From 811bc1b8e514e46da7de5ab250c94b9a31657157 Mon Sep 17 00:00:00 2001
From: Cornelius Mika <cornelius.mika@gmail.com>
Date: Mon, 6 Nov 2017 10:28:47 +0100
Subject: [PATCH] files: extract common variable

Also improve the pattern used to determine whether a symlink target
points to a Home Manager file path.
---
 modules/files.nix | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/modules/files.nix b/modules/files.nix
index 011f685e3..8871aa1a2 100644
--- a/modules/files.nix
+++ b/modules/files.nix
@@ -31,6 +31,10 @@ let
     in
       "home_file_" + safeName;
 
+  # A symbolic link whose target path matches this pattern will be
+  # considered part of a Home Manager generation.
+  homeFilePattern = "${builtins.storeDir}/*-home-manager-files/*";
+
 in
 
 {
@@ -140,7 +144,6 @@ in
     # overwrite an existing file.
     home.activation.checkLinkTargets = dagEntryBefore ["writeBoundary"] (
       let
-        pattern = "-home-manager-files/";
         check = pkgs.writeText "check" ''
           . ${./lib-bash/color-echo.sh}
 
@@ -150,7 +153,7 @@ in
             relativePath="''${sourcePath#$newGenFiles/}"
             targetPath="$HOME/$relativePath"
             if [[ -e "$targetPath" \
-                && ! "$(readlink "$targetPath")" =~ "${pattern}" ]] ; then
+                && ! "$(readlink "$targetPath")" == ${homeFilePattern} ]] ; then
               errorEcho "Existing file '$targetPath' is in the way"
               collision=1
             fi
@@ -176,8 +179,6 @@ in
 
     home.activation.linkGeneration = dagEntryAfter ["writeBoundary"] (
       let
-        pattern = "-home-manager-files/";
-
         link = pkgs.writeText "link" ''
           newGenFiles="$1"
           shift
@@ -200,7 +201,7 @@ in
             targetPath="$HOME/$relativePath"
             if [[ -e "$newGenFiles/$relativePath" ]] ; then
               $VERBOSE_ECHO "Checking $targetPath: exists"
-            elif [[ ! "$(readlink "$targetPath")" =~ "${pattern}" ]] ; then
+            elif [[ ! "$(readlink "$targetPath")" == ${homeFilePattern} ]] ; then
               warnEcho "Path '$targetPath' not link into Home Manager generation. Skipping delete."
             else
               $VERBOSE_ECHO "Checking $targetPath: gone (deleting)"