Inspection IO is now async and poll checks for cancellation (#192).

CheckStyle-IDEA.ipr

@@ -29,12 +29,14 @@
   <component name="CheckStyle-IDEA">
     <option name="configuration">
       <map>
-        <entry key="active-configuration" value="LOCAL_FILE:$PRJ_DIR$/test-configs/yazino-checkstyle-rules.xml:Yazino" />
+        <entry key="active-configuration" value="LOCAL_FILE:$PRJ_DIR$/test-configs/issue-193.xml:Issue 193" />
         <entry key="check-nonjava-files" value="false" />
         <entry key="check-test-classes" value="false" />
-        <entry key="location-0" value="CLASSPATH:/sun_checks.xml:The default Checkstyle rules" />
-        <entry key="location-1" value="LOCAL_FILE:$PRJ_DIR$/test-configs/yazino-checkstyle-rules.xml:Yazino" />
-        <entry key="property-1.checkstyle.suppressions.file" value="" />
+        <entry key="location-0" value="LOCAL_FILE:$PRJ_DIR$/test-configs/issue-193.xml:Issue 193" />
+        <entry key="location-1" value="HTTP_URL:http://localhost/cs/issue-193.xml:Issue 193 via HTTP" />
+        <entry key="location-2" value="CLASSPATH:/sun_checks.xml:The default Checkstyle rules" />
+        <entry key="location-3" value="LOCAL_FILE:$PRJ_DIR$/test-configs/yazino-checkstyle-rules.xml:Yazino" />
+        <entry key="property-3.checkstyle.suppressions.file" value="" />
         <entry key="suppress-errors" value="false" />
         <entry key="thirdparty-classpath" value="$PROJECT_DIR$/../Third Party/CreateYourOwnCheckStyleCheck/BlundellCheckstyle/target/blundell-checkstyle-checks-1.0.jar;$PRJ_DIR$/test-configs/issue-164/vdna-checkstyle-2.1.1-SNAPSHOT.jar" />
       </map>

README.md

@@ -12,14 +12,13 @@ Released under a BSD-style licence - please see the LICENCE file for details.
 > default IDEA package for OS X runs on Java 6, please make use of the versions
 > with the bundled JDK, e.g.
 >
-> [Community Edition (14.1.5)](https://download.jetbrains.com/idea/ideaIC-14.1.5-custom-jdk-bundled.dmg)
->
-> [Ultimate Edition (14.1.5)](https://download.jetbrains.com/idea/ideaIU-14.1.5-custom-jdk-bundled.dmg)
+> * [Community Edition (14.1.5)](https://download.jetbrains.com/idea/ideaIC-14.1.5-custom-jdk-bundled.dmg)
+> * [Ultimate Edition (14.1.5)](https://download.jetbrains.com/idea/ideaIU-14.1.5-custom-jdk-bundled.dmg)
 >
 > or, for Brew Cask users,
 >
->   brew cask install intellij-idea-ce-bundled-jdk
->   brew cask install intellij-idea-bundled-jdk
+> * brew cask install intellij-idea-ce-bundled-jdk
+> * brew cask install intellij-idea-bundled-jdk
 >
 > All other users please note - we require IDEA to be running on JDK 8.
 
@@ -137,6 +136,7 @@ This code is released under a BSD licence, as specified in the accompanying LICE
 
 ## Version History
 
+* **4.20.1** Fixed: Inspection now checks for cancellation (#192).
 * **4.20.1** Fixed: Rules accessed via HTTP no longer use temporary files (#67).
 * **4.20.0** New: Updated to CheckStyle 6.11.2 (#189).
 * **4.19.1** Fixed: Improved handling of unparsable files (#185).

src/main/java/org/infernus/idea/checkstyle/CheckStyleInspection.java

@@ -25,14 +25,15 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 import static java.util.Collections.singletonList;
+import static java.util.Optional.ofNullable;
+import static org.infernus.idea.checkstyle.util.Async.asyncResultOf;
 
 public class CheckStyleInspection extends LocalInspectionTool {
 
     private static final Log LOG = LogFactory.getLog(CheckStyleInspection.class);
-    private static final ProblemDescriptor[] NO_PROBLEMS_FOUND = null;
+    private static final List<Problem> NO_PROBLEMS_FOUND = Collections.emptyList();
 
     private final CheckStyleInspectionPanel configPanel = new CheckStyleInspectionPanel();
 
@@ -49,10 +50,16 @@ public JComponent createOptionsPanel() {
         return configPanel;
     }
 
