allow to open IDEA diff when IDEA is running (IDEA-67894)

platform/platform-api/src/com/intellij/openapi/application/ApplicationStarter.java

@@ -15,14 +15,20 @@
  */
 package com.intellij.openapi.application;
 
+import com.intellij.ExtensionPoints;
+import com.intellij.openapi.extensions.ExtensionPointName;
 import org.jetbrains.annotations.NonNls;
 
 /**
  * Implementors of this interface declared via {@link com.intellij.ExtensionPoints#APPLICATION_STARTER} contribute a
  * command line application based on IDEA platform.
+ *
  * @author max
+ * @see ApplicationStarterEx
  */
 public interface ApplicationStarter {
+  ExtensionPointName<ApplicationStarter> EP_NAME = ExtensionPointName.create(ExtensionPoints.APPLICATION_STARTER);
+
   /**
    * Command line switch to start with this runner. For example return "inspect" if you'd like to start app with
    * <code>idea.exe inspect</code> cmdline.

platform/platform-api/src/com/intellij/openapi/application/ApplicationStarterEx.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2000-2011 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.openapi.application;
+
+/**
+ * Implementors of this interface declared via {@link com.intellij.ExtensionPoints#APPLICATION_STARTER} are also capable of processing
+ * an external command line within a running IntelliJ Platform instance.
+
+ * @author yole
+ */
+public interface ApplicationStarterEx extends ApplicationStarter {
+  void processExternalCommandLine(String[] args);
+}

platform/platform-api/src/com/intellij/openapi/diff/DiffApplication.java

@@ -15,8 +15,10 @@
  */
 package com.intellij.openapi.diff;
 
-import com.intellij.openapi.application.ApplicationStarter;
+import com.intellij.openapi.application.ApplicationNamesInfo;
+import com.intellij.openapi.application.ApplicationStarterEx;
 import com.intellij.openapi.fileEditor.FileDocumentManager;
+import com.intellij.openapi.ui.Messages;
 import com.intellij.openapi.vfs.LocalFileSystem;
 import com.intellij.openapi.vfs.VirtualFile;
 
@@ -26,7 +28,7 @@ import java.io.FileNotFoundException;
 /**
  * @author max
  */
-public class DiffApplication implements ApplicationStarter {
+public class DiffApplication implements ApplicationStarterEx {
   public String getCommandName() {
     return "diff";
   }
@@ -37,21 +39,14 @@ public class DiffApplication implements ApplicationStarter {
     }
   }
 
-  private void printHelp() {
+  private static void printHelp() {
     System.err.println(DiffBundle.message("diff.application.usage.parameters.and.description"));
     System.exit(1);
   }
 
   public void main(String[] args) {
     try {
-      String path1 = args[1];
-      String path2 = args[2];
-      VirtualFile file1 = findFile(path1);
-      VirtualFile file2 = findFile(path2);
-      SimpleDiffRequest request = SimpleDiffRequest.compareFiles(file1, file2, null);
-      request.addHint(DiffTool.HINT_SHOW_MODAL_DIALOG);
-      DiffManager.getInstance().getIdeaDiffTool().show(request);
-      FileDocumentManager.getInstance().saveAllDocuments();
+      processDiffCommand(args);
     }
     catch (FileNotFoundException e) {
       System.err.println(e.getMessage());
@@ -65,7 +60,34 @@ public class DiffApplication implements ApplicationStarter {
     }
   }
 
-  private VirtualFile findFile(final String path1) throws FileNotFoundException {
+  @Override
+  public void processExternalCommandLine(String[] args) {
+    if (args.length != 3) {
+      String productName = ApplicationNamesInfo.getInstance().getProductName();
+      Messages.showMessageDialog("Usage: " + productName.toLowerCase() + " diff <file1> <file2>",
+                                 "Diff", Messages.getInformationIcon());
+      return;
+    }
+    try {
+      processDiffCommand(args);
+    }
+    catch(Exception e) {
+      Messages.showMessageDialog("Error showing diff: " + e.getMessage(), "Diff", Messages.getErrorIcon());
+    }
+  }
+
+  private static void processDiffCommand(String[] args) throws FileNotFoundException {
+    String path1 = args[1];
+    String path2 = args[2];
+    VirtualFile file1 = findFile(path1);
+    VirtualFile file2 = findFile(path2);
+    SimpleDiffRequest request = SimpleDiffRequest.compareFiles(file1, file2, null);
+    request.addHint(DiffTool.HINT_SHOW_MODAL_DIALOG);
+    DiffManager.getInstance().getIdeaDiffTool().show(request);
+    FileDocumentManager.getInstance().saveAllDocuments();
+  }
+
+  private static VirtualFile findFile(final String path1) throws FileNotFoundException {
     final VirtualFile vFile = LocalFileSystem.getInstance().findFileByIoFile(new File(path1));
     if (vFile == null) {
       throw new FileNotFoundException(DiffBundle.message("cannot.file.file.error.message", path1));

platform/platform-impl/src/com/intellij/ide/CommandLineProcessor.java

@@ -18,7 +18,10 @@ package com.intellij.ide;
 import com.intellij.ide.highlighter.ProjectFileType;
 import com.intellij.ide.impl.ProjectUtil;
 import com.intellij.idea.StartupUtil;
+import com.intellij.openapi.application.ApplicationStarter;
+import com.intellij.openapi.application.ApplicationStarterEx;
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.extensions.Extensions;
 import com.intellij.openapi.fileEditor.OpenFileDescriptor;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.project.ProjectManager;
@@ -28,6 +31,7 @@ import com.intellij.openapi.vfs.LocalFileSystem;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.platform.PlatformProjectOpenProcessor;
 import com.intellij.projectImport.ProjectOpenProcessor;
+import com.intellij.util.ArrayUtil;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
@@ -118,7 +122,17 @@ public class CommandLineProcessor {
       }
     }
     LOG.info("-----");
-    // TODO[yole] handle AppStarters here?
+
+    if (args.size() > 0) {
+      String command = args.get(0);
+      for(ApplicationStarter starter: Extensions.getExtensions(ApplicationStarter.EP_NAME)) {
+        if (starter instanceof ApplicationStarterEx && command.equals(starter.getCommandName())) {
+          ((ApplicationStarterEx) starter).processExternalCommandLine(ArrayUtil.toStringArray(args));
+          return null;
+        }
+      }
+    }
+
     Project lastOpenedProject = null;
     int line = -1;
     for (int i = 0, argsSize = args.size(); i < argsSize; i++) {