forked from rtomayko/tilt
/
tilt.rb
394 lines (323 loc) · 11.1 KB
/
tilt.rb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
module Tilt
VERSION = '0.3'
@template_mappings = {}
# Hash of template path pattern => template implementation
# class mappings.
def self.mappings
@template_mappings
end
# Register a template implementation by file extension.
def self.register(ext, template_class)
ext = ext.to_s.sub(/^\./, '')
mappings[ext.downcase] = template_class
end
# Create a new template for the given file using the file's extension
# to determine the the template mapping.
def self.new(file, line=nil, options={}, &block)
if template_class = self[file]
template_class.new(file, line, options, &block)
else
fail "No template engine registered for #{File.basename(file)}"
end
end
# Lookup a template class given for the given filename or file
# extension. Return nil when no implementation is found.
def self.[](file)
if @template_mappings.key?(pattern = file.to_s.downcase)
@template_mappings[pattern]
elsif @template_mappings.key?(pattern = File.basename(pattern))
@template_mappings[pattern]
else
while !pattern.empty?
if @template_mappings.key?(pattern)
return @template_mappings[pattern]
else
pattern = pattern.sub(/^[^.]*\.?/, '')
end
end
nil
end
end
# Base class for template implementations. Subclasses must implement
# the #compile! method and one of the #evaluate or #template_source
# methods.
class Template
# Template source; loaded from a file or given directly.
attr_reader :data
# The name of the file where the template data was loaded from.
attr_reader :file
# The line number in #file where template data was loaded from.
attr_reader :line
# A Hash of template engine specific options. This is passed directly
# to the underlying engine and is not used by the generic template
# interface.
attr_reader :options
# Create a new template with the file, line, and options specified. By
# default, template data is read from the file specified. When a block
# is given, it should read template data and return as a String. When
# file is nil, a block is required.
def initialize(file=nil, line=1, options={}, &block)
raise ArgumentError, "file or block required" if file.nil? && block.nil?
options, line = line, 1 if line.is_a?(Hash)
@file = file
@line = line || 1
@options = options || {}
@reader = block || lambda { |t| File.read(file) }
end
# Load template source and compile the template. The template is
# loaded and compiled the first time this method is called; subsequent
# calls are no-ops.
def compile
if @data.nil?
@data = @reader.call(self)
compile!
end
end
# Render the template in the given scope with the locals specified. If a
# block is given, it is typically available within the template via
# +yield+.
def render(scope=Object.new, locals={}, &block)
compile
evaluate scope, locals || {}, &block
end
# The basename of the template file.
def basename(suffix='')
File.basename(file, suffix) if file
end
# The template file's basename with all extensions chomped off.
def name
basename.split('.', 2).first if basename
end
# The filename used in backtraces to describe the template.
def eval_file
file || '(__TEMPLATE__)'
end
protected
# Do whatever preparation is necessary to "compile" the template.
# Called immediately after template #data is loaded. Instance variables
# set in this method are available when #evaluate is called.
#
# Subclasses must provide an implementation of this method.
def compile!
raise NotImplementedError
end
# Process the template and return the result. Subclasses should override
# this method unless they implement the #template_source.
def evaluate(scope, locals, &block)
source, offset = local_assignment_code(locals)
source = [source, template_source].join("\n")
scope.instance_eval source, eval_file, line - offset
end
# Return a string containing the (Ruby) source code for the template. The
# default Template#evaluate implementation requires this method be
# defined.
def template_source
raise NotImplementedError
end
private
def local_assignment_code(locals)
return ['', 1] if locals.empty?
source = locals.collect { |k,v| "#{k} = locals[:#{k}]" }
[source.join("\n"), source.length]
end
def require_template_library(name)
if Thread.list.size > 1
warn "WARN: tilt autoloading '#{name}' in a non thread-safe way; " +
"explicit require '#{name}' suggested."
end
require name
end
end
# Extremely simple template cache implementation.
class Cache
def initialize
@cache = {}
end
def fetch(*key)
key = key.map { |part| part.to_s }.join(":")
@cache[key] ||= yield
end
def clear
@cache = {}
end
end
# Template Implementations ================================================
# The template source is evaluated as a Ruby string. The #{} interpolation
# syntax can be used to generated dynamic output.
class StringTemplate < Template
def compile!
