avoid reposize database locking overhead when not needed

Only when the preferred content expression being matched uses balanced
preferred content is this overhead needed.

It might be possible to eliminate the locking entirely. Eg, check the
live changes before and after the action and re-run if they are not
stable. For now, this is good enough, it avoids existing preferred
content getting slow. If balanced preferred content turns out to be too
slow to check, that could be tried later.

Limit.hs

@@ -114,6 +114,7 @@ limitInclude glob = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "include" =? glob
 	}
 
@@ -128,6 +129,7 @@ limitExclude glob = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "exclude" =? glob
 	}
 
@@ -153,6 +155,7 @@ limitIncludeSameContent glob = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "includesamecontent" =? glob
 	}
 
@@ -168,6 +171,7 @@ limitExcludeSameContent glob = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "excludesamecontent" =? glob
 	}
 
@@ -244,6 +248,7 @@ matchMagic limitname querymagic selectprovidedinfo selectuserprovidedinfo (Just
 		, matchNeedsFileContent = True
 		, matchNeedsKey = False
 		, matchNeedsLocationLog = False
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = limitname =? glob
 		}
   where
@@ -271,6 +276,7 @@ addUnlocked = addLimit $ Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "unlocked"
 	}
 
@@ -281,6 +287,7 @@ addLocked = addLimit $ Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "locked"
 	}
 
@@ -316,6 +323,7 @@ addIn s = do
 		, matchNeedsFileContent = False
 		, matchNeedsKey = True
 		, matchNeedsLocationLog = not inhere
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = "in" =? s
 		}
 	checkinuuid u notpresent key
@@ -346,6 +354,7 @@ addExpectedPresent = do
 		, matchNeedsFileContent = False
 		, matchNeedsKey = True
 		, matchNeedsLocationLog = True
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = matchDescSimple "expected-present"
 		}
 
@@ -363,6 +372,7 @@ limitPresent u = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = not (isNothing u)
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "present"
 	}
 
@@ -374,6 +384,7 @@ limitInDir dir desc = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple desc
 	}
   where
@@ -406,6 +417,7 @@ limitCopies want = case splitc ':' want of
 			, matchNeedsFileContent = False
 			, matchNeedsKey = True
 			, matchNeedsLocationLog = True
+			, matchNeedsLiveRepoSize = False
 			, matchDesc = "copies" =? want
 			}
 	go' n good notpresent key = do
@@ -431,6 +443,7 @@ limitLackingCopies desc approx want = case readish want of
 		, matchNeedsFileContent = False
 		, matchNeedsKey = True
 		, matchNeedsLocationLog = True
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = matchDescSimple desc
 		}
 	Nothing -> Left "bad value for number of lacking copies"
@@ -461,6 +474,7 @@ limitUnused = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "unused"
 	}
   where
@@ -484,6 +498,7 @@ limitAnything = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "anything"
 	}
 
@@ -499,6 +514,7 @@ limitNothing = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = False
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "nothing"
 	}
 
@@ -522,6 +538,7 @@ limitInAllGroup getgroupmap groupname = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = True
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "inallgroup" =? groupname
 	}
   where
@@ -547,6 +564,7 @@ limitOnlyInGroup getgroupmap groupname = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = True
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "inallgroup" =? groupname
 	}
   where
@@ -592,6 +610,7 @@ limitBalanced' termname fullybalanced mu groupname = do
 			matchNeedsLocationLog present ||
 			matchNeedsLocationLog fullybalanced ||
 			matchNeedsLocationLog copies
+		, matchNeedsLiveRepoSize = True
 		, matchDesc = termname =? groupname
 		}
 
@@ -677,6 +696,7 @@ limitFullyBalanced''' filtercandidates termname mu getgroupmap g n want = Right
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = True
 	, matchDesc = termname =? want
 	}
 
@@ -736,6 +756,7 @@ limitInBackend name = Right $ MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = "inbackend" =? name
 	}
   where
@@ -753,6 +774,7 @@ limitSecureHash = MatchFiles
 	, matchNeedsFileContent = False
 	, matchNeedsKey = True
 	, matchNeedsLocationLog = False
+	, matchNeedsLiveRepoSize = False
 	, matchDesc = matchDescSimple "securehash"
 	}
 
@@ -774,6 +796,7 @@ limitSize lb desc vs s = case readSize dataUnits s of
 		, matchNeedsFileContent = False
 		, matchNeedsKey = False
 		, matchNeedsLocationLog = False
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = desc =? s
 		}
   where
@@ -804,6 +827,7 @@ limitMetaData s = case parseMetaDataMatcher s of
 		, matchNeedsFileContent = False
 		, matchNeedsKey = True
 		, matchNeedsLocationLog = False
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = "metadata" =? s
 		}
   where
@@ -820,6 +844,7 @@ addAccessedWithin duration = do
 		, matchNeedsFileContent = False
 		, matchNeedsKey = False
 		, matchNeedsLocationLog = False
+		, matchNeedsLiveRepoSize = False
 		, matchDesc = "accessedwithin" =? fromDuration duration
 		}
   where