UI 'accurateness' control

plugins/org.chromium.debug.ui/src/org/chromium/debug/ui/propertypages/AccuratenessControl.java

Index: plugins/org.chromium.debug.ui/src/org/chromium/debug/ui/propertypages/AccuratenessControl.java
diff --git a/plugins/org.chromium.debug.ui/src/org/chromium/debug/ui/propertypages/AccuratenessControl.java b/plugins/org.chromium.debug.ui/src/org/chromium/debug/ui/propertypages/AccuratenessControl.java
new file mode 100644
index 0000000000000000000000000000000000000000..0c8515e52e26d88e2a325717bea8fe38921cfcea
--- /dev/null
+++ b/plugins/org.chromium.debug.ui/src/org/chromium/debug/ui/propertypages/AccuratenessControl.java
@@ -0,0 +1,247 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.debug.ui.propertypages;
+
+import org.chromium.debug.ui.DialogUtils.Updater;
+import org.chromium.debug.ui.DialogUtils.ValueConsumer;
+import org.chromium.debug.ui.DialogUtils.ValueSource;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.custom.StyleRange;
+import org.eclipse.swt.custom.StyledText;
+import org.eclipse.swt.events.SelectionEvent;
+import org.eclipse.swt.events.SelectionListener;
+import org.eclipse.swt.layout.GridData;
+import org.eclipse.swt.layout.GridLayout;
+import org.eclipse.swt.widgets.Button;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
+
+/**
+ * UI control element that shows several last segments of the file path and allow to show more
+ * or less. The segments is used in the system to match file in remote VM, thus showing more
+ * segments makes matching more accurate. Accurateness value is the number of visible segments.
+ */
+class AccuratenessControl {
+  private final Logic logic;
+
+  AccuratenessControl(Composite composite, String[] pathSegments, int initialAccuratenessValue) {
+    Composite inner;
+    {
+      inner = new Composite(composite, SWT.NONE);
+      GridLayout topLayout = new GridLayout();
+      topLayout.numColumns = 1;
+      inner.setLayout(topLayout);
+      inner.setLayoutData(new GridData(GridData.FILL_BOTH));
+    }
+
+    final PathLabel pathLabel = new PathLabel(inner, pathSegments);
+    pathLabel.getControl().setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
+
+    pathLabel.setVisiblePart(initialAccuratenessValue);
+
+    final Button less;
+    final Button more;
+    {
+      Composite buttonsGroup = new Composite(inner, SWT.NONE);
+      GridLayout topLayout = new GridLayout();
+      topLayout.numColumns = 2;
+      buttonsGroup.setLayout(topLayout);
+      buttonsGroup.setLayoutData(new GridData(GridData.FILL_BOTH));
+
+      less = new Button(buttonsGroup, SWT.NONE);
+      less.setText(Messages.AccuratenessControl_LESS_BUTTON);
+      more = new Button(buttonsGroup, SWT.NONE);
+      more.setText(Messages.AccuratenessControl_MORE_BUTTON);
+    }
+
+    Elements elements = new Elements() {
+      @Override
+      public AccuratenessControl.PathLabel getPathLabel() {
+        return pathLabel;
+      }
+
+      @Override
+      public Button getMoreButton() {
+        return more;
+      }
+
+      @Override
+      public Button getLessButton() {
+        return less;
+      }
+    };
+
+    logic = createLogic(elements);
+
+    logic.updateAll();
+  }
+
+  int getAccuratenessValue() {
+    return logic.getAccuratenessValue();
+  }
+
+  private static Logic createLogic(final Elements elements) {
+    // The logic is Updater-based.
+    // Presented path of several visible segments influences whether 'more' or 'less'
+    // buttons enabled.
+    final Updater updater = new Updater();
+
+    final AccuratenessControl.PathLabel pathElement = elements.getPathLabel();
+    final ValueSource<Integer> visiblePartSource = new ValueSource<Integer>() {
+      @Override
+      public Integer getValue() {
+        return pathElement.getVisiblePartSize();
+      }
+    };
+
+    updater.addSource(updater.rootScope(), visiblePartSource);
+
+    // Wraps button as ValueConsumer.
