TorAddr`
in the main crate-level doc; this is already well-documented elsewhere,
and is something users should discover organically later.
fixes arti#326
`StateMgr` got a new `unlock()` method that does what it says on the
tin. We now call it from `bootstrap()` using the new
`util::StateMgrUnlockGuard`, which works in a manner similar to the
`BoolResetter` from `tor_dirmgr`.
(A decent small little task in future might be to unify these types in
some sort of general arti utility crate?)
closes arti#335
This lint is IMO inherently ill-conceived.
I have looked for the reasons why this might be thought to be a good
idea and there were basically two (and they are sort of contradictory):
I. "Calling ‘.clone()` on an Rc, Arc, or Weak can obscure the fact
that only the pointer is being cloned, not the underlying data."
This is the wording from
https://rust-lang.github.io/rust-clippy/v0.0.212/#clone_on_ref_ptr
It is a bit terse; we are left to infer why it is a bad idea to
obscure this fact. It seems to me that if it is bad to obscure some
fact, that must be because the fact is a hazard. But why would it be
a hazard to not copy the underlying data ?
In other languages, faliing to copy the underlying data is a serious
correctness hazard. There is a whose class of bugs where things were
not copied, and then mutated and/or reused in multiple places in ways
that were not what the programmer intended. In my experience, this is
a very common bug when writing Python and Javascript. I'm told it's
common in golang too.
But in Rust this bug is much much harder to write. The data inside an
Arc is immutable. To have this bug you'd have use interior mutability
- ie mess around with Mutex or RefCell. That provides a good barrier
to these kind of accidents.
II. "The reason for writing Rc::clone and Arc::clone [is] to make it
clear that only the pointer is being cloned, as opposed to the
underlying data. The former is always fast, while the latter can
be very expensive depending on what is being cloned."
This is the reasoning found here
https://github.com/rust-lang/rust-clippy/issues/2048
This is saying that *not* using Arc::clone is hazardous.
Specifically, that a deep clone is a performance hazard.
But for this argument, the lint is precisely backwards. It's linting
the "good" case and asking for it to be written in a more explicit
way; while the supposedly bad case can be written conveniently.
Also, many objects (in our codebase, and in all the libraries we use)
that are Clone are in fact simply handles. They contain Arc(s) (or
similar) and are cheap to clone. Indeed, that is the usual case.
It does not make sense to distinguish in the syntax we use to clone
such a handle, whether the handle is a transparent Arc, or an opaque
struct containing one or more other handles.
Forcing Arc::clone to be written as such makes for code churn when a
type is changed from Arc<Something> to Something: Clone, or vice
versa.
This patch removes the EventStream associated type and the Runtime
parameter. The Runtime parameter wasn't actually used for anything,
and the EventStream was easy enough to replace with a BoxStream in
this case.
Also replaced DirBootstrapEvents with a BoxStream to avoid tying
anything to our backend.
Try to make the `hook-tcp` example a bit easier to read by
adding/changing comments, and renaming the lifetimes for
`async_trait`-generated trait methods.
This is the first one where anyhow::Error impl AsRef<dyn StdError>
We want this because we want to add error reporting functionality
which works with all kinds of errors, which means we need an
anyhow::Error which can be vieweed as a StdError.
(The alternative would be to deref at the call sites of
report_and_exit, making it less ergonomic.)
anyhow 1.0.23 is from November 2019.
The new `BootstrapBehavior` enum controls whether an unbootstrapped
`TorClient` will bootstrap itself automatically (`Ondemand`) when an
attempt is made to use it, or whether the user must perform
bootstrapping themselves (`Manual`).
The `lazy-init` example shows how you could write a simple
`get_tor_client()` function that used a global `OnceCell` to share
a Tor client across an entire application with this API.
closes arti#278
Ian Jackson
Nick Mathewson
Ian Jackson
eta
trinity-1686a
Christian Grigis
Dimitris Apostolou
Yuan Lyu