Branches and Tags links in commit message viewer

Some analog of 'gitk' utility links. Added following info to commit
message viewer:
Branches - links to branch refs
Tags - list of tags pointing to this commit
Follows - link to previous tag in history
Precedes - link to next tag in history

Bug: 336223
Change-Id: I1c61d2c7eca14ba534302eec6e38bdbe85e0107f
Signed-off-by: ilya.ivanov <ilya.ivanov@intland.com>
Signed-off-by: Dariusz Luksza <dariusz@luksza.org>

4 files changed, 223 insertions, 8 deletions

diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
index acd4e04541..d03560d7a3 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
@@ -1684,6 +1684,18 @@ public class UIText extends NLS {
 	public static String CommitMessageViewer_child;
 
 	/** */
+	public static String CommitMessageViewer_branches;
+
+	/** */
+	public static String CommitMessageViewer_tags;
+
+	/** */
+	public static String CommitMessageViewer_follows;
+
+	/** */
+	public static String CommitMessageViewer_precedes;
+
+	/** */
 	public static String CommitMessageViewer_commit;
 
 	/** */
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitGraphTable.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitGraphTable.java
index 0f21ab52fb..ccc9c69de4 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitGraphTable.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitGraphTable.java
@@ -109,6 +109,9 @@ class CommitGraphTable {
 
 	private SWTCommitList allCommits;
 
+	// used for resolving PlotCommit objects by ids
+	private HashMap<String, PlotCommit> commitsMap = null;
+
 	private RevFlag highlight;
 
 	private HistoryPageInput input;
@@ -164,8 +167,8 @@ class CommitGraphTable {
 
 	CommitGraphTable(final Composite parent, final IPageSite site,
 			final MenuManager menuMgr) {
-         this(parent);
- 		final IAction selectAll = createStandardAction(ActionFactory.SELECT_ALL);
+		this(parent);
+		final IAction selectAll = createStandardAction(ActionFactory.SELECT_ALL);
 		getControl().addFocusListener(new FocusListener() {
 			public void focusLost(FocusEvent e) {
 				site.getActionBars().setGlobalActionHandler(
@@ -231,8 +234,14 @@ class CommitGraphTable {
 	}
 
 	void selectCommit(final RevCommit c) {
-		table.setSelection(new StructuredSelection(c));
-		table.reveal(c);
+		if (c instanceof PlotCommit) {
+			table.setSelection(new StructuredSelection(c));
+			table.reveal(c);
+		} else {
+			PlotCommit swtCommit = commitsMap.get(c.getId().name());
+			table.setSelection(new StructuredSelection(swtCommit));
+			table.reveal(swtCommit);
+		}
 	}
 
 	void addSelectionChangedListener(final ISelectionChangedListener l) {
@@ -276,13 +285,21 @@ class CommitGraphTable {
 		allCommits = list;
 		table.setInput(asArray);
 		if (asArray != null && asArray.length > 0) {
-			if (oldList != list)
+			if (oldList != list) {
 				selectCommit(asArray[0]);
+				initCommitsMap();
+			}
 		} else {
 			table.getTable().deselectAll();
 		}
 	}
 
+	private void initCommitsMap() {
+		commitsMap = new HashMap<String, PlotCommit>();
+		for (PlotCommit commit : allCommits)
+			commitsMap.put(commit.getId().name(), commit);
+	}
+
 	private void createColumns(final Table rawTable, final TableLayout layout) {
 		final TableColumn graph = new TableColumn(rawTable, SWT.NONE);
 		graph.setResizable(true);
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitMessageViewer.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitMessageViewer.java
index 049cef089b..ab234b61bd 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitMessageViewer.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/history/CommitMessageViewer.java
@@ -18,6 +18,10 @@ import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -42,10 +46,16 @@ import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jgit.diff.DiffFormatter;
 import org.eclipse.jgit.diff.RawText;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revplot.PlotCommit;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.SWT;
@@ -305,7 +315,7 @@ class CommitMessageViewer extends TextViewer implements
 		for (int i = 0; i < commit.getChildCount(); i++) {
 			final RevCommit p = commit.getChild(i);
 			d.append(UIText.CommitMessageViewer_child);
-			d.append(":  "); //$NON-NLS-1$
+			d.append(": "); //$NON-NLS-1$
 			addLink(d, styles, p);
 			d.append(" ("); //$NON-NLS-1$
 			d.append(p.getShortMessage());
@@ -313,6 +323,63 @@ class CommitMessageViewer extends TextViewer implements
 			d.append(LF);
 		}
 
