forked from JuliaLang/julia
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
minor event and I/O code reorg (JuliaLang#31506)
- remove unused argument to `process_events` - a bit of file renaming and reorg; remove some dead code - this allows code in libuv.jl to use locks and other things in Threads
- Loading branch information
1 parent
dbe50f9
commit 9686d88
Showing
8 changed files
with
208 additions
and
240 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,155 @@ | ||
| # This file is a part of Julia. License is MIT: https://julialang.org/license | ||
|
|
||
| ## thread/task locking abstraction | ||
|
|
||
| """ | ||
| AbstractLock | ||
| Abstract supertype describing types that | ||
| implement the synchronization primitives: | ||
| [`lock`](@ref), [`trylock`](@ref), [`unlock`](@ref), and [`islocked`](@ref). | ||
| """ | ||
| abstract type AbstractLock end | ||
| function lock end | ||
| function unlock end | ||
| function trylock end | ||
| function islocked end | ||
| unlockall(l::AbstractLock) = unlock(l) # internal function for implementing `wait` | ||
| relockall(l::AbstractLock, token::Nothing) = lock(l) # internal function for implementing `wait` | ||
| assert_havelock(l::AbstractLock) = assert_havelock(l, Threads.threadid()) | ||
| assert_havelock(l::AbstractLock, tid::Integer) = | ||
| (islocked(l) && tid == Threads.threadid()) ? nothing : error("concurrency violation detected") | ||
| assert_havelock(l::AbstractLock, tid::Task) = | ||
| (islocked(l) && tid === current_task()) ? nothing : error("concurrency violation detected") | ||
| assert_havelock(l::AbstractLock, tid::Nothing) = error("concurrency violation detected") | ||
|
|
||
| """ | ||
| AlwaysLockedST | ||
| This struct does not implement a real lock, but instead | ||
| pretends to be always locked on the original thread it was allocated on, | ||
| and simply ignores all other interactions. | ||
| It also does not synchronize tasks; for that use a real lock such as [`RecursiveLock`](@ref). | ||
| This can be used in the place of a real lock to, instead, simply and cheaply assert | ||
| that the operation is only occurring on a single cooperatively-scheduled thread. | ||
| It is thus functionally equivalent to allocating a real, recursive, task-unaware lock | ||
| immediately calling `lock` on it, and then never calling a matching `unlock`, | ||
| except that calling `lock` from another thread will throw a concurrency violation exception. | ||
| """ | ||
| struct AlwaysLockedST <: AbstractLock | ||
| ownertid::Int16 | ||
| AlwaysLockedST() = new(Threads.threadid()) | ||
| end | ||
| assert_havelock(l::AlwaysLockedST) = assert_havelock(l, l.ownertid) | ||
| lock(l::AlwaysLockedST) = assert_havelock(l) | ||
| unlock(l::AlwaysLockedST) = assert_havelock(l) | ||
| trylock(l::AlwaysLockedST) = l.ownertid == Threads.threadid() | ||
| islocked(::AlwaysLockedST) = true | ||
|
|
||
|
|
||
| ## condition variables | ||
|
|
||
| """ | ||
| GenericCondition | ||
| Abstract implementation of a condition object | ||
| for synchonizing tasks objects with a given lock. | ||
| """ | ||
| struct GenericCondition{L<:AbstractLock} | ||
| waitq::InvasiveLinkedList{Task} | ||
| lock::L | ||
|
|
||
| GenericCondition{L}() where {L<:AbstractLock} = new{L}(InvasiveLinkedList{Task}(), L()) | ||
| GenericCondition{L}(l::L) where {L<:AbstractLock} = new{L}(InvasiveLinkedList{Task}(), l) | ||
| GenericCondition(l::AbstractLock) = new{typeof(l)}(InvasiveLinkedList{Task}(), l) | ||
| end | ||
|
|
||
| assert_havelock(c::GenericCondition) = assert_havelock(c.lock) | ||
| lock(c::GenericCondition) = lock(c.lock) | ||
