require 'erb'
require 'set'
require 'enumerator'
require 'stringio'
require 'strscan'
require 'haml/root'
require 'haml/util/subset_map'
module Haml
# A module containing various useful functions.
module Util
extend self
# An array of ints representing the Ruby version number.
# @api public
RUBY_VERSION = ::RUBY_VERSION.split(".").map {|s| s.to_i}
# Returns the path of a file relative to the Haml root directory.
#
# @param file [String] The filename relative to the Haml root
# @return [String] The filename relative to the the working directory
def scope(file)
File.join(Haml::ROOT_DIR, file)
end
# Converts an array of `[key, value]` pairs to a hash.
# For example:
#
# to_hash([[:foo, "bar"], [:baz, "bang"]])
# #=> {:foo => "bar", :baz => "bang"}
#
# @param arr [Array<(Object, Object)>] An array of pairs
# @return [Hash] A hash
def to_hash(arr)
arr.compact.inject({}) {|h, (k, v)| h[k] = v; h}
end
# Maps the keys in a hash according to a block.
# For example:
#
# map_keys({:foo => "bar", :baz => "bang"}) {|k| k.to_s}
# #=> {"foo" => "bar", "baz" => "bang"}
#
# @param hash [Hash] The hash to map
# @yield [key] A block in which the keys are transformed
# @yieldparam key [Object] The key that should be mapped
# @yieldreturn [Object] The new value for the key
# @return [Hash] The mapped hash
# @see #map_vals
# @see #map_hash
def map_keys(hash)
to_hash(hash.map {|k, v| [yield(k), v]})
end
# Maps the values in a hash according to a block.
# For example:
#
# map_values({:foo => "bar", :baz => "bang"}) {|v| v.to_sym}
# #=> {:foo => :bar, :baz => :bang}
#
# @param hash [Hash] The hash to map
# @yield [value] A block in which the values are transformed
# @yieldparam value [Object] The value that should be mapped
# @yieldreturn [Object] The new value for the value
# @return [Hash] The mapped hash
# @see #map_keys
# @see #map_hash
def map_vals(hash)
to_hash(hash.map {|k, v| [k, yield(v)]})
end
# Maps the key-value pairs of a hash according to a block.
# For example:
#
# map_hash({:foo => "bar", :baz => "bang"}) {|k, v| [k.to_s, v.to_sym]}
# #=> {"foo" => :bar, "baz" => :bang}
#
# @param hash [Hash] The hash to map
# @yield [key, value] A block in which the key-value pairs are transformed
# @yieldparam [key] The hash key
# @yieldparam [value] The hash value
# @yieldreturn [(Object, Object)] The new value for the `[key, value]` pair
# @return [Hash] The mapped hash
# @see #map_keys
# @see #map_vals
def map_hash(hash, &block)
to_hash(hash.map(&block))
end
# Computes the powerset of the given array.
# This is the set of all subsets of the array.
# For example:
#
# powerset([1, 2, 3]) #=>
# Set[Set[], Set[1], Set[2], Set[3], Set[1, 2], Set[2, 3], Set[1, 3], Set[1, 2, 3]]
#
# @param arr [Enumerable]
# @return [Set<Set>] The subsets of `arr`
def powerset(arr)
arr.inject([Set.new].to_set) do |powerset, el|
new_powerset = Set.new
powerset.each do |subset|
new_powerset << subset
new_powerset << subset + [el]
end
new_powerset
end
end
# Restricts a number to falling within a given range.
# Returns the number if it falls within the range,
# or the closest value in the range if it doesn't.
#
# @param value [Numeric]
# @param range [Range<Numeric>]
# @return [Numeric]
def restrict(value, range)
[[value, range.first].max, range.last].min
end
# Concatenates all strings that are adjacent in an array,
# while leaving other elements as they are.
# For example:
#
# merge_adjacent_strings([1, "foo", "bar", 2, "baz"])
# #=> [1, "foobar", 2, "baz"]
#
# @param enum [Enumerable]
# @return [Array] The enumerable with strings merged
def merge_adjacent_strings(enum)
enum.inject([]) do |a, e|
if e.is_a?(String)
if a.last.is_a?(String)