+		List<Ref> branches = getBranches();
+		if (!branches.isEmpty()) {
+			d.append(UIText.CommitMessageViewer_branches);
+			d.append(": "); //$NON-NLS-1$
+			for (Iterator<Ref> i = branches.iterator(); i.hasNext(); ) {
+				Ref head = i.next();
+				RevCommit p;
+				try {
+					p = new RevWalk(db).parseCommit(head.getObjectId());
+					addLink(d, formatHeadRef(head), styles, p);
+					if (i.hasNext())
+						d.append(", "); //$NON-NLS-1$
+				} catch (MissingObjectException e) {
+					Activator.logError(e.getMessage(), e);
+				} catch (IncorrectObjectTypeException e) {
+					Activator.logError(e.getMessage(), e);
+				} catch (IOException e) {
+					Activator.logError(e.getMessage(), e);
+				}
+			}
+			d.append(LF);
+		}
+
+		String tagsString = getTagsString();
+		if (tagsString.length() > 0) {
+			d.append(UIText.CommitMessageViewer_tags);
+			d.append(": "); //$NON-NLS-1$
+			d.append(tagsString);
+			d.append(LF);
+		}
+
+		try {
+			Ref followingTag = getNextTag(false);
+			if (followingTag != null) {
+				d.append(UIText.CommitMessageViewer_follows);
+				d.append(": "); //$NON-NLS-1$
+				RevCommit p = new RevWalk(db).parseCommit(followingTag.getObjectId());
+				addLink(d, formatTagRef(followingTag), styles, p);
+				d.append(LF);
+			}
+		} catch (IOException e) {
+			Activator.logError(e.getMessage(), e);
+		}
+
+		try {
+			Ref precedingTag = getNextTag(true);
+			if (precedingTag != null) {
+				d.append(UIText.CommitMessageViewer_precedes);
+				d.append(": "); //$NON-NLS-1$
+				RevCommit p = new RevWalk(db).parseCommit(precedingTag.getObjectId());
+				addLink(d, formatTagRef(precedingTag), styles, p);
+				d.append(LF);
+			}
+		} catch (IOException e) {
+			Activator.logError(e.getMessage(), e);
+		}
+
 		makeGrayText(d, styles);
 		d.append(LF);
 		String msg = commit.getFullMessage();
@@ -349,6 +416,37 @@ class CommitMessageViewer extends TextViewer implements
 		getTextWidget().setStyleRanges(arr);
 	}
 
+	private String getTagsString() {
+		StringBuilder sb = new StringBuilder();
+		Map<String, Ref> tagsMap = db.getTags();
+		for (String tagName : tagsMap.keySet()) {
+			ObjectId peeledId = tagsMap.get(tagName).getPeeledObjectId();
+			if (peeledId != null && peeledId.equals(commit)) {
+				if (sb.length() > 0)
+					sb.append(", "); //$NON-NLS-1$
+				sb.append(tagName);
+			}
+		}
+
+		return sb.toString();
+	}
+
+	private String formatHeadRef(Ref ref) {
+		final String name = ref.getName();
+		if (name.startsWith(Constants.R_HEADS))
+			return name.substring(Constants.R_HEADS.length());
+		else if (name.startsWith(Constants.R_REMOTES))
+			return name.substring(Constants.R_REMOTES.length());
+		return name;
+	}
+
+	private String formatTagRef(Ref ref) {
+		final String name = ref.getName();
+		if (name.startsWith(Constants.R_TAGS))
+			return name.substring(Constants.R_TAGS.length());
+		return name;
+	}
+
 	private void makeGrayText(StringBuilder d, ArrayList<StyleRange> styles) {
 		int p0 = 0;
 		for (int i = 0; i < styles.size(); ++i) {
@@ -371,18 +469,23 @@ class CommitMessageViewer extends TextViewer implements
 		}
 	}
 
-	private void addLink(final StringBuilder d,
+	private void addLink(final StringBuilder d, String linkLabel,
 			final ArrayList<StyleRange> styles, final RevCommit to) {
 		final ObjectLink sr = new ObjectLink();
 		sr.targetCommit = to;
 		sr.foreground = sys_linkColor;
 		sr.underline = true;
 		sr.start = d.length();
-		d.append(to.getId().name());
+		d.append(linkLabel);
 		sr.length = d.length() - sr.start;
 		styles.add(sr);
 	}
 
