From d8c423da72506f8688a609c2a3bd9caf5f5bd93a Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sat, 30 Aug 2008 19:24:59 +0200
Subject: [PATCH] First bones of the transaction system's skeleton.

---
 ucw/Makefile |  6 +++--
 ucw/trans.h  | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 ucw/trans.h

diff --git a/ucw/Makefile b/ucw/Makefile
index 174e51b2..f7835977 100644
--- a/ucw/Makefile
+++ b/ucw/Makefile
@@ -33,7 +33,8 @@ LIBUCW_MODS= \
 	string str-esc str-split str-match str-imatch str-hex \
 	bbuf gary \
 	getopt \
-	strtonum
+	strtonum \
+	trans
 
 LIBUCW_MAIN_INCLUDES= \
 	lib.h log.h threads.h \
@@ -59,7 +60,8 @@ LIBUCW_MAIN_INCLUDES= \
 	qache.h \
 	kmp.h kmp-search.h binsearch.h \
 	partmap.h \
-	strtonum.h
+	strtonum.h \
+	trans.h
 
 ifdef CONFIG_UCW_THREADS
 # Some modules require threading
diff --git a/ucw/trans.h b/ucw/trans.h
new file mode 100644
index 00000000..7ba8e6ff
--- /dev/null
+++ b/ucw/trans.h
@@ -0,0 +1,75 @@
+/*
+ *	The UCW Library -- Transactions
+ *
+ *	(c) 2008 Martin Mares <mj@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#ifndef _UCW_TRANS_H
+#define _UCW_TRANS_H
+
+#include "ucw/clists.h"
+#include "ucw/mempool.h"
+
+#include <jmpbuf.h>
+
+/* Resource pools */
+
+struct respool {
+  clist resources;
+  struct mempool *mp;		// If set, resources are allocated from the mempool, otherwise by xmalloc()
+};
+
+struct resource {
+  cnode n;
+  struct res_class *rclass;
+  void *priv;			// Private to the class
+};
+
+struct res_class {
+  const char *name;
+  void (*undo)(struct res *t);
+  void (*dump)(struct res *t);
+};
+
+struct respool *rp_new(void);
+void rp_delete(struct respool *rp);
+void rp_dump(struct respool *rp);
+
+struct resource *res_alloc(struct respool *rp);
+void res_fix(struct resource *r);
+void res_undo(struct resource *r);
+void res_dump(struct resource *r);
+
+static inline struct resource *
+res_new(struct respool *rp, struct res_class *rc, void *priv)
+{
+  struct resource *r = res_alloc(rp);
+  r->rclass = rc;
+  r->priv = priv;
+  return r;
+}
+
+/* Transactions */
+
+struct trans {
+  struct trans *prev;
+  struct mempool_state trans_pool_state;
+  struct respool res_pool;
+  jmp_buf jmp;
+};
+
+void trans_init(void);		// Called automatically on trans_open() if needed
+void trans_cleanup(void);	// Free memory occupied by the transaction system pools
+
+struct trans *trans_open(void);
+struct trans *trans_get_current(void);
+void trans_commit(void);
+void trans_rollback(void);
+void trans_dump(void);
+
+/* Exceptions */
+
+#endif
-- 
2.39.2