Introduce MarkwonVisitorFactory

markwon-core/src/main/java/io/noties/markwon/MarkwonBuilderImpl.java

@@ -104,11 +104,17 @@ class MarkwonBuilderImpl implements Markwon.Builder {
 
         final RenderProps renderProps = new RenderPropsImpl();
 
+        // @since 4.1.1-SNAPSHOT
+        final MarkwonVisitorFactory visitorFactory = MarkwonVisitorFactory.create(
+                visitorBuilder,
+                configuration,
+                renderProps);
+
         return new MarkwonImpl(
                 bufferType,
                 textSetter,
                 parserBuilder.build(),
-                visitorBuilder.build(configuration, renderProps),
+                visitorFactory,
                 Collections.unmodifiableList(plugins)
         );
     }

markwon-core/src/main/java/io/noties/markwon/MarkwonImpl.java

@@ -20,7 +20,7 @@ class MarkwonImpl extends Markwon {
 
     private final TextView.BufferType bufferType;
     private final Parser parser;
-    private final MarkwonVisitor visitor;
+    private final MarkwonVisitorFactory visitorFactory; // @since 4.1.1-SNAPSHOT
     private final List<MarkwonPlugin> plugins;
 
     // @since 4.1.0
@@ -31,12 +31,12 @@ class MarkwonImpl extends Markwon {
             @NonNull TextView.BufferType bufferType,
             @Nullable TextSetter textSetter,
             @NonNull Parser parser,
-            @NonNull MarkwonVisitor visitor,
+            @NonNull MarkwonVisitorFactory visitorFactory,
             @NonNull List<MarkwonPlugin> plugins) {
         this.bufferType = bufferType;
         this.textSetter = textSetter;
         this.parser = parser;
-        this.visitor = visitor;
+        this.visitorFactory = visitorFactory;
         this.plugins = plugins;
     }
 
@@ -60,16 +60,22 @@ class MarkwonImpl extends Markwon {
             plugin.beforeRender(node);
         }
 
+        // @since 4.1.1-SNAPSHOT obtain visitor via factory
+        final MarkwonVisitor visitor = visitorFactory.create();
+
         node.accept(visitor);
 
         for (MarkwonPlugin plugin : plugins) {
             plugin.afterRender(node, visitor);
         }
 
+        //noinspection UnnecessaryLocalVariable
         final Spanned spanned = visitor.builder().spannableStringBuilder();
 
         // clear render props and builder after rendering
-        visitor.clear();
+        // @since 4.1.1-SNAPSHOT as we no longer reuse visitor - there is no need to clean it
+        //  we might still do it if we introduce a thread-local storage though
+//        visitor.clear();
 
         return spanned;
     }

markwon-core/src/main/java/io/noties/markwon/MarkwonVisitorFactory.java

@@ -0,0 +1,26 @@
+package io.noties.markwon;
+
+import androidx.annotation.NonNull;
+
+/**
+ * @since 4.1.1-SNAPSHOT
+ */
+abstract class MarkwonVisitorFactory {
+
+    @NonNull
+    abstract MarkwonVisitor create();
+
+    @NonNull
+    static MarkwonVisitorFactory create(
+            @NonNull final MarkwonVisitorImpl.Builder builder,
+            @NonNull final MarkwonConfiguration configuration,
+            @NonNull final RenderProps renderProps) {
+        return new MarkwonVisitorFactory() {
+            @NonNull
+            @Override
+            MarkwonVisitor create() {
+                return builder.build(configuration, renderProps);
+            }
+        };
+    }
+}

markwon-core/src/main/java/io/noties/markwon/MarkwonVisitorImpl.java

@@ -269,6 +269,11 @@ class MarkwonVisitorImpl implements MarkwonVisitor {
         @NonNull
         @Override
         public <N extends Node> Builder on(@NonNull Class<N> node, @Nullable NodeVisitor<? super N> nodeVisitor) {
+
+            // @since 4.1.1-SNAPSHOT we might actually introduce a local flag to check if it's been built
+            //  and throw an exception here if some modification is requested
+            //  NB, as we might be built from different threads this flag must be synchronized
+
             // we should allow `null` to exclude node from being visited (for example to disable
             // some functionality)
             if (nodeVisitor == null) {

markwon-core/src/test/java/io/noties/markwon/MarkwonImplTest.java

@@ -31,6 +31,7 @@ import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.RETURNS_MOCKS;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -47,7 +48,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class),
+                mock(MarkwonVisitorFactory.class),
                 Collections.singletonList(plugin));
 
         impl.parse("whatever");
@@ -70,7 +71,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 parser,
-                mock(MarkwonVisitor.class),
+                mock(MarkwonVisitorFactory.class),
                 Arrays.asList(first, second));
 
         impl.parse("zero");
@@ -89,6 +90,7 @@ public class MarkwonImplTest {
 
         final MarkwonPlugin plugin = mock(MarkwonPlugin.class);
 
