add a LinkTarget type to disambiguate parameters of isSymlinkedTo

Something about making symlinks is very confusing about which parameter is
which. It perhaps doesn't help that isSymlinkedTo has the target second,
while ln has it first. Let's use a type to prevent confusion.

Also, simplified some properties that now use isSymlinkedTo. Since
isSymlinkedTo checks the link target, these properties don't need to check
themselves that the link is in place.

4 files changed, 14 insertions, 28 deletions

diff --git a/src/Propellor/Property/File.hs b/src/Propellor/Property/File.hs
index 07ace24b..08fdc780 100644
--- a/src/Propellor/Property/File.hs
+++ b/src/Propellor/Property/File.hs
@@ -97,14 +97,14 @@ dirExists :: FilePath -> Property NoInfo
 dirExists d = check (not <$> doesDirectoryExist d) $ property (d ++ " exists") $
 	makeChange $ createDirectoryIfMissing True d
 
+-- | The location that a symbolic link points to.
+newtype LinkTarget = LinkTarget FilePath
+
 -- | Creates or atomically updates a symbolic link.
 --
--- The first parameter is what the link should point to.
---
--- The second parameter is the name of the symbolic link to create.
 -- Does not overwrite regular files or directories.
-isSymlinkedTo :: FilePath -> FilePath -> Property NoInfo
-link `isSymlinkedTo` target = property desc $
+isSymlinkedTo :: FilePath -> LinkTarget -> Property NoInfo
+link `isSymlinkedTo` (LinkTarget target) = property desc $
 	go =<< (liftIO $ tryIO $ getSymbolicLinkStatus link)
   where
 	desc = link ++ " is symlinked to " ++ target
diff --git a/src/Propellor/Property/Nginx.hs b/src/Propellor/Property/Nginx.hs
index 1bd285c7..c9b4d8fd 100644
--- a/src/Propellor/Property/Nginx.hs
+++ b/src/Propellor/Property/Nginx.hs
@@ -6,23 +6,17 @@ import Propellor.Base
 import qualified Propellor.Property.File as File
 import qualified Propellor.Property.Apt as Apt
 import qualified Propellor.Property.Service as Service
-import System.Posix.Files
 
 type ConfigFile = [String]
 
 siteEnabled :: HostName -> ConfigFile -> RevertableProperty
 siteEnabled hn cf = enable <!> disable
   where
-	enable = check test prop
+	enable = siteVal hn `File.isSymlinkedTo` siteValRelativeCfg hn
 		`describe` ("nginx site enabled " ++ hn)
 		`requires` siteAvailable hn cf
 		`requires` installed
 		`onChange` reloaded
-	  where
-		test = not <$> doesFileExist (siteVal hn)
-		prop = dir `File.isSymlinkedTo` target
-		target = siteValRelativeCfg hn
-		dir = siteVal hn
 	disable = trivial $ File.notPresent (siteVal hn)
 		`describe` ("nginx site disable" ++ hn)
 		`requires` installed
@@ -40,8 +34,8 @@ siteCfg hn = "/etc/nginx/sites-available/" ++ hn
 siteVal :: HostName -> FilePath
 siteVal hn = "/etc/nginx/sites-enabled/" ++ hn
 
-siteValRelativeCfg :: HostName -> FilePath
-siteValRelativeCfg hn = "../sites-available/" ++ hn
+siteValRelativeCfg :: HostName -> File.LinkTarget
+siteValRelativeCfg hn = File.LinkTarget ("../sites-available/" ++ hn)
 
 installed :: Property NoInfo
 installed = Apt.installed ["nginx"]
diff --git a/src/Propellor/Property/Prosody.hs b/src/Propellor/Property/Prosody.hs
index 7dbfb1e1..0e379e63 100644
--- a/src/Propellor/Property/Prosody.hs
+++ b/src/Propellor/Property/Prosody.hs
@@ -6,7 +6,6 @@ import Propellor.Base
 import qualified Propellor.Property.File as File
 import qualified Propellor.Property.Apt as Apt
 import qualified Propellor.Property.Service as Service
-import System.Posix.Files
 
 type ConfigFile = [String]
 
@@ -15,17 +14,16 @@ type Conf = String
 confEnabled :: Conf -> ConfigFile -> RevertableProperty
 confEnabled conf cf = enable <!> disable
   where
-	enable = check test prop
+	enable = dir `File.isSymlinkedTo` target
 		`describe` ("prosody conf enabled " ++ conf)
 		`requires` confAvailable conf cf
 		`requires` installed
 		`onChange` reloaded
 	  where
-		test = not <$> doesFileExist (confValPath conf)
-		prop = dir `File.isSymlinkedTo` target
 		target = confValRelativePath conf
 		dir = confValPath conf
-		confValRelativePath conf' = "../conf.avail" </> conf' <.> "cfg.lua"
+		confValRelativePath conf' = File.LinkTarget $
+			"../conf.avail" </> conf' <.> "cfg.lua"
 	disable = trivial $ File.notPresent (confValPath conf)
 		`describe` ("prosody conf disabled " ++ conf)
 		`requires` installed
diff --git a/src/Propellor/Property/Uwsgi.hs b/src/Propellor/Property/Uwsgi.hs
index c6ae880b..7de1a85a 100644
--- a/src/Propellor/Property/Uwsgi.hs
+++ b/src/Propellor/Property/Uwsgi.hs
@@ -6,7 +6,6 @@ import Propellor.Base
 import qualified Propellor.Property.File as File
 import qualified Propellor.Property.Apt as Apt
 import qualified Propellor.Property.Service as Service
-import System.Posix.Files
 
 type ConfigFile = [String]
 
@@ -15,16 +14,11 @@ type AppName = String
 appEnabled :: AppName -> ConfigFile -> RevertableProperty
 appEnabled an cf = enable <!> disable
   where
-	enable = check test prop
+	enable = appVal an `File.isSymlinkedTo` appValRelativeCfg an
 		`describe` ("uwsgi app enabled " ++ an)
 		`requires` appAvailable an cf
 		`requires` installed
 		`onChange` reloaded
-	  where
-		test = not <$> doesFileExist (appVal an)
-		prop = dir `File.isSymlinkedTo` target
-		target = appValRelativeCfg an
-		dir = appVal an
 	disable = trivial $ File.notPresent (appVal an)
 		`describe` ("uwsgi app disable" ++ an)
 		`requires` installed
@@ -42,8 +36,8 @@ appCfg an = "/etc/uwsgi/apps-available/" ++ an
 appVal :: AppName -> FilePath
 appVal an = "/etc/uwsgi/apps-enabled/" ++ an
 
-appValRelativeCfg :: AppName -> FilePath
-appValRelativeCfg an = "../apps-available/" ++ an
+appValRelativeCfg :: AppName -> File.LinkTarget
+appValRelativeCfg an = File.LinkTarget $ "../apps-available/" ++ an
 
 installed :: Property NoInfo
 installed = Apt.installed ["uwsgi"]