From 2cdb73b442169b48da1588ab7cfaac7256677a5e Mon Sep 17 00:00:00 2001
From: Philip L. McMahon <philip.l.mcmahon@gmail.com>
Date: Sat, 28 Jan 2012 13:57:39 -0500
Subject: [PATCH] RepositoryModel will use String rather than RefModel to track the current symbolic head and available heads.

---
 src/com/gitblit/utils/JGitUtils.java |   86 ++++++++++++++++++++++++++++++-------------
 1 files changed, 60 insertions(+), 26 deletions(-)

diff --git a/src/com/gitblit/utils/JGitUtils.java b/src/com/gitblit/utils/JGitUtils.java
index 05c0852..6470634 100644
--- a/src/com/gitblit/utils/JGitUtils.java
+++ b/src/com/gitblit/utils/JGitUtils.java
@@ -1156,49 +1156,60 @@
 	}
 
 	/**
-	 * Returns the default HEAD for a repository. Normally returns the ref HEAD points to, but if HEAD points to nothing
-	 * it returns null.
+	 * Returns the target of the symbolic HEAD reference for a repository.
+	 * Normally returns a branch reference name, but when HEAD is detached,
+	 * the commit is matched against the known tags. The most recent matching
+	 * tag ref name will be returned if it references the HEAD commit. If
+	 * no match is found, the SHA1 is returned.
 	 *
 	 * @param repository
-	 * @return the refmodel for HEAD or null
+	 * @return the ref name or the SHA1 for detached HEADs
 	 */
-	public static RefModel getDefaultHead(Repository repository) {
-		RefModel ref = null;
+	public static String getSymbolicHeadTarget(Repository repository) {
+		String target = null;
 		try {
-			Ref head = repository.getRef(Constants.HEAD);
-			if (head != null) {
-				Ref target = head.getTarget();
-				RevWalk rw = new RevWalk(repository);
-				ObjectId targetId = target.getObjectId();
-				if (targetId != null) {
-					RevObject object = rw.parseAny(targetId);
-					ref = new RefModel(target.getName(), target, object);
+			target = repository.getFullBranch();
+			if (!target.startsWith(Constants.R_HEADS)) {
+				// refers to an actual commit, probably a tag
+				// find latest tag that matches the commit, if any
+				List<RefModel> tagModels = getTags(repository, true, -1);
+				if (tagModels.size() > 0) {
+					RefModel tag = null;
+					Date lastDate = new Date(0);
+					for (RefModel tagModel : tagModels) {
+						if (tagModel.getReferencedObjectId().getName().equals(target) &&
+								tagModel.getDate().after(lastDate)) {
+							tag = tagModel;
+							lastDate = tag.getDate();
+						}
+					}
+					target = tag.getName();
 				}
-				rw.dispose();
 			}
 		} catch (Throwable t) {
-			LOGGER.error("Failed to get default head!", t);
+			error(t, repository, "{0} failed to get symbolic HEAD target");
 		}
-		return ref;
+		return target;
 	}
-
+	
 	/**
-	 * Sets the default HEAD symbolic ref for a repository.
+	 * Sets the HEAD symbolic ref name for a repository. The HEAD will
+	 * be detached if the name does not reference a branch.
 	 *
 	 * @param repository
-	 * @param ref
+	 * @param name
 	 */
-	public static void setDefaultHead(Repository repository, Ref ref) {
+	public static void setSymbolicHeadTarget(Repository repository, String name) {
 		try {
-			boolean detach = !ref.getName().startsWith(Constants.R_HEADS); // detach if not a branch
+			boolean detach = !name.startsWith(Constants.R_HEADS); // detach if not a branch
 			RefUpdate.Result result;
 			RefUpdate head = repository.updateRef(Constants.HEAD, detach);
 			if (detach) { // Tag
-				RevCommit commit = getCommit(repository, ref.getObjectId().getName());
+				RevCommit commit = getCommit(repository, name);
 				head.setNewObjectId(commit.getId());
 				result = head.forceUpdate();
 			} else {
-				result = head.link(ref.getName());
+				result = head.link(name);
 			}
 			switch (result) {
 			case NEW:
@@ -1207,13 +1218,36 @@
 			case FAST_FORWARD:
 				break;
 			default:
-				LOGGER.error(MessageFormat.format("{0} failed to set default head to {1} ({2})",
-						repository.getDirectory().getAbsolutePath(), ref.getName(), result));
+				LOGGER.error(MessageFormat.format("{0} symbolic HEAD update to {1} returned result {2}",
+						repository.getDirectory().getAbsolutePath(), name, result));
 			}
 		} catch (Throwable t) {
-			error(t, repository, "{0} failed to set default head to {1}", ref.getName());
+			error(t, repository, "{0} failed to set symbolic HEAD to {1}", name);
 		}
 	}
+	
+	/**
+	 * Get the full branch and tag ref names for any potential symbolic head targets.
+	 *
+	 * @param repository
+	 * @return a list of ref names
+	 */
+	public static List<String> getAvailableHeadTargets(Repository repository) {
+		List<String> targets = new ArrayList<String>();
+		List<RefModel> branchModels = JGitUtils.getLocalBranches(repository, true, -1);
+		if (branchModels.size() > 0) {
+			for (RefModel branchModel : branchModels) {
+				targets.add(branchModel.getName());
+			}
+		}
+		List<RefModel> tagModels = JGitUtils.getTags(repository, true, -1);
+		if (tagModels.size() > 0) {
+			for (RefModel tagModel : tagModels) {
+				targets.add(tagModel.getName());
+			}
+		}
+		return targets;
+	}
 
 	/**
 	 * Returns all refs grouped by their associated object id.

--
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