module Sprockets::Utils

Internal: Utils, we didn't know where else to put it! Functions may eventually be shuffled into more specific drawers.

Constants

UNBOUND_METHODS_BIND_TO_ANY_OBJECT

Internal: Feature detect if UnboundMethods can bind to any Object or just Objects that share the same super class. Basically if RUBY_VERSION >= 2.

Public Instance Methods

concat_javascript_sources(buf, source) click to toggle source

Internal: Accumulate asset source to buffer and append a trailing semicolon if necessary.

buf - String buffer to append to source - String source to append

Returns buf String.

# File lib/sprockets/utils.rb, line 104
def concat_javascript_sources(buf, source)
  if source.bytesize > 0
    buf << source

    # If the source contains non-ASCII characters, indexing on it becomes O(N).
    # This will lead to O(N^2) performance in string_end_with_semicolon?, so we should use 32 bit encoding to make sure indexing stays O(1)
    source = source.encode(Encoding::UTF_32LE) unless source.ascii_only?

    if !string_end_with_semicolon?(source)
      buf << ";\n"
    elsif source[source.size - 1].ord != 0x0A
      buf << "\n"
    end
  end

  buf
end
dfs(initial) { |node).reverse)| ... } click to toggle source

Internal: Post-order Depth-First search algorithm.

Used for resolving asset dependencies.

initial - Initial Array of nodes to traverse. block -

node  - Current node to get children of

Returns a Set of nodes.

# File lib/sprockets/utils.rb, line 190
def dfs(initial)
  nodes, seen = Set.new, Set.new
  stack = Array(initial).reverse

  while node = stack.pop
    if seen.include?(node)
      nodes.add(node)
    else
      seen.add(node)
      stack.push(node)
      stack.concat(Array(yield node).reverse)
    end
  end

  nodes
end
dfs_paths(path) { |last).reverse_each do |node| push(path + [node])| ... } click to toggle source

Internal: Post-order Depth-First search algorithm that gathers all paths along the way.

TODO: Rename function.

path - Initial Array node path block -

node - Current node to get children of

Returns an Array of node Arrays.

# File lib/sprockets/utils.rb, line 217
def dfs_paths(path)
  paths = []
  stack, seen = [path], Set.new

  while path = stack.pop
    if !seen.include?(path.last)
      seen.add(path.last)
      paths << path if path.size > 1

      Array(yield path.last).reverse_each do |node|
        stack.push(path + [node])
      end
    end
  end
duplicable?(obj) click to toggle source

Internal: Check if object can safely be .dup'd.

Similar to ActiveSupport duplicable? check.

obj - Any Object

Returns false if .dup would raise a TypeError, otherwise true.

# File lib/sprockets/utils.rb, line 16
def duplicable?(obj)
  if RUBY_VERSION >= "2.4.0"
    true
  else
    case obj
    when NilClass, FalseClass, TrueClass, Symbol, Numeric
      false
    else
      true
    end
  end
end
hash_reassoc(hash, *keys, &block) click to toggle source

Internal: Duplicate and store key/value on new frozen hash.

Similar to Hash#store for nested frozen hashes.

hash - Hash key - Object keys. Use multiple keys for nested hashes. block - Receives current value at key.

Examples

config = {paths: ["/bin", "/sbin"]}.freeze
new_config = hash_reassoc(config, :paths) do |paths|
  paths << "/usr/local/bin"
end

Returns duplicated frozen Hash.

# File lib/sprockets/utils.rb, line 63
def hash_reassoc(hash, *keys, &block)
  if keys.size == 1
    hash_reassoc1(hash, keys[0], &block)
  else
    hash_reassoc1(hash, keys[0]) do |value|
      hash_reassoc(value, *keys[1..-1], &block)
    end
  end
end
hash_reassoc1(hash, key) { |old_value| ... } click to toggle source

Internal: Duplicate and store key/value on new frozen hash.

Seperated for recursive calls, always use hash_reassoc(hash, *keys).

hash - Hash key - Object key

Returns Hash.

# File lib/sprockets/utils.rb, line 37
def hash_reassoc1(hash, key)
  hash = hash.dup if hash.frozen?
  old_value = hash[key]
  old_value = old_value.dup if duplicable?(old_value)
  new_value = yield old_value
  new_value.freeze if duplicable?(new_value)
  hash.store(key, new_value)
  hash.freeze
end
module_include(base, mod) { || ... } click to toggle source

Internal: Inject into target module for the duration of the block.

mod - Module

Returns result of block.

# File lib/sprockets/utils.rb, line 155
def module_include(base, mod)
  old_methods = {}

  mod.instance_methods.each do |sym|
    old_methods[sym] = base.instance_method(sym) if base.method_defined?(sym)
  end

  unless UNBOUND_METHODS_BIND_TO_ANY_OBJECT
    base.send(:include, mod) unless base < mod
  end

  mod.instance_methods.each do |sym|
    method = mod.instance_method(sym)
    base.send(:define_method, sym, method)
  end

  yield
ensure
  mod.instance_methods.each do |sym|
    base.send(:undef_method, sym) if base.method_defined?(sym)
  end
  old_methods.each do |sym, method|
    base.send(:define_method, sym, method)
  end
end
normalize_extension(extension) click to toggle source

Internal: Prepends a leading “.” to an extension if its missing.

normalize_extension("js")
# => ".js"

normalize_extension(".css")
# => ".css"
# File lib/sprockets/utils.rb, line 130
def normalize_extension(extension)
  extension = extension.to_s
  if extension[/^\./]
    extension
  else
    ".#{extension}"
  end
end
string_end_with_semicolon?(str) click to toggle source

Internal: Check if string has a trailing semicolon.

str - String

Returns true or false.

# File lib/sprockets/utils.rb, line 78
def string_end_with_semicolon?(str)
  i = str.size - 1
  while i >= 0
    c = str[i].ord
    i -= 1

    # Need to compare against the ordinals because the string can be UTF_8 or UTF_32LE encoded
    # 0x0A == "\n"
    # 0x20 == " "
    # 0x09 == "\t"
    # 0x3B == ";"
    unless c == 0x0A || c == 0x20 || c == 0x09
      return c === 0x3B
    end
  end

  true
end