a.last << e
else
a << e.dup
end
else
a << e
end
a
end
end
# Intersperses a value in an enumerable, as would be done with `Array#join`
# but without concatenating the array together afterwards.
#
# @param enum [Enumerable]
# @param val
# @return [Array]
def intersperse(enum, val)
enum.inject([]) {|a, e| a << e << val}[0...-1]
end
# Substitutes a sub-array of one array with another sub-array.
#
# @param ary [Array] The array in which to make the substitution
# @param from [Array] The sequence of elements to replace with `to`
# @param to [Array] The sequence of elements to replace `from` with
def substitute(ary, from, to)
res = ary.dup
i = 0
while i < res.size
if res[i...i+from.size] == from
res[i...i+from.size] = to
end
i += 1
end
res
end
# Destructively strips whitespace from the beginning and end
# of the first and last elements, respectively,
# in the array (if those elements are strings).
#
# @param arr [Array]
# @return [Array] `arr`
def strip_string_array(arr)
arr.first.lstrip! if arr.first.is_a?(String)
arr.last.rstrip! if arr.last.is_a?(String)
arr
end
# Return an array of all possible paths through the given arrays.
#
# @param arrs [Array<Array>]
# @return [Array<Arrays>]
#
# @example
# paths([[1, 2], [3, 4], [5]]) #=>
# # [[1, 3, 5],
# # [2, 3, 5],
# # [1, 4, 5],
# # [2, 4, 5]]
def paths(arrs)
arrs.inject([[]]) do |paths, arr|
flatten(arr.map {|e| paths.map {|path| path + [e]}}, 1)
end
end
# Computes a single longest common subsequence for `x` and `y`.
# If there are more than one longest common subsequences,
# the one returned is that which starts first in `x`.
#
# @param x [Array]
# @param y [Array]
# @yield [a, b] An optional block to use in place of a check for equality
# between elements of `x` and `y`.
# @yieldreturn [Object, nil] If the two values register as equal,
# this will return the value to use in the LCS array.
# @return [Array] The LCS
def lcs(x, y, &block)
x = [nil, *x]
y = [nil, *y]
block ||= proc {|a, b| a == b && a}
lcs_backtrace(lcs_table(x, y, &block), x, y, x.size-1, y.size-1, &block)
end
# Returns information about the caller of the previous method.
#
# @param entry [String] An entry in the `#caller` list, or a similarly formatted string
# @return [[String, Fixnum, (String, nil)]] An array containing the filename, line, and method name of the caller.
# The method name may be nil
def caller_info(entry = caller[1])
info = entry.scan(/^(.*?):(-?.*?)(?::.*`(.+)')?$/).first
info[1] = info[1].to_i
# This is added by Rubinius to designate a block, but we don't care about it.
info[2].sub!(/ \{\}\Z/, '') if info[2]
info
end
# Silence all output to STDERR within a block.
#
# @yield A block in which no output will be printed to STDERR
def silence_warnings
the_real_stderr, $stderr = $stderr, StringIO.new
yield
ensure
$stderr = the_real_stderr
end
@@silence_warnings = false
# Silences all Haml warnings within a block.
#
# @yield A block in which no Haml warnings will be printed
def silence_haml_warnings
old_silence_warnings = @@silence_warnings
@@silence_warnings = true
yield
ensure
@@silence_warnings = old_silence_warnings
end
# The same as `Kernel#warn`, but is silenced by \{#silence\_haml\_warnings}.
#
# @param msg [String]
def haml_warn(msg)
return if @@silence_warnings
warn(msg)
end
## Cross Rails Version Compatibility
# Returns the root of the Rails application,
# if this is running in a Rails context.
# Returns `nil` if no such root is defined.
#
# @return [String, nil]
def rails_root
if defined?(Rails.root)
return Rails.root.to_s if Rails.root
raise "ERROR: Rails.root is nil!"
end
return RAILS_ROOT.to_s if defined?(RAILS_ROOT)
return nil
end
# Returns the environment of the Rails application,
# if this is running in a Rails context.
# Returns `nil` if no such environment is defined.
#
# @return [String, nil]
def rails_env
return Rails.env.to_s if defined?(Rails.root)
return RAILS_ENV.to_s if defined?(RAILS_ENV)
return nil
end
# Returns whether this environment is using ActionPack
# version 3.0.0 or greater.
#
# @return [Boolean]
def ap_geq_3?
