split update.sh into multiple files

7 files changed, 516 insertions, 486 deletions

diff --git a/README.md b/README.md
index 3a96530..7011b4b 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ This description is obviously confusing; see the complete usage example below.
 Usage
 -----
 
-Symlinks are managed by `update.sh`.
+Symlinks are managed by `bin/update.sh`.
 
 ```
 usage: update.sh [-h|--help] [-d|--database PATH] [-s|--shared-dir DIR] [-n|--dry-run]
@@ -34,7 +34,7 @@ In this example, the symlinks to files in "../src" must appear in
 
 ```
 > pwd
-/cygdrive/d/workspace/personal/config-links
+/cygdrive/d/workspace/personal/config-links/bin
 
 > tree /test/dest/
 /test/dest/
diff --git a/bin/update.sh b/bin/update.sh
new file mode 100644
index 0000000..31f6494
--- /dev/null
+++ b/bin/update.sh
@@ -0,0 +1,139 @@
+#!/usr/bin/env bash
+
+# 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.
+
+# This script relies on the availability of native symlinks.
+# Those are indeed supported by NTFS, but require Administrator privileges for
+# creation.
+# It likely won't bother you as long as you don't use the functions defined in
+# this file.
+# In any case, you will see `ln` complaining about some access being denied in
+# case something goes wrong.
+#
+# Remember that in order to force `ln` to use native NTFS symlinks, your
+# `CYGWIN` Windows environment variable value **must** include either
+# `winsymlinks:native` or `winsymlinks:nativestrict`!
+
+# usage: ./update.sh [-h|--help] [-d|--database PATH] [-s|--shared-dir DIR] [-n|--dry-run]
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+script_name="$( basename -- "${BASH_SOURCE[0]}" )"
+readonly script_name
+script_dir="$( dirname -- "${BASH_SOURCE[0]}" )"
+script_dir="$( cd -- "$script_dir" && pwd )"
+readonly script_dir
+src_dir="$( cd -- "$script_dir/../src" && pwd )"
+readonly src_dir
+
+. "$src_dir/common.sh"
+. "$src_dir/path.sh"
+. "$src_dir/vars.sh"
+. "$src_dir/db.sh"
+
+# Cygwin-related stuff
+
+os="$( uname -o )"
+readonly os
+
+is_cygwin() {
+    test "$os" == 'Cygwin'
+}
+
+check_symlinks_enabled_cygwin() {
+    case "${CYGWIN-}" in
+        *winsymlinks:native*)       ;;
+        *winsymlinks:nativestrict*) ;;
+
+        *)
+            dump "native Windows symlinks aren't enabled in Cygwin" >&2
+            return 1
+            ;;
+    esac
+}
+
+# Main routines
+
+script_usage() {
+    local msg
+    for msg; do
+        echo "$script_name: $msg"
+    done
+
+    echo "usage: $script_name [-h|--help] [-d|--database PATH] [-s|--shared-dir DIR] [-n|--dry-run]
+  -h,--help          show this message and exit
+  -d,--database      set database file path
+  -s,--shared-dir    set top-level shared directory path
+                     (current working directory by default)
+  -n,--dry-run       don't actually do anything intrusive"
+}
+
+parse_script_options() {
+    while [ "$#" -gt 0 ]; do
+        local key="$1"
+        shift
+
+        case "$key" in
+            -h|--help)
+                script_usage
+                exit 0
+                ;;
+            -n|--dry-run)
+                set_dry_run
+                continue
+                ;;
+            -d|--database|-s|--shared-dir)
+                ;;
+            *)
+                script_usage "unrecognized parameter: $key" >&2
+                exit 1
+                ;;
+        esac
+
+        if [ "$#" -eq 0 ]; then
+            script_usage "missing argument for parameter: $key" >&2
+            exit 1
+        fi
+
+        local value="$1"
+        shift
+
+        case "$key" in
+            -d|--database)
+                update_database_path "$value"
+                ;;
+            -s|--shared-dir)
+                update_shared_dir "$value"
+                ;;
+            *)
+                script_usage "unrecognized parameter: $key" >&2
+                exit 1
+                ;;
+        esac
+    done
+}
+
+check_symlinks_enabled() {
+    if is_cygwin; then
+        check_symlinks_enabled_cygwin
+    else
+        return 0
+    fi
+}
+
+main() {
+    parse_script_options "$@"
+    check_symlinks_enabled
+    ensure_database_exists
+    read_database
+    delete_obsolete_entries
+    discover_new_entries
+    write_database
+}
+
+main "$@"
diff --git a/src/common.sh b/src/common.sh
new file mode 100644
index 0000000..18df4ce
--- /dev/null
+++ b/src/common.sh
@@ -0,0 +1,22 @@
+# Copyright (c) 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "Configuration file sharing" project.