+        final MarkwonVisitorFactory visitorFactory = mock(MarkwonVisitorFactory.class);
         final MarkwonVisitor visitor = mock(MarkwonVisitor.class);
         final SpannableBuilder builder = mock(SpannableBuilder.class);
 
@@ -96,9 +98,10 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                visitor,
+                visitorFactory,
                 Collections.singletonList(plugin));
 
+        when(visitorFactory.create()).thenReturn(visitor);
         when(visitor.builder()).thenReturn(builder);
 
         final Node node = mock(Node.class);
@@ -132,24 +135,30 @@ public class MarkwonImplTest {
     public void render_clears_visitor() {
         // each render call should have empty-state visitor (no previous rendering info)
 
+        final MarkwonVisitorFactory visitorFactory = mock(MarkwonVisitorFactory.class);
         final MarkwonVisitor visitor = mock(MarkwonVisitor.class, RETURNS_MOCKS);
 
+        when(visitorFactory.create()).thenReturn(visitor);
+
         final MarkwonImpl impl = new MarkwonImpl(
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                visitor,
+                visitorFactory,
                 Collections.<MarkwonPlugin>emptyList());
 
         impl.render(mock(Node.class));
 
-        verify(visitor, times(1)).clear();
+        // obsolete starting with 4.1.1-SNAPSHOT
+//        verify(visitor, times(1)).clear();
+        verify(visitor, never()).clear();
     }
 
     @Test
     public void render_props() {
         // render props are configured properly and cleared after render function
 
+        final MarkwonVisitorFactory visitorFactory = mock(MarkwonVisitorFactory.class);
         final MarkwonVisitor visitor = mock(MarkwonVisitor.class, RETURNS_MOCKS);
 
         final RenderProps renderProps = mock(RenderProps.class);
@@ -161,6 +170,7 @@ public class MarkwonImplTest {
             }
         }).when(visitor).clear();
 
+        when(visitorFactory.create()).thenReturn(visitor);
         when(visitor.renderProps()).thenReturn(renderProps);
 
         final MarkwonPlugin plugin = mock(MarkwonPlugin.class);
@@ -169,7 +179,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                visitor,
+                visitorFactory,
                 Collections.singletonList(plugin));
 
         final AtomicBoolean flag = new AtomicBoolean(false);
@@ -191,7 +201,9 @@ public class MarkwonImplTest {
 
         assertTrue(flag.get());
 
-        verify(renderProps, times(1)).clearAll();
+        // obsolete starting with 4.1.1-SNAPSHOT
+//        verify(renderProps, times(1)).clearAll();
+        verify(renderProps, never()).clearAll();
     }
 
     @Test
@@ -205,7 +217,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.EDITABLE,
                 null,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class, RETURNS_MOCKS),
+                mock(MarkwonVisitorFactory.class, RETURNS_MOCKS),
                 Collections.singletonList(plugin));
 
         final TextView textView = mock(TextView.class);
@@ -252,7 +264,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class),
+                mock(MarkwonVisitorFactory.class),
                 plugins);
 
         assertTrue("First", impl.hasPlugin(First.class));
@@ -274,7 +286,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.EDITABLE,
                 textSetter,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class),
+                mock(MarkwonVisitorFactory.class),
                 Collections.singletonList(plugin));
 
         final TextView textView = mock(TextView.class);
@@ -317,7 +329,8 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class), plugins);
+                mock(MarkwonVisitorFactory.class),
+                plugins);
 
         // should be returned
         assertNotNull(impl.requirePlugin(MarkwonPlugin.class));
@@ -346,7 +359,7 @@ public class MarkwonImplTest {
                 TextView.BufferType.SPANNABLE,
                 null,
                 mock(Parser.class),
-                mock(MarkwonVisitor.class),
+                mock(MarkwonVisitorFactory.class),
                 plugins);
 
         final List<? extends MarkwonPlugin> list = impl.getPlugins();