# The ActionPack module is always loaded automatically in Rails >= 3
return false unless defined?(ActionPack) && defined?(ActionPack::VERSION)
version =
if defined?(ActionPack::VERSION::MAJOR)
ActionPack::VERSION::MAJOR
else
# Rails 1.2
ActionPack::VERSION::Major
end
version >= 3
end
# Returns whether this environment is using ActionPack
# version 3.0.0.beta.3 or greater.
#
# @return [Boolean]
def ap_geq_3_beta_3?
# The ActionPack module is always loaded automatically in Rails >= 3
return false unless defined?(ActionPack) && defined?(ActionPack::VERSION)
version =
if defined?(ActionPack::VERSION::MAJOR)
ActionPack::VERSION::MAJOR
else
# Rails 1.2
ActionPack::VERSION::Major
end
version >= 3 &&
((defined?(ActionPack::VERSION::TINY) &&
ActionPack::VERSION::TINY.is_a?(Fixnum) &&
ActionPack::VERSION::TINY >= 1) ||
(defined?(ActionPack::VERSION::BUILD) &&
ActionPack::VERSION::BUILD =~ /beta(\d+)/ &&
$1.to_i >= 3))
end
# Returns an ActionView::Template* class.
# In pre-3.0 versions of Rails, most of these classes
# were of the form `ActionView::TemplateFoo`,
# while afterwards they were of the form `ActionView;:Template::Foo`.
#
# @param name [#to_s] The name of the class to get.
# For example, `:Error` will return `ActionView::TemplateError`
# or `ActionView::Template::Error`.
def av_template_class(name)
return ActionView.const_get("Template#{name}") if ActionView.const_defined?("Template#{name}")
return ActionView::Template.const_get(name.to_s)
end
## Rails XSS Safety
# Whether or not ActionView's XSS protection is available and enabled,
# as is the default for Rails 3.0+, and optional for version 2.3.5+.
# Overridden in haml/template.rb if this is the case.
#
# @return [Boolean]
def rails_xss_safe?
false
end
# Returns the given text, marked as being HTML-safe.
# With older versions of the Rails XSS-safety mechanism,
# this destructively modifies the HTML-safety of `text`.
#
# @param text [String, nil]
# @return [String, nil] `text`, marked as HTML-safe
def html_safe(text)
return unless text
return text.html_safe if defined?(ActiveSupport::SafeBuffer)
text.html_safe!
end
# Assert that a given object (usually a String) is HTML safe
# according to Rails' XSS handling, if it's loaded.
#
# @param text [Object]
def assert_html_safe!(text)
return unless rails_xss_safe? && text && !text.to_s.html_safe?
raise Haml::Error.new("Expected #{text.inspect} to be HTML-safe.")
end
# The class for the Rails SafeBuffer XSS protection class.
# This varies depending on Rails version.
#
# @return [Class]
def rails_safe_buffer_class
# It's important that we check ActiveSupport first,
# because in Rails 2.3.6 ActionView::SafeBuffer exists
# but is a deprecated proxy object.
return ActiveSupport::SafeBuffer if defined?(ActiveSupport::SafeBuffer)
return ActionView::SafeBuffer
end
## Cross-Ruby-Version Compatibility
# Whether or not this is running under Ruby 1.8 or lower.
#
# @return [Boolean]
def ruby1_8?
Haml::Util::RUBY_VERSION[0] == 1 && Haml::Util::RUBY_VERSION[1] < 9
end
# Whether or not this is running under Ruby 1.8.6 or lower.
# Note that lower versions are not officially supported.
#
# @return [Boolean]
def ruby1_8_6?
ruby1_8? && Haml::Util::RUBY_VERSION[2] < 7
end
# Checks that the encoding of a string is valid in Ruby 1.9
# and cleans up potential encoding gotchas like the UTF-8 BOM.
# If it's not, yields an error string describing the invalid character
# and the line on which it occurrs.
#
# @param str [String] The string of which to check the encoding
# @yield [msg] A block in which an encoding error can be raised.
# Only yields if there is an encoding error
# @yieldparam msg [String] The error message to be raised
# @return [String] `str`, potentially with encoding gotchas like BOMs removed
def check_encoding(str)
if ruby1_8?
return str.gsub(/\A\xEF\xBB\xBF/, '') # Get rid of the UTF-8 BOM
elsif str.valid_encoding?
