SideBySide2: Add download links

Re-implemented the old download links. To avoid adding bogus links
on empty files, PatchSetSelectBox2 needs to know the meta info
for the diff. Don't add the download link if meta == null.

Change-Id: Ied3e0287a17144ab2d6d50289625495568cb53a6

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.java

@@ -133,9 +133,9 @@ class DiffTable extends Composite {
     return fileCommentRow.getOffsetHeight() + patchSetSelectBoxA.getOffsetHeight();
   }
 
-  void setUpPatchSetNav(JsArray<RevisionInfo> list) {
-    patchSetSelectBoxA.setUpPatchSetNav(list);
-    patchSetSelectBoxB.setUpPatchSetNav(list);
+  void setUpPatchSetNav(JsArray<RevisionInfo> list, DiffInfo info) {
+    patchSetSelectBoxA.setUpPatchSetNav(list, info.meta_a());
+    patchSetSelectBoxB.setUpPatchSetNav(list, info.meta_b());
   }
 
   void add(Widget widget) {

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/PatchSetSelectBox2.java

@@ -20,6 +20,7 @@ import com.google.gerrit.client.changes.ChangeInfo.RevisionInfo;
 import com.google.gerrit.client.patches.PatchUtil;
 import com.google.gerrit.client.ui.InlineHyperlink;
 import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Patch;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gwt.core.client.GWT;
 import com.google.gwt.core.client.JsArray;
@@ -28,14 +29,14 @@ import com.google.gwt.resources.client.CssResource;
 import com.google.gwt.uibinder.client.UiBinder;
 import com.google.gwt.uibinder.client.UiField;
 import com.google.gwt.uibinder.client.UiHandler;
+import com.google.gwt.user.client.ui.Anchor;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.HTMLPanel;
 import com.google.gwt.user.client.ui.Image;
+import com.google.gwt.user.client.ui.ImageResourceRenderer;
+import com.google.gwtorm.client.KeyUtil;
 
-/**
- * HTMLPanel to select among patch sets
- * TODO: Implement download link.
- */
+/** HTMLPanel to select among patch sets */
 class PatchSetSelectBox2 extends Composite {
   interface Binder extends UiBinder<HTMLPanel, PatchSetSelectBox2> {}
   private static final Binder uiBinder = GWT.create(Binder.class);
@@ -71,7 +72,7 @@ class PatchSetSelectBox2 extends Composite {
     this.path = path;
   }
 
-  void setUpPatchSetNav(JsArray<RevisionInfo> list) {
+  void setUpPatchSetNav(JsArray<RevisionInfo> list, DiffInfo.FileMeta meta) {
     InlineHyperlink baseLink = null;
     InlineHyperlink selectedLink = null;
     if (sideA) {
@@ -92,6 +93,9 @@ class PatchSetSelectBox2 extends Composite {
     } else if (sideA) {
       baseLink.setStyleName(style.selected());
     }
+    if (meta != null && !Patch.COMMIT_MSG.equals(path)) {
+      linkPanel.add(createDownloadLink());
+    }
   }
 
   static void link(PatchSetSelectBox2 a, PatchSetSelectBox2 b) {
@@ -110,6 +114,17 @@ class PatchSetSelectBox2 extends Composite {
         path));
   }
 
+  private Anchor createDownloadLink() {
+    PatchSet.Id id = (idActive == null) ? other.idActive : idActive;
+    String sideURL = (idActive == null) ? "1" : "0";
+    String base = GWT.getHostPageBaseURL() + "cat/";
+    Anchor anchor = new Anchor(
+        new ImageResourceRenderer().render(Gerrit.RESOURCES.downloadIcon()),
+        base + KeyUtil.encode(id + "," + path) + "^" + sideURL);
+    anchor.setTitle(PatchUtil.C.download());
+    return anchor;
+  }
+
   @UiHandler("icon")
   void onIconClick(ClickEvent e) {
     table.createOrEditFileComment(side);

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java

@@ -204,6 +204,18 @@ public class SideBySide2 extends Screen {
       CommentApi.drafts(revision, group.add(getCommentCallback(DisplaySide.B, true)));
     }
 
+    RestApi call = ChangeApi.detail(changeId.get());
+    ChangeList.addOptions(call, EnumSet.of(
+        ListChangesOption.ALL_REVISIONS));
+    call.get(group.add(new GerritCallback<ChangeInfo>() {
+      @Override
+      public void onSuccess(ChangeInfo info) {
+        info.revisions().copyKeysIntoChildren("name");
+        JsArray<RevisionInfo> list = info.revisions().values();
+        RevisionInfo.sortRevisionInfoByNumber(list);
+        diffTable.setUpPatchSetNav(list, diff);
+      }}));
+
     ConfigInfoCache.get(changeId, group.addFinal(
         new ScreenLoadCallback<ConfigInfoCache.Entry>(SideBySide2.this) {
           @Override
@@ -216,18 +228,6 @@ public class SideBySide2 extends Screen {
             display(diffInfo);
           }
         }));
-
-    RestApi call = ChangeApi.detail(changeId.get());
-    ChangeList.addOptions(call, EnumSet.of(
-        ListChangesOption.ALL_REVISIONS));
-    call.get(new GerritCallback<ChangeInfo>() {
-      @Override
-      public void onSuccess(ChangeInfo info) {
-        info.revisions().copyKeysIntoChildren("name");
-        JsArray<RevisionInfo> list = info.revisions().values();
-        RevisionInfo.sortRevisionInfoByNumber(list);
-        diffTable.setUpPatchSetNav(list);
-      }});
   }
 
   @Override