Prevent dangling JS values

As opposed to QtScript, such values cannot be re-used in QuickJS. This
was overlooked in 087c22e17721f37490dd2048a567b6a58065d939.
I assume this is the culprit for seemingly random crashes and "not a
function" messages we have been seeing sometimes when building with Qt
Creator.

Change-Id: Ia4e7aed0cda97439ac75db5ecfbf08ff096a02b2
Reviewed-by: Ivan Komissarov <ABBAPOH@gmail.com>

2 files changed, 5 insertions, 16 deletions

diff --git a/src/lib/corelib/buildgraph/depscanner.cpp b/src/lib/corelib/buildgraph/depscanner.cpp
index e4e10f477..01e781a54 100644
--- a/src/lib/corelib/buildgraph/depscanner.cpp
+++ b/src/lib/corelib/buildgraph/depscanner.cpp
@@ -238,16 +238,11 @@ QStringList UserDependencyScanner::evaluate(Artifact *artifact,
     const ScopedJsValueList argsMgr(m_engine->context(), args);
 
     const TemporaryGlobalObjectSetter gos(m_engine, m_global);
-    JSValue &function = script.scriptFunction;
-    if (!JS_IsFunction(m_engine->context(), function)) {
-        function = m_engine->evaluate(JsValueOwner::ScriptEngine, script.sourceCode());
-        if (Q_UNLIKELY(!JS_IsFunction(m_engine->context(), function)))
-            throw ErrorInfo(Tr::tr("Invalid scan script."), script.location());
-    }
+    const JSValue function = script.getFunction(m_engine, Tr::tr("Invalid scan script."));
     const ScopedJsValue result(
                 m_engine->context(),
                 JS_Call(m_engine->context(), function, m_engine->globalObject(),
-                        int(args.size()), args.data()));
+                int(args.size()), args.data()));
     m_engine->clearRequestedProperties();
     if (JsException ex = m_engine->checkAndClearException(script.location())) {
         ErrorInfo err = ex.toErrorInfo();
diff --git a/src/lib/corelib/buildgraph/transformer.cpp b/src/lib/corelib/buildgraph/transformer.cpp
index ae044cd2c..2346ad5c9 100644
--- a/src/lib/corelib/buildgraph/transformer.cpp
+++ b/src/lib/corelib/buildgraph/transformer.cpp
@@ -259,18 +259,12 @@ AbstractCommandPtr Transformer::createCommandFromScriptValue(
 void Transformer::createCommands(ScriptEngine *engine, const PrivateScriptFunction &script,
                                  const JSValueList &args)
 {
-    if (JS_IsUndefined(script.scriptFunction))  {
-        script.scriptFunction = engine->evaluate(JsValueOwner::ScriptEngine, script.sourceCode(),
-                                                  script.location().filePath(),
-                                                  script.location().line());
-        if (Q_UNLIKELY(!JS_IsFunction(engine->context(), script.scriptFunction)))
-            throw ErrorInfo(Tr::tr("Invalid prepare script."), script.location());
-    }
     JSValueList argv(args.cbegin(), args.cend());
+    const JSValue function = script.getFunction(engine, Tr::tr("Invalid prepare script."));
     const ScopedJsValue scriptValue(
                 engine->context(),
-                JS_Call(engine->context(), script.scriptFunction, engine->globalObject(),
-                        int(argv.size()), argv.data()));
+                JS_Call(engine->context(), function, engine->globalObject(),
+                int(argv.size()), argv.data()));
     propertiesRequestedInPrepareScript = engine->propertiesRequestedInScript();
     propertiesRequestedFromArtifactInPrepareScript = engine->propertiesRequestedFromArtifact();
     importedFilesUsedInPrepareScript = engine->importedFilesUsedInScript();