IDEA-108655 Don't suggest a maven pom.xml reload for every single little change made to any pom.xml

plugins/maven/src/main/java/org/jetbrains/idea/maven/utils/MavenUtil.java

@@ -22,6 +22,8 @@ import com.intellij.codeInsight.template.impl.TemplateImpl;
 import com.intellij.execution.configurations.ParametersList;
 import com.intellij.ide.fileTemplates.FileTemplate;
 import com.intellij.ide.fileTemplates.FileTemplateManager;
+import com.intellij.lexer.FilterLexer;
+import com.intellij.lexer.Lexer;
 import com.intellij.lexer.XmlLexer;
 import com.intellij.notification.Notification;
 import com.intellij.notification.NotificationType;
@@ -755,42 +757,75 @@ public class MavenUtil {
     void waitFor();
   }
 
-  public static int crcWithoutSpaces(@NotNull VirtualFile xmlFile) throws IOException {
-    String text = VfsUtil.loadText(xmlFile);
+  private static void processToken(CRC32 crc, Lexer lexer) {
+    String text = (String)lexer.getBufferSequence();
 
-    XmlLexer lexer = new XmlLexer();
-    lexer.start(text);
+    for (int i = lexer.getTokenStart(), end = lexer.getTokenEnd(); i < end; i++) {
+      char a = text.charAt(i);
+      crc.update(a);
+      crc.update(a >>> 8);
+    }
+  }
+
+  public static int crcWithoutSpaces(@NotNull String xmlText) {
+    Lexer lexer = new FilterLexer(new XmlLexer(), new FilterLexer.SetFilter(XmlTokenType.COMMENTS));
+    lexer.start(xmlText);
 
     CRC32 crc = new CRC32();
 
-    boolean isCommentOrSpace = false;
-
     while (true) {
       IElementType tokenType = lexer.getTokenType();
       if (tokenType == null) break;
 
-      if (XmlTokenType.WHITESPACES.contains(tokenType) || XmlTokenType.COMMENTS.contains(tokenType) || tokenType == XmlTokenType.XML_REAL_WHITE_SPACE) {
-        if (!isCommentOrSpace) {
-          crc.update(1);
-          isCommentOrSpace = true;
+      if (tokenType == XmlTokenType.XML_DATA_CHARACTERS) {
+        processToken(crc, lexer);
+
+        int spacesCrc = 0;
+
+        IElementType t;
+        while (true) {
+          lexer.advance();
+          t = lexer.getTokenType();
+
+          if (t == XmlTokenType.XML_DATA_CHARACTERS) {
+            if (spacesCrc != 0) {
+              crc.update(spacesCrc & 0xFF);
+              crc.update((spacesCrc >>> 8) & 0xFF);
+            }
+
+            processToken(crc, lexer);
+            spacesCrc = 0;
+            continue;
+          }
+
+          if (XmlTokenType.WHITESPACES.contains(t) || t == XmlTokenType.XML_REAL_WHITE_SPACE) {
+            for (int i = lexer.getTokenStart(), end = lexer.getTokenEnd(); i < end; i++) {
+              spacesCrc = spacesCrc * 31 + xmlText.charAt(i);
+            }
+            continue;
+          }
+
+          break;
         }
       }
+      else if (XmlTokenType.WHITESPACES.contains(tokenType) || tokenType == XmlTokenType.XML_REAL_WHITE_SPACE) {
+        // skip spaces
+        lexer.advance();
+      }
       else {
-        isCommentOrSpace = false;
-
-        for (int start = lexer.getTokenStart(), end = lexer.getTokenEnd(); start < end; start++) {
-          char a = text.charAt(start);
-          crc.update(a);
-          crc.update(a >>> 8);
-        }
+        processToken(crc, lexer);
+        lexer.advance();
       }
-
-      lexer.advance();
     }
 
     return (int)crc.getValue();
   }
 
+  public static int crcWithoutSpaces(@NotNull VirtualFile xmlFile) throws IOException {
+    String text = VfsUtil.loadText(xmlFile);
+    return crcWithoutSpaces(text);
+  }
+
   public static String getSdkPath(@Nullable Sdk sdk) {
     if (sdk == null) return null;
 

plugins/maven/src/test/java/org/jetbrains/idea/maven/importing/MavenXmlCrcTest.groovy

@@ -0,0 +1,152 @@
+package org.jetbrains.idea.maven.importing
+
+import junit.framework.TestCase
+import org.intellij.lang.annotations.Language
+import org.jetbrains.idea.maven.utils.MavenUtil
+
+/**
+ * @author Sergey Evdokimov
+ */
+class MavenXmlCrcTest extends TestCase {
+
+  public void testCrc() {
+    same("""
+<project a="a" b="b">
+</project>
+""", """
+<project a="a"
+         b="b"   >
+</project>
+""");
+
+    same("""
+<project>
+  <build><a>value</a></build>
+</project>
+""", """
+<project>
+  <build>
+    <a>value</a>
+  </build>
+</project>
+""")
+
+    same("""
+<project></project>
+""", """
+<project>
+      <!-- comment -->
+</project>
+"""
+    );
+
+    different("""
+<project>
+  <a>foo</a>
+</project>
+""", """
+<project>
+  <a>foo</a> text
+</project>
+""")
+
+    different("""
+<project>
+  <a>foo</a>
+</project>
+""", """
+<project>
+  <b>foo</b>
+</project>
+""")
+
+    same("""
+<project>
+  <a>foo</a>
+</project>
+""", """
+<project>
+  <a><!-- comment -->foo<!-- comment --></a>
+</project>
+""")
+
+    same("""
+<project>
+  <a>foo</a>
+</project>
+""", """
+<project>
+  <a>
+  <!-- comment -->foo<!-- comment -->
+  </a>
+</project>
+""")
+
+    same("""
+<project>
+  <a>foo</a>
+</project>
+""", """
+<project>
+  <a>fo<!-- comment -->o</a>
+</project>
+""")
+
+    same("""
+<project>
+  ab <a/>cd
+</project>
+""", """
+<project>
+  ab <a/> <!-- c --> cd
+</project>
+""")
+
+    different("""
+<project>
+  <a>foo bar</a>
+</project>
+""", """
+<project>
+  <a>foo    bar</a>
+</project>
+""")
+
+    different("""
+<project>
+  <a>foo bar</a>
+</project>
+""", """
+<project>
+  <a>foo\tbar</a>
+</project>
+""")
+
+    different("""
+<project>
+  <a>111</a>
+</project>
+""", """
+<project>
+  <a>222</a>
+</project>
+""")
+
+  }
+
+  private static void same(@Language("XML") String xml1, @Language("XML") String xml2) {
+    int crc1 = MavenUtil.crcWithoutSpaces(xml1);
+    int crc2 = MavenUtil.crcWithoutSpaces(xml2);
+
+    assert crc1 == crc2;
+  }
+
+  private static void different(@Language("XML") String xml1, @Language("XML") String xml2) {
+    int crc1 = MavenUtil.crcWithoutSpaces(xml1);
+    int crc2 = MavenUtil.crcWithoutSpaces(xml2);
+
+    assert crc1 != crc2;
+  }
+
+
+}