allow the summary path builder to be re-used

Author: StevenArzt

soot-infoflow-summaries/src/soot/jimple/infoflow/methodSummary/postProcessor/InfoflowResultPostProcessor.java

@@ -163,6 +163,7 @@ public MethodSummaries postProcess(MethodSummaries flows) {
 					pathBuilder.clear();
 				}
 			}
+			pathBuilder.shutdown();
 		}
 
 		// Compact the flow set to remove paths that are over-approximations of

soot-infoflow-summaries/src/soot/jimple/infoflow/methodSummary/postProcessor/SummaryPathBuilder.java

@@ -253,4 +253,17 @@ protected Runnable getTaintPathTask(AbstractionAtSink abs) {
 		return null;
 	}
 
+	@Override
+	protected void onTaintPathsComputed() {
+		// Don't shut down the executor, because we reset it and run several iterations
+		// on the same path builder.
+	}
+
+	/**
+	 * Terminates the path builder. Afterwards, no new tasks can be scheduled.
+	 */
+	public void shutdown() {
+		executor.shutdown();
+	}
+
 }

soot-infoflow/src/soot/jimple/infoflow/data/pathBuilders/ContextSensitivePathBuilder.java

@@ -226,6 +226,12 @@ public void computeTaintPaths(Set<AbstractionAtSink> res) {
 		} catch (InterruptedException e) {
 			logger.error("Could not wait for executor termination", e);
 		}
+	}
+
+	/**
+	 * Method that is called when the taint paths have been computed
+	 */
+	protected void onTaintPathsComputed() {
 		executor.shutdown();
 	}