Fix to fine-tune URI link for Haskell BCOMMENT

Also, handle that URI ending-pushback may be
present before collateral capture.

Author: idodeclare

src/org/opensolaris/opengrok/analysis/JFlexXref.java

@@ -270,16 +270,28 @@ protected void appendLink(String url, boolean doEndingPushback,
             throws IOException {
 
         int n = 0;
-        if (doEndingPushback) {
-            n = StringUtils.countURIEndingPushback(url);
-        }
-        int ccn = StringUtils.countPushback(url, collateralCapture);
-        if (ccn > n) n = ccn;
-        // Push back if positive, but not if equal to the current length.
-        if (n > 0 && n < url.length()) {
-            yypushback(n);
-            url = url.substring(0, url.length() - n);
-        }
+        int subn;
+        do {
+            // An ending-pushback could be present before a collateral capture,
+            // so detect both in a loop (on a shrinking `url') until no more
+            // shrinking should occur.
+
+            subn = 0;
+            if (doEndingPushback) {
+                subn = StringUtils.countURIEndingPushback(url);
+            }
+            int ccn = StringUtils.countPushback(url, collateralCapture);
+            if (ccn > subn) subn = ccn;
+
+            // Push back if positive, but not if equal to the current length.
+            if (subn > 0 && subn < url.length()) {
+                url = url.substring(0, url.length() - subn);
+                n += subn;
+            } else {
+                subn = 0;
+            }
+        } while (subn != 0);
+        if (n > 0) yypushback(n);
 
         out.write("<a href=\"");
         out.write(Util.formQuoteEscape(url));

src/org/opensolaris/opengrok/analysis/haskell/HaskellUtils.java

@@ -0,0 +1,51 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * See LICENSE.txt included in this distribution for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at LICENSE.txt.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2017, Chris Fraire <[email protected]>.
+ */
+
+package org.opensolaris.opengrok.analysis.haskell;
+
+import java.util.regex.Pattern;
+
+/**
+ * Represents a container for Haskell-related utility methods
+ */
+public class HaskellUtils {
+
+    /**
+     * Matches either the end of a Haskell nested comment or a superfluous
+     * right curly bracket (which is not a valid BrowseableURI character)
+     * captured in order to be able to detect the end of a Haskell nested
+     * comment:
+     * <pre>
+     * {@code # [ignore the following right brace {]
+     * \-?\}
+     * }
+     * </pre>
+     * (Edit above and paste below [in NetBeans] for easy String escaping.)
+     */
+    public static final Pattern MAYBE_END_NESTED_COMMENT =
+        Pattern.compile("\\-?\\}");
+
+    /** Private to enforce static. */
+    private HaskellUtils() {
+    }
+}

src/org/opensolaris/opengrok/analysis/haskell/HaskellXref.lex

@@ -152,8 +152,24 @@ import org.opensolaris.opengrok.web.Util;
 
 <STRING, COMMENT, BCOMMENT> {
     {FPath} { out.write(Util.breadcrumbPath(urlPrefix + "path=", yytext(), '/')); }
+    {FNameChar}+ "@" {FNameChar}+ "." {FNameChar}+ { writeEMailAddress(yytext()); }
+}
+
+<STRING, COMMENT> {
     {BrowseableURI}    {
         appendLink(yytext(), true);
     }
-    {FNameChar}+ "@" {FNameChar}+ "." {FNameChar}+ { writeEMailAddress(yytext()); }
+}
+
+<BCOMMENT> {
+    /*
+     * Right curly bracket is not a valid URI character, so it won't be in a
+     * {BrowseableURI} capture, but a hyphen is valid. Thus a nested comment
+     * ending token, -}, can hide at the end of a URI. Work around this by
+     * capturing a possibly-trailing right curly bracket, and match a special,
+     * Haskell-specific collateral capture pattern.
+     */
+    {BrowseableURI} \}?    {
+        appendLink(yytext(), true, HaskellUtils.MAYBE_END_NESTED_COMMENT);
+    }
 }

test/org/opensolaris/opengrok/analysis/haskell/sample2_xref.html

@@ -264,5 +264,5 @@
 <a class="l" name="261" href="#261">261</a><span class="c">{- comment {- comment -}
 <a class="l" name="262" href="#262">262</a>comment
 <a class="l" name="263" href="#263">263</a>-}</span>
-<a class="l" name="264" href="#264">264</a><span class="c">{-<a href="http://example.com.-">http://example.com.-</a>}
-<a class="l" name="265" href="#265">265</a></span></pre></div></body></html>
+<a class="l" name="264" href="#264">264</a><span class="c">{-<a href="http://example.com">http://example.com</a>.-}</span>
+<a class="l" name="265" href="#265">265</a></pre></div></body></html>