Swift3: SR-2656: extra releases of dispatch_data_t objects on Linux #177
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Fixes an over-release problem in the wrapping overlay that occurred in callback blocks that take DispatchData structs. Just going through the glue layer between the Swift and C APIs should not result in a net change in the reference count of the dispatch_data_t object that the CDispatch layer is giving us to hand to the Swift callback block. However, when the temporary DispatchData struct we created in the wrapping layer (and its wrapped __DispatchData object) went out of scope at the end of the callback, the dispatch_data_t was released by __DispatchData's deinit resulting in an unintended net -1 from the glue code. We either need to add a compensating retain before entering the callback block or suppress the release in the deinit. This patch suppresses the release by adding an internal init that can create DispatchData's with borrowed dispatch_data_t objects that are not released on deinitialization.
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#175 for swift3 branch |
das
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Fixes an over-release problem in the wrapping overlay that
occurred in callback blocks that take DispatchData structs.
Just going through the glue layer between the Swift and C APIs
should not result in a net change in the reference count of
the dispatch_data_t object that the CDispatch layer is giving
us to hand to the Swift callback block. However, when the
temporary DispatchData struct we created in the wrapping layer
(and its wrapped __DispatchData object) went out of scope at
the end of the callback, the dispatch_data_t was released
by __DispatchData's deinit resulting in an unintended net -1
from the glue code.
We either need to add a compensating retain before entering the
callback block or suppress the release in the deinit. This patch
suppresses the release by adding an internal init that can
create DispatchData's with borrowed dispatch_data_t objects that
are not released on deinitialization.