included new file diff capability to new unified diff parser

wumpz · wumpz · commit 3b236562607b · 2020-01-04T01:18:22.000+01:00
diff --git a/java-diff-utils/src/main/java/com/github/difflib/unifieddiff/UnifiedDiffWriter.java b/java-diff-utils/src/main/java/com/github/difflib/unifieddiff/UnifiedDiffWriter.java
@@ -44,7 +44,9 @@ public static void write(UnifiedDiff diff, Function<String, List<String>> origin
     }
 
     public static void write(UnifiedDiff diff, Function<String, List<String>> originalLinesProvider, Consumer<String> writer, int contextSize) throws IOException {
-        writer.accept(diff.getHeader());
+        if (diff.getHeader() != null) {
+            writer.accept(diff.getHeader());
+        }
 
         for (UnifiedDiffFile file : diff.getFiles()) {
             List<AbstractDelta<String>> patchDeltas = new ArrayList<>(
@@ -54,9 +56,9 @@ public static void write(UnifiedDiff diff, Function<String, List<String>> origin
                 if (file.getIndex() != null) {
                     writer.accept("index " + file.getIndex());
                 }
-                if (file.getFromFile() != null) {
-                    writer.accept("--- " + file.getFromFile());
-                }
+
+                writer.accept("--- " + file.getFromFile());
+
                 if (file.getToFile() != null) {
                     writer.accept("+++ " + file.getToFile());
                 }
@@ -83,7 +85,7 @@ public static void write(UnifiedDiff diff, Function<String, List<String>> origin
                             // if it isn't, output the current set,
                             // then create a new set and add the current Delta to
                             // it.
-                            processDeltas(writer, originalLines, deltas, contextSize);
+                            processDeltas(writer, originalLines, deltas, contextSize, false);
                             deltas.clear();
                             deltas.add(nextDelta);
                         }
@@ -92,7 +94,8 @@ public static void write(UnifiedDiff diff, Function<String, List<String>> origin
 
                 }
                 // don't forget to process the last set of Deltas
-                processDeltas(writer, originalLines, deltas, contextSize);
+                processDeltas(writer, originalLines, deltas, contextSize, 
+                        patchDeltas.size() == 1 && file.getFromFile() == null);
             }
 
         }
@@ -104,18 +107,23 @@ public static void write(UnifiedDiff diff, Function<String, List<String>> origin
 
     private static void processDeltas(Consumer<String> writer,
             List<String> origLines, List<AbstractDelta<String>> deltas,
-            int contextSize) {
+            int contextSize, boolean newFile) {
         List<String> buffer = new ArrayList<>();
         int origTotal = 0; // counter for total lines output from Original
         int revTotal = 0; // counter for total lines output from Original
         int line;
 
         AbstractDelta<String> curDelta = deltas.get(0);
 
-        // NOTE: +1 to overcome the 0-offset Position
-        int origStart = curDelta.getSource().getPosition() + 1 - contextSize;
-        if (origStart < 1) {
-            origStart = 1;
+        int origStart;
+        if (newFile) {
+            origStart = 0;
+        } else {
+            // NOTE: +1 to overcome the 0-offset Position
+            origStart = curDelta.getSource().getPosition() + 1 - contextSize;
+            if (origStart < 1) {
+                origStart = 1;
+            }
         }
 
         int revStart = curDelta.getTarget().getPosition() + 1 - contextSize;
diff --git a/java-diff-utils/src/test/java/com/github/difflib/GenerateUnifiedDiffTest.java b/java-diff-utils/src/test/java/com/github/difflib/GenerateUnifiedDiffTest.java
@@ -120,6 +120,8 @@ public void testNewFileCreation() throws DiffException {
         List<String> udiff = UnifiedDiffUtils.generateUnifiedDiff(null, "revised",
                 original, patch, 10);
         
+        assertEquals("--- null", udiff.get(0));
+        assertEquals("+++ revised", udiff.get(1));
         assertEquals("@@ -0,0 +1,2 @@", udiff.get(2));
         
         UnifiedDiffUtils.parseUnifiedDiff(udiff);
diff --git a/java-diff-utils/src/test/java/com/github/difflib/unifieddiff/UnifiedDiffWriterTest.java b/java-diff-utils/src/test/java/com/github/difflib/unifieddiff/UnifiedDiffWriterTest.java
@@ -15,6 +15,9 @@
  */
 package com.github.difflib.unifieddiff;
 
+import com.github.difflib.DiffUtils;
+import com.github.difflib.algorithm.DiffException;
+import com.github.difflib.patch.Patch;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.StringWriter;
@@ -23,6 +26,9 @@
 import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+import static org.junit.Assert.assertEquals;
 import org.junit.Test;
 
 /**
@@ -43,6 +49,33 @@ public void testWrite() throws URISyntaxException, IOException {
 //        UnifiedDiffWriter.write(diff, writer);
 //        System.out.println(writer.toString());
     }
+    
+    /**
+     * Issue 47
+     */
+    @Test
+    public void testWriteWithNewFile() throws URISyntaxException, IOException, DiffException {
+        
+        List<String> original = new ArrayList<>();
+        List<String> revised = new ArrayList<>();
+
+        revised.add("line1");
+        revised.add("line2");
+
+        Patch<String> patch = DiffUtils.diff(original, revised);
+        UnifiedDiff diff = new UnifiedDiff();
+        diff.addFile( UnifiedDiffFile.from(null, "revised", patch) );
+
+        StringWriter writer = new StringWriter();
+        UnifiedDiffWriter.write(diff, f -> original, writer, 5);
+        System.out.println(writer.toString());
+        
+        String[] lines = writer.toString().split("\\n");
+        
+        assertEquals("--- null", lines[0]);
+        assertEquals("+++ revised", lines[1]);
+        assertEquals("@@ -0,0 +1,2 @@", lines[2]);
+    }
 
     static String readFile(URI path, Charset encoding)
             throws IOException {
