--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/jface/text/source/LineChangeHover.d	Sat Aug 23 19:10:48 2008 +0200
@@ -0,0 +1,332 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2008 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.jface.text.source.LineChangeHover;
+
+import dwt.dwthelper.utils;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+import dwt.graphics.Point;
+import dwt.widgets.Shell;
+import dwtx.jface.action.ToolBarManager;
+import dwtx.jface.text.DefaultInformationControl;
+import dwtx.jface.text.IDocument;
+import dwtx.jface.text.IInformationControl;
+import dwtx.jface.text.IInformationControlCreator;
+import dwtx.jface.text.information.IInformationProviderExtension2;
+
+
+/**
+ * A hover for line oriented diffs. It determines the text to show as hover for a certain line in the
+ * document.
+ *
+ * @since 3.0
+ */
+public class LineChangeHover : IAnnotationHover, IAnnotationHoverExtension, IInformationProviderExtension2 {
+
+    /*
+     * @see dwtx.jface.text.source.IAnnotationHover#getHoverInfo(dwtx.jface.text.source.ISourceViewer, int)
+     */
+    public String getHoverInfo(ISourceViewer sourceViewer, int lineNumber) {
+        return null;
+    }
+
+    /**
+     * Formats the source w/ syntax coloring etc. This implementation replaces tabs with spaces.
+     * May be overridden by subclasses.
+     *
+     * @param content the hover content
+     * @return <code>content</code> reformatted
+     */
+    protected String formatSource(String content) {
+        if (content !is null) {
+            StringBuffer sb= new StringBuffer(content);
+            final String tabReplacement= getTabReplacement();
+            for (int pos= 0; pos < sb.length(); pos++) {
+                if (sb.charAt(pos) is '\t')
+                    sb.replace(pos, pos + 1, tabReplacement);
+            }
+            return sb.toString();
+        }
+        return content;
+    }
+
+    /**
+     * Returns a replacement for the tab character. The default implementation
+     * returns a tabulator character, but subclasses may override to specify a
+     * number of spaces.
+     *
+     * @return a whitespace String that will be substituted for the tabulator
+     *         character
+     */
+    protected String getTabReplacement() {
+        return "\t"; //$NON-NLS-1$
+    }
+
+    /**
+     * Computes the content of the hover for the document contained in <code>viewer</code> on
+     * line <code>line</code>.
+     *
+     * @param viewer the connected viewer
+     * @param first the first line in <code>viewer</code>'s document to consider
+     * @param last the last line in <code>viewer</code>'s document to consider
+     * @param maxLines the max number of lines
+     * @return The hover content corresponding to the parameters
+     * @see #getHoverInfo(ISourceViewer, int)
+     * @see #getHoverInfo(ISourceViewer, ILineRange, int)
+     */
+    private String computeContent(ISourceViewer viewer, int first, int last, int maxLines) {
+        ILineDiffer differ= getDiffer(viewer);
+        if (differ is null)
+            return null;
+
+        final List lines= new LinkedList();
+        for (int l= first; l <= last; l++) {
+            ILineDiffInfo info= differ.getLineInfo(l);
+            if (info !is null)
+                lines.add(info);
+        }
+
+        return decorateText(lines, maxLines);
+    }
+
+    /**
+     * Takes a list of <code>ILineDiffInfo</code>s and computes a hover of at most <code>maxLines</code>.
+     * Added lines are prefixed with a <code>'+'</code>, changed lines with <code>'>'</code> and
+     * deleted lines with <code>'-'</code>.
+     * <p>Deleted and added lines can even each other out, so that a number of deleted lines get
+     * displayed where - in the current document - the added lines are.
+     *
+     * @param diffInfos a <code>List</code> of <code>ILineDiffInfo</code>
+     * @param maxLines the maximum number of lines. Note that adding up all annotations might give
+     * more than that due to deleted lines.
+     * @return a <code>String</code> suitable for hover display
+     */
+    protected String decorateText(List diffInfos, int maxLines) {
+        /* maxLines controls the size of the hover (not more than what fits into the display are of
+         * the viewer).
