From ddd817596245c575197aefa26dc9379be47f841f Mon Sep 17 00:00:00 2001
From: peter <peter@jetbrains.com>
Date: Mon, 18 Feb 2013 13:46:27 +0100
Subject: [PATCH] allow to save documents with lookup open unless trailing
 whitespace stripping will really cause the lookup to close (IDEA-101293)

---
 .../impl/LookupDocumentSavingVetoer.java      | 37 ++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupDocumentSavingVetoer.java b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupDocumentSavingVetoer.java
index 62c8ef6f104c..de0324541c9c 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupDocumentSavingVetoer.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/lookup/impl/LookupDocumentSavingVetoer.java
@@ -15,12 +15,18 @@
  */
 package com.intellij.codeInsight.lookup.impl;
 
+import com.intellij.codeInsight.lookup.Lookup;
+import com.intellij.codeInsight.lookup.LookupEx;
 import com.intellij.codeInsight.lookup.LookupManager;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.ex.EditorSettingsExternalizable;
 import com.intellij.openapi.fileEditor.FileDocumentSynchronizationVetoer;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.project.ProjectManager;
 import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.impl.source.tree.injected.InjectedLanguageUtil;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -29,17 +35,46 @@ import org.jetbrains.annotations.NotNull;
 public class LookupDocumentSavingVetoer implements FileDocumentSynchronizationVetoer {
   @Override
   public boolean maySaveDocument(@NotNull Document document) {
+    if (ApplicationManager.getApplication().isDisposed()) {
+      return true;
+    }
+
+    final EditorSettingsExternalizable settings = EditorSettingsExternalizable.getInstance();
+    if (settings == null || EditorSettingsExternalizable.STRIP_TRAILING_SPACES_NONE.equals(settings.getStripTrailingSpaces())) {
+      return true;
+    }
+
     for (Project project : ProjectManager.getInstance().getOpenProjects()) {
       if (!project.isInitialized() || project.isDisposed()) {
         continue;
       }
-      if (LookupManager.getInstance(project).getActiveLookup() != null) {
+      LookupEx lookup = LookupManager.getInstance(project).getActiveLookup();
+      if (lookup != null && isInTrailingSpace(lookup, document)) {
         return false;
       }
     }
     return true;
   }
 
+  private static boolean isInTrailingSpace(Lookup lookup, Document document) {
+    Editor editor = InjectedLanguageUtil.getTopLevelEditor(lookup.getEditor());
+    if (editor.getDocument() != document) {
+      return false;
+    }
+
+    int caret = editor.getCaretModel().getOffset();
+    if (caret <= 0 || caret >= document.getTextLength()) {
+      return false;
+    }
+
+    CharSequence seq = document.getCharsSequence();
+    if (seq.charAt(caret) == '\n' && Character.isWhitespace(seq.charAt(caret - 1))) {
+      return true;
+    }
+
+    return false;
+  }
+
   @Override
   public boolean mayReloadFileContent(VirtualFile file, @NotNull Document document) {
     return true;