feat!: Rework how .files are managed

1 files changed, 183 insertions, 0 deletions

diff --git a/make b/make
new file mode 100755
index 0000000..9731008
--- /dev/null
+++ b/make
@@ -0,0 +1,183 @@
+#!/bin/sh
+# IMPORTANT NOTE: The "local" keyword is not defined in POSIX, so I've decided to work without it.
+#                 For this reason, I do "$X/$f" instead of assigning local variables.
+#                 Another thing to consider is that in recursive functions, backtracking logic
+#                 CANNOT depend on variables, which are changed somewhere in the body before
+#                 the recursive step.
+
+cd "${0%/*}"
+
+[ -z "$HOSTNAME" ] && HOSTNAME="$(hostname)"
+if [ -z "$HOSTNAME" ]
+then
+	echo "Set HOSTNAME variable to the system's name!" >/dev/stderr
+	exit 1
+fi
+if [ ! -f "./SYSTEM/$HOSTNAME" ]
+then
+	echo "No configuration in ./SYSTEM for '$HOSTNAME'!" >/dev/stderr
+	exit 1
+fi
+
+# __merge_link <.FILES_DIR> <HOME_DIR>
+__merge_link() {
+	while read -r f
+	do
+		# Output file doesn't exist -> Create link
+		# This is also true on broken symlinks
+		if [ ! -e "$2/$f" ]
+		then
+			if [ -h "$2/$f" ]
+			then
+				echo "Warn: '$2/$f' is a broken link to '$(readlink "$2/$f")', updating!"
+				rm "$2/$f"
+			fi
+			ln -s "$1/$f" "$2/$f"
+		# Output file is already linked to current -> Do nothing
+		elif [ -h "$2/$f" -a "$(readlink $2/$f)" = "$1/$f" ]
+		then
+			:
+		# Current file is a file (and output exists) -> Create link but also update current
+		elif [ -f "$1/$f" ]
+		then
+			if [ -f "$2/$f" ]
+			then
+				# When output is NOT a link inside .files,
+				# update current file with the contents of the output
+				# Otherwise,
+				# replace output file with (link to) current
+				if ! cmp -s "$1/$f" "$2/$f"
+				then
+					if [ -h "$2/$f" ]
+					then
+						real="$(readlink "$2/$f")"
+						if [ "${real#$PWD}" = "$real" ]
+						then
+							cp "$real" "$1/$f" 2>/dev/null
+							echo "Warn: '$2/$f' already existed, '$1/$f' updated with its contents!" >/dev/stderr
+						fi
+					else
+						cp "$2/$f" "$1/$f"
+						echo "Warn: '$2/$f' already existed, '$1/$f' updated with its contents!" >/dev/stderr
+					fi
+				fi
+				rm "$2/$f"
+
+				ln -s "$1/$f" "$2/$f"
+			else
+				echo "Error: '$2/$f' already exists and is not a regular file!"
+			fi
+		# Current file is a directory (and output exists) -> Link current's files & dirs in output directory
+		elif [ -d "$1/$f" ]
+		then
+			if [ -d "$2/$f" ]
+			then
+				# If output is a link to directory in .files, continuing with merge
+				# will place links inside a directory in .files, which is bad.
+				# Instead, we'll make the link to directory become a directory with
+				# links to all inner files.
+				if [ -h "$2/$f" ]
+				then
+					real="$(realpath "$2/$f")"
+					if [ "${real#$PWD}" != "$real" ]
+					then
+						rm "$2/$f"
+						mkdir "$2/$f"
+						while read -r ff
+						do
+							ln -s "$real/$ff" "$2/$f/$ff"
+						done <<FILES
+$(ls -A1 "$real")
+FILES
+					fi
+				fi
+				__merge_link "$1/$f" "$2/$f"
+			else
+				echo "Error: '$2/$f' already exists and is not a directory!"
+			fi
+		else
+			echo "Error: '$1/$f' is neither a file or directory!"
+		fi
+	done <<FILES
+$(ls -A1 "$1")
+FILES
+}
+
+link() {
+	while read -r dir
+	do
+		dir="${dir%%*/}"
+		if [ ! -d "./$dir" ]
+		then
+			echo "Unknown directory '$dir'!" >/dev/stderr
+			continue
+		fi
+
+		__merge_link "$PWD/$dir" "$HOME"
+		echo "Linked $dir"
+	done <"./SYSTEM/$HOSTNAME"
+}
+
+# __remove_link <.FILES_DIR> <HOME_DIR>
+__remove_link() {
+	while read -r f
+	do
+		if [ -h "$2/$f" ]
+		then
+			real="$(realpath "$2/$f")"
+			# Output file exists and is a link to current -> Remove output
+			if [ "$real" = "$1/$f" ]
+			then
+				rm "$2/$f"
+				continue
+			# Output file exists and is a link in .files -> Do nothing (do not remove from .files)
+			# This is possible in the case when we have .files/X/A and .files/Y/A, and we linked
+			# .files/X but are now unlinking .files/Y
+			elif [ "${real#$PWD}" != "$real" ]
+			then
+				continue
+			fi
+		fi
+		if [ -d "$1/$f" -a -d "$2/$f" ]
+		then
+			__remove_link "$1/$f" "$2/$f"
+		fi
+	done <<FILES
+$(ls -A1 "$1")
+FILES
+	# See IMPORTANT NOTE, since we're aiming for full POSIX compatibility,
+	# the variable f will be overwritten by recursive calls, so this loop
+	# cannot be merged with the loop above (remove dirs on backtracking)
+	while read -r f
+	do
+		# Output file exists and is an empty directory -> Remove it
+		# We're assuming this directory was created by the script and/or the user
+		# will not care for empty dirs
+		if [ -d "$2/$f" -a -z "$(ls -A "$2/$f" 2>/dev/null)" ]
+		then
+			rm -r "$2/$f"
+		fi
+	done <<FILES
+$(ls -A1 "$1")
+FILES
+}
+
+unlink() {
+	while read -r dir
+	do
+		dir="${dir%%*/}"
+		if [ ! -d "./$dir" ]
+		then
+			echo "Unknown directory '$dir'!" >/dev/stderr
+			continue
+		fi
+
+		__remove_link "$PWD/$dir" "$HOME"
+		echo "Unlinked $dir"
+	done <"./SYSTEM/$HOSTNAME"
+}
+
+case "$1" in
+	(unlink) unlink ;;
+	(link|*) link ;;
+esac