| unlock(c::GenericCondition) = unlock(c.lock) | ||
| trylock(c::GenericCondition) = trylock(c.lock) | ||
| islocked(c::GenericCondition) = islocked(c.lock) | ||
|
|
||
| """ | ||
| wait([x]) | ||
| Block the current task until some event occurs, depending on the type of the argument: | ||
| * [`Channel`](@ref): Wait for a value to be appended to the channel. | ||
| * [`Condition`](@ref): Wait for [`notify`](@ref) on a condition. | ||
| * `Process`: Wait for a process or process chain to exit. The `exitcode` field of a process | ||
| can be used to determine success or failure. | ||
| * [`Task`](@ref): Wait for a `Task` to finish. If the task fails with an exception, the | ||
| exception is propagated (re-thrown in the task that called `wait`). | ||
| * [`RawFD`](@ref): Wait for changes on a file descriptor (see the `FileWatching` package). | ||
| If no argument is passed, the task blocks for an undefined period. A task can only be | ||
| restarted by an explicit call to [`schedule`](@ref) or [`yieldto`](@ref). | ||
| Often `wait` is called within a `while` loop to ensure a waited-for condition is met before | ||
| proceeding. | ||
| """ | ||
| function wait(c::GenericCondition) | ||
| ct = current_task() | ||
| assert_havelock(c) | ||
| push!(c.waitq, ct) | ||
| token = unlockall(c.lock) | ||
| try | ||
| return wait() | ||
| catch | ||
| list_deletefirst!(c.waitq, ct) | ||
| rethrow() | ||
| finally | ||
| relockall(c.lock, token) | ||
| end | ||
| end | ||
|
|
||
| """ | ||
| notify(condition, val=nothing; all=true, error=false) | ||
| Wake up tasks waiting for a condition, passing them `val`. If `all` is `true` (the default), | ||
| all waiting tasks are woken, otherwise only one is. If `error` is `true`, the passed value | ||
| is raised as an exception in the woken tasks. | ||
| Return the count of tasks woken up. Return 0 if no tasks are waiting on `condition`. | ||
| """ | ||
| notify(c::GenericCondition, @nospecialize(arg = nothing); all=true, error=false) = notify(c, arg, all, error) | ||
| function notify(c::GenericCondition, @nospecialize(arg), all, error) | ||
| assert_havelock(c) | ||
| cnt = 0 | ||
| while !isempty(c.waitq) | ||
| t = popfirst!(c.waitq) | ||
| schedule(t, arg, error=error) | ||
| cnt += 1 | ||
| all || break | ||
| end | ||
| return cnt | ||
| end | ||
|
|
||
| notify_error(c::GenericCondition, err) = notify(c, err, true, true) | ||
|
|
||
| n_waiters(c::GenericCondition) = length(c.waitq) | ||
|
|
||
| """ | ||
| isempty(condition) | ||
| Return `true` if no tasks are waiting on the condition, `false` otherwise. | ||
| """ | ||
| isempty(c::GenericCondition) = isempty(c.waitq) | ||
|
|
||
|
|
||
| # default (Julia v1.0) is currently single-threaded | ||
| # (although it uses MT-safe versions, when possible) | ||
| """ | ||
| Condition() | ||
| Create an edge-triggered event source that tasks can wait for. Tasks that call [`wait`](@ref) on a | ||
| `Condition` are suspended and queued. Tasks are woken up when [`notify`](@ref) is later called on | ||
| the `Condition`. Edge triggering means that only tasks waiting at the time [`notify`](@ref) is | ||
| called can be woken up. For level-triggered notifications, you must keep extra state to keep | ||
| track of whether a notification has happened. The [`Channel`](@ref) and [`Event`](@ref) types do | ||
| this, and can be used for level-triggered events. | ||
| This object is NOT thread-safe. See [`Threads.Condition`](@ref) for a thread-safe version. | ||
| """ | ||
| const Condition = GenericCondition{AlwaysLockedST} |
Oops, something went wrong.