@code = "%Q{#{data}}"
end
def template_source
@code
end
end
register 'str', StringTemplate
# ERB template implementation. See:
# http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/classes/ERB.html
class ERBTemplate < Template
def compile!
require_template_library 'erb' unless defined?(::ERB)
@engine = ::ERB.new(data, options[:safe], options[:trim], '@_out_buf')
end
def template_source
@engine.src
end
def evaluate(scope, locals, &block)
source, offset = local_assignment_code(locals)
source = [source, template_source].join("\n")
original_out_buf =
scope.instance_variables.any? { |var| var.to_sym == :@_out_buf } &&
scope.instance_variable_get(:@_out_buf)
scope.instance_eval source, eval_file, line - offset
output = scope.instance_variable_get(:@_out_buf)
scope.instance_variable_set(:@_out_buf, original_out_buf)
output
end
private
# ERB generates a line to specify the character coding of the generated
# source in 1.9. Account for this in the line offset.
if RUBY_VERSION >= '1.9.0'
def local_assignment_code(locals)
source, offset = super
[source, offset + 1]
end
end
end
%w[erb rhtml].each { |ext| register ext, ERBTemplate }
# Erubis template implementation. See:
# http://www.kuwata-lab.com/erubis/
class ErubisTemplate < ERBTemplate
def compile!
require_template_library 'erubis' unless defined?(::Erubis)
Erubis::Eruby.class_eval(%Q{def add_preamble(src) src << "@_out_buf = _buf = '';" end})
@engine = ::Erubis::Eruby.new(data, options)
end
end
register 'erubis', ErubisTemplate
# Haml template implementation. See:
# http://haml.hamptoncatlin.com/
class HamlTemplate < Template
def compile!
require_template_library 'haml' unless defined?(::Haml::Engine)
@engine = ::Haml::Engine.new(data, haml_options)
end
def evaluate(scope, locals, &block)
@engine.render(scope, locals, &block)
end
private
def haml_options
options.merge(:filename => eval_file, :line => line)
end
end
register 'haml', HamlTemplate
# Sass template implementation. See:
# http://haml.hamptoncatlin.com/
#
# Sass templates do not support object scopes, locals, or yield.
class SassTemplate < Template
def compile!
require_template_library 'sass' unless defined?(::Sass::Engine)
@engine = ::Sass::Engine.new(data, sass_options)
end
def evaluate(scope, locals, &block)
@engine.render
end
private
def sass_options
options.merge(:filename => eval_file, :line => line)
end
end
register 'sass', SassTemplate
# Builder template implementation. See:
# http://builder.rubyforge.org/
class BuilderTemplate < Template
def compile!
require_template_library 'builder' unless defined?(::Builder)
end
def evaluate(scope, locals, &block)
xml = ::Builder::XmlMarkup.new(:indent => 2)
if data.respond_to?(:to_str)
locals[:xml] = xml
super(scope, locals, &block)
elsif data.kind_of?(Proc)
data.call(xml)
end
xml.target!
end
def template_source
data.to_str
end
end
register 'builder', BuilderTemplate
# Liquid template implementation. See:
# http://liquid.rubyforge.org/
#
# LiquidTemplate does not support scopes or yield blocks.
#
# It's suggested that your program require 'liquid' at load
# time when using this template engine.
class LiquidTemplate < Template
def compile!
require_template_library 'liquid' unless defined?(::Liquid::Template)
@engine = ::Liquid::Template.parse(data)
end
def evaluate(scope, locals, &block)
locals = locals.inject({}) { |hash,(k,v)| hash[k.to_s] = v ; hash }
@engine.render(locals)
end
end
register 'liquid', LiquidTemplate
# Discount Markdown implementation.
class RDiscountTemplate < Template
def compile!
require_template_library 'rdiscount' unless defined?(::RDiscount)
@engine = RDiscount.new(data)
end
def evaluate(scope, locals, &block)
@engine.to_html
end
end
register 'markdown', RDiscountTemplate
register 'md', RDiscountTemplate
# Mustache is written and maintained by Chris Wanstrath. See:
# http://github.com/defunkt/mustache
#
# When a scope argument is provided to MustacheTemplate#render, the
# instance variables are copied from the scope object to the Mustache
# view.
class MustacheTemplate < Template
attr_reader :engine
# Locates and compiles the Mustache object used to create new views. The
def compile!
require_template_library 'mustache' unless defined?(::Mustache)
# Set the Mustache view namespace if we can
Mustache.view_namespace = options[:namespace]
# Figure out which Mustache class to use.
@engine = options[:view] || Mustache.view_class(name)
# set options on the view class
options.each do |key, value|
next if %w[view namespace mustaches].include?(key.to_s)
@engine.send("#{key}=", value) if @engine.respond_to? "#{key}="
end
end
def evaluate(scope=nil, locals={}, &block)
# Create a new instance for playing with
instance = @engine.new
# Copy instance variables from scope to the view
scope.instance_variables.each do |name|
instance.instance_variable_set(name, scope.instance_variable_get(name))
end
# Locals get added to the view's context
locals.each do |local, value|
instance[local] = value
end
# If we're passed a block it's a subview. Sticking it in yield
# lets us use {{yield}} in layout.html to render the actual page.
instance[:yield] = block.call if block
instance.template = data unless instance.compiled?
instance.to_html
end
end
register 'mustache', MustacheTemplate
end