+# For details, see https://github.com/egor-tensin/config-links.
+# Distributed under the MIT License.
+
+dump() {
+    local prefix="${FUNCNAME[0]}"
+    [ "${#FUNCNAME[@]}" -gt 1 ] && prefix="${FUNCNAME[1]}"
+
+    local msg
+    for msg; do
+        echo "$prefix: $msg"
+    done
+}
+
+set_dry_run() {
+    dry_run=1
+}
+
+is_dry_run() {
+    test -n "${dry_run+x}"
+}
diff --git a/src/db.sh b/src/db.sh
new file mode 100644
index 0000000..6d733ef
--- /dev/null
+++ b/src/db.sh
@@ -0,0 +1,201 @@
+# 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' )
+}
diff --git a/src/path.sh b/src/path.sh
new file mode 100644
index 0000000..b1b1e8f
--- /dev/null
+++ b/src/path.sh
@@ -0,0 +1,94 @@
+# 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.
+
+# Making sure paths point to files/directories
+
+_traverse_path_usage() {
+    local prefix="${FUNCNAME[0]}"
+    [ "${#FUNCNAME[@]}" -gt 1 ] && prefix="${FUNCNAME[1]}"
+
+    local msg
+    for msg; do
+        echo "$prefix: $msg"
+    done
+
+    echo "usage: $prefix [-h|--help] [-0|--null|-z|--zero] [-e|--exist] [-f|--file] [-d|--directory] [--] [PATH]..."
+}
+
+traverse_path() {
+    local -a paths=()
+
+    local must_exist=
+    local type_flag=
+    local type_name=
+
+    local fmt='%s\n'
+
+    while [ "$#" -gt 0 ]; do
+        local key="$1"
+        shift
+
+        case "$key" in
+            -h|--help)
+                _traverse_path_usage
+                return 0
+                ;;
+            -0|--null|-z|--zero)
+                fmt='%s\0'
+                ;;
+            --)
+                break
+                ;;
+            -e|--exist)
+                must_exist=1
+                ;;
+            -d|--directory)
+                type_flag=-d
+                type_name="directory"
+                ;;
+            -f|--file)
+                type_flag=-f
+                type_name="regular file"
+                ;;
+            -*)
+                _traverse_path_usage "unrecognized parameter: $key" >&2
+                return 1
+                ;;
+            *)
+                paths+=("$key")
+                ;;
+        esac
+    done
+
+    paths+=("$@")
+
+    [ "${#paths[@]}" -eq 0 ] && return 0
+
+    if is_cygwin; then
+        local i
+        for i in "${!paths[@]}"; do
+            paths[$i]="$( cygpath -- "${paths[$i]}" )"
+        done
+    fi
+
+    local -a abs_paths=()
+
+    local path
+    while IFS= read -d '' -r path; do
+        if [ -n "$must_exist" ] && [ ! -e "$path" ]; then
+            dump "must exist: $path" >&2
+            return 1
+        fi
+
+        if [ -e "$path" ] && [ -n "$type_flag" ] && ! test "$type_flag" "$path"; then
+            dump "must be a $type_name: $path" >&2
+            return 1
+        fi
+
+        abs_paths+=("$path")
+    done < <( readlink -z --canonicalize-missing -- ${paths[@]+"${paths[@]}"} )
+
+    printf -- "$fmt" ${abs_paths[@]+"${abs_paths[@]}"}
+}
diff --git a/src/vars.sh b/src/vars.sh
new file mode 100644
index 0000000..d74506b
--- /dev/null
+++ b/src/vars.sh
@@ -0,0 +1,58 @@
+# 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.
