Add new method IndexDiff#getPathsWithIndexMode

Get the list of paths that have the given file mode.

This helps EGit to efficiently determine which modified files are
symlinks and should be shown with a symlink icon in the staging view.

Bug: 429302
Change-Id: Id15f0c6f265667f5b8b57cc2d9f97de568371919
Signed-off-by: Axel Richard <axel.richard@obeo.fr>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java

@@ -3,6 +3,7 @@
  * Copyright (C) 2007-2008, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2010, Jens Baumgart <jens.baumgart@sap.com>
  * Copyright (C) 2013, Robin Stocker <robin@nibor.org>
+ * Copyright (C) 2014, Axel Richard <axel.richard@obeo.fr>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -276,6 +277,8 @@ public class IndexDiff {
 
 	private IgnoreSubmoduleMode ignoreSubmoduleMode = null;
 
+	private Map<FileMode, Set<String>> fileModes = new HashMap<FileMode, Set<String>>();
+
 	/**
 	 * Construct an IndexDiff
 	 *
@@ -425,6 +428,7 @@ public class IndexDiff {
 		indexDiffFilter = new IndexDiffFilter(INDEX, WORKDIR);
 		filters.add(indexDiffFilter);
 		treeWalk.setFilter(AndTreeFilter.create(filters));
+		fileModes.clear();
 		while (treeWalk.next()) {
 			AbstractTreeIterator treeIterator = treeWalk.getTree(TREE,
 					AbstractTreeIterator.class);
@@ -497,6 +501,17 @@ public class IndexDiff {
 					}
 				}
 			}
+
+			for (int i = 0; i < treeWalk.getTreeCount(); i++) {
+				Set<String> values = fileModes.get(treeWalk.getFileMode(i));
+				String path = treeWalk.getPathString();
+				if (path != null) {
+					if (values == null)
+						values = new HashSet<String>();
+					values.add(path);
+					fileModes.put(treeWalk.getFileMode(i), values);
+				}
+			}
 		}
 
 		if (ignoreSubmoduleMode != IgnoreSubmoduleMode.ALL) {
@@ -539,6 +554,7 @@ public class IndexDiff {
 					}
 				}
 			}
+
 		}
 
 		// consume the remaining work
@@ -675,4 +691,20 @@ public class IndexDiff {
 		final DirCacheEntry entry = dirCache.getEntry(path);
 		return entry != null ? entry.getFileMode() : FileMode.MISSING;
 	}
+
+	/**
+	 * Get the list of paths that IndexDiff has detected to differ and have the
+	 * given file mode
+	 *
+	 * @param mode
+	 * @return the list of paths that IndexDiff has detected to differ and have
+	 *         the given file mode
+	 * @since 3.6
+	 */
+	public Set<String> getPathsWithIndexMode(final FileMode mode) {
+		Set<String> paths = fileModes.get(mode);
+		if (paths == null)
+			paths = new HashSet<String>();
+		return paths;
+	}
 }