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//===--- SwiftPrivateThreadExtras.swift -----------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file contains wrappers for pthread APIs that are less painful to use
// than the C APIs.
//
//===----------------------------------------------------------------------===//
#if canImport(Darwin)
import Darwin
#elseif canImport(Glibc)
import Glibc
#elseif canImport(Musl)
import Musl
#elseif canImport(Android)
import Android
#elseif os(WASI)
import WASILibc
#elseif os(Windows)
import CRT
import WinSDK
#endif
/// An abstract base class to encapsulate the context necessary to invoke
/// a block from pthread_create.
internal class ThreadBlockContext {
/// Execute the block, and return an `UnsafeMutablePointer` to memory
/// allocated with `UnsafeMutablePointer.alloc` containing the result of the
/// block.
func run() -> UnsafeMutableRawPointer { fatalError("abstract") }
}
internal class ThreadBlockContextImpl<Argument, Result>: ThreadBlockContext {
let block: (Argument) -> Result
let arg: Argument
init(block: @escaping (Argument) -> Result, arg: Argument) {
self.block = block
self.arg = arg
super.init()
}
override func run() -> UnsafeMutableRawPointer {
let result = UnsafeMutablePointer<Result>.allocate(capacity: 1)
result.initialize(to: block(arg))
return UnsafeMutableRawPointer(result)
}
}
/// Entry point for `pthread_create` that invokes a block context.
internal func invokeBlockContext(
_ contextAsVoidPointer: UnsafeMutableRawPointer?
) -> UnsafeMutableRawPointer! {
// The context is passed in +1; we're responsible for releasing it.
let context = Unmanaged<ThreadBlockContext>
.fromOpaque(contextAsVoidPointer!)
.takeRetainedValue()
return context.run()
}
#if os(Windows)
public typealias ThreadHandle = HANDLE
#else
public typealias ThreadHandle = pthread_t
#if (os(Linux) && !canImport(Musl)) || os(Android)
internal func _make_pthread_t() -> pthread_t {
return pthread_t()
}
#else
internal func _make_pthread_t() -> pthread_t? {
return nil
}
#endif
#endif
/// Block-based wrapper for `pthread_create`.
public func _stdlib_thread_create_block<Argument, Result>(
_ start_routine: @escaping (Argument) -> Result,
_ arg: Argument
) -> (CInt, ThreadHandle?) {
let context = ThreadBlockContextImpl(block: start_routine, arg: arg)
// We hand ownership off to `invokeBlockContext` through its void context
// argument.
let contextAsVoidPointer = Unmanaged.passRetained(context).toOpaque()
#if os(Windows)
let threadID =
_beginthreadex(nil, 0, { invokeBlockContext($0)!
.assumingMemoryBound(to: UInt32.self).pointee },
contextAsVoidPointer, 0, nil)
if threadID == 0 {
return (errno, nil)
} else {
return (0, ThreadHandle(bitPattern: threadID))
}
#elseif os(WASI)
// WASI environment is single-threaded
return (0, nil)
#else
var threadID = _make_pthread_t()
let result = pthread_create(&threadID, nil,
{ invokeBlockContext($0) }, contextAsVoidPointer)
if result == 0 {
return (result, threadID)
} else {
return (result, nil)
}
#endif
}
/// Block-based wrapper for `pthread_join`.
public func _stdlib_thread_join<Result>(
_ thread: ThreadHandle,
_ resultType: Result.Type
) -> (CInt, Result?) {
#if os(Windows)
let result = WaitForSingleObject(thread, INFINITE)
guard result == WAIT_OBJECT_0 else { return (CInt(result), nil) }
var dwResult: DWORD = 0
GetExitCodeThread(thread, &dwResult)
CloseHandle(thread)
let value: Result = withUnsafePointer(to: &dwResult) {
$0.withMemoryRebound(to: Result.self, capacity: 1) {
$0.pointee
}
}
return (CInt(result), value)
#elseif os(WASI)
// WASI environment has a only single thread
return (0, nil)
#else
var threadResultRawPtr: UnsafeMutableRawPointer?
let result = pthread_join(thread, &threadResultRawPtr)
if result == 0 {
let threadResultPtr = threadResultRawPtr!.assumingMemoryBound(
to: Result.self)
let threadResult = threadResultPtr.pointee
threadResultPtr.deinitialize(count: 1)
threadResultPtr.deallocate()
return (result, threadResult)
} else {
return (result, nil)
}
#endif
}
public class _stdlib_Barrier {
var _threadBarrier: _stdlib_thread_barrier_t
var _threadBarrierPtr: UnsafeMutablePointer<_stdlib_thread_barrier_t> {
return _getUnsafePointerToStoredProperties(self)
.assumingMemoryBound(to: _stdlib_thread_barrier_t.self)
}
public init(threadCount: Int) {
self._threadBarrier = _stdlib_thread_barrier_t()
let ret = _stdlib_thread_barrier_init(
_threadBarrierPtr, CUnsignedInt(threadCount))
if ret != 0 {
fatalError("_stdlib_thread_barrier_init() failed")
}
}
deinit {
_stdlib_thread_barrier_destroy(_threadBarrierPtr)
}
public func wait() {
let ret = _stdlib_thread_barrier_wait(_threadBarrierPtr)
if !(ret == 0 || ret == _stdlib_THREAD_BARRIER_SERIAL_THREAD) {
fatalError("_stdlib_thread_barrier_wait() failed")
}
}
}
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