BlockHandler abstraction in core module

CHANGELOG.md

@@ -14,6 +14,7 @@ dependency (must be explicitly added to `Markwon` whilst configuring)
 * non-empty bounds for `AsyncDrawable` when no dimensions are not yet available ([#189])
 * `linkify` - option to use `LinkifyCompat` in `LinkifyPlugin` ([#201])
 <br>Thanks to [@drakeet]
+* `MarkwonVisitor.BlockHandler` and `BlockHandlerDef` implementation to control how blocks insert new lines after them
 
 
 ```java

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

@@ -0,0 +1,23 @@
+package io.noties.markwon;
+
+import androidx.annotation.NonNull;
+
+import org.commonmark.node.Node;
+
+/**
+ * @since $nap;
+ */
+public class BlockHandlerDef implements MarkwonVisitor.BlockHandler {
+    @Override
+    public void blockStart(@NonNull MarkwonVisitor visitor, @NonNull Node node) {
+        visitor.ensureNewLine();
+    }
+
+    @Override
+    public void blockEnd(@NonNull MarkwonVisitor visitor, @NonNull Node node) {
+        if (visitor.hasNext(node)) {
+            visitor.ensureNewLine();
+            visitor.forceNewLine();
+        }
+    }
+}

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

@@ -23,6 +23,19 @@ public interface MarkwonVisitor extends Visitor {
         void visit(@NonNull MarkwonVisitor visitor, @NonNull N n);
     }
 
+    /**
+     * Primary purpose is to control the spacing applied before/after certain blocks, which
+     * visitors are created elsewhere
+     *
+     * @since $nap;
+     */
+    interface BlockHandler {
+
+        void blockStart(@NonNull MarkwonVisitor visitor, @NonNull Node node);
+
+        void blockEnd(@NonNull MarkwonVisitor visitor, @NonNull Node node);
+    }
+
     interface Builder {
 
         /**
@@ -33,6 +46,16 @@ public interface MarkwonVisitor extends Visitor {
         @NonNull
         <N extends Node> Builder on(@NonNull Class<N> node, @Nullable NodeVisitor<? super N> nodeVisitor);
 
+        /**
+         * @param blockHandler to handle block start/end
+         * @see BlockHandler
+         * @see BlockHandlerDef
+         * @since $nap;
+         */
+        @SuppressWarnings("UnusedReturnValue")
+        @NonNull
+        Builder blockHandler(@NonNull BlockHandler blockHandler);
+
         @NonNull
         MarkwonVisitor build(@NonNull MarkwonConfiguration configuration, @NonNull RenderProps renderProps);
     }
@@ -133,4 +156,14 @@ public interface MarkwonVisitor extends Visitor {
      */
     @SuppressWarnings("unused")
     <N extends Node> void setSpansForNodeOptional(@NonNull Class<N> node, int start);
+
+    /**
+     * @since $nap;
+     */
+    void blockStart(@NonNull Node node);
+
+    /**
+     * @since $nap;
+     */
+    void blockEnd(@NonNull Node node);
 }

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

@@ -45,15 +45,20 @@ class MarkwonVisitorImpl implements MarkwonVisitor {
 
     private final Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes;
 
+    // @since $nap;
+    private final BlockHandler blockHandler;
+
     MarkwonVisitorImpl(
             @NonNull MarkwonConfiguration configuration,
             @NonNull RenderProps renderProps,
             @NonNull SpannableBuilder builder,
-            @NonNull Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes) {
+            @NonNull Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes,
+            @NonNull BlockHandler blockHandler) {
         this.configuration = configuration;
         this.renderProps = renderProps;
         this.builder = builder;
         this.nodes = nodes;
+        this.blockHandler = blockHandler;
     }
 
     @Override
@@ -268,9 +273,20 @@ class MarkwonVisitorImpl implements MarkwonVisitor {
         }
     }
 
+    @Override
+    public void blockStart(@NonNull Node node) {
+        blockHandler.blockStart(this, node);
+    }
+
+    @Override
+    public void blockEnd(@NonNull Node node) {
+        blockHandler.blockEnd(this, node);
+    }
+
     static class BuilderImpl implements Builder {
 
         private final Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes = new HashMap<>();
+        private BlockHandler blockHandler;
 
         @NonNull
         @Override
@@ -290,14 +306,28 @@ class MarkwonVisitorImpl implements MarkwonVisitor {
             return this;
         }
 
+        @NonNull
+        @Override
+        public Builder blockHandler(@NonNull BlockHandler blockHandler) {
+            this.blockHandler = blockHandler;
+            return this;
+        }
+
         @NonNull
         @Override
         public MarkwonVisitor build(@NonNull MarkwonConfiguration configuration, @NonNull RenderProps renderProps) {
+            // @since $nap;
+            BlockHandler blockHandler = this.blockHandler;
+            if (blockHandler == null) {
+                blockHandler = new BlockHandlerDef();
+            }
+
             return new MarkwonVisitorImpl(
                     configuration,
                     renderProps,
                     new SpannableBuilder(),
-                    Collections.unmodifiableMap(nodes));
