[elephant-cvs] CVS update: elephant/src/libsleepycat.c

[blee at common-lisp.net]

Update of /project/elephant/cvsroot/elephant/src
In directory common-lisp.net:/tmp/cvs-serv22122/src

Modified Files:
	libsleepycat.c 
Log Message:
poor man's counters

Date: Sat Aug 28 08:40:33 2004
Author: blee

Index: elephant/src/libsleepycat.c
diff -u elephant/src/libsleepycat.c:1.3 elephant/src/libsleepycat.c:1.4
--- elephant/src/libsleepycat.c:1.3	Fri Aug 27 19:32:44 2004
+++ elephant/src/libsleepycat.c	Sat Aug 28 08:40:33 2004
@@ -368,6 +368,26 @@
   return env->lock_id_free(env, id);
 }
 
+int db_env_lock_get(DB_ENV *env, u_int32_t locker,
+		    u_int32_t flags, char *object, u_int32_t object_length,
+		    const db_lockmode_t lock_mode, DB_LOCK *lock) {
+  DBT DBTObject;
+  memset(&DBTObject, 0, sizeof(DBT));
+  DBTObject.data = object;
+  DBTObject.size = object_length;
+
+  return env->lock_get(env, locker, flags, &DBTObject, lock_mode, lock);
+}
+
+int db_env_lock_put(DB_ENV *env, DB_LOCK *lock) {
+  return env->lock_put(env, lock);
+}
+
+int db_env_lock_vec(DB_ENV *env, u_int32_t locker, u_int32_t flags,
+		    DB_LOCKREQ list[], int nlist, DB_LOCKREQ **elistp) {
+  return env->lock_vec(env, locker, flags, list, nlist, elistp);
+}
+
 /* db_timeout_t = u_int32_t */
 int db_env_set_timeout(DB_ENV *env, db_timeout_t timeout, u_int32_t flags) {
   return env->set_timeout(env, timeout, flags);
@@ -390,3 +410,72 @@
     return env->lock_detect(env, flags, atype, aborted);
 }
 
+/* Poor man's counters */
+
+int next_counter(DB_ENV *env, DB *db, char *key, u_int32_t key_length,
+		 char *lockid, u_int32_t lockid_length) {
+  DB_LOCK lock;
+  DBT DBTKey, DBTData; 
+  DB_TXN *tid; 
+  int counter, tries, ret, t_ret;
+  u_int32_t id;
+
+  /* Initialization. */ 
+  memset(&lock, 0, sizeof(lock)); 
+  memset(&DBTKey, 0, sizeof(DBTKey)); 
+  memset(&DBTData, 0, sizeof(DBTData)); 
+  DBTKey.data = key;
+  DBTKey.size = key_length;
+  DBTData.data = lockid;
+  DBTData.size = lockid_length;
+  tries = 0;
+
+ loop:
+  /* Begin the transaction. */ 
+  if ((ret = env->txn_begin(env, NULL, &tid, 0)) != 0) { 
+    env->err(env, ret, "DB_ENV->txn_begin"); 
+    return (-1); 
+  }
+
+  id = tid->id(tid);
+
+  if ((ret = env->lock_get(env, id, 0, &DBTData, DB_LOCK_WRITE, &lock)) != 0)
+    goto fail;
+
+  memset(&DBTData, 0, sizeof(DBTData)); 
+  DBTData.data = &counter;
+  DBTData.ulen = sizeof(counter);
+  DBTData.flags |= DB_DBT_USERMEM;
+
+  if ((ret = db->get(db, tid, &DBTKey, &DBTData, 0)) != 0) 
+    goto fail;
+
+  ++counter;
+
+  memset(&DBTData, 0, sizeof(DBTData)); 
+  DBTData.data = &counter;
+  DBTData.size = sizeof(counter);
+
+  if ((ret = db->put(db, tid, &DBTKey, &DBTData, 0)) != 0) 
+    goto fail;
+
+  if ((ret = env->lock_put(env, &lock)) != 0) 
+    goto fail;
+
+  if ((ret = tid->commit(tid, 0)) != 0) { 
+    env->err(env, ret, "DB_TXN->commit"); 
+    return (-2); 
+  } 
+  return (counter); 
+
+
+ fail:
+  /* Abort and retry the operation. */ 
+  if ((t_ret = tid->abort(tid)) != 0) { 
+    env->err(env, t_ret, "DB_TXN->abort"); 
+    return (-3);
+  } 
+  if (tries++ == 100)
+    return (-4); 
+  goto loop;
+}