todo

doc/todo/adb_import.mdwn

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+Make adb special remote support import tree.
+
+This would be very useful for syncing with an android device without
+needing to run git-annex on it. While git-annex works well enough in
+termux, the horribleness of android's /sdcard makes it unappealing to put a
+git annex repository on it (direct mode is still the best option there;
+v7 unlocked works but without hard links has to store two copies of each
+file).
+
+This needs at a minimum a way to list files in a directory via adb,
+in order to find new files. `adb shell find /sdcard/ -type f` seems to work
+across a range of android versions (5.1, 8.1).
+
+To avoid re-downloading each file each import, a way to list files
+along with a good content identifier is needed.
+`adb shell find /sdcard/ -type f -exec stat -c "'%d %i %s %Y %n'" {} +`
+works on (5.1, 8.1) (note the weird quoting that it needs)
+
+To avoid losing modifications to files 
+that the user makes using the android device while the same files are being
+exported to it would need an upload to a temp location followed by a check
+that the original is unmodified before renaming. This needs
+shell scripting in android's limited shell environment, or
+`adb shell stat 'origfile'` followed by `adb shell mv 'tmpfile' 'origfile'`.
+
+That is necessarily racy, although the race window is
+probably not much wider than the similar races when git checkout stats
+work tree files before overwriting them.
+
+Alternatively, the documentation could tell the user to avoid modifying files
+on their android device while git-annex is exporting to it, or to instead
+only ever modify files on the android device, and import from it, but not
+export any changes to it. (Or some combination of those 
+for different subdirectories on it.)