require "pathname"
require "active_support/core_ext/class"
require "active_support/core_ext/module/attribute_accessors"
require "action_view/template"
require "thread"
require "concurrent/map"
module ActionView
# = Action View Resolver
class Resolver
# Keeps all information about view path and builds virtual path.
class Path
attr_reader :name, :prefix, :partial, :virtual
alias_method :partial?, :partial
def self.build(name, prefix, partial)
virtual = ""
virtual << "#{prefix}/" unless prefix.empty?
virtual << (partial ? "_#{name}" : name)
new name, prefix, partial, virtual
end
def initialize(name, prefix, partial, virtual)
@name = name
@prefix = prefix
@partial = partial
@virtual = virtual
end
def to_str
@virtual
end
alias :to_s :to_str
end
# Threadsafe template cache
class Cache #:nodoc:
class SmallCache < Concurrent::Map
def initialize(options = {})
super(options.merge(:initial_capacity => 2))
end
end
# preallocate all the default blocks for performance/memory consumption reasons
PARTIAL_BLOCK = lambda {|cache, partial| cache[partial] = SmallCache.new}
PREFIX_BLOCK = lambda {|cache, prefix| cache[prefix] = SmallCache.new(&PARTIAL_BLOCK)}
NAME_BLOCK = lambda {|cache, name| cache[name] = SmallCache.new(&PREFIX_BLOCK)}
KEY_BLOCK = lambda {|cache, key| cache[key] = SmallCache.new(&NAME_BLOCK)}
# usually a majority of template look ups return nothing, use this canonical preallocated array to save memory
NO_TEMPLATES = [].freeze
def initialize
@data = SmallCache.new(&KEY_BLOCK)
@query_cache = SmallCache.new
end
def inspect
"#<#{self.class.name}:0x#{(object_id << 1).to_s(16)} keys=#{@data.size} queries=#{@query_cache.size}>"
end
# Cache the templates returned by the block
def cache(key, name, prefix, partial, locals)
if Resolver.caching?
@data[key][name][prefix][partial][locals] ||= canonical_no_templates(yield)
else
fresh_templates = yield
cached_templates = @data[key][name][prefix][partial][locals]
if templates_have_changed?(cached_templates, fresh_templates)
@data[key][name][prefix][partial][locals] = canonical_no_templates(fresh_templates)
else
cached_templates || NO_TEMPLATES
end
end
end
def cache_query(query) # :nodoc:
if Resolver.caching?
@query_cache[query] ||= canonical_no_templates(yield)
else
yield
end
end
def clear
@data.clear
@query_cache.clear
end
# Get the cache size. Do not call this
# method. This method is not guaranteed to be here ever.
def size # :nodoc:
size = 0
@data.each_value do |v1|
v1.each_value do |v2|
v2.each_value do |v3|
v3.each_value do |v4|
size += v4.size
end
end
end
end
size + @query_cache.size
end
private
def canonical_no_templates(templates)
templates.empty? ? NO_TEMPLATES : templates
end
def templates_have_changed?(cached_templates, fresh_templates)
# if either the old or new template list is empty, we don't need to (and can't)
# compare modification times, and instead just check whether the lists are different
if cached_templates.blank? || fresh_templates.blank?
return fresh_templates.blank? != cached_templates.blank?
end
cached_templates_max_updated_at = cached_templates.map(&:updated_at).max
# if a template has changed, it will be now be newer than all the cached templates
fresh_templates.any? { |t| t.updated_at > cached_templates_max_updated_at }
end
end
cattr_accessor :caching
self.caching = true
class << self
alias :caching? :caching
end
def initialize
@cache = Cache.new
end
def clear_cache
@cache.clear
end
# Normalizes the arguments and passes it on to find_templates.
def find_all(name, prefix=nil, partial=false, details={}, key=nil, locals=[])
cached(key, [name, prefix, partial], details, locals) do
find_templates(name, prefix, partial, details)
end
end
def find_all_anywhere(name, prefix, partial=false, details={}, key=nil, locals=[])
cached(key, [name, prefix, partial], details, locals) do
find_templates(name, prefix, partial, details, true)
end
end
def find_all_with_query(query) # :nodoc:
@cache.cache_query(query) { find_template_paths(File.join(@path, query)) }
end
private
delegate :caching?, to: :class
# This is what child classes implement. No defaults are needed
# because Resolver guarantees that the arguments are present and
# normalized.
def find_templates(name, prefix, partial, details)
raise NotImplementedError, "Subclasses must implement a find_templates(name, prefix, partial, details) method"
end
# Helpers that builds a path. Useful for building virtual paths.
def build_path(name, prefix, partial)
Path.build(name, prefix, partial)
end
# Handles templates caching. If a key is given and caching is on
# always check the cache before hitting the resolver. Otherwise,
# it always hits the resolver but if the key is present, check if the
# resolver is fresher before returning it.
def cached(key, path_info, details, locals) #:nodoc:
name, prefix, partial = path_info
locals = locals.map(&:to_s).sort!
if key
@cache.cache(key, name, prefix, partial, locals) do
decorate(yield, path_info, details, locals)
end
else
decorate(yield, path_info, details, locals)
end
end
# Ensures all the resolver information is set in the template.
def decorate(templates, path_info, details, locals) #:nodoc:
cached = nil
templates.each do |t|
t.locals = locals
t.formats = details[:formats] || [:html] if t.formats.empty?
t.variants = details[:variants] || [] if t.variants.empty?
