From ca8e40fe1d40210b55309aa786d6971368d65ad7 Mon Sep 17 00:00:00 2001
From: Shawn Pearce <sop@google.com>
Date: Fri, 9 Aug 2013 14:12:58 -0700
Subject: [PATCH] Softly grey the common part of paths in ChangeScreen2

When displaying the table of file paths, grey out the part that
is common with the prior row. This makes changes in packages more
visible as the uncommon prefix on the next row will be black rather
than the softer grey color.

For example the common prefix in () would be grey:

 gerrit-httpd/src/main/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
 gerrit-server/src/main/java/com/google/gerrit/server/ change/GetContent.java
(gerrit-server/src/main/java/com/google/gerrit/server/)project/GarbageCollect.java

Change-Id: Ia63d79fe56c023838dc091fcfe5db8d30337616e
---
 .../gerrit/client/change/FileTable.java       | 40 ++++++++++++++++---
 .../gerrit/client/change/file_table.css       |  6 +++
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/FileTable.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/FileTable.java
index 1bcab1af46..10c2bc6f6e 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/FileTable.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/FileTable.java
@@ -71,6 +71,7 @@ class FileTable extends FlowPanel {
     String commentColumn();
     String deltaColumn1();
     String deltaColumn2();
+    String commonPrefix();
     String inserted();
     String deleted();
   }
@@ -323,6 +324,7 @@ class FileTable extends FlowPanel {
     private int row;
     private double start;
     private ProgressBar meter;
+    private String lastPath = "";
 
     private int inserted;
     private int deleted;
@@ -448,14 +450,42 @@ class FileTable extends FlowPanel {
         .setStyleName(R.css().pathColumn())
         .openAnchor()
         .setAttribute("href", "#" + url(info))
-        .setAttribute("onclick", OPEN + "(event," + info._row() + ")")
-        .append(Patch.COMMIT_MSG.equals(info.path())
-            ? Util.C.commitMessage()
-            : info.path())
-        .closeAnchor()
+        .setAttribute("onclick", OPEN + "(event," + info._row() + ")");
+
+      String path = info.path();
+      if (Patch.COMMIT_MSG.equals(path)) {
+        sb.append(Util.C.commitMessage());
+      } else {
+        int commonPrefixLen = commonPrefix(path);
+        if (commonPrefixLen > 0) {
+          sb.openSpan().setStyleName(R.css().commonPrefix())
+            .append(path.substring(0, commonPrefixLen))
+            .closeSpan();
+        }
+        sb.append(path.substring(commonPrefixLen));
+        lastPath = path;
+      }
+
+      sb.closeAnchor()
         .closeTd();
     }
 
+    private int commonPrefix(String path) {
+      for (int n = path.length(); n > 0;) {
+        int s = path.lastIndexOf('/', n);
+        if (s < 0) {
+          return 0;
+        }
+
+        String p = path.substring(0, s + 1);
+        if (lastPath.startsWith(p)) {
+          return s + 1;
+        }
+        n = s - 1;
+      }
+      return 0;
+    }
+
     private void columnComments(SafeHtmlBuilder sb, FileInfo info) {
       JsArray<CommentInfo> cList = get(info.path(), comments);
       JsArray<CommentInfo> dList = get(info.path(), drafts);
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/file_table.css b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/file_table.css
index 25724dcbcd..943f9f1ac4 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/file_table.css
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/file_table.css
@@ -23,6 +23,12 @@
   white-space: nowrap;
   min-width: 600px;
 }
+.pathColumn a {
+  color: #000;
+}
+.commonPrefix {
+  color: #888;
+}
 
 .draftColumn,
 .newColumn,