storageutil: move metadata parsing and packing from revlog (API)
Parsing and writing of revision text metadata is likely identical
across storage backends. Let's move the code out of revlog so we
don't need to import the revlog module in order to use it.
Differential Revision: https://phab.mercurial-scm.org/D4754
basic:
* neither file exists
creating
* neither file still exists
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating
fakeuncacheable:
* neither file exists
creating
* neither file still exists
creating
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
creating
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1
setbeforeget:
* neither file exists
string set externally
* file x created
creating
string from function
* string set externally again
string 2 set externally
* file y created
creating
string from function
antiambiguity: