SideBySide2: Allow the user to select the syntax highlighter

This can be useful if Gerrit does not magically recognize a
particular file format. Temporarily forcing on a single mode
may make it easier to review the file.

Change-Id: I61af2841bdc76cb29b124f10b0946b39c804d823

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

@@ -32,6 +32,8 @@ import com.google.gerrit.reviewdb.client.AccountDiffPreference;
 import com.google.gerrit.reviewdb.client.AccountDiffPreference.Theme;
 import com.google.gerrit.reviewdb.client.AccountDiffPreference.Whitespace;
 import com.google.gwt.core.client.GWT;
+import com.google.gwt.core.client.Scheduler;
+import com.google.gwt.core.client.Scheduler.RepeatingCommand;
 import com.google.gwt.event.dom.client.ChangeEvent;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.dom.client.KeyDownEvent;
@@ -52,6 +54,12 @@ import com.google.gwt.user.client.ui.ListBox;
 import com.google.gwt.user.client.ui.PopupPanel;
 import com.google.gwt.user.client.ui.ToggleButton;
 
+import net.codemirror.lib.ModeInjector;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+
 /** Displays current diff preferences. */
 class PreferencesBox extends Composite {
   interface Binder extends UiBinder<HTMLPanel, PreferencesBox> {}
@@ -83,6 +91,7 @@ class PreferencesBox extends Composite {
   @UiField ToggleButton expandAllComments;
   @UiField ToggleButton renderEntireFile;
   @UiField ListBox theme;
+  @UiField ListBox mode;
   @UiField Button apply;
   @UiField Button save;
 
@@ -92,6 +101,7 @@ class PreferencesBox extends Composite {
     initWidget(uiBinder.createAndBindUi(this));
     initIgnoreWhitespace();
     initTheme();
+    initMode();
   }
 
   @Override
@@ -146,6 +156,11 @@ class PreferencesBox extends Composite {
     renderEntireFile.setEnabled(view.canEnableRenderEntireFile(prefs));
     setTheme(prefs.theme());
 
+    mode.setEnabled(prefs.syntaxHighlighting());
+    if (prefs.syntaxHighlighting()) {
+      setMode(view.getContentType());
+    }
+
     switch (view.getIntraLineStatus()) {
       case OFF:
       case OK:
@@ -288,9 +303,35 @@ class PreferencesBox extends Composite {
   @UiHandler("syntaxHighlighting")
   void onSyntaxHighlighting(ValueChangeEvent<Boolean> e) {
     prefs.syntaxHighlighting(e.getValue());
+    mode.setEnabled(prefs.syntaxHighlighting());
+    if (prefs.syntaxHighlighting()) {
+      setMode(view.getContentType());
+    }
     view.setSyntaxHighlighting(prefs.syntaxHighlighting());
   }
 
+  @UiHandler("mode")
+  void onMode(ChangeEvent e) {
+    final String m = mode.getValue(mode.getSelectedIndex());
+    prefs.syntaxHighlighting(true);
+    syntaxHighlighting.setValue(true, false);
+    Scheduler.get().scheduleFixedDelay(new RepeatingCommand() {
+      @Override
+      public boolean execute() {
+        if (prefs.syntaxHighlighting() && view.isAttached()) {
+          view.operation(new Runnable() {
+            @Override
+            public void run() {
+              view.getCmFromSide(DisplaySide.A).setOption("mode", m);
+              view.getCmFromSide(DisplaySide.B).setOption("mode", m);
+            }
+          });
+        }
+        return false;
+      }
+    }, 50);
+  }
+
   @UiHandler("whitespaceErrors")
   void onWhitespaceErrors(ValueChangeEvent<Boolean> e) {
     prefs.showWhitespaceErrors(e.getValue());
@@ -385,6 +426,51 @@ class PreferencesBox extends Composite {
         IGNORE_ALL_SPACE.name());
   }
 
+  private static final Map<String, String> NAME_TO_MODE;
+  private static final Map<String, String> NORMALIZED_MODES;
+  static {
+    NAME_TO_MODE = new TreeMap<String, String>();
+    NORMALIZED_MODES = new HashMap<String, String>();
+    for (String type : ModeInjector.getKnownMimeTypes()) {
+      String name = type;
+      if (name.startsWith("text/x-")) {
+        name = name.substring("text/x-".length());
+      } else if (name.startsWith("text/")) {
+        name = name.substring("text/".length());
+      } else if (name.startsWith("application/")) {
+        name = name.substring("application/".length());
+      }
+
+      String normalized = NAME_TO_MODE.get(name);
+      if (normalized == null) {
+        normalized = type;
+        NAME_TO_MODE.put(name, normalized);
+      }
+      NORMALIZED_MODES.put(type, normalized);
+    }
+  }
+
+  private void initMode() {
+    for (Map.Entry<String, String> e : NAME_TO_MODE.entrySet()) {
+      mode.addItem(e.getKey(), e.getValue());
+    }
+  }
+
+  private void setMode(String modeType) {
+    if (modeType != null && !modeType.isEmpty()) {
+      if (NORMALIZED_MODES.containsKey(modeType)) {
+        modeType =NORMALIZED_MODES.get(modeType);
+      }
+      for (int i = 0; i < mode.getItemCount(); i++) {
+        if (mode.getValue(i).equals(modeType)) {
+          mode.setSelectedIndex(i);
+          return;
+        }
+      }
+    }
+    mode.setSelectedIndex(0);
+  }
+
   private void setTheme(Theme v) {
     String name = v != null ? v.name() : Theme.DEFAULT.name();
     for (int i = 0; i < theme.getItemCount(); i++) {

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/PreferencesBox.ui.xml

@@ -203,6 +203,10 @@ limitations under the License.
           <g:downFace><ui:msg>Show</ui:msg></g:downFace>
         </g:ToggleButton></td>
       </tr>
+      <tr>
+        <th><ui:msg>Language</ui:msg></th>
+        <td><g:ListBox ui:field='mode'/></td>
+      </tr>
       <tr>
         <th><ui:msg>Whitespace Errors</ui:msg></th>
         <td><g:ToggleButton ui:field='whitespaceErrors'>

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

@@ -591,6 +591,10 @@ public class SideBySide2 extends Screen {
         || (prefs.context() != WHOLE_FILE_CONTEXT && prefs.context() < 100);
   }
 
+  String getContentType() {
+    return getContentType(diff.meta_b());
+  }
+
   void setThemeStyles(boolean d) {
     if (d) {
       diffTable.addStyleName(DiffTable.style.dark());

gerrit-gwtui/src/main/java/net/codemirror/lib/ModeInjector.java

@@ -21,6 +21,7 @@ import com.google.gwt.user.client.rpc.AsyncCallback;
 
 import net.codemirror.mode.Modes;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -94,6 +95,10 @@ public class ModeInjector {
     return real != null ? real : mode;
   }
 
+  public static Collection<String> getKnownMimeTypes() {
+    return mimeModes.keySet();
+  }
+
   private static native boolean isModeLoaded(String n)
   /*-{ return $wnd.CodeMirror.modes.hasOwnProperty(n); }-*/;