Restrict time given for JavaScript evaluation to max. 2 seconds.

Possible improvement: alert the user of the timeout and offer
the option to continue or abort execution.

CMakeLists.txt

@@ -339,6 +339,16 @@ if (KF5JS_FOUND)
             core/script/kjs_ocg.cpp
     )
     target_link_libraries(okularcore PRIVATE KF5::JS KF5::JSApi)
+    set(CMAKE_REQUIRED_LIBRARIES KF5::JSApi)
+    check_cxx_source_compiles("
+#include <kjs/kjsinterpreter.h>
+int main()
+{
+  KJSInterpreter *ip = 0;
+  ip->setTimeoutTime(0);
+  return 0;
+}
+"   HAVE_KJS_TIMEOUT)
 endif()
 
 set_target_properties(okularcore PROPERTIES VERSION 9.0.0 SOVERSION 9 OUTPUT_NAME Okular5Core EXPORT_NAME Core)

config-okular.h.cmake

@@ -7,3 +7,5 @@
 /* Defines whether the malloc_trim method from malloc.h is available */
 #cmakedefine01 HAVE_MALLOC_TRIM
 
+/* Defines if we have timeout support in the KJS library */
+#cmakedefine HAVE_KJS_TIMEOUT 1

core/script/executor_kjs.cpp

@@ -21,6 +21,7 @@
 #include "../document_p.h"
 
 #include "event_p.h"
+#include "config-okular.h"
 #include "kjs_app_p.h"
 #include "kjs_console_p.h"
 #include "kjs_data_p.h"
@@ -60,6 +61,9 @@ void ExecutorKJSPrivate::initTypes()
     m_docObject = JSDocument::wrapDocument( m_doc );
     m_interpreter = new KJSInterpreter( m_docObject );
 
+#ifdef HAVE_KJS_TIMEOUT
+    m_interpreter->setTimeoutTime( 2000 ); // max 2 secs allowed
+#endif
     KJSContext *ctx = m_interpreter->globalContext();
 
     JSApp::initType( ctx );
@@ -113,9 +117,15 @@ void ExecutorKJS::execute( const QString &script, Event *event )
 
     d->m_docObject.setProperty( ctx, QStringLiteral("event"), event ? JSEvent::wrapEvent( ctx, event ) : KJSUndefined() );
 
+#ifdef HAVE_KJS_TIMEOUT
+    d->m_interpreter->startTimeoutCheck();
+#endif
     KJSResult result = d->m_interpreter->evaluate( QStringLiteral("okular.js"), 1,
                                                    script, &d->m_docObject );
-    
+#ifdef HAVE_KJS_TIMEOUT
+    d->m_interpreter->stopTimeoutCheck();
+#endif
+
     if ( result.isException() || ctx->hasException() )
     {
         qCDebug(OkularCoreDebug) << "JS exception" << result.errorMessage();

core/script/kjs_app.cpp

@@ -11,6 +11,7 @@
 #include "kjs_app_p.h"
 
 #include <kjs/kjsarguments.h>
+#include <kjs/kjsinterpreter.h>
 #include <kjs/kjsobject.h>
 #include <kjs/kjsprototype.h>
 
@@ -25,6 +26,7 @@
 
 #include "../document_p.h"
 #include "../scripter.h"
+#include "config-okular.h"
 #include "kjs_fullscreen_p.h"
 
 using namespace Okular;
@@ -236,9 +238,19 @@ static KJSObject appAlert( KJSContext *context, void *,
         box.setCheckBox( checkBox );
 
     }
-    
+
+#ifdef HAVE_KJS_TIMEOUT
+    // halt timeout until the user has responded
+    context->interpreter().stopTimeoutCheck();
+#endif
+
     int button = box.exec();
 
+#ifdef HAVE_KJS_TIMEOUT
+    // restart max allowed time
+    context->interpreter().startTimeoutCheck();
+#endif
+
     int ret;
 
     switch( button )