+    abstract class ButtonController implements ValueConsumer {
+      private final Button button;
+
+      ButtonController(Button button) {
+        this.button = button;
+
+        button.addSelectionListener(new SelectionListener() {
+          @Override
+          public void widgetSelected(SelectionEvent e) {
+            int size = pathElement.getVisiblePartSize();
+            if (!isEnabled(size)) {
+              return;
+            }
+            int newSize = getNewValue(size);
+            pathElement.setVisiblePart(newSize);
+            updater.reportChanged(visiblePartSource);
+            updater.update();
+          }
+
+          @Override
+          public void widgetDefaultSelected(SelectionEvent e) {
+          }
+        });
+      }
+
+      @Override
+      public void update(Updater updater) {
+        int size = pathElement.getVisiblePartSize();
+        boolean enabled = isEnabled(size);
+        button.setEnabled(enabled);
+      }
+
+      // Defines button logic.
+      protected abstract boolean isEnabled(int visiblePartSize);
+
+      // Defines button logic.
+      protected abstract int getNewValue(int currentValue);
+    }
+
+    ValueConsumer lessController = new ButtonController(elements.getLessButton()) {
+      @Override
+      protected boolean isEnabled(int visiblePartSize) {
+        return visiblePartSize > 1;
+      }
+
+      @Override
+      protected int getNewValue(int currentValue) {
+        return currentValue - 1;
+      }
+    };
+
+    updater.addConsumer(updater.rootScope(), lessController);
+    updater.addDependency(lessController, visiblePartSource);
+
+    final int size = elements.getPathLabel().size();
+    ValueConsumer moreController = new ButtonController(elements.getMoreButton()) {
+      @Override
+      protected boolean isEnabled(int visiblePartSize) {
+        return visiblePartSize < size;
+      }
+
+      @Override
+      protected int getNewValue(int currentValue) {
+        return currentValue + 1;
+      }
+    };
+
+    updater.addConsumer(updater.rootScope(), moreController);
+    updater.addDependency(moreController, visiblePartSource);
+
+    return new Logic() {
+      @Override
+      public int getAccuratenessValue() {
+        return elements.getPathLabel().getVisiblePartSize();
+      }
+      @Override
+      public void updateAll() {
+        updater.updateAll();
+      }
+    };
+  }
+
+  private interface Elements {
+    AccuratenessControl.PathLabel getPathLabel();
+    Button getLessButton();
+    Button getMoreButton();
+  }
+
+  private interface Logic {
+    int getAccuratenessValue();
+    void updateAll();
+  }
+
+  /**
+   * UI elements that shows several last segments of a particular file path
+   * (called visible part size).
+   * Last segment is always visible and is presented in bold font.
+   */
+  private static class PathLabel {
+    private final String[] components;
+    private final StyledText styledText;
+    private int visiblePartSize = 1;
+
+    /**
+     * @param components input file path components
+     */
+    PathLabel(Composite composite, String[] components) {
+      this.components = components;
+      styledText = new StyledText(composite, SWT.NONE);
+      styledText.setEditable(false);
+      styledText.setCaret(null);
+      styledText.setBackground(composite.getBackground());
+    }
+
+    public Control getControl() {
+      return styledText;
+    }
+
+    int size() {
+      return components.length;
+    }
+
+    int getVisiblePartSize() {
+      return visiblePartSize;
+    }
+
+    void setVisiblePart(int visiblePartSize) {
+      this.visiblePartSize = visiblePartSize;
+      int size = components.length;
+      StringBuilder builder = new StringBuilder();
+      for (int i = size - visiblePartSize; i < size - 1; i++) {
+        builder.append(components[i]);
+        builder.append("/"); //$NON-NLS-1$
+      }
+      int lastComponentStart = builder.length();
+      builder.append(components[size - 1]);
+      int lastComponentEnd = builder.length();
+      styledText.setText(builder.toString());
+      StyleRange boldRange = new StyleRange(lastComponentStart,
+          lastComponentEnd - lastComponentStart, null, null, SWT.BOLD);
+      StyleRange[] ranges = { boldRange };
+      styledText.setStyleRanges(ranges);
+      styledText.setCaretOffset(lastComponentStart);
+    }
+  }
+}