Put a system-wide lock on the build directory.

So that two qbs instances can't overwrite each other's
build graphs. In practice, this is probably most relevant
for IDEs, as these hold a build graph for potentially long
periods of time.
Facilitates QLockFile that was introduced in Qt 5.1. For older
Qt versions, no locking happens.

Task-number: QBS-162
Change-Id: Ib598617fb1742eb57b6a017f40b9631d1d54e627
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/lib/corelib/api/internaljobs.cpp b/src/lib/corelib/api/internaljobs.cpp
index 840d7cc1c..ededa3279 100644
--- a/src/lib/corelib/api/internaljobs.cpp
+++ b/src/lib/corelib/api/internaljobs.cpp
@@ -42,6 +42,7 @@
 #include <language/loader.h>
 #include <logging/logger.h>
 #include <logging/translator.h>
+#include <tools/buildgraphlocker.h>
 #include <tools/error.h>
 #include <tools/progressobserver.h>
 #include <tools/preferences.h>
@@ -228,14 +229,23 @@ TopLevelProjectPtr InternalSetupProjectJob::project() const
 
 void InternalSetupProjectJob::start()
 {
+    BuildGraphLocker *bgLocker = 0;
     try {
         const ErrorInfo err = m_parameters.expandBuildConfiguration();
         if (err.hasError())
             throw err;
+        const QString projectId = TopLevelProject::deriveId(m_parameters.topLevelProfile(),
+                m_parameters.finalBuildConfigurationTree());
+        const QString buildDir
+                = TopLevelProject::deriveBuildDirectory(m_parameters.buildRoot(), projectId);
+        bgLocker = new BuildGraphLocker(ProjectBuildData::deriveBuildGraphFilePath(buildDir,
+                                                                                   projectId));
         execute();
+        m_project->bgLocker = bgLocker;
     } catch (const ErrorInfo &error) {
         m_project.clear();
         setError(error);
+        delete bgLocker;
     }
     emit finished(this);
 }