t.virtual_path ||= (cached ||= build_path(*path_info))
end
end
end
# An abstract class that implements a Resolver with path semantics.
class PathResolver < Resolver #:nodoc:
EXTENSIONS = { :locale => ".", :formats => ".", :variants => "+", :handlers => "." }
DEFAULT_PATTERN = ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}"
def initialize(pattern=nil)
@pattern = pattern || DEFAULT_PATTERN
super()
end
private
def find_templates(name, prefix, partial, details, outside_app_allowed = false)
path = Path.build(name, prefix, partial)
query(path, details, details[:formats], outside_app_allowed)
end
def query(path, details, formats, outside_app_allowed)
query = build_query(path, details)
template_paths = find_template_paths(query)
template_paths = reject_files_external_to_app(template_paths) unless outside_app_allowed
template_paths.map do |template|
handler, format, variant = extract_handler_and_format_and_variant(template, formats)
contents = File.binread(template)
Template.new(contents, File.expand_path(template), handler,
:virtual_path => path.virtual,
:format => format,
:variant => variant,
:updated_at => mtime(template)
)
end
end
def reject_files_external_to_app(files)
files.reject { |filename| !inside_path?(@path, filename) }
end
def find_template_paths(query)
Dir[query].uniq.reject do |filename|
File.directory?(filename) ||
# deals with case-insensitive file systems.
!File.fnmatch(query, filename, File::FNM_EXTGLOB)
end
end
def inside_path?(path, filename)
filename = File.expand_path(filename)
path = File.join(path, '')
filename.start_with?(path)
end
# Helper for building query glob string based on resolver's pattern.
def build_query(path, details)
query = @pattern.dup
prefix = path.prefix.empty? ? '' : "#{escape_entry(path.prefix)}\\1"
query.gsub!(/:prefix(\/)?/, prefix)
partial = escape_entry(path.partial? ? "_#{path.name}" : path.name)
query.gsub!(/:action/, partial)
details.each do |ext, candidates|
if ext == :variants && candidates == :any
query.gsub!(/:#{ext}/, "*")
else
query.gsub!(/:#{ext}/, "{#{candidates.compact.uniq.join(',')}}")
end
end
File.expand_path(query, @path)
end
def escape_entry(entry)
entry.gsub(/[*?{}\[\]]/, '\\\\\\&'.freeze)
end
# Returns the file mtime from the filesystem.
def mtime(p)
File.mtime(p)
end
# Extract handler, formats and variant from path. If a format cannot be found neither
# from the path, or the handler, we should return the array of formats given
# to the resolver.
def extract_handler_and_format_and_variant(path, default_formats)
pieces = File.basename(path).split('.'.freeze)
pieces.shift
extension = pieces.pop
handler = Template.handler_for_extension(extension)
format, variant = pieces.last.split(EXTENSIONS[:variants], 2) if pieces.last
format &&= Template::Types[format]
[handler, format, variant]
end
end
# A resolver that loads files from the filesystem. It allows setting your own
# resolving pattern. Such pattern can be a glob string supported by some variables.
#
# ==== Examples
#
# Default pattern, loads views the same way as previous versions of rails, eg. when you're
# looking for `users/new` it will produce query glob: `users/new{.{en},}{.{html,js},}{.{erb,haml},}`
#
# FileSystemResolver.new("/path/to/views", ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
#
# This one allows you to keep files with different formats in separate subdirectories,
# eg. `users/new.html` will be loaded from `users/html/new.erb` or `users/new.html.erb`,
# `users/new.js` from `users/js/new.erb` or `users/new.js.erb`, etc.
#
# FileSystemResolver.new("/path/to/views", ":prefix/{:formats/,}:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}")
#
# If you don't specify a pattern then the default will be used.
#
# In order to use any of the customized resolvers above in a Rails application, you just need
# to configure ActionController::Base.view_paths in an initializer, for example:
#
# ActionController::Base.view_paths = FileSystemResolver.new(
# Rails.root.join("app/views"),
# ":prefix/:action{.:locale,}{.:formats,}{+:variants,}{.:handlers,}",
# )
#
# ==== Pattern format and variables
#
# Pattern has to be a valid glob string, and it allows you to use the
# following variables:
#
# * <tt>:prefix</tt> - usually the controller path
# * <tt>:action</tt> - name of the action
# * <tt>:locale</tt> - possible locale versions
# * <tt>:formats</tt> - possible request formats (for example html, json, xml...)
# * <tt>:variants</tt> - possible request variants (for example phone, tablet...)
# * <tt>:handlers</tt> - possible handlers (for example erb, haml, builder...)
#
class FileSystemResolver < PathResolver
def initialize(path, pattern=nil)
raise ArgumentError, "path already is a Resolver class" if path.is_a?(Resolver)
super(pattern)
@path = File.expand_path(path)
end
def to_s
@path.to_s
end
alias :to_path :to_s
def eql?(resolver)
self.class.equal?(resolver.class) && to_path == resolver.to_path
end
alias :== :eql?
end
# An Optimized resolver for Rails' most common case.
class OptimizedFileSystemResolver < FileSystemResolver #:nodoc:
def build_query(path, details)
query = escape_entry(File.join(@path, path))
exts = EXTENSIONS.map do |ext, prefix|
if ext == :variants && details[ext] == :any
"{#{prefix}*,}"
else
"{#{details[ext].compact.uniq.map { |e| "#{prefix}#{e}," }.join}}"
end
end.join
query + exts
end
end
# The same as FileSystemResolver but does not allow templates to store
# a virtual path since it is invalid for such resolvers.
class FallbackFileSystemResolver < FileSystemResolver #:nodoc:
def self.instances
[new(""), new("/")]
end
def decorate(*)
super.each { |t| t.virtual_path = nil }
end
end
end
