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BufferProvider: inline the buildHandle function to simplify calls

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In the old version of `BufferProvider`, there was a single
backend implementation, which was assumed to call-back into
`buildHandle(typeID, storage, localTag)` after allocating memory.
This implies, the state transition to `LOCKED` happened there.

My next goal is to clarify and abstract also the state transition API,
and this refactoring helps a lot to see the underlying call structure.
This commit is contained in:
Fischlurch 2026-02-13 22:43:24 +01:00
parent 70e32a3e66
commit 9b66818bda
3 changed files with 15 additions and 30 deletions
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2
src/steam/engine/buffer-metadata.hpp
View file

@ -377,7 +377,7 @@ namespace engine {
__buffer_required();
if (nontrivial (instanceFunc_))
instanceFunc_.destroyAttached (buffer_);
buffer_ = 0;
buffer_ = nullptr;
}
private:

41
src/steam/engine/buffer-provider.cpp
View file

@ -78,25 +78,6 @@ namespace engine {
}
/**
* Callback from implementation to build and enrol a BufferHandle,
* to be returned to the client as result of the #lockBuffer call.
* Performs the necessary metadata state transition leading from an
* abstract buffer type to a metadata::Entry corresponding to an
* actual buffer, which is locked for exclusive use by one client.
* @note the implementation is free to provide an opaque \a implMarker,
* which becomes part of the key to designate this specific buffer.
*/
BuffHandle
BufferProvider::buildHandle (HashVal typeID, Buff* storage, LocalTag implMarker)
{
metadata::Key& typeKey = bufferStage_->get (typeID);
metadata::Entry& entry = bufferStage_->markLocked (typeKey, storage, implMarker);
return BuffHandle (BuffDescr(*this, entry), storage);
}
/** BufferProvider API: declare in advance the need for working buffers.
* This optional call allows client code to ensure the availability of the
* necessary working space, prior to starting the actual operations. The
@ -123,10 +104,15 @@ namespace engine {
/** BufferProvider API: retrieve a single buffer for exclusive use.
* This call actually claims a buffer of this type and marks it for
* use by client code. The returned handle allows for convenient access,
* but provides no automatic tracking or memory management. The client is
* explicitly responsible to invoke #releaseBuffer (which can be done directly
* on the BuffHandle).
* use by client code. Performs the necessary metadata state transition
* leading from an abstract buffer type to a derived metadata::Entry
* that corresponds to an actual buffer and has a lifecycle state.
* This entry is marked as _locked_ for exclusive use by one client.
* The returned handle allows to query state and perform further
* state transitions (_emitted_, _released_), yet provides no
* automatic tracking and clean-up. The client is explicitly
* responsible to invoke #releaseBuffer (either on the
* BufferProvider, or directly on the BuffHandle).
* @return a copyable handle, representing this buffer and this usage transaction.
* @throw error::State when unable to provide this buffer
* @note this function may be used right away, without prior announcing, but then
@ -138,10 +124,11 @@ namespace engine {
BufferProvider::lockBuffer (BuffDescr const& type)
{
REQUIRE (was_created_by_this_provider (type));
metadata::Entry& metaEntry = bufferStage_->get (type);
size_t buffSiz = metaEntry.storageSize();
auto [storage, implMarker] = bufferStore_->provideBuffer (buffSiz, type, metaEntry.localTag());
return buildHandle (type, storage, implMarker);
metadata::Key& typeKey = bufferStage_->get (type);
auto [storage, implMarker] = bufferStore_->provideBuffer (typeKey.storageSize(), type, typeKey.localTag());
metadata::Entry& entry = bufferStage_->markLocked (typeKey, storage, implMarker);
return BuffHandle (BuffDescr(*this, entry), storage);
}

2
src/steam/engine/buffer-provider.hpp
View file

@ -180,8 +180,6 @@ namespace engine {
/// placeholder marker type for an actual data buffer
using Buff = StreamType::ImplFacade::DataBuffer;
BuffHandle buildHandle (HashVal typeID, Buff* storage, LocalTag =LocalTag::UNKNOWN);
bool was_created_by_this_provider (BuffDescr const&) const;