Fix multiple of 3 rule for emphasis parsing (see commonmark/cmark#177)

commonmark · Aug 24, 2017 · ba53b35 · ba53b35
1 parent abe7269
commit ba53b35
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Showing 5 changed files with 30 additions and 10 deletions.
diff --git a/commonmark/src/main/java/org/commonmark/internal/Delimiter.java b/commonmark/src/main/java/org/commonmark/internal/Delimiter.java
@@ -24,7 +24,8 @@ public class Delimiter implements DelimiterRun {
     public Delimiter previous;
     public Delimiter next;
 
-    public int numDelims = 1;
+    public int length = 1;
+    public int originalLength = 1;
 
     public Delimiter(Text node, char delimiterChar, boolean canOpen, boolean canClose, Delimiter previous) {
         this.node = node;
@@ -46,6 +47,11 @@ public boolean canClose() {
 
     @Override
     public int length() {
-        return numDelims;
+        return length;
+    }
+
+    @Override
+    public int originalLength() {
+        return originalLength;
     }
 }
diff --git a/commonmark/src/main/java/org/commonmark/internal/InlineParserImpl.java b/commonmark/src/main/java/org/commonmark/internal/InlineParserImpl.java
@@ -448,15 +448,16 @@ private boolean parseDelimiters(DelimiterProcessor delimiterProcessor, char deli
         if (res == null) {
             return false;
         }
-        int numDelims = res.count;
+        int length = res.count;
         int startIndex = index;
 
-        index += numDelims;
+        index += length;
         Text node = appendText(input, startIndex, index);
 
         // Add entry to stack for this opener
         lastDelimiter = new Delimiter(node, delimiterChar, res.canOpen, res.canClose, lastDelimiter);
-        lastDelimiter.numDelims = numDelims;
+        lastDelimiter.length = length;
+        lastDelimiter.originalLength = length;
         if (lastDelimiter.previous != null) {
             lastDelimiter.previous.next = lastDelimiter;
         }
@@ -853,8 +854,8 @@ private void processDelimiters(Delimiter stackBottom) {
             Text closerNode = closer.node;
 
             // Remove number of used delimiters from stack and inline nodes.
-            opener.numDelims -= useDelims;
-            closer.numDelims -= useDelims;
+            opener.length -= useDelims;
+            closer.length -= useDelims;
             openerNode.setLiteral(
                     openerNode.getLiteral().substring(0,
                             openerNode.getLiteral().length() - useDelims));
@@ -869,11 +870,11 @@ private void processDelimiters(Delimiter stackBottom) {
             delimiterProcessor.process(openerNode, closerNode, useDelims);
 
             // No delimiter characters left to process, so we can remove delimiter and the now empty node.
-            if (opener.numDelims == 0) {
+            if (opener.length == 0) {
                 removeDelimiterAndNode(opener);
             }
 
-            if (closer.numDelims == 0) {
+            if (closer.length == 0) {
                 Delimiter next = closer.next;
                 removeDelimiterAndNode(closer);
                 closer = next;

diff --git a/commonmark/src/main/java/org/commonmark/internal/inline/EmphasisDelimiterProcessor.java b/commonmark/src/main/java/org/commonmark/internal/inline/EmphasisDelimiterProcessor.java
@@ -33,7 +33,7 @@ public int getMinLength() {
     @Override
     public int getDelimiterUse(DelimiterRun opener, DelimiterRun closer) {
         // "multiple of 3" rule for internal delimiter runs
-        if ((opener.canClose() || closer.canOpen()) && (opener.length() + closer.length()) % 3 == 0) {
+        if ((opener.canClose() || closer.canOpen()) && (opener.originalLength() + closer.originalLength()) % 3 == 0) {
             return 0;
         }
         // calculate actual number of delimiters used from this closer

diff --git a/commonmark/src/main/java/org/commonmark/parser/delimiter/DelimiterRun.java b/commonmark/src/main/java/org/commonmark/parser/delimiter/DelimiterRun.java
@@ -19,4 +19,10 @@ public interface DelimiterRun {
      * @return the number of characters in this delimiter run (that are left for processing)
      */
     int length();
+
+    /**
+     * @return the number of characters originally in this delimiter run; at the start of processing, this is the same
+     * as {{@link #length()}}
+     */
+    int originalLength();
 }
diff --git a/commonmark/src/test/java/org/commonmark/test/SpecialInputTest.java b/commonmark/src/test/java/org/commonmark/test/SpecialInputTest.java
@@ -107,8 +107,15 @@ public void linkLabelLength() {
                 "<p>[foo][12" + label2 + "]</p>\n<p>[12" + label2 + "]: /</p>\n");
     }
 
+    // commonmark/CommonMark#468
     @Test
     public void linkReferenceBackslash() {
         assertRendering("[\\]: test", "<p>[]: test</p>\n");
     }
+
+    // commonmark/cmark#177
+    @Test
+    public void emphasisMultipleOf3Rule() {
+        assertRendering("a***b* c*", "<p>a*<em><em>b</em> c</em></p>\n");
+    }
 }