read-only index storage

java/java-tests/testSrc/com/intellij/index/IndexTest.groovy

@@ -64,6 +64,7 @@ import com.intellij.testFramework.SkipSlowTestLocally
 import com.intellij.testFramework.exceptionCases.IllegalArgumentExceptionCase
 import com.intellij.testFramework.fixtures.JavaCodeInsightFixtureTestCase
 import com.intellij.util.FileContentUtil
+import com.intellij.util.IncorrectOperationException
 import com.intellij.util.Processor
 import com.intellij.util.indexing.*
 import com.intellij.util.io.*
@@ -86,7 +87,7 @@ class IndexTest extends JavaCodeInsightFixtureTestCase {
   }
 
   void testUpdate() throws StorageException, IOException {
-    StringIndex index = createIndex(getTestName(false), new EnumeratorStringDescriptor())
+    StringIndex index = createIndex(getTestName(false), new EnumeratorStringDescriptor(), false)
 
     try {
       // build index
@@ -133,7 +134,7 @@ class IndexTest extends JavaCodeInsightFixtureTestCase {
   }
 
   void testUpdateWithCustomEqualityPolicy() {
-    def index = createIndex(getTestName(false), new CaseInsensitiveEnumeratorStringDescriptor())
+    def index = createIndex(getTestName(false), new CaseInsensitiveEnumeratorStringDescriptor(), false)
     try {
       index.update("a.java", "x", null)
       assertDataEquals(index.getFilesByWord("x"), "a.java")
@@ -151,12 +152,12 @@ class IndexTest extends JavaCodeInsightFixtureTestCase {
     }
   }
 
-  private static StringIndex createIndex(String testName, EnumeratorStringDescriptor keyDescriptor) {
+  private static StringIndex createIndex(String testName, EnumeratorStringDescriptor keyDescriptor, boolean readOnly) {
     final File storageFile = FileUtil.createTempFile("index_test", "storage")
     final File metaIndexFile = FileUtil.createTempFile("index_test_inputs", "storage")
     PersistentHashMap<Integer, Collection<String>>  index = createMetaIndex(metaIndexFile)
-    final VfsAwareMapIndexStorage indexStorage = new VfsAwareMapIndexStorage(storageFile, keyDescriptor, new EnumeratorStringDescriptor(), 16 * 1024)
-    return new StringIndex(testName, indexStorage, index)
+    final VfsAwareMapIndexStorage indexStorage = new VfsAwareMapIndexStorage(storageFile, keyDescriptor, new EnumeratorStringDescriptor(), 16 * 1024, readOnly)
+    return new StringIndex(testName, indexStorage, index, !readOnly)
   }
   
   private static PersistentHashMap<Integer, Collection<String>> createMetaIndex(File metaIndexFile) throws IOException {
@@ -665,6 +666,15 @@ class IndexTest extends JavaCodeInsightFixtureTestCase {
     assert JavaFileElementType.isInSourceContent(myFixture.tempDirFixture.getFile('another/doo/A.java'))
   }
 
+  void "test read-only index access"() {
+    StringIndex index = createIndex(getTestName(false), new EnumeratorStringDescriptor(), true)
+    assertFalse(index.update("qwe/asd", "some_string", null))
+    def rebuildException = index.getRebuildException()
+    assertInstanceOf(rebuildException, StorageException.class)
+    def rebuildCause = rebuildException.getCause()
+    assertInstanceOf(rebuildCause, IncorrectOperationException.class)
+  }
+
   @CompileStatic
   void "test Vfs Events Processing Performance"() {
     def filename = 'A.java'

java/java-tests/testSrc/com/intellij/index/StringIndex.java

@@ -40,8 +40,11 @@ import java.util.Map;
  */
 public class StringIndex {
   private final MapReduceIndex<String, String, PathContentPair> myIndex;
-  
-  public StringIndex(String testName, final IndexStorage<String, String> storage, final PersistentHashMap<Integer, Collection<String>> inputIndex)
+  private volatile Exception myRebuildException;
+  public StringIndex(String testName,
+                     final IndexStorage<String, String> storage,
+                     final PersistentHashMap<Integer, Collection<String>> inputIndex,
+                     boolean failOnRebuildRequest)
     throws IOException {
     ID<String, String> id = ID.create(testName + "string_index");
     IndexExtension<String, String, PathContentPair> extension = new IndexExtension<String, String, PathContentPair>() {
@@ -83,7 +86,11 @@ public class StringIndex {
     }) {
       @Override
       public void requestRebuild(@NotNull Exception ex) {
-        Assert.fail();
+        if (failOnRebuildRequest) {
+          Assert.fail();
+        } else {
+          myRebuildException = ex;
+        }
       }
 
     };
@@ -93,8 +100,8 @@ public class StringIndex {
     return ContainerUtil.collect(myIndex.getData(word).getValueIterator());
   }
   
-  public void update(final String path, @Nullable String content, @Nullable String oldContent) throws StorageException {
-    myIndex.update(Math.abs(path.hashCode()), toInput(path, content)).compute();
+  public boolean update(final String path, @Nullable String content, @Nullable String oldContent) throws StorageException {
+    return myIndex.update(Math.abs(path.hashCode()), toInput(path, content)).compute();
   }
 
   public void flush() throws StorageException {
@@ -110,6 +117,10 @@ public class StringIndex {
     return content != null ? new PathContentPair(path, content) : null;
   }
 
+  public Exception getRebuildException() {
+    return myRebuildException;
+  }
+
   private static class Indexer implements DataIndexer<String, String, PathContentPair> {
     @Override
     @NotNull