# Get rid of the Unicode BOM if possible
if str.encoding.name =~ /^UTF-(8|16|32)(BE|LE)?$/
return str.gsub(Regexp.new("\\A\uFEFF".encode(str.encoding.name)), '')
else
return str
end
end
encoding = str.encoding
newlines = Regexp.new("\r\n|\r|\n".encode(encoding).force_encoding("binary"))
str.force_encoding("binary").split(newlines).each_with_index do |line, i|
begin
line.encode(encoding)
rescue Encoding::UndefinedConversionError => e
yield <<MSG.rstrip, i + 1
Invalid #{encoding.name} character #{e.error_char.dump}
MSG
end
end
return str
end
# Like {\#check\_encoding}, but also checks for a Ruby-style `-# coding:` comment
# at the beginning of the template and uses that encoding if it exists.
#
# The Sass encoding rules are simple.
# If a `-# coding:` comment exists,
# we assume that that's the original encoding of the document.
# Otherwise, we use whatever encoding Ruby has.
#
# Haml uses the same rules for parsing coding comments as Ruby.
# This means that it can understand Emacs-style comments
# (e.g. `-*- encoding: "utf-8" -*-`),
# and also that it cannot understand non-ASCII-compatible encodings
# such as `UTF-16` and `UTF-32`.
#
# @param str [String] The Haml template of which to check the encoding
# @yield [msg] A block in which an encoding error can be raised.
# Only yields if there is an encoding error
# @yieldparam msg [String] The error message to be raised
# @return [String] The original string encoded properly
# @raise [ArgumentError] if the document declares an unknown encoding
def check_haml_encoding(str, &block)
return check_encoding(str, &block) if ruby1_8?
bom, encoding = parse_haml_magic_comment(str)
if encoding; str.force_encoding(encoding)
elsif bom; str.force_encoding("UTF-8")
end
return check_encoding(str, &block)
end
# Like {\#check\_encoding}, but also checks for a `@charset` declaration
# at the beginning of the file and uses that encoding if it exists.
#
# The Sass encoding rules are simple.
# If a `@charset` declaration exists,
# we assume that that's the original encoding of the document.
# Otherwise, we use whatever encoding Ruby has.
# Then we convert that to UTF-8 to process internally.
# The UTF-8 end result is what's returned by this method.
#
# @param str [String] The string of which to check the encoding
# @yield [msg] A block in which an encoding error can be raised.
# Only yields if there is an encoding error
# @yieldparam msg [String] The error message to be raised
# @return [(String, Encoding)] The original string encoded as UTF-8,
# and the source encoding of the string (or `nil` under Ruby 1.8)
# @raise [Encoding::UndefinedConversionError] if the source encoding
# cannot be converted to UTF-8
# @raise [ArgumentError] if the document uses an unknown encoding with `@charset`
def check_sass_encoding(str, &block)
return check_encoding(str, &block), nil if ruby1_8?
# We allow any printable ASCII characters but double quotes in the charset decl
bin = str.dup.force_encoding("BINARY")
encoding = Haml::Util::ENCODINGS_TO_CHECK.find do |enc|
bin =~ Haml::Util::CHARSET_REGEXPS[enc]
end
charset, bom = $1, $2
if charset
charset = charset.force_encoding(encoding).encode("UTF-8")
if endianness = encoding[/[BL]E$/]
begin
Encoding.find(charset + endianness)
charset << endianness
rescue ArgumentError # Encoding charset + endianness doesn't exist
end
end
str.force_encoding(charset)
elsif bom
str.force_encoding(encoding)
end
str = check_encoding(str, &block)
return str.encode("UTF-8"), str.encoding
end
unless ruby1_8?
