support for checking presence of objects in direct mode

Also for dropping objects in direct mode.

Checking presence reliably needs a cache of mtime, size, and inode.
This way, if a file is modified, keys that point to it are no longer
present.

Also, the code for restoring the symlink when removing objects is
unnecessarily messy. calcGitLink was generating links starting with
"../../remote/.git/", when running "git annex move --from remote".
I put in a workaround, but calcGitLink should probably be fixed.

There is not yet support for getting objects from repositories in direct
mode; it still looks for content in .git/annex/objects, and there's no
once place I can change to fix that.

Also, getting objects from direct mode repositories is problematic since
the can be changed while the object is being transferred. It probably needs
to quarantine it first.

1 files changed, 10 insertions, 3 deletions

diff --git a/doc/design/assistant/desymlink.mdwn b/doc/design/assistant/desymlink.mdwn
index df36c036f..13a51890d 100644
--- a/doc/design/assistant/desymlink.mdwn
+++ b/doc/design/assistant/desymlink.mdwn
@@ -43,11 +43,12 @@ is converted to a real file when it becomes present.
 
 ## concrete design
 
-* Enable with annex.nosymlink or such config option.
-* Use .git/ for the git repo, but `.git/annex/objects` won't be used.
+* Enable with annex.direct
+* Use .git/ for the git repo, but `.git/annex/objects` won't be used
+  for object storage.
 * `git status` and similar will show all files as type changed, and
   `git commit` would be a very bad idea. Just don't support users running
-  git commands that affect the repository in this mode.
+  git commands that affect the repository in this mode. Probably.
 * However, `git status` and similar also will show deleted and new files,
   which will be helpful for the assistant to use when starting up.
 * Cache the mtime, size etc of files, and use this to detect when they've been
@@ -61,6 +62,8 @@ is converted to a real file when it becomes present.
   can map to multiple files. And that when a file is deleted or moved, the
   mapping needs to be updated.
 * May need a reverse mapping, from files in the tree to keys? TBD
+  (Needed to make things like `git annex drop` that want to map from the
+  file back to the key work.)
 * The existing watch code detects when a file gets closed, and in this
   mode, it could be a new file, or a modified file, or an unchanged file.
   For a modified file, can compare mtime, size, etc, to see if it needs
@@ -73,3 +76,7 @@ is converted to a real file when it becomes present.
   to files in this remote would not be noticed and committed, unless
   a git-annex command were added to do so.
   Getting it basically working as a remote would be a good 1st step.
+* It could also be used without the assistant as a repository that
+  the user uses directly. Would need some git-annex commands
+  to merge changes into the repo, update caches, and commit changes.
+  This could all be done by "git annex sync".