split update.sh into multiple files

4 files changed, 375 insertions, 0 deletions

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
+}