# @private
def _enc(string, encoding)
string.encode(encoding).force_encoding("BINARY")
end
# We could automatically add in any non-ASCII-compatible encodings here,
# but there's not really a good way to do that
# without manually checking that each encoding
# encodes all ASCII characters properly,
# which takes long enough to affect the startup time of the CLI.
ENCODINGS_TO_CHECK = %w[UTF-8 UTF-16BE UTF-16LE UTF-32BE UTF-32LE]
CHARSET_REGEXPS = Hash.new do |h, e|
h[e] =
begin
# /\A(?:\uFEFF)?@charset "(.*?)"|\A(\uFEFF)/
Regexp.new(/\A(?:#{_enc("\uFEFF", e)})?#{
_enc('@charset "', e)}(.*?)#{_enc('"', e)}|\A(#{
_enc("\uFEFF", e)})/)
rescue
# /\A@charset "(.*?)"/
Regexp.new(/\A#{_enc('@charset "', e)}(.*?)#{_enc('"', e)}/)
end
end
end
# Checks to see if a class has a given method.
# For example:
#
# Haml::Util.has?(:public_instance_method, String, :gsub) #=> true
#
# Method collections like `Class#instance_methods`
# return strings in Ruby 1.8 and symbols in Ruby 1.9 and on,
# so this handles checking for them in a compatible way.
#
# @param attr [#to_s] The (singular) name of the method-collection method
# (e.g. `:instance_methods`, `:private_methods`)
# @param klass [Module] The class to check the methods of which to check
# @param method [String, Symbol] The name of the method do check for
# @return [Boolean] Whether or not the given collection has the given method
def has?(attr, klass, method)
klass.send("#{attr}s").include?(ruby1_8? ? method.to_s : method.to_sym)
end
# A version of `Enumerable#enum_with_index` that works in Ruby 1.8 and 1.9.
#
# @param enum [Enumerable] The enumerable to get the enumerator for
# @return [Enumerator] The with-index enumerator
def enum_with_index(enum)
ruby1_8? ? enum.enum_with_index : enum.each_with_index
end
# A version of `Enumerable#enum_cons` that works in Ruby 1.8 and 1.9.
#
# @param enum [Enumerable] The enumerable to get the enumerator for
# @param n [Fixnum] The size of each cons
# @return [Enumerator] The consed enumerator
def enum_cons(enum, n)
ruby1_8? ? enum.enum_cons(n) : enum.each_cons(n)
end
# A version of `Enumerable#enum_slice` that works in Ruby 1.8 and 1.9.
#
# @param enum [Enumerable] The enumerable to get the enumerator for
# @param n [Fixnum] The size of each slice
# @return [Enumerator] The consed enumerator
def enum_slice(enum, n)
ruby1_8? ? enum.enum_slice(n) : enum.each_slice(n)
end
# Returns the ASCII code of the given character.
#
# @param c [String] All characters but the first are ignored.
# @return [Fixnum] The ASCII code of `c`.
def ord(c)
ruby1_8? ? c[0] : c.ord
end
# Flattens the first `n` nested arrays in a cross-version manner.
#
# @param arr [Array] The array to flatten
# @param n [Fixnum] The number of levels to flatten
# @return [Array] The flattened array
def flatten(arr, n)
return arr.flatten(n) unless ruby1_8_6?
return arr if n == 0
arr.inject([]) {|res, e| e.is_a?(Array) ? res.concat(flatten(e, n - 1)) : res << e}
end
# Returns the hash code for a set in a cross-version manner.
# Aggravatingly, this is order-dependent in Ruby 1.8.6.
#
# @param set [Set]
# @return [Fixnum] The order-independent hashcode of `set`
def set_hash(set)
return set.hash unless ruby1_8_6?
set.map {|e| e.hash}.uniq.sort.hash
end
# Tests the hash-equality of two sets in a cross-version manner.
# Aggravatingly, this is order-dependent in Ruby 1.8.6.
#
# @param set1 [Set]
# @param set2 [Set]
# @return [Boolean] Whether or not the sets are hashcode equal
def set_eql?(set1, set2)
return set1.eql?(set2) unless ruby1_8_6?
set1.to_a.uniq.sort_by {|e| e.hash}.eql?(set2.to_a.uniq.sort_by {|e| e.hash})
end
## Static Method Stuff
# The context in which the ERB for \{#def\_static\_method} will be run.
class StaticConditionalContext
# @param set [#include?] The set of variables that are defined for this context.
def initialize(set)
@set = set
end
# Checks whether or not a variable is defined for this context.
#
# @param name [Symbol] The name of the variable
# @return [Boolean]
def method_missing(name, *args, &block)
super unless args.empty? && block.nil?