+         * added controls how many lines are added - added lines are
+         */
+        String text= ""; //$NON-NLS-1$
+        int added= 0;
+        for (Iterator it= diffInfos.iterator(); it.hasNext();) {
+            ILineDiffInfo info= (ILineDiffInfo)it.next();
+            String[] original= info.getOriginalText();
+            int type= info.getChangeType();
+            int i= 0;
+            if (type is ILineDiffInfo.ADDED)
+                added++;
+            else if (type is ILineDiffInfo.CHANGED) {
+                text += "> " + (original.length > 0 ? original[i++] : ""); //$NON-NLS-1$ //$NON-NLS-2$
+                maxLines--;
+            } else if (type is ILineDiffInfo.UNCHANGED) {
+                maxLines++;
+            }
+            if (maxLines is 0)
+                return trimTrailing(text);
+            for (; i < original.length; i++) {
+                text += "- " + original[i]; //$NON-NLS-1$
+                added--;
+                if (--maxLines is 0)
+                    return trimTrailing(text);
+            }
+        }
+        text= text.trim();
+        if (text.length() is 0 && added-- > 0 && maxLines-- > 0)
+            text += "+ "; //$NON-NLS-1$
+        while (added-- > 0 && maxLines-- > 0)
+            text += "\n+ "; //$NON-NLS-1$
+        return text;
+    }
+
+    /**
+     * Trims trailing spaces
+     *
+     * @param text a <code>String</code>
+     * @return a copy of <code>text</code> with trailing spaces removed
+     */
+    private String trimTrailing(String text) {
+        int pos= text.length() - 1;
+        while (pos >= 0 && Character.isWhitespace(text.charAt(pos))) {
+            pos--;
+        }
+        return text.substring(0, pos + 1);
+    }
+
+    /**
+     * Extracts the line differ - if any - from the viewer's document's annotation model.
+     * @param viewer the viewer
+     * @return a line differ for the document displayed in viewer, or <code>null</code>.
+     */
+    private ILineDiffer getDiffer(ISourceViewer viewer) {
+        IAnnotationModel model= viewer.getAnnotationModel();
+
+        if (model is null)
+            return null;
+
+        if (model instanceof IAnnotationModelExtension) {
+            IAnnotationModel diffModel= ((IAnnotationModelExtension)model).getAnnotationModel(IChangeRulerColumn.QUICK_DIFF_MODEL_ID);
+            if (diffModel !is null)
+                model= diffModel;
+        }
+        if (model instanceof ILineDiffer) {
+            if (model instanceof ILineDifferExtension2 && ((ILineDifferExtension2)model).isSuspended())
+                return null;
+            return (ILineDiffer)model;
+        }
+        return null;
+    }
+
+    /**
+     * Computes the block of lines which form a contiguous block of changes covering <code>line</code>.
+     *
+     * @param viewer the source viewer showing
+     * @param line the line which a hover is displayed for
+     * @param min the first line in <code>viewer</code>'s document to consider
+     * @param max the last line in <code>viewer</code>'s document to consider
+     * @return the selection in the document displayed in <code>viewer</code> containing <code>line</code>
+     * that is covered by the hover information returned by the receiver.
+     */
+    protected Point computeLineRange(ISourceViewer viewer, int line, int min, int max) {
+        /* Algorithm:
+         * All lines that have changes to themselves (added, changed) are taken that form a
+         * contiguous block of lines that includes <code>line</code>.
+         *
+         * If <code>line</code> is itself unchanged, if there is a deleted line either above or
+         * below, or both, the lines +/- 1 from <code>line</code> are included in the search as well,
+         * without applying this last rule to them, though. (I.e., if <code>line</code> is unchanged,
+         * but has a deleted line above, this one is taken in. If the line above has changes, the block
+         * is extended from there. If the line has no changes itself, the search stops).
+         *
+         * The block never extends the visible line range of the viewer.