+                    Collections.unmodifiableMap(nodes),
+                    blockHandler);
         }
     }
 }

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

@@ -19,7 +19,7 @@ public class SoftBreakAddsNewLinePlugin extends AbstractMarkwonPlugin {
         builder.on(SoftLineBreak.class, new MarkwonVisitor.NodeVisitor<SoftLineBreak>() {
             @Override
             public void visit(@NonNull MarkwonVisitor visitor, @NonNull SoftLineBreak softLineBreak) {
-                visitor.forceNewLine();
+                visitor.ensureNewLine();
             }
         });
     }

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

@@ -210,17 +210,14 @@ public class CorePlugin extends AbstractMarkwonPlugin {
             @Override
             public void visit(@NonNull MarkwonVisitor visitor, @NonNull BlockQuote blockQuote) {
 
-                visitor.ensureNewLine();
+                visitor.blockStart(blockQuote);
 
                 final int length = visitor.length();
 
                 visitor.visitChildren(blockQuote);
                 visitor.setSpansForNodeOptional(blockQuote, length);
 
-                if (visitor.hasNext(blockQuote)) {
+                visitor.blockEnd(blockQuote);
-                    visitor.ensureNewLine();
-                    visitor.forceNewLine();
-                }
             }
         });
     }
@@ -316,7 +313,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
             @NonNull String code,
             @NonNull Node node) {
 
-        visitor.ensureNewLine();
+        visitor.blockStart(node);
 
         final int length = visitor.length();
 
@@ -333,10 +330,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
 
         visitor.setSpansForNodeOptional(node, length);
 
-        if (visitor.hasNext(node)) {
+        visitor.blockEnd(node);
-            visitor.ensureNewLine();
-            visitor.forceNewLine();
-        }
     }
 
     private static void bulletList(@NonNull MarkwonVisitor.Builder builder) {
@@ -402,7 +396,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
             @Override
             public void visit(@NonNull MarkwonVisitor visitor, @NonNull ThematicBreak thematicBreak) {
 
-                visitor.ensureNewLine();
+                visitor.blockStart(thematicBreak);
 
                 final int length = visitor.length();
 
@@ -411,10 +405,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
 
                 visitor.setSpansForNodeOptional(thematicBreak, length);
 
-                if (visitor.hasNext(thematicBreak)) {
+                visitor.blockEnd(thematicBreak);
-                    visitor.ensureNewLine();
-                    visitor.forceNewLine();
-                }
             }
         });
     }
@@ -424,7 +415,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
             @Override
             public void visit(@NonNull MarkwonVisitor visitor, @NonNull Heading heading) {
 
-                visitor.ensureNewLine();
+                visitor.blockStart(heading);
 
                 final int length = visitor.length();
                 visitor.visitChildren(heading);
@@ -433,10 +424,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
 
                 visitor.setSpansForNodeOptional(heading, length);
 
-                if (visitor.hasNext(heading)) {
+                visitor.blockEnd(heading);
-                    visitor.ensureNewLine();
-                    visitor.forceNewLine();
-                }
             }
         });
     }
@@ -467,7 +455,7 @@ public class CorePlugin extends AbstractMarkwonPlugin {
                 final boolean inTightList = isInTightList(paragraph);
 
                 if (!inTightList) {
-                    visitor.ensureNewLine();
+                    visitor.blockStart(paragraph);
                 }
 
                 final int length = visitor.length();
@@ -478,9 +466,8 @@ public class CorePlugin extends AbstractMarkwonPlugin {
                 // @since 1.1.1 apply paragraph span
                 visitor.setSpansForNodeOptional(paragraph, length);
 
-                if (!inTightList && visitor.hasNext(paragraph)) {
+                if (!inTightList) {
-                    visitor.ensureNewLine();
+                    visitor.blockEnd(paragraph);
-                    visitor.forceNewLine();
                 }
             }
         });

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

@@ -17,19 +17,16 @@ public class SimpleBlockNodeVisitor implements MarkwonVisitor.NodeVisitor<Node>
     @Override
     public void visit(@NonNull MarkwonVisitor visitor, @NonNull Node node) {
 
+        visitor.blockStart(node);
+
         // @since 3.0.1 we keep track of start in order to apply spans (optionally)
         final int length = visitor.length();
 
-        visitor.ensureNewLine();
-
         visitor.visitChildren(node);
 
         // @since 3.0.1 we apply optional spans
         visitor.setSpansForNodeOptional(node, length);
 
-        if (visitor.hasNext(node)) {
+        visitor.blockEnd(node);
-            visitor.ensureNewLine();
-            visitor.forceNewLine();
-        }
     }
 }

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

@@ -12,7 +12,8 @@ public class AbstractMarkwonVisitorImpl extends MarkwonVisitorImpl {
             @NonNull MarkwonConfiguration configuration,
             @NonNull RenderProps renderProps,
             @NonNull SpannableBuilder spannableBuilder,
-            @NonNull Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes) {
+            @NonNull Map<Class<? extends Node>, NodeVisitor<? extends Node>> nodes,
-        super(configuration, renderProps, spannableBuilder, nodes);
+            @NonNull BlockHandler blockHandler) {
+        super(configuration, renderProps, spannableBuilder, nodes, blockHandler);
     }
 }

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

@@ -43,7 +43,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 renderProps,
                 spannableBuilder,
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         impl.clear();
 
@@ -61,7 +62,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 mock(RenderProps.class),
                 builder,
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         // at the start - won't add anything
         impl.ensureNewLine();
@@ -92,7 +94,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 mock(RenderProps.class),
                 builder,
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         assertEquals(0, builder.length());
 
@@ -144,7 +147,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 mock(RenderProps.class),
                 mock(SpannableBuilder.class),
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         final BlockQuote node = mock(BlockQuote.class);
         final Node child = mock(Node.class);
@@ -163,7 +167,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 mock(RenderProps.class),
                 mock(SpannableBuilder.class),
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         final Node noNext = mock(Node.class);
         assertFalse(impl.hasNext(noNext));
@@ -195,7 +200,8 @@ public class MarkwonVisitorImplTest {
                 mock(MarkwonConfiguration.class),
                 mock(RenderProps.class),
                 builder,
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         for (int i = 0; i < 13; i++) {
             builder.setLength(i);
@@ -221,7 +227,8 @@ public class MarkwonVisitorImplTest {
                 configuration,
                 mock(RenderProps.class),
                 mock(SpannableBuilder.class),
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         impl.setSpansForNode(Node.class, 0);
 
@@ -252,7 +259,8 @@ public class MarkwonVisitorImplTest {
                 configuration,
                 mock(RenderProps.class),
                 builder,
-                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap());
+                Collections.<Class<? extends Node>, MarkwonVisitor.NodeVisitor<? extends Node>>emptyMap(),
+                mock(MarkwonVisitor.BlockHandler.class));
 
         // append something
         builder.append("no-spans-test");

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

@@ -107,6 +107,12 @@ public class CorePluginTest {
                 return this;
             }
 
+            @NonNull
+            @Override
+            public MarkwonVisitor.Builder blockHandler(@NonNull MarkwonVisitor.BlockHandler blockHandler) {
+                throw new RuntimeException();
+            }
+
             @NonNull
             @Override
             public MarkwonVisitor build(@NonNull MarkwonConfiguration configuration, @NonNull RenderProps renderProps) {

markwon-core/src/test/java/io/noties/markwon/syntax/SyntaxHighlightTest.java

@@ -91,7 +91,8 @@ public class SyntaxHighlightTest {
                 configuration,
                 mock(RenderProps.class),
                 new SpannableBuilder(),
-                visitorMap);
+                visitorMap,
+                mock(MarkwonVisitor.BlockHandler.class));
 
         final SpannableBuilder builder = visitor.builder();
 

markwon-ext-latex/src/main/java/io/noties/markwon/ext/latex/JLatexMathPlugin.java

@@ -191,7 +191,7 @@ public class JLatexMathPlugin extends AbstractMarkwonPlugin {
             @Override
             public void visit(@NonNull MarkwonVisitor visitor, @NonNull JLatexMathBlock jLatexMathBlock) {
 
-                visitor.ensureNewLine();
+                visitor.blockStart(jLatexMathBlock);
 
                 final String latex = jLatexMathBlock.latex();
 
@@ -217,10 +217,7 @@ public class JLatexMathPlugin extends AbstractMarkwonPlugin {
 
                 visitor.setSpans(length, span);
 
-                if (visitor.hasNext(jLatexMathBlock)) {
+                visitor.blockEnd(jLatexMathBlock);
-                    visitor.ensureNewLine();
-                    visitor.forceNewLine();
-                }
             }
         });
     }

markwon-ext-tables/src/main/java/io/noties/markwon/ext/tables/TablePlugin.java

@@ -121,12 +121,15 @@ public class TablePlugin extends AbstractMarkwonPlugin {
                         @Override
