From 287590eea2249f9008644355c4c1f3b3fe974c20 Mon Sep 17 00:00:00 2001
From: Matthias Kuhn <matthias@opengis.ch>
Date: Thu, 24 Sep 2015 08:16:26 +0200
Subject: [PATCH] Fix concurrency issue in snap indexing

---
 qgis-test-travis.ctest        | 4 ++--
 src/core/qgssnappingutils.cpp | 6 ++++++
 src/core/qgssnappingutils.h   | 3 +++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/qgis-test-travis.ctest b/qgis-test-travis.ctest
index 80d9ea0d20b..e12629430ec 100644
--- a/qgis-test-travis.ctest
+++ b/qgis-test-travis.ctest
@@ -69,14 +69,14 @@ ENDIF(NOT ${BUILDRES} EQUAL 0 OR NOT ${NUMERR} EQUAL 0)
 IF(NOT ${NUMWARN} EQUAL 0)
   ctest_submit (RETRY_COUNT 3 RETRY_DELAY 30)
   MESSAGE("${Yellow}Test results submitted to${ColorReset}")
-  MESSAGE("${BoldYellow}${SHORTURL}{ColorReset}" )
+  MESSAGE("${BoldYellow}${SHORTURL}${ColorReset}" )
   MESSAGE( FATAL_ERROR "${Red}Build warnings found, aborting test.${ColorReset}" )
 ENDIF(NOT ${NUMWARN} EQUAL 0)
 ctest_test (BUILD "${CTEST_BINARY_DIRECTORY}" PARALLEL_LEVEL 2 RETURN_VALUE TESTRES)
 IF(NOT ${TESTRES} EQUAL 0)
   ctest_submit (RETRY_COUNT 3 RETRY_DELAY 30)
   MESSAGE("${Yellow}Test results submitted to${ColorReset}")
-  MESSAGE("${BoldYellow}${SHORTURL}{ColorReset}" )
+  MESSAGE("${BoldYellow}${SHORTURL}${ColorReset}" )
   MESSAGE( FATAL_ERROR "Tests failed" )
 ENDIF(NOT ${TESTRES} EQUAL 0)
 
diff --git a/src/core/qgssnappingutils.cpp b/src/core/qgssnappingutils.cpp
index 1165d134db0..5ae3ff02b49 100644
--- a/src/core/qgssnappingutils.cpp
+++ b/src/core/qgssnappingutils.cpp
@@ -30,6 +30,7 @@ QgsSnappingUtils::QgsSnappingUtils( QObject* parent )
     , mDefaultTolerance( 10 )
     , mDefaultUnit( QgsTolerance::Pixels )
     , mSnapOnIntersection( false )
+    , mIsIndexing( false )
 {
   connect( QgsMapLayerRegistry::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( onLayersWillBeRemoved( QStringList ) ) );
 }
@@ -306,6 +307,10 @@ QgsPointLocator::Match QgsSnappingUtils::snapToMap( const QgsPoint& pointMap, Qg
 
 void QgsSnappingUtils::prepareIndex( const QList<QgsVectorLayer*>& layers )
 {
+  if ( mIsIndexing )
+    return;
+  mIsIndexing = true;
+
   // check if we need to build any index
   QList<QgsVectorLayer*> layersToIndex;
   Q_FOREACH ( QgsVectorLayer* vl, layers )
@@ -329,6 +334,7 @@ void QgsSnappingUtils::prepareIndex( const QList<QgsVectorLayer*>& layers )
     prepareIndexProgress( ++i );
   }
   QgsDebugMsg( QString( "Prepare index total: %1 ms" ).arg( t.elapsed() ) );
+  mIsIndexing = false;
 }
 
 
diff --git a/src/core/qgssnappingutils.h b/src/core/qgssnappingutils.h
index f7bdea3b680..7e1ed52ac2f 100644
--- a/src/core/qgssnappingutils.h
+++ b/src/core/qgssnappingutils.h
@@ -172,6 +172,9 @@ class CORE_EXPORT QgsSnappingUtils : public QObject
     LocatorsMap mTemporaryLocators;
     //! list of layer IDs that are too large to be indexed (hybrid strategy will use temporary locators for those)
     QSet<QString> mHybridNonindexableLayers;
+
+    //! internal flag that an indexing process is going on. Prevents starting two processes in parallel.
+    bool mIsIndexing;
 };