+         */
+
+        ILineDiffer differ= getDiffer(viewer);
+        if (differ is null)
+            return new Point(-1, -1);
+
+        // backward search
+
+        int l= line;
+        ILineDiffInfo info= differ.getLineInfo(l);
+        // search backwards until a line has no changes to itself
+        while (l >= min && info !is null && (info.getChangeType() is ILineDiffInfo.CHANGED || info.getChangeType() is ILineDiffInfo.ADDED)) {
+            info= differ.getLineInfo(--l);
+        }
+
+        int first= Math.min(l + 1, line);
+
+        // forward search
+
+        l= line;
+        info= differ.getLineInfo(l);
+        // search forward until a line has no changes to itself
+        while (l <= max && info !is null && (info.getChangeType() is ILineDiffInfo.CHANGED || info.getChangeType() is ILineDiffInfo.ADDED)) {
+            info= differ.getLineInfo(++l);
+        }
+
+        int last= Math.max(l - 1, line);
+
+        return new Point(first, last);
+    }
+
+    /*
+     * @see dwtx.jface.text.source.IAnnotationHoverExtension#getHoverInfo(dwtx.jface.text.source.ISourceViewer, dwtx.jface.text.source.ILineRange, int)
+     */
+    public Object getHoverInfo(ISourceViewer sourceViewer, ILineRange lineRange, int visibleLines) {
+        int first= adaptFirstLine(sourceViewer, lineRange.getStartLine());
+        int last= adaptLastLine(sourceViewer, lineRange.getStartLine() + lineRange.getNumberOfLines() - 1);
+        String content= computeContent(sourceViewer, first, last, visibleLines);
+        return formatSource(content);
+    }
+
+    /**
+     * Adapts the start line to the implementation of <code>ILineDiffInfo</code>.
+     *
+     * @param viewer the source viewer
+     * @param startLine the line to adapt
+     * @return <code>startLine - 1</code> if that line exists and is an
+     *         unchanged line followed by deletions, <code>startLine</code>
+     *         otherwise
+     */
+    private int adaptFirstLine(ISourceViewer viewer, int startLine) {
+        ILineDiffer differ= getDiffer(viewer);
+        if (differ !is null && startLine > 0) {
+            int l= startLine - 1;
+            ILineDiffInfo info= differ.getLineInfo(l);
+            if (info !is null && info.getChangeType() is ILineDiffInfo.UNCHANGED && info.getRemovedLinesBelow() > 0)
+                return l;
+        }
+        return startLine;
+    }
+
+    /**
+     * Adapts the last line to the implementation of <code>ILineDiffInfo</code>.
+     *
+     * @param viewer the source viewer
+     * @param lastLine the line to adapt
+     * @return <code>lastLine - 1</code> if that line exists and is an
+     *         unchanged line followed by deletions, <code>startLine</code>
+     *         otherwise
+     */
+    private int adaptLastLine(ISourceViewer viewer, int lastLine) {
+        ILineDiffer differ= getDiffer(viewer);
+        if (differ !is null && lastLine > 0) {
+            ILineDiffInfo info= differ.getLineInfo(lastLine);
+            if (info !is null && info.getChangeType() is ILineDiffInfo.UNCHANGED)
+                return lastLine - 1;
+        }
+        return lastLine;
+    }
+
+    /*
+     * @see dwtx.jface.text.source.IAnnotationHoverExtension#getHoverLineRange(dwtx.jface.text.source.ISourceViewer, int)
+     */
+    public ILineRange getHoverLineRange(ISourceViewer viewer, int lineNumber) {
+        IDocument document= viewer.getDocument();
+        if (document !is null) {
+            Point range= computeLineRange(viewer, lineNumber, 0, Math.max(0, document.getNumberOfLines() - 1));
+            if (range.x !is -1 && range.y !is -1)
+                return new LineRange(range.x, range.y - range.x + 1);
+        }
+        return null;
+    }
+
+    /*
+     * @see dwtx.jface.text.source.IAnnotationHoverExtension#canHandleMouseCursor()
+     */
+    public bool canHandleMouseCursor() {
+        return false;
+    }
+
+    /*
+     * @see dwtx.jface.text.source.IAnnotationHoverExtension#getHoverControlCreator()
+     */
+    public IInformationControlCreator getHoverControlCreator() {
+        return null;
+    }
+
+    /*
+     * @see dwtx.jface.text.information.IInformationProviderExtension2#getInformationPresenterControlCreator()
+     * @since 3.2
+     */
+    public IInformationControlCreator getInformationPresenterControlCreator() {
+        return new IInformationControlCreator() {
+            public IInformationControl createInformationControl(Shell parent) {
+                return new DefaultInformationControl(parent, (ToolBarManager)null, null);
+            }
+        };
+    }
+}