AU: tolerate files that are symlinks in src image, yet not in new image.

delta_diff_generator.cc

Index: delta_diff_generator.cc
diff --git a/delta_diff_generator.cc b/delta_diff_generator.cc
index 0d1e4cef2360af47c1004c256f762b01d97b646b..e113f7b91734816a1172f803ac25c0485c67c1bd 100644
--- a/delta_diff_generator.cc
+++ b/delta_diff_generator.cc
@@ -141,6 +141,7 @@ bool DeltaReadFiles(Graph* graph,
                     int data_fd,
                     off_t* data_file_size) {
   set<ino_t> visited_inodes;
+  set<ino_t> visited_src_inodes;
   for (FilesystemIterator fs_iter(new_root,
                                   utils::SetWithValue<string>("/lost+found"));
        !fs_iter.IsEnd(); fs_iter.Increment()) {
@@ -156,10 +157,22 @@ bool DeltaReadFiles(Graph* graph,
 
     LOG(INFO) << "Encoding file " << fs_iter.GetPartialPath();
 
+    bool should_diff_from_source = true;
+    string src_path = old_root + fs_iter.GetPartialPath();
+    if (utils::FileExists(src_path.c_str())) {
+      struct stat src_stbuf;
+      TEST_AND_RETURN_FALSE_ERRNO(0 == stat(src_path.c_str(), &src_stbuf));
+      should_diff_from_source = !utils::SetContainsKey(visited_src_inodes,

[petkov, 2011/02/15 06:01:38]

Add a comment what this is trying to catch and what action is taken?

+                                                       src_stbuf.st_ino);
+      visited_src_inodes.insert(src_stbuf.st_ino);
+    }
+
     TEST_AND_RETURN_FALSE(DeltaReadFile(graph,
                                         Vertex::kInvalidIndex,
                                         blocks,
-                                        old_root,
+                                        (should_diff_from_source ?
+                                         old_root :
+                                         "/-!@:&*nonexistent_path"),

[petkov, 2011/02/15 06:01:38]

This feels a bit of a hack. Maybe use an empty string and check for it
explicitly in DeltaReadFile?

                                         new_root,
                                         fs_iter.GetPartialPath(),
                                         data_fd,