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100 lines
3.4 KiB
100 lines
3.4 KiB
2 months ago
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/*
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* The UCW Library -- Transactions
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*
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* (c) 2008--2011 Martin Mares <mj@ucw.cz>
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*
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* This software may be freely distributed and used according to the terms
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* of the GNU Lesser General Public License.
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*/
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#ifndef _UCW_TRANS_H
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#define _UCW_TRANS_H
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#include <ucw/mempool.h>
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#include <setjmp.h>
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#ifdef CONFIG_UCW_CLEAN_ABI
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#define trans_caught ucw_trans_caught
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#define trans_cleanup ucw_trans_cleanup
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#define trans_commit ucw_trans_commit
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#define trans_current_exc ucw_trans_current_exc
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#define trans_dump ucw_trans_dump
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#define trans_fold ucw_trans_fold
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#define trans_get_current ucw_trans_get_current
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#define trans_get_pool ucw_trans_get_pool
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#define trans_init ucw_trans_init
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#define trans_open ucw_trans_open
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#define trans_rollback ucw_trans_rollback
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#define trans_throw ucw_trans_throw
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#define trans_throw_exc ucw_trans_throw_exc
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#define trans_vthrow ucw_trans_vthrow
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#endif
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/** A structure describing a transaction. All fields are for internal use only. **/
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struct trans {
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struct trans *prev_trans;
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struct mempool_state *trans_pool_state;
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struct respool *rpool;
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struct respool *prev_rpool;
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struct exception *thrown_exc;
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jmp_buf jmp;
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};
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void trans_init(void); /** Initializes the transaction system for the current thread. Called automatically as needed. **/
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void trans_cleanup(void); /** Frees memory occupied by the transaction system pools for the current thread. **/
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struct trans *trans_open(void); /** Creates a new transaction. Used inside `TRANS_TRY`. **/
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struct trans *trans_get_current(void); /** Get a pointer to the currently running transaction, or NULL if there is none. **/
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void trans_commit(void); /** Commits the current transaction. **/
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void trans_rollback(void); /** Rolls back the current transaction. **/
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void trans_fold(void); /** Folds the current transaction to its parent. **/
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void trans_dump(void); /** Prints out a debugging dump of the transaction stack to stdout. **/
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struct mempool *trans_get_pool(void);
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/**
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* Data associated with an exception. Usually, this structure is created
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* by calling @trans_throw(), but if you want to pass more data, you can
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* create your own exception and throw it using @trans_throw_exc().
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**/
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struct exception {
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const char *id; // Hierarchical identifier of the exception
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const char *msg; // Error message to present to the user
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void *object; // Object on which the exception happened
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// More data specific for the particular `id' can follow
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};
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/** Creates an exception and throws it. The error message can contain `printf`-like formatting. **/
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void trans_throw(const char *id, void *object, const char *fmt, ...) FORMAT_CHECK(printf,3,4) NONRET;
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/** A `va_list` variant of @trans_throw(). **/
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void trans_vthrow(const char *id, void *object, const char *fmt, va_list args) NONRET;
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/** Throw an already constructed exception (or re-throw an exception you have caught). **/
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void trans_throw_exc(struct exception *x) NONRET;
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/** Declare the current exception caught and roll back the current transaction. Called from `TRANS_END`. **/
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void trans_caught(void);
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struct exception *trans_current_exc(void); /** Return the exception in flight, or NULL if there is none. **/
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#define TRANS_TRY do { \
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struct trans *_t = trans_open(); \
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if (!setjmp(_t->jmp)) \
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{
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#define TRANS_CATCH(x) \
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trans_commit(); \
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} \
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else \
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{ \
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struct exception *x UNUSED = trans_current_exc();
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#define TRANS_END \
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trans_caught(); \
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} \
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} while(0)
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#endif
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