-    @Nullable
+    @Override
     public ProblemDescriptor[] checkFile(@NotNull final PsiFile psiFile,
                                          @NotNull final InspectionManager manager,
                                          final boolean isOnTheFly) {
+        return asProblemDescriptors(asyncResultOf(() -> inspectFile(psiFile, manager), NO_PROBLEMS_FOUND), manager);
+    }
+
+    @Nullable
+    public List<Problem> inspectFile(@NotNull final PsiFile psiFile,
+                                     @NotNull final InspectionManager manager) {
         LOG.debug("Inspection has been invoked.");
 
         final CheckStylePlugin plugin = plugin(manager.getProject());
@@ -69,12 +76,11 @@ public ProblemDescriptor[] checkFile(@NotNull final PsiFile psiFile,
 
             scannableFiles.addAll(ScannableFile.createAndValidate(singletonList(psiFile), plugin, module));
 
-            return asArray(checkerFactory(psiFile.getProject())
+            return checkerFactory(psiFile.getProject())
                     .checker(module, configurationLocation)
                     .map(checker -> checker.scan(scannableFiles, plugin.getConfiguration()))
                     .map(results -> results.get(psiFile))
-                    .map(results -> asProblemDescriptors(results, manager))
-                    .orElseGet(Collections::emptyList));
+                    .orElseGet(() -> NO_PROBLEMS_FOUND);
 
         } catch (ProcessCanceledException | AssertionError e) {
             LOG.debug("Process cancelled when scanning: " + psiFile.getName());
@@ -104,25 +110,22 @@ private void blacklist(final ConfigurationLocation configurationLocation) {
         }
     }
 
-    private List<ProblemDescriptor> asProblemDescriptors(final List<Problem> results, final InspectionManager manager) {
-        return results.stream()
-                .map(problem -> problem.toProblemDescriptor(manager))
-                .collect(Collectors.toList());
+    @NotNull
+    private ProblemDescriptor[] asProblemDescriptors(final List<Problem> results, final InspectionManager manager) {
+        return ofNullable(results)
+                .map(problems -> problems.stream()
+                        .map(problem -> problem.toProblemDescriptor(manager))
+                        .toArray(ProblemDescriptor[]::new))
+                .orElseGet(() -> ProblemDescriptor.EMPTY_ARRAY);
     }
 
     private Module moduleOf(@NotNull final PsiFile psiFile) {
         return ModuleUtil.findModuleForPsiElement(psiFile);
     }
 
-    private ProblemDescriptor[] asArray(final List<ProblemDescriptor> problems) {
-        if (problems != null) {
-            return problems.toArray(new ProblemDescriptor[problems.size()]);
-        }
-        return NO_PROBLEMS_FOUND;
-    }
-
     private CheckerFactory checkerFactory(final Project project) {
         return ServiceManager.getService(project, CheckerFactory.class);
     }
 
+
 }

src/main/java/org/infernus/idea/checkstyle/util/Async.java

@@ -0,0 +1,44 @@
+package org.infernus.idea.checkstyle.util;
+
+import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.progress.ProgressManager;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Future;
+
+public class Async {
+    private static final int FIFTY_MS = 50;
+
+    @Nullable
+    public static <T> T asyncResultOf(@NotNull final Callable<T> callable,
+                                      @Nullable final T defaultValue) {
+        try {
+            return whenFinished(executeOnPooledThread(callable)).get();
+
+        } catch (Exception e) {
+            return defaultValue;
+        }
+    }
+
+    private static <T> Future<T> executeOnPooledThread(final Callable<T> callable) {
+        return ApplicationManager.getApplication().executeOnPooledThread(callable);
+    }
+
+    private static <T> Future<T> whenFinished(final Future<T> future) {
+        while (!future.isDone() && !future.isCancelled()) {
+            ProgressManager.checkCanceled();
+            waitFor(FIFTY_MS);
+        }
+        return future;
+    }
+
+    private static void waitFor(final int millis) {
+        try {
+            Thread.sleep(millis);
+        } catch (InterruptedException ignored) {
+            // ignored
+        }
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -19,6 +19,7 @@
     <change-notes>
         <![CDATA[
 <ul>
+    <li>4.20.1: Fixed: Inspection now checks for cancellation (#192).</li>
     <li>4.20.1: Fixed: Rules accessed via HTTP no longer use temporary files (#67).</li>
     <li>4.20.0: New: Updated to CheckStyle 6.11.2 (#189).</li>
     <li>4.19.1: Fixed: Improved handling of unparsable files (#185).</li>