Merge pull request #198 from dgrove-oss/SR-3477
SR-3477: replace unsafeBitCast by withoutActuallyEscaping
diff --git a/src/swift/Data.swift b/src/swift/Data.swift
index fc0bc09..d51205c 100644
--- a/src/swift/Data.swift
+++ b/src/swift/Data.swift
@@ -91,14 +91,18 @@
public func enumerateBytes(
block: (_ buffer: UnsafeBufferPointer<UInt8>, _ byteIndex: Int, _ stop: inout Bool) -> Void)
{
- // FIXME: When SR-2313 (withoutActuallyEscaping) is implemented, use it to replace unsafeBitCast
- let nonEscapingBlock = unsafeBitCast(block, to: _enumerateBytesBlock.self)
- _ = CDispatch.dispatch_data_apply(__wrapped.__wrapped) { (_, offset: Int, ptr: UnsafeRawPointer, size: Int) in
- let bytePtr = ptr.bindMemory(to: UInt8.self, capacity: size)
- let bp = UnsafeBufferPointer(start: bytePtr, count: size)
- var stop = false
- nonEscapingBlock(bp, offset, &stop)
- return !stop
+ // we know that capturing block in the closure being created/passed to dispatch_data_apply
+ // does not cause block to escape because dispatch_data_apply does not allow its
+ // block argument to escape. Therefore, the usage of withoutActuallyEscaping to
+ // bypass the Swift type system is safe.
+ withoutActuallyEscaping(block) { escapableBlock in
+ _ = CDispatch.dispatch_data_apply(__wrapped.__wrapped) { (_, offset: Int, ptr: UnsafeRawPointer, size: Int) in
+ let bytePtr = ptr.bindMemory(to: UInt8.self, capacity: size)
+ let bp = UnsafeBufferPointer(start: bytePtr, count: size)
+ var stop = false
+ escapableBlock(bp, offset, &stop)
+ return !stop
+ }
}
}
@@ -273,8 +277,6 @@
internal var _position: DispatchData.Index
}
-typealias _enumerateBytesBlock = (_ buffer: UnsafeBufferPointer<UInt8>, _ byteIndex: Int, _ stop: inout Bool) -> Void
-
@_silgen_name("_swift_dispatch_data_empty")
internal func _swift_dispatch_data_empty() -> dispatch_data_t
