dirstate-tree: Borrow copy source paths from the "on disk" bytes
Use std::borrow::Cow to avoid some memory allocations and copying.
These particular allocations are not visible when profiling (as many files
in a typical repo don’t have a copy source). This change is "warm up"
for doing the same with paths of files themselves, which is more involved
since those paths are used as `HashMap` keys. This gets of the way the
addition of a lifetime parameter to several types.
Differential Revision: https://phab.mercurial-scm.org/D10559
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# Copyright (C) 2005 TK Soh.
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complete hg \
'n/--cwd/d/' 'n/-R/d/' 'n/--repository/d/' \
'C/-/( -R --repository \
--cwd \
-y --noninteractive \
-q --quiet \
-v --verbose \
--config \
--debug \
--debugger \
--encoding \
--encodingmode \
--traceback \
--time \
--profile \
--version \
-h --help)/' \
'p/1/(add addremove annotate blame archive \
backout bisect bookmarks branch branches \
bundle cat clone commit ci \
copy cp debugancestor debugbuilddag debugcheckstate \
debugcommands debugcomplete debugdag debugdata debugdate \
debugfsinfo debugignore debugindex debugindexdot debuginstall \
debugpushkey debugrebuildstate debugrename debugrevspec debugsetparents \
debugstate debugsub debugwalk diff export \
forget grep heads help identify \
id import patch incoming in \
init locate log history manifest \
merge outgoing out parents paths \
pull push recover remove rm \
rename move mv resolve revert \
rollback root serve showconfig debugconfig \
status st summary sum tag \
tags tip unbundle update up \
checkout co verify version)/'