Use a shared_mutex to read/write lock the nickIndex

Fixes sentry kicad-ax

common/lib_table_base.cpp

@@ -193,6 +193,8 @@ LIB_TABLE_ROW* LIB_TABLE::findRow( const wxString& aNickName, bool aCheckIfEnabl
     {
         cur->ensureIndex();
 
+        std::shared_lock<std::shared_mutex> lock( m_nickIndexMutex );
+
         for( const std::pair<const wxString, int>& entry : cur->m_nickIndex )
         {
             if( entry.first == aNickName )
@@ -303,7 +305,7 @@ bool LIB_TABLE::InsertRow( LIB_TABLE_ROW* aRow, bool doReplace )
 {
     ensureIndex();
 
-    std::lock_guard<std::mutex> lock( m_nickIndexMutex );
+    std::lock_guard<std::shared_mutex> lock( m_nickIndexMutex );
 
     INDEX_CITER it = m_nickIndex.find( aRow->GetNickName() );
 

include/lib_table_base.h

@@ -30,7 +30,7 @@
 #include <boost/noncopyable.hpp>
 #include <boost/ptr_container/ptr_vector.hpp>
 #include <memory>
-#include <mutex>
+#include <shared_mutex>
 #include <project.h>
 #include <string_utf8_map.h>
 #include <richio.h>
@@ -329,7 +329,7 @@ public:
     /// Delete all rows.
     void Clear()
     {
-        std::lock_guard<std::mutex> lock( m_nickIndexMutex );
+        std::lock_guard<std::shared_mutex> lock( m_nickIndexMutex );
 
         m_rows.clear();
         m_nickIndex.clear();
@@ -541,7 +541,7 @@ protected:
 
     void reindex()
     {
-        std::lock_guard<std::mutex> lock( m_nickIndexMutex );
+        std::lock_guard<std::shared_mutex> lock( m_nickIndexMutex );
 
         m_nickIndex.clear();
 
@@ -580,7 +580,7 @@ protected:
     mutable int m_version;
 
     /// Mutex to protect access to the nickIndex variable
-    mutable std::mutex m_nickIndexMutex;
+    mutable std::shared_mutex m_nickIndexMutex;
 };
 
 #endif  // _LIB_TABLE_BASE_H_