+	private void addLink(final StringBuilder d,
+			final ArrayList<StyleRange> styles, final RevCommit to) {
+		addLink(d, to.getId().name(), styles, to);
+	}
+
 	private void addDiff(final StringBuilder d,
 			final ArrayList<StyleRange> styles) {
 		final DiffFormatter diffFmt = new DiffFormatter(
@@ -527,4 +630,83 @@ class CommitMessageViewer extends TextViewer implements
 
 	}
 
+	/**
+	 * Finds nextdoor tagged revition. Searches forwards (in descendants) or backwards (in ancestors)
+	 * @param searchDescendant if <code>false</code>, will search for tagged revision in ancestors
+	 * @return {@link Ref} or <code>null</code> if no tag found
+	 * @throws IOException
+	 */
+	private Ref getNextTag(boolean searchDescendant) throws IOException {
+		RevWalk revWalk = new RevWalk(db);
+
+		Map<String, Ref> tagsMap = db.getTags();
+		Ref tagRef = null;
+
+		for (String tagName : tagsMap.keySet()) {
+			// both RevCommits must be allocated using same RevWalk instance,
+			// otherwise isMergedInto returns wrong result!
+			RevCommit current = revWalk.parseCommit(commit);
+			RevCommit newTag = revWalk.parseCommit(tagsMap.get(tagName).getObjectId());
+
+			if (newTag.getId().equals(commit))
+				continue;
+
+			// check if newTag matches our criteria
+			if (isMergedInto(revWalk, newTag, current, searchDescendant)) {
+				if (tagRef != null) {
+					RevCommit oldTag = revWalk.parseCommit(tagRef.getObjectId());
+
+					// both oldTag and newTag satisfy search criteria, so taking the closest one
+					if (isMergedInto(revWalk, oldTag, newTag, searchDescendant))
+						tagRef = tagsMap.get(tagName);
+				} else
+					tagRef = tagsMap.get(tagName);
+			}
+		}
+
+		return tagRef;
+	}
+
+	/**
+	 * @param rw
+	 * @param base
+	 * @param tip
+	 * @param swap if <code>true</code>, base and tip arguments are swapped
+	 * @return <code>true</code> if there is a path directly from tip to base (and thus base is fully merged into tip); <code>false</code> otherwise.
+	 * @throws IOException
+	 */
+	private boolean isMergedInto(final RevWalk rw, final RevCommit base, final RevCommit tip, boolean swap)
+			throws IOException {
+		return !swap ? rw.isMergedInto(base, tip) : rw.isMergedInto(tip, base);
+	}
+
+	/**
+	 * @return List of heads from those current commit is reachable
+	 */
+	private List<Ref> getBranches() {
+		RevWalk revWalk = new RevWalk(db);
+		List<Ref> result = new ArrayList<Ref>();
+
+		try {
+			Map<String, Ref> refsMap = new HashMap<String, Ref>();
+			refsMap.putAll(db.getRefDatabase().getRefs(Constants.R_HEADS));
+			// add remote heads to search
+			refsMap.putAll(db.getRefDatabase().getRefs(Constants.R_REMOTES));
+
+			for (String headName : refsMap.keySet()) {
+				RevCommit headCommit = revWalk.parseCommit(refsMap.get(headName).getObjectId());
+				// the base RevCommit also must be allocated using same RevWalk instance,
+				// otherwise isMergedInto returns wrong result!
+				RevCommit base = revWalk.parseCommit(commit);
+
+				if (revWalk.isMergedInto(base, headCommit))
+					result.add(refsMap.get(headName));	// commit is reachable from this head
+			}
+		} catch (IOException e) {
+			// skip exception
+		}
+
+		return result;
+	}
+
 }
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
index 9a5181c063..cc1c23382b 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
@@ -552,6 +552,10 @@ SpellCheckingMessageArea_paste=&Paste
 SpellCheckingMessageArea_selectAll=Select &All
 CommitMessageViewer_author=Author
 CommitMessageViewer_child=Child
+CommitMessageViewer_branches=Branches
+CommitMessageViewer_tags=Tags
+CommitMessageViewer_follows=Follows
+CommitMessageViewer_precedes=Precedes
 CommitMessageViewer_commit=commit
 CommitMessageViewer_committer=Committer
 CommitMessageViewer_errorGettingFileDifference=Can't get file difference of {0}.