@set.include?(name)
end
end
# This is used for methods in {Haml::Buffer} that need to be very fast,
# and take a lot of boolean parameters
# that are known at compile-time.
# Instead of passing the parameters in normally,
# a separate method is defined for every possible combination of those parameters;
# these are then called using \{#static\_method\_name}.
#
# To define a static method, an ERB template for the method is provided.
# All conditionals based on the static parameters
# are done as embedded Ruby within this template.
# For example:
#
# def_static_method(Foo, :my_static_method, [:foo, :bar], :baz, :bang, <<RUBY)
# <% if baz && bang %>
# return foo + bar
# <% elsif baz || bang %>
# return foo - bar
# <% else %>
# return 17
# <% end %>
# RUBY
#
# \{#static\_method\_name} can be used to call static methods.
#
# @overload def_static_method(klass, name, args, *vars, erb)
# @param klass [Module] The class on which to define the static method
# @param name [#to_s] The (base) name of the static method
# @param args [Array<Symbol>] The names of the arguments to the defined methods
# (**not** to the ERB template)
# @param vars [Array<Symbol>] The names of the static boolean variables
# to be made available to the ERB template
# @param erb [String] The template for the method code
def def_static_method(klass, name, args, *vars)
erb = vars.pop
info = caller_info
powerset(vars).each do |set|
context = StaticConditionalContext.new(set).instance_eval {binding}
klass.class_eval(<<METHOD, info[0], info[1])
def #{static_method_name(name, *vars.map {|v| set.include?(v)})}(#{args.join(', ')})
#{ERB.new(erb).result(context)}
end
METHOD
end
end
# Computes the name for a method defined via \{#def\_static\_method}.
#
# @param name [String] The base name of the static method
# @param vars [Array<Boolean>] The static variable assignment
# @return [String] The real name of the static method
def static_method_name(name, *vars)
"#{name}_#{vars.map {|v| !!v}.join('_')}"
end
private
# Calculates the memoization table for the Least Common Subsequence algorithm.
# Algorithm from [Wikipedia](http://en.wikipedia.org/wiki/Longest_common_subsequence_problem#Computing_the_length_of_the_LCS)
def lcs_table(x, y)
c = Array.new(x.size) {[]}
x.size.times {|i| c[i][0] = 0}
y.size.times {|j| c[0][j] = 0}
(1...x.size).each do |i|
(1...y.size).each do |j|
c[i][j] =
if yield x[i], y[j]
c[i-1][j-1] + 1
else
[c[i][j-1], c[i-1][j]].max
end
end
end
return c
end
# Computes a single longest common subsequence for arrays x and y.
# Algorithm from [Wikipedia](http://en.wikipedia.org/wiki/Longest_common_subsequence_problem#Reading_out_an_LCS)
def lcs_backtrace(c, x, y, i, j, &block)
return [] if i == 0 || j == 0
if v = yield(x[i], y[j])
return lcs_backtrace(c, x, y, i-1, j-1, &block) << v
end
return lcs_backtrace(c, x, y, i, j-1, &block) if c[i][j-1] > c[i-1][j]
return lcs_backtrace(c, x, y, i-1, j, &block)
end
# Parses a magic comment at the beginning of a Haml file.
# The parsing rules are basically the same as Ruby's.
#
# @return [(Boolean, String or nil)]
# Whether the document begins with a UTF-8 BOM,
# and the declared encoding of the document (or nil if none is declared)
def parse_haml_magic_comment(str)
scanner = StringScanner.new(str.dup.force_encoding("BINARY"))
bom = scanner.scan(/\xEF\xBB\xBF/n)
return bom unless scanner.scan(/-\s*#\s*/n)
if coding = try_parse_haml_emacs_magic_comment(scanner)
return bom, coding
end
return bom unless scanner.scan(/.*?coding[=:]\s*([\w-]+)/in)
return bom, scanner[1]
end
def try_parse_haml_emacs_magic_comment(scanner)
pos = scanner.pos
return unless scanner.scan(/.*?-\*-\s*/n)
# From Ruby's parse.y
return unless scanner.scan(/([^\s'":;]+)\s*:\s*("(?:\\.|[^"])*"|[^"\s;]+?)[\s;]*-\*-/n)
name, val = scanner[1], scanner[2]
return unless name =~ /(en)?coding/in
val = $1 if val =~ /^"(.*)"$/n
return val
ensure
scanner.pos = pos
end
end
end