From dbd2d7c83bc8a3a72a9ce6c4d8d0ae575e381588 Mon Sep 17 00:00:00 2001
From: "Shawn O. Pearce" <spearce@spearce.org>
Date: Tue, 24 Aug 2010 17:52:26 -0700
Subject: [PATCH] Support parsing commit:path style blob references

We can now resolve expressions that reference a path within a
commit, designating a specific revision of a specific tree or
file in the project.

Change-Id: Ie6a8be629d264d72209db894bd680c5900035cc0
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../jgit/lib/RepositoryResolveTest.java       | 21 ++++++++++++++
 .../src/org/eclipse/jgit/lib/Repository.java  | 29 +++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
index 4ca9ba020..0aa8db474 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RepositoryResolveTest.java
@@ -160,4 +160,25 @@ public void testParseGitDescribeOutput() throws IOException {
 		assertEquals(db.resolve("b^1"), db.resolve("B-6-g7f82283^1"));
 		assertEquals(db.resolve("b~2"), db.resolve("B-6-g7f82283~2"));
 	}
+
+	public void testParseLookupPath() throws IOException {
+		ObjectId b2_txt = id("10da5895682013006950e7da534b705252b03be6");
+		ObjectId b3_b2_txt = id("e6bfff5c1d0f0ecd501552b43a1e13d8008abc31");
+		ObjectId b_root = id("acd0220f06f7e4db50ea5ba242f0dfed297b27af");
+		ObjectId master_txt = id("82b1d08466e9505f8666b778744f9a3471a70c81");
+
+		assertEquals(b2_txt, db.resolve("b:b/b2.txt"));
+		assertEquals(b_root, db.resolve("b:"));
+		assertEquals(master_txt, db.resolve(":master.txt"));
+		assertEquals(b3_b2_txt, db.resolve("b~3:b/b2.txt"));
+
+		assertNull("no FOO", db.resolve("b:FOO"));
+		assertNull("no b/FOO", db.resolve("b:b/FOO"));
+		assertNull("no b/FOO", db.resolve(":b/FOO"));
+		assertNull("no not-a-branch:", db.resolve("not-a-branch:"));
+	}
+
+	private static ObjectId id(String name) {
+		return ObjectId.fromString(name);
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
index 8a0420568..c3d1d4948 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
@@ -74,8 +74,10 @@
 import org.eclipse.jgit.revwalk.RevBlob;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevObject;
+import org.eclipse.jgit.revwalk.RevTree;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.file.ReflogReader;
+import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.RawParseUtils;
@@ -577,6 +579,33 @@ && isHex(rev[i + 2]) && isHex(rev[i + 3])) {
 					}
 				}
 				break;
+			case ':': {
+				RevTree tree;
+				if (ref == null) {
+					// We might not yet have parsed the left hand side.
+					ObjectId id;
+					try {
+						if (i == 0)
+							id = resolve(rw, Constants.HEAD);
+						else
+							id = resolve(rw, new String(rev, 0, i));
+					} catch (RevisionSyntaxException badSyntax) {
+						throw new RevisionSyntaxException(revstr);
+					}
+					if (id == null)
+						return null;
+					tree = rw.parseTree(id);
+				} else {
+					tree = rw.parseTree(ref);
+				}
+
+				if (i == rev.length - i)
+					return tree.copy();
+
+				TreeWalk tw = TreeWalk.forPath(rw.getObjectReader(),
+						new String(rev, i + 1, rev.length - i - 1), tree);
+				return tw != null ? tw.getObjectId(0) : null;
+			}
 
 			default:
 				if (ref != null)