Add Diff lexer

components/jygments/source/com/threecrickets/jygments/contrib/DiffLexer.java

@@ -0,0 +1,69 @@
+/**
+ * Copyright 2010-2016 Three Crickets LLC.
+ * <p>
+ * The contents of this file are subject to the terms of a BSD license. See
+ * attached license.txt.
+ * <p>
+ * Alternatively, you can obtain a royalty free commercial license with less
+ * limitations, transferable or non-transferable, directly from Three Crickets
+ * at http://threecrickets.com/
+ */
+
+package com.threecrickets.jygments.contrib;
+
+import java.util.regex.Pattern;
+
+/**
+ * @author Stephen Just
+ */
+public class DiffLexer extends RegexLexer {
+
+    public DiffLexer() {
+        super();
+
+        addFilename("*.patch");
+        addFilename("*.diff");
+
+        addAlias("diff");
+        addAlias("udiff");
+
+        addMimeType("text/x-diff");
+        addMimeType("text/x-patch");
+
+        int flags = Pattern.MULTILINE;
+        include("root", "header");
+
+        rule("header", "([Ii]ndex|diff).*\\n", flags, "Generic.Heading", "basics");
+        rule("header", "[A-zA-z\\-]+:", flags, "Generic.Strong", "noparse");
+        rule("header", "---\\n", flags, "Generic.Heading");
+        rule("header", ".*\\n", flags, "Text");
+
+        rule("basics", "\\n", flags, "Text");
+        rule("basics", "\\+.*\\n", flags, "Generic.Inserted");
+        rule("basics", "-.*\\n", flags, "Generic.Deleted");
+        rule("basics", "!.*\\n", flags, "Generic.Strong");
+        rule("basics", "@.*\\n", flags, "Generic.Subheading");
+        rule("basics", "([Ii]ndex|diff|[Nn]ew|[Dd]eleted|[Mm]ode).*\\n", flags, "Generic.Heading");
+        rule("basics", "=.*\\n", flags, "Generic.Heading");
+        rule("basics", ".*\\n", flags, "Text");
+
+        rule("noparse", ".*\\n", flags, "Text", "#pop");
+
+        try {
+            resolve();
+        } catch (ResolutionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public float analyzeText(String text) {
+        if (text.startsWith("Index: "))
+            return 1.0f;
+        if (text.startsWith("diff "))
+            return 1.0f;
+        if (text.startsWith("--- "))
+            return 0.9f;
+        return 0.0f;
+    }
+}