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Subject: svn commit: r1142026 - in /subversion/branches/svn_mutex/subversion:
 include/private/svn_mutex.h libsvn_subr/svn_mutex.c
Date: Fri, 01 Jul 2011 19:04:30 -0000
To: commits@subversion.apache.org
From: stefan2@apache.org
Message-Id: <20110701190430.1F18623888CE@eris.apache.org>

Author: stefan2
Date: Fri Jul  1 19:04:29 2011
New Revision: 1142026

URL: http://svn.apache.org/viewvc?rev=1142026&view=rev
Log:
Introduce the svn_mutex API and implement it

* subversion/include/private/svn_mutex.h
  new private API header
* subversion/libsvn_subr/svn_mutex.c
  implement the new API

Added:
    subversion/branches/svn_mutex/subversion/include/private/svn_mutex.h
    subversion/branches/svn_mutex/subversion/libsvn_subr/svn_mutex.c

Added: subversion/branches/svn_mutex/subversion/include/private/svn_mutex.h
URL: http://svn.apache.org/viewvc/subversion/branches/svn_mutex/subversion/include/private/svn_mutex.h?rev=1142026&view=auto
==============================================================================
--- subversion/branches/svn_mutex/subversion/include/private/svn_mutex.h (added)
+++ subversion/branches/svn_mutex/subversion/include/private/svn_mutex.h Fri Jul  1 19:04:29 2011
@@ -0,0 +1,82 @@
+/**
+ * @copyright
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you under the Apache License, Version 2.0 (the
+ *    "License"); you may not use this file except in compliance
+ *    with the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing,
+ *    software distributed under the License is distributed on an
+ *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *    KIND, either express or implied.  See the License for the
+ *    specific language governing permissions and limitations
+ *    under the License.
+ * ====================================================================
+ * @endcopyright
+ *
+ * @file svn_mutex.h
+ * @brief Strutures and functions for mutual exclusion
+ */
+
+#ifndef SVN_MUTEX_H
+#define SVN_MUTEX_H
+
+#include <apr_thread_mutex.h>
+#include "svn_error.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * This is a simple wrapper around @c apr_thread_mutex_t and will be a
+ * valid identifier even if APR does not support threading.
+ */
+typedef struct svn_mutex__t
+{
+#if APR_HAS_THREADS
+
+  /** A mutex for synchronization between threads. It may be NULL, in
+   * which case no synchronization will take place. The latter is useful,
+   * if implement some functionality where synchronization is optional.
+   */
+  apr_thread_mutex_t *mutex;
+  
+#endif
+} svn_mutex__t;
+
+/** Initialize the @a *mutex with a lifetime defined by @a pool, if
+ * @a enable_mutex is TRUE and with @c NULL otherwise. If @a enable_mutex
+ * is set but threading is not supported by APR, this function returns an
+ * @c APR_ENOTIMPL error.
+ */
+svn_error_t *
+svn_mutex__init(svn_mutex__t *mutex,
+                svn_boolean_t enable_mutex,
+                apr_pool_t *pool);
+
+/** Acquire the @a mutex, if that has been enabled in @ref svn_mutex__init.
+ * Make sure to call @ref svn_mutex__unlock some time later in the same 
+ * thread to release the mutex again. Recursive locking are not supported.
+ */
+svn_error_t *
+svn_mutex__lock(svn_mutex__t mutex);
+
+/** Release the @a mutex, previously acquired using @ref svn_mutex__lock
+ * that has been enabled in @ref svn_mutex__init.
+ */
+svn_error_t *
+svn_mutex__unlock(svn_mutex__t mutex,
+                  svn_error_t *err);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* SVN_MUTEX_H */
\ No newline at end of file

Added: subversion/branches/svn_mutex/subversion/libsvn_subr/svn_mutex.c
URL: http://svn.apache.org/viewvc/subversion/branches/svn_mutex/subversion/libsvn_subr/svn_mutex.c?rev=1142026&view=auto
==============================================================================
--- subversion/branches/svn_mutex/subversion/libsvn_subr/svn_mutex.c (added)
+++ subversion/branches/svn_mutex/subversion/libsvn_subr/svn_mutex.c Fri Jul  1 19:04:29 2011
@@ -0,0 +1,80 @@
+/*
+ * svn_mutex.c: in-memory caching for Subversion
+ *
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you under the Apache License, Version 2.0 (the
+ *    "License"); you may not use this file except in compliance
+ *    with the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing,
+ *    software distributed under the License is distributed on an
+ *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *    KIND, either express or implied.  See the License for the
+ *    specific language governing permissions and limitations
+ *    under the License.
+ * ====================================================================
+ */
+
+#include "svn_private_config.h"
+#include "private/svn_mutex.h"
+
+svn_error_t *
+svn_mutex__init(svn_mutex__t *mutex, 
+                svn_boolean_t enable_mutex, 
+                apr_pool_t *pool)
+{
+#if APR_HAS_THREADS
+  mutex->mutex = NULL;
+  if (enable_mutex)
+    {
+      apr_status_t status =
+          apr_thread_mutex_create(&mutex->mutex,
+                                  APR_THREAD_MUTEX_DEFAULT,
+                                  pool);
+      if (status)
+        return svn_error_wrap_apr(status, _("Can't create mutex"));
+    }
+#else
+  if (enable_mutex)
+    return svn_error_wrap_apr(APR_ENOTIMPL, _("APR doesn't support threads"));
+#endif
+    
+  return SVN_NO_ERROR;
+}
+
+svn_error_t *
+svn_mutex__lock(svn_mutex__t mutex)
+{
+#if APR_HAS_THREADS
+  if (mutex.mutex)
+    {
+      apr_status_t status = apr_thread_mutex_lock(mutex.mutex);
+      if (status)
+        return svn_error_wrap_apr(status, _("Can't lock mutex"));
+    }
+#endif
+
+  return SVN_NO_ERROR;
+}
+
+svn_error_t *
+svn_mutex__unlock(svn_mutex__t mutex, 
+                  svn_error_t *err)
+{
+#if APR_HAS_THREADS
+  if (mutex.mutex)
+    {
+      apr_status_t status = apr_thread_mutex_unlock(mutex.mutex);
+      if (status && !err)
+        return svn_error_wrap_apr(status, _("Can't unlock mutex"));
+    }
+#endif
+
+  return err;
+}