+
+# Variable resolution
+
+declare -A cached_paths
+
+resolve_variable() {
+    if [ "$#" -ne 1 ]; then
+        echo "usage: ${FUNCNAME[0]} VAR_NAME" >&2
+        return 1
+    fi
+
+    local var_name="$1"
+
+    if [ -n "${cached_paths[$var_name]+x}" ]; then
+        echo "${cached_paths[$var_name]}"
+        return 0
+    fi
+
+    if [ "$var_name" = "$root_var_name" ]; then
+        echo ''
+        return 0
+    fi
+
+    if [ -z "${!var_name+x}" ]; then
+        dump "variable is not set: $var_name" >&2
+        return 1
+    fi
+
+    local var_path="${!var_name}"
+    traverse_path --exist --directory -- "$var_path"
+}
+
+cache_variable() {
+    local var_name
+    for var_name; do
+        [ -n "${cached_paths[$var_name]+x}" ] && continue
+        cached_paths[$var_name]="$( resolve_variable "$var_name" )"
+    done
+}
+
+readonly root_var_name='CONFIG_LINKS_ROOT'
+readonly var_name_regex='%\([_[:alpha:]][_[:alnum:]]*\)%'
+
+extract_variable_name() {
+    local s
+    for s; do
+        local var_name
+        if ! var_name="$( expr "$s" : "$var_name_regex/" )"; then
+            dump "couldn't extract variable name from: $s" >&2
+            return 1
+        fi
+        echo "$var_name"
+    done
+}
diff --git a/update.sh b/update.sh
deleted file mode 100755
index 3d64cb6..0000000
--- a/update.sh
+++ /dev/null
@@ -1,484 +0,0 @@
-#!/usr/bin/env bash
-
-# 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.
-
-# This script relies on the availability of native symlinks.
-# Those are indeed supported by NTFS, but require Administrator privileges for
-# creation.
-# It likely won't bother you as long as you don't use the functions defined in
-# this file.
-# In any case, you will see `ln` complaining about some access being denied in
-# case something goes wrong.
-#
-# Remember that in order to force `ln` to use native NTFS symlinks, your
-# `CYGWIN` Windows environment variable value **must** include either
-# `winsymlinks:native` or `winsymlinks:nativestrict`!
-
-# usage: ./update.sh [-h|--help] [-d|--database PATH] [-s|--shared-dir DIR] [-n|--dry-run]
-
-set -o errexit
-set -o nounset
-set -o pipefail
-
-dump() {
-    local prefix="${FUNCNAME[0]}"
-    [ "${#FUNCNAME[@]}" -gt 1 ] && prefix="${FUNCNAME[1]}"
-
-    local msg
-    for msg; do
-        echo "$prefix: $msg"
-    done
-}
-
-# Cygwin-related stuff
-
-os="$( uname -o )"
-readonly os
-
-is_cygwin() {
-    test "$os" == 'Cygwin'
-}
-
-check_symlinks_enabled_cygwin() {
-    case "${CYGWIN-}" in
-        *winsymlinks:native*)       ;;
-        *winsymlinks:nativestrict*) ;;
-
-        *)
-            dump "native Windows symlinks aren't enabled in Cygwin" >&2
-            return 1
-            ;;
-    esac
-}
-
-# Making sure paths point to files/directories
-
-_traverse_path_usage() {
-    local prefix="${FUNCNAME[0]}"
-    [ "${#FUNCNAME[@]}" -gt 1 ] && prefix="${FUNCNAME[1]}"
-
-    local msg
-    for msg; do
-        echo "$prefix: $msg"
-    done
-
-    echo "usage: $prefix [-h|--help] [-0|--null|-z|--zero] [-e|--exist] [-f|--file] [-d|--directory] [--] [PATH]..."