                         public void visit(@NonNull MarkwonVisitor visitor, @NonNull TableBlock tableBlock) {
 
+                            visitor.blockStart(tableBlock);
+
                             visitor.visitChildren(tableBlock);
 
-                            if (visitor.hasNext(tableBlock)) {
+//                            if (visitor.hasNext(tableBlock)) {
-                                visitor.ensureNewLine();
+//                                visitor.ensureNewLine();
-                                visitor.forceNewLine();
+//                                visitor.forceNewLine();
-                            }
+//                            }
+                            visitor.blockEnd(tableBlock);
                         }
                     })
                     .on(TableBody.class, new MarkwonVisitor.NodeVisitor<TableBody>() {

sample/src/main/java/io/noties/markwon/sample/basicplugins/BasicPluginsActivity.java

@@ -11,19 +11,19 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import org.commonmark.node.Heading;
+import org.commonmark.node.Node;
 import org.commonmark.node.Paragraph;
 
 import java.util.Collection;
 import java.util.Collections;
 
 import io.noties.markwon.AbstractMarkwonPlugin;
+import io.noties.markwon.BlockHandlerDef;
 import io.noties.markwon.Markwon;
 import io.noties.markwon.MarkwonConfiguration;
 import io.noties.markwon.MarkwonSpansFactory;
 import io.noties.markwon.MarkwonVisitor;
-import io.noties.markwon.RenderProps;
 import io.noties.markwon.SoftBreakAddsNewLinePlugin;
-import io.noties.markwon.SpanFactory;
 import io.noties.markwon.core.CoreProps;
 import io.noties.markwon.core.MarkwonTheme;
 import io.noties.markwon.core.spans.LastLineSpacingSpan;
@@ -52,7 +52,9 @@ public class BasicPluginsActivity extends ActivityWithMenuOptions {
                 .add("softBreakAddsSpace", this::softBreakAddsSpace)
                 .add("softBreakAddsNewLine", this::softBreakAddsNewLine)
                 .add("additionalSpacing", this::additionalSpacing)
-                .add("headingNoSpace", this::headingNoSpace);
+                .add("headingNoSpace", this::headingNoSpace)
+                .add("headingNoSpaceBlockHandler", this::headingNoSpaceBlockHandler)
+                .add("allBlocksNoForcedLine", this::allBlocksNoForcedLine);
     }
 
     @Override
@@ -311,6 +313,68 @@ public class BasicPluginsActivity extends ActivityWithMenuOptions {
         markwon.setMarkdown(textView, md);
     }
 
+    private void headingNoSpaceBlockHandler() {
+        final Markwon markwon = Markwon.builder(this)
+                .usePlugin(new AbstractMarkwonPlugin() {
+                    @Override
+                    public void configureVisitor(@NonNull MarkwonVisitor.Builder builder) {
+                        builder.blockHandler(new BlockHandlerDef() {
+                            @Override
+                            public void blockEnd(@NonNull MarkwonVisitor visitor, @NonNull Node node) {
+                                if (node instanceof Heading) {
+                                    if (visitor.hasNext(node)) {
+                                        visitor.ensureNewLine();
+                                        // ensure new line but do not force insert one
+                                    }
+                                } else {
+                                    super.blockEnd(visitor, node);
+                                }
+                            }
+                        });
+                    }
+                })
+                .build();
+
+        final String md = "" +
+                "# Title title title title title title title title title title \n\ntext text text text";
+
+        markwon.setMarkdown(textView, md);
+    }
+
+    private void allBlocksNoForcedLine() {
+        final MarkwonVisitor.BlockHandler blockHandler = new BlockHandlerDef() {
+            @Override
+            public void blockEnd(@NonNull MarkwonVisitor visitor, @NonNull Node node) {
+                if (visitor.hasNext(node)) {
+                    visitor.ensureNewLine();
+                }
+            }
+        };
+
+        final Markwon markwon = Markwon.builder(this)
+                .usePlugin(new AbstractMarkwonPlugin() {
+                    @Override
+                    public void configureVisitor(@NonNull MarkwonVisitor.Builder builder) {
+                        builder.blockHandler(blockHandler);
+                    }
+                })
+                .build();
+
+        final String md = "" +
+                "# Hello there!\n\n" +
+                "* a first\n" +
+                "* second\n" +
+                "- third\n" +
+                "* * nested one\n\n" +
+                "> block quote\n\n" +
+                "> > and nested one\n\n" +
+                "```java\n" +
+                "final int i = 0;\n" +
+                "```\n\n";
+
+        markwon.setMarkdown(textView, md);
+    }
+
 //    public void step_6() {
 //
 //        final Markwon markwon = Markwon.builder(this)