From: Robert Roebling <robert@roebling.de>
Date: Fri, 5 Sep 2008 08:54:09 +0000 (+0000)
Subject: Made wxMSW wxMutex non-recursive by checking reentrance
X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/424c9ce771d938db96d41135ba402a3a1134fa65

Made wxMSW wxMutex non-recursive by checking reentrance

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@55469 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---

diff --git a/interface/wx/thread.h b/interface/wx/thread.h
index b6eedd71c1..0e83c26d40 100644
--- a/interface/wx/thread.h
+++ b/interface/wx/thread.h
@@ -860,7 +860,7 @@ public:
 */
 enum wxMutexType
 {
-    /** Normal mutex: try to always use this one. Recursive under Windows. */
+    /** Normal non-recursive mutex: try to always use this one. */
     wxMUTEX_DEFAULT,   
 
     /** Recursive mutex: don't use these ones with wxCondition. */
@@ -909,9 +909,9 @@ enum wxMutexError
     had already locked before (instead of dead locking the entire process in this
     situation by starting to wait on a mutex which will never be released while the
     thread is waiting) but using them is not recommended under Unix and they are
-    @b not recursive there by default. The reason for this is that recursive
+    @b not recursive by default. The reason for this is that recursive
     mutexes are not supported by all Unix flavours and, worse, they cannot be used
-    with wxCondition. On the other hand, Win32 mutexes are always recursive.
+    with wxCondition.
 
     For example, when several threads use the data stored in the linked list,
     modifications to the list should only be allowed to one thread at a time
diff --git a/src/msw/thread.cpp b/src/msw/thread.cpp
index 072df5b373..f6d9939eb4 100644
--- a/src/msw/thread.cpp
+++ b/src/msw/thread.cpp
@@ -189,12 +189,16 @@ private:
     wxMutexError LockTimeout(DWORD milliseconds);
 
     HANDLE m_mutex;
+    
+    unsigned long m_owningThread;
+    bool m_isLocked;
+    wxMutexType m_type;
 
     DECLARE_NO_COPY_CLASS(wxMutexInternal)
 };
 
 // all mutexes are recursive under Win32 so we don't use mutexType
-wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
+wxMutexInternal::wxMutexInternal(wxMutexType mutexType)
 {
     // create a nameless (hence intra process and always private) mutex
     m_mutex = ::CreateMutex
@@ -204,10 +208,15 @@ wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
                     NULL        // no name
                 );
 
+    m_type = mutexType;
+    m_owningThread = 0;
+    m_isLocked = false;
+
     if ( !m_mutex )
     {
         wxLogLastError(_T("CreateMutex()"));
     }
+    
 }
 
 wxMutexInternal::~wxMutexInternal()
@@ -231,6 +240,16 @@ wxMutexError wxMutexInternal::TryLock()
 
 wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 {
+    if (m_type == wxMUTEX_DEFAULT)
+    {
+        // Don't allow recursive
+        if (m_isLocked)
+        {
+            if (m_owningThread == wxThread::GetCurrentId())
+                return wxMUTEX_DEAD_LOCK;
+        }
+    }
+
     DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
     if ( rc == WAIT_ABANDONED )
     {
@@ -261,6 +280,13 @@ wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
             return wxMUTEX_MISC_ERROR;
     }
 
+    if (m_type == wxMUTEX_DEFAULT)
+    { 
+        // required for checking recursiveness
+        m_isLocked = true;
+        m_owningThread = wxThread::GetCurrentId();
+    }
+    
     return wxMUTEX_NO_ERROR;
 }
 
@@ -272,6 +298,9 @@ wxMutexError wxMutexInternal::Unlock()
 
         return wxMUTEX_MISC_ERROR;
     }
+    
+    // required for checking recursiveness
+    m_isLocked = false;
 
     return wxMUTEX_NO_ERROR;
 }