-}
-
-traverse_path() {
-    local -a paths=()
-
-    local must_exist=
-    local type_flag=
-    local type_name=
-
-    local fmt='%s\n'
-
-    while [ "$#" -gt 0 ]; do
-        local key="$1"
-        shift
-
-        case "$key" in
-            -h|--help)
-                _traverse_path_usage
-                return 0
-                ;;
-            -0|--null|-z|--zero)
-                fmt='%s\0'
-                ;;
-            --)
-                break
-                ;;
-            -e|--exist)
-                must_exist=1
-                ;;
-            -d|--directory)
-                type_flag=-d
-                type_name="directory"
-                ;;
-            -f|--file)
-                type_flag=-f
-                type_name="regular file"
-                ;;
-            -*)
-                _traverse_path_usage "unrecognized parameter: $key" >&2
-                return 1
-                ;;
-            *)
-                paths+=("$key")
-                ;;
-        esac
-    done
-
-    paths+=("$@")
-
-    [ "${#paths[@]}" -eq 0 ] && return 0
-
-    if is_cygwin; then
-        local i
-        for i in "${!paths[@]}"; do
-            paths[$i]="$( cygpath -- "${paths[$i]}" )"
-        done
-    fi
-
-    local -a abs_paths=()
-
-    local path
-    while IFS= read -d '' -r path; do
-        if [ -n "$must_exist" ] && [ ! -e "$path" ]; then
-            dump "must exist: $path" >&2
-            return 1
-        fi
-
-        if [ -e "$path" ] && [ -n "$type_flag" ] && ! test "$type_flag" "$path"; then
-            dump "must be a $type_name: $path" >&2
-            return 1
-        fi
-
-        abs_paths+=("$path")
-    done < <( readlink -z --canonicalize-missing -- ${paths[@]+"${paths[@]}"} )
-
-    printf -- "$fmt" ${abs_paths[@]+"${abs_paths[@]}"}
-}
-
-# Variable resolution
-
-declare -A cached_paths
-
-resolve_variable() {
-    if [ "$#" -ne 1 ]; then
-        echo "usage: ${FUNCNAME[0]} VAR_NAME" >&2
-        return 1
-    fi
-
-    local var_name="$1"
-
-    if [ -n "${cached_paths[$var_name]+x}" ]; then
-        echo "${cached_paths[$var_name]}"
-        return 0
-    fi
-
-    if [ "$var_name" = "$root_var_name" ]; then
-        echo ''
-        return 0
-    fi
-
-    if [ -z "${!var_name+x}" ]; then
-        dump "variable is not set: $var_name" >&2
-        return 1
-    fi
-
-    local var_path="${!var_name}"
-    traverse_path --exist --directory -- "$var_path"
-}
-
-cache_variable() {
-    local var_name
-    for var_name; do
-        [ -n "${cached_paths[$var_name]+x}" ] && continue
-        cached_paths[$var_name]="$( resolve_variable "$var_name" )"
-    done
-}
-
-readonly root_var_name='CONFIG_LINKS_ROOT'
-readonly var_name_regex='%\([_[:alpha:]][_[:alnum:]]*\)%'
-
-extract_variable_name() {
-    local s
-    for s; do
-        local var_name
-        if ! var_name="$( expr "$s" : "$var_name_regex/" )"; then
-            dump "couldn't extract variable name from: $s" >&2
-            return 1
-        fi
-        echo "$var_name"
-    done
-}
-
-# 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' )
-}
-
-# Main routines
-
-script_name="$( basename -- "${BASH_SOURCE[0]}" )"
-readonly script_name
-
-script_usage() {
-    local msg
-    for msg; do
-        echo "$script_name: $msg"
-    done
-
-    echo "usage: $script_name [-h|--help] [-d|--database PATH] [-s|--shared-dir DIR] [-n|--dry-run]
-  -h,--help          show this message and exit
-  -d,--database      set database file path
-  -s,--shared-dir    set top-level shared directory path
-                     (current working directory by default)
-  -n,--dry-run       don't actually do anything intrusive"
-}
-
-parse_script_options() {
-    while [ "$#" -gt 0 ]; do
-        local key="$1"
-        shift
-
-        case "$key" in
-            -h|--help)
-                script_usage
-                exit 0
-                ;;
-            -n|--dry-run)
-                dry_run=1
-                continue
-                ;;
-            -d|--database|-s|--shared-dir)
-                ;;
-            *)
-                script_usage "unrecognized parameter: $key" >&2
-                exit 1
-                ;;
-        esac
-
-        if [ "$#" -eq 0 ]; then
-            script_usage "missing argument for parameter: $key" >&2
-            exit 1
-        fi
-
-        local value="$1"
-        shift
-
-        case "$key" in
-            -d|--database)
-                update_database_path "$value"
-                ;;
-            -s|--shared-dir)
-                update_shared_dir "$value"
-                ;;
-            *)
-                script_usage "unrecognized parameter: $key" >&2
-                exit 1
-                ;;
-        esac
-    done
-}
-
-is_dry_run() {
-    test -n "${dry_run+x}"
-}
-
-check_symlinks_enabled() {
-    if is_cygwin; then
-        check_symlinks_enabled_cygwin
-    else
-        return 0
-    fi
-}
-
-main() {
-    parse_script_options "$@"
-    check_symlinks_enabled
-    ensure_database_exists
-    read_database
-    delete_obsolete_entries
-    discover_new_entries
-    write_database
-}
-
-main "$@"