TapTap
18d1b84246
Add a NULL guard to protocol_release_memory_for_session so it no-ops like the sibling session setters. Correct the Data.owner doc comment, which implied a non-zero protocol_charge always has an owner; document that owner may be NULL for uncharged/ownerless Data, that any such charge falls back to the bound session, and that a charged Data must not outlive its owning session. Note the lifetime contract on the release API too. Extend tests/test_protocol.c to cover destroying a charged Data with no session bound (the other half of the original bug) and to assert that data_create/data_create_reserve start with owner == NULL and protocol_charge == 0.
38 lines
1.5 KiB
C
38 lines
1.5 KiB
C
#ifndef DATA_H
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#define DATA_H
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#include <stdlib.h>
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/* Forward declaration for the connection budget a received Data is charged
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* against; defined in protocol.h (which includes this header). */
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typedef struct ProtocolSession ProtocolSession;
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typedef struct {
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void* data;
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size_t size;
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/* Non-zero only for a buffer charged to the protocol connection budget. */
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size_t protocol_charge;
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/* Session whose budget `protocol_charge` was reserved from. When non-NULL,
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* the charge is returned to this session directly, regardless of which
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* session (if any) is bound to the destroying thread. owner is not
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* guaranteed to be set whenever protocol_charge is non-zero: it is NULL for
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* uncharged Data and for Data that has no recorded owner, in which case any
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* charge falls back to the session bound at destroy time.
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*
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* Lifetime contract: a Data with a non-NULL owner must not outlive that
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* ProtocolSession -- data_destroy dereferences owner to return the charge. */
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ProtocolSession* owner;
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} Data;
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Data* data_create_empty(size_t data_size);
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Data* data_create_reserve(size_t size);
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Data* data_create(void* data, size_t data_size);
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void data_destroy(Data* data);
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void protocol_release_memory(size_t charge);
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/* Release `charge` against `session` directly instead of the thread-local bound
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* session. Used by data_destroy to honor Data.owner; `session` must outlive
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* the Data whose charge is being returned. A NULL session is a no-op. */
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void protocol_release_memory_for_session(ProtocolSession* session, size_t charge);
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#endif
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