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-rw-r--r--src/db.sh201
1 files changed, 201 insertions, 0 deletions
diff --git a/src/db.sh b/src/db.sh
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+# Copyright (c) 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "Configuration file sharing" project.
+# For details, see https://github.com/egor-tensin/config-links.
+# Distributed under the MIT License.
+
+# Shared directory settings
+
+shared_dir="$( pwd )"
+
+update_shared_dir() {
+ if [ "$#" -ne 1 ]; then
+ echo "usage: ${FUNCNAME[0]} DIR" >&2
+ return 1
+ fi
+
+ local new_shared_dir
+ new_shared_dir="$( traverse_path --exist --directory -- "$1" )"
+
+ [ "$db_path" == "$shared_dir/$default_db_name" ] \
+ && db_path="$new_shared_dir/$default_db_name"
+
+ shared_dir="$new_shared_dir"
+}
+
+# Database maintenance
+
+readonly default_db_name='links.bin'
+db_path="$shared_dir/$default_db_name"
+declare -A database
+
+update_database_path() {
+ if [ "$#" -ne 1 ]; then
+ echo "usage: ${FUNCNAME[0]} PATH" >&2
+ return 1
+ fi
+
+ db_path="$( traverse_path --file -- "$1" )"
+
+ local db_dir
+ db_dir="$( dirname -- "$db_path" )"
+ mkdir -p -- "$db_dir"
+}
+
+ensure_database_exists() {
+ [ -f "$db_path" ] || is_dry_run || > "$db_path"
+}
+
+read_database() {
+ [ ! -f "$db_path" ] && is_dry_run && return 0
+
+ local entry
+ while IFS= read -d '' -r entry; do
+ database[$entry]=1
+ done < "$db_path"
+}
+
+write_database() {
+ is_dry_run && return 0
+
+ > "$db_path"
+
+ local entry
+ for entry in "${!database[@]}"; do
+ printf -- '%s\0' "$entry" >> "$db_path"
+ done
+}
+
+delete_obsolete_dirs() {
+ if [ "$#" -ne 2 ]; then
+ echo "usage: ${FUNCNAME[0]} BASE_DIR DIR" >&2
+ return 1
+ fi
+
+ is_dry_run && return 0
+
+ local base_dir="$1"
+ local dir="$2"
+
+ base_dir="$( traverse_path --exist --directory -- "$base_dir" )"
+ dir="$( traverse_path --exist --directory -- "$dir" )"
+
+ [ "$base_dir" == "$dir" ] && return 0
+
+ local subpath="${dir##$base_dir/}"
+
+ if [ "$subpath" == "$dir" ]; then
+ dump "base directory: $base_dir" >&2
+ dump "... is not a parent of: $dir" >&2
+ return 1
+ fi
+
+ ( cd -- "$base_dir/" && rmdir -p --ignore-fail-on-non-empty -- "$subpath" )
+}
+
+delete_obsolete_entries() {
+ local entry
+ for entry in "${!database[@]}"; do
+ dump "entry: $entry"
+ unset -v 'database[$entry]'
+
+ local var_name
+ var_name="$( extract_variable_name "$entry" )" || continue
+ cache_variable "$var_name"
+
+ local symlink_var_dir
+ symlink_var_dir="$( resolve_variable "$var_name" )" || continue
+ local shared_var_dir="$shared_dir/%$var_name%"
+ local subpath="${entry#%$var_name%/}"
+ local symlink_path="$symlink_var_dir/$subpath"
+ local shared_path="$shared_var_dir/$subpath"
+
+ dump " shared file path: $shared_path"
+ dump " symlink path: $symlink_path"
+
+ if [ ! -L "$shared_path" ] && [ ! -e "$shared_path" ]; then
+ dump ' the shared file is missing, so going to delete the symlink'
+ is_dry_run && continue
+
+ if [ ! -L "$symlink_path" ]; then
+ dump " not a symlink or doesn't exist, so won't delete"
+ continue
+ fi
+
+ local target_path
+ target_path="$( traverse_path -- "$symlink_path" )"
+
+ if [ "$shared_path" != "$target_path" ]; then
+ dump " doesn't point to the shared file, so won't delete"
+ continue
+ fi
+
+ rm -f -- "$symlink_path"
+
+ local symlink_dir
+ symlink_dir="$( dirname -- "$symlink_path" )"
+ delete_obsolete_dirs "$symlink_var_dir" "$symlink_dir" || true
+
+ continue
+ fi
+
+ if [ ! -L "$symlink_path" ]; then
+ dump " not a symlink or doesn't exist"
+ continue
+ fi
+
+ local target_path
+ target_path="$( traverse_path -- "$symlink_path" )"
+
+ if [ "$target_path" != "$shared_path" ]; then
+ dump " doesn't point to the shared file"
+ continue
+ fi
+
+ dump ' ... points to the shared file'
+ database[$entry]=1
+ done
+}
+
+discover_new_entries() {
+ local shared_var_dir
+ while IFS= read -d '' -r shared_var_dir; do
+ dump "shared directory: $shared_dir/$shared_var_dir"
+
+ local var_name
+ var_name="$( extract_variable_name "$shared_var_dir" )"
+ cache_variable "$var_name"
+
+ shared_var_dir="$shared_dir/$shared_var_dir"
+
+ local symlink_var_dir
+ symlink_var_dir="$( resolve_variable "$var_name" )" || continue
+ dump " symlinks directory: $symlink_var_dir"
+
+ local shared_path
+ while IFS= read -d '' -r shared_path; do
+ dump " shared file path: $shared_path"
+
+ local entry="%$var_name%/${shared_path:${#shared_var_dir}}"
+
+ if [ -n "${database[$entry]+x}" ]; then
+ dump ' ... already has a symlink'
+ continue
+ fi
+
+ local subpath="${shared_path:${#shared_var_dir}}"
+ local symlink_path="$symlink_var_dir/$subpath"
+
+ dump " symlink path: $symlink_path"
+
+ is_dry_run && continue
+
+ local symlink_dir
+ symlink_dir="$( dirname -- "$symlink_path" )"
+ mkdir -p -- "$symlink_dir"
+ ln -f -s --no-target-directory -- "$shared_path" "$symlink_path"
+
+ database[$entry]=1
+ done < <( find "$shared_var_dir" -type f -print0 )
+
+ done < <( find "$shared_dir" -regextype posix-basic -mindepth 1 -maxdepth 1 -type d -regex ".*/$var_name_regex\$" -printf '%P/\0' )
+}