From: Alain Spineux <alain@baculasystems.com>
Date: Mon, 6 Jul 2020 13:11:00 +0000 (+0200)
Subject: Add LOCK_GUARD() macro that add _FILE_ & _LINE_ to the lock_guard class
X-Git-Tag: Release-11.3.2~1404
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=095dbe2e3d722f65129e783ecbcb00b2257ebc72;p=thirdparty%2Fbacula.git

Add LOCK_GUARD() macro that add _FILE_ & _LINE_ to the lock_guard class

- LOCK_GUARD() create a lock_guard variable with an "automatic" name
  that try to be unique,merging "lock_guard_" and the current line number
  __LINE__.
  to use __LINE__ in an identifier, we need two level of macro
---

diff --git a/bacula/src/lib/lockmgr.h b/bacula/src/lib/lockmgr.h
index 34e5c93226..21eeec24a5 100644
--- a/bacula/src/lib/lockmgr.h
+++ b/bacula/src/lib/lockmgr.h
@@ -283,18 +283,53 @@ int bthread_kill(pthread_t thread, int sig,
 class lock_guard
 {
 public:
-   
+
    pthread_mutex_t &m_mutex; /* the class keeps a reference on the mutex*/
+   const char *file;
+   int line;
 
-   explicit lock_guard(pthread_mutex_t &mutex) : m_mutex(mutex)
+   explicit lock_guard(pthread_mutex_t &mutex) : m_mutex(mutex),
+         file(NULL), line(0)
    {
       P(m_mutex); /* constructor locks the mutex*/
    }
-   
+
+   explicit lock_guard(pthread_mutex_t &mutex, const char *file, int line) :
+         m_mutex(mutex), file(file), line(line)
+   {
+      #ifdef LOCKMGR_COMPLIANT
+         lmgr_p(&m_mutex);
+      #else
+         bthread_mutex_lock_p(&mutex, file, line);
+      #endif
+   }
+
    ~lock_guard()
    {
-      V(m_mutex); /* destructor unlocks the mutex*/
+      #ifdef LOCKMGR_COMPLIANT
+         lmgr_v(&m_mutex);
+      #else
+         if (file != NULL) {
+            bthread_mutex_unlock_p(&m_mutex, file, line);
+         } else {
+            bthread_mutex_unlock_p(&m_mutex, __FILE__, __LINE__);
+         }
+      #endif
    }
 };
 
+// Do magic! Creates a unique name using the line number, this need two level
+#define _DO_JOIN( symbol1, symbol2 ) _DO_JOIN2( symbol1, symbol2 )
+#define _DO_JOIN2( symbol1, symbol2 ) symbol1##symbol2
+
+/* You can check it by creating a variable with the expected name and see if the
+ * compiler complain, for example
+ * > LOCK_GUARD(mutex);  // this is line 123
+ * > lock_guard lock_guard_123(mutex);
+ */
+
+#define LOCK_GUARD(mutex) lock_guard _DO_JOIN(lock_guard_, __LINE__) (mutex, __FILE__, __LINE__)
+// If you have collision anyway, use the "postfix" version with a name you have chosen
+#define LOCK_GUARD_POSTFIX(mutex, postfix) lock_guard _DO_JOIN2(lock_guard_, postfix) (mutex, __FILE__, __LINE__)
+
 #endif  /* LOCKMGR_H */