no preview available message

python/python-rest/src/com/jetbrains/rest/RestPythonPreviewProvider.java

@@ -1,43 +0,0 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
-package com.jetbrains.rest;
-
-import com.google.common.collect.Lists;
-import com.intellij.execution.configurations.GeneralCommandLine;
-import com.intellij.execution.process.ProcessOutput;
-import com.intellij.openapi.module.Module;
-import com.intellij.openapi.project.Project;
-import com.intellij.openapi.projectRoots.Sdk;
-import com.intellij.openapi.roots.ProjectFileIndex;
-import com.intellij.openapi.vfs.CharsetToolkit;
-import com.intellij.openapi.vfs.VirtualFile;
-import com.jetbrains.python.sdk.PySdkUtil;
-import com.jetbrains.python.sdk.PythonSdkType;
-import com.jetbrains.rest.editor.RestPreviewProvider;
-import org.jetbrains.annotations.Nullable;
-
-import static com.jetbrains.python.PythonHelper.REST_RUNNER;
-
-public class RestPythonPreviewProvider extends RestPreviewProvider {
-
-  @Nullable
-  public String toHtml(String text, VirtualFile virtualFile, Project project) {
-    Module module = ProjectFileIndex.SERVICE.getInstance(project).getModuleForFile(virtualFile);
-    if (module == null) return null;
-
-    final Sdk sdk = PythonSdkType.findPythonSdk(module);
-    if (sdk == null) {
-      return null;
-    }
-    final String sdkHomePath = sdk.getHomePath();
-    if (sdkHomePath == null) {
-      return null;
-    }
-
-    final GeneralCommandLine commandLine = REST_RUNNER.newCommandLine(sdkHomePath, Lists.newArrayList("rst2html"));
-    final ProcessOutput output = PySdkUtil.getProcessOutput(commandLine, virtualFile.getParent().getPath(), null, 5000,
-                                                            text.getBytes(CharsetToolkit.UTF8_CHARSET), true);
-    if (output.isCancelled() || output.isTimeout()) return null;
-
-    return output.getStdout();
-  }
-}

python/python-rest/src/com/jetbrains/rest/RestPythonPreviewProvider.kt

@@ -0,0 +1,27 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.jetbrains.rest
+
+import com.google.common.collect.Lists
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.roots.ProjectFileIndex
+import com.intellij.openapi.vfs.CharsetToolkit
+import com.intellij.openapi.vfs.VirtualFile
+import com.jetbrains.python.PythonHelper.REST_RUNNER
+import com.jetbrains.python.sdk.PySdkUtil
+import com.jetbrains.python.sdk.PythonSdkType
+import com.jetbrains.rest.editor.RestPreviewProvider
+
+class RestPythonPreviewProvider : RestPreviewProvider() {
+
+  override fun toHtml(text: String, virtualFile: VirtualFile, project: Project): Pair<String, String>? {
+    val module = ProjectFileIndex.SERVICE.getInstance(project).getModuleForFile(virtualFile) ?: return null
+
+    val sdk = PythonSdkType.findPythonSdk(module) ?: return null
+    val sdkHomePath = sdk.homePath ?: return null
+
+    val commandLine = REST_RUNNER.newCommandLine(sdkHomePath, Lists.newArrayList("rst2html"))
+    val output = PySdkUtil.getProcessOutput(commandLine, virtualFile.parent.path, null, 5000,
+                                            text.toByteArray(CharsetToolkit.UTF8_CHARSET), true)
+    return if (output.isCancelled || output.isTimeout) null else Pair(output.stdout, output.stderr)
+  }
+}

python/rest/src/com/jetbrains/rest/editor/RestPreviewFileEditor.java

@@ -17,6 +17,7 @@ import com.intellij.openapi.util.UserDataHolderBase;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.ui.javafx.JavaFxHtmlPanel;
 import com.intellij.util.Alarm;
+import kotlin.Pair;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.owasp.html.HtmlPolicyBuilder;
@@ -28,6 +29,7 @@ import java.beans.PropertyChangeListener;
 
 public class RestPreviewFileEditor extends UserDataHolderBase implements FileEditor {
   private final static long PARSING_CALL_TIMEOUT_MS = 50L;
+  private final static String NO_PREVIEW = "<h2>No preview available.</h2><br/><br/><h3>Error output:</h3>";
 
   private final static long RENDERING_DELAY_MS = 20L;
 
@@ -140,9 +142,12 @@ public class RestPreviewFileEditor extends UserDataHolderBase implements FileEdi
       return;
     }
 
-    final String html = RestPreviewProvider.getProviders()[0].toHtml(myDocument.getText(), myFile, myProject);
-    if (html == null) {
-      return;
+    final Pair<String, String> htmlAndError = RestPreviewProvider.getProviders()[0].toHtml(myDocument.getText(), myFile, myProject);
+    if (htmlAndError == null) return;
+
+    String html = htmlAndError.getFirst();
+    if (html.isEmpty()) {
+      html = NO_PREVIEW + htmlAndError.getSecond();
     }
 
     // EA-75860: The lines to the top may be processed slowly; Since we're in pooled thread, we can be disposed already.
@@ -154,8 +159,9 @@ public class RestPreviewFileEditor extends UserDataHolderBase implements FileEdi
       if (myLastRequest != null) {
         mySwingAlarm.cancelRequest(myLastRequest);
       }
+      String finalHtml = html;
       myLastRequest = () -> {
-        final String currentHtml = "<html>" + SANITIZER_VALUE.getValue().sanitize(html) + "</html>";
+        final String currentHtml = "<html>" + SANITIZER_VALUE.getValue().sanitize(finalHtml) + "</html>";
         if (!currentHtml.equals(myLastRenderedHtml)) {
           myLastRenderedHtml = currentHtml;
           myPanel.setHtml(myLastRenderedHtml);

python/rest/src/com/jetbrains/rest/editor/RestPreviewProvider.java

@@ -4,6 +4,7 @@ package com.jetbrains.rest.editor;
 import com.intellij.openapi.extensions.ExtensionPointName;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.vfs.VirtualFile;
+import kotlin.Pair;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -12,7 +13,7 @@ public abstract class RestPreviewProvider {
     ExtensionPointName.create("restructured.text.html.preview.provider");
 
   @Nullable
-  public abstract String toHtml(String text, VirtualFile virtualFile, Project project);
+  public abstract Pair<String, String> toHtml(String text, VirtualFile virtualFile, Project project);
 
   @NotNull
   public static RestPreviewProvider[] getProviders() {