diff options
Diffstat (limited to 'railties/lib/binding_of_caller.rb')
-rw-r--r-- | railties/lib/binding_of_caller.rb | 168 |
1 files changed, 83 insertions, 85 deletions
diff --git a/railties/lib/binding_of_caller.rb b/railties/lib/binding_of_caller.rb index 759e760016..d18fbdef3d 100644 --- a/railties/lib/binding_of_caller.rb +++ b/railties/lib/binding_of_caller.rb @@ -1,85 +1,83 @@ -begin - require 'simplecc' -rescue LoadError - class Continuation #:nodoc: - def self.create(*args, &block) - cc = nil; result = callcc {|c| cc = c; block.call(cc) if block and args.empty?} - result ||= args - return *[cc, *result] - end - end -end - -class Binding #:nodoc: - # This method returns the binding of the method that called your - # method. It will raise an Exception when you're not inside a method. - # - # It's used like this: - # def inc_counter(amount = 1) - # Binding.of_caller do |binding| - # # Create a lambda that will increase the variable 'counter' - # # in the caller of this method when called. - # inc = eval("lambda { |arg| counter += arg }", binding) - # # We can refer to amount from inside this block safely. - # inc.call(amount) - # end - # # No other statements can go here. Put them inside the block. - # end - # counter = 0 - # 2.times { inc_counter } - # counter # => 2 - # - # Binding.of_caller must be the last statement in the method. - # This means that you will have to put everything you want to - # do after the call to Binding.of_caller into the block of it. - # This should be no problem however, because Ruby has closures. - # If you don't do this an Exception will be raised. Because of - # the way that Binding.of_caller is implemented it has to be - # done this way. - def self.of_caller(&block) - old_critical = Thread.critical - Thread.critical = true - count = 0 - cc, result, error, extra_data = Continuation.create(nil, nil) - error.call if error - - tracer = lambda do |*args| - type, context, extra_data = args[0], args[4], args - if type == "return" - count += 1 - # First this method and then calling one will return -- - # the trace event of the second event gets the context - # of the method which called the method that called this - # method. - if count == 2 - # It would be nice if we could restore the trace_func - # that was set before we swapped in our own one, but - # this is impossible without overloading set_trace_func - # in current Ruby. - set_trace_func(nil) - cc.call(eval("binding", context), nil, extra_data) - end - elsif type == "line" then - nil - elsif type == "c-return" and extra_data[3] == :set_trace_func then - nil - else - set_trace_func(nil) - error_msg = "Binding.of_caller used in non-method context or " + - "trailing statements of method using it aren't in the block." - cc.call(nil, lambda { raise(ArgumentError, error_msg) }, nil) - end - end - - unless result - set_trace_func(tracer) - return nil - else - Thread.critical = old_critical - case block.arity - when 1 then yield(result) - else yield(result, extra_data) - end - end - end -end
\ No newline at end of file +begin
+ require 'simplecc'
+rescue LoadError
+ class Continuation; end # :nodoc: # for RDoc
+ def Continuation.create(*args, &block) # :nodoc:
+ cc = nil; result = callcc {|c| cc = c; block.call(cc) if block and args.empty?}
+ result ||= args
+ return *[cc, *result]
+ end
+end
+
+class Binding; end # for RDoc
+# This method returns the binding of the method that called your
+# method. It will raise an Exception when you're not inside a method.
+#
+# It's used like this:
+# def inc_counter(amount = 1)
+# Binding.of_caller do |binding|
+# # Create a lambda that will increase the variable 'counter'
+# # in the caller of this method when called.
+# inc = eval("lambda { |arg| counter += arg }", binding)
+# # We can refer to amount from inside this block safely.
+# inc.call(amount)
+# end
+# # No other statements can go here. Put them inside the block.
+# end
+# counter = 0
+# 2.times { inc_counter }
+# counter # => 2
+#
+# Binding.of_caller must be the last statement in the method.
+# This means that you will have to put everything you want to
+# do after the call to Binding.of_caller into the block of it.
+# This should be no problem however, because Ruby has closures.
+# If you don't do this an Exception will be raised. Because of
+# the way that Binding.of_caller is implemented it has to be
+# done this way.
+def Binding.of_caller(&block)
+ old_critical = Thread.critical
+ Thread.critical = true
+ count = 0
+ cc, result, error, extra_data = Continuation.create(nil, nil)
+ error.call if error
+
+ tracer = lambda do |*args|
+ type, context, extra_data = args[0], args[4], args
+ if type == "return"
+ count += 1
+ # First this method and then calling one will return --
+ # the trace event of the second event gets the context
+ # of the method which called the method that called this
+ # method.
+ if count == 2
+ # It would be nice if we could restore the trace_func
+ # that was set before we swapped in our own one, but
+ # this is impossible without overloading set_trace_func
+ # in current Ruby.
+ set_trace_func(nil)
+ cc.call(eval("binding", context), nil, extra_data)
+ end
+ elsif type == "line" then
+ nil
+ elsif type == "c-return" and extra_data[3] == :set_trace_func then
+ nil
+ else
+ set_trace_func(nil)
+ error_msg = "Binding.of_caller used in non-method context or " +
+ "trailing statements of method using it aren't in the block."
+ cc.call(nil, lambda { raise(ArgumentError, error_msg) }, nil)
+ end
+ end
+
+ unless result
+ set_trace_func(tracer)
+ return nil
+ else
+ Thread.critical = old_critical
+ case block.arity
+ when 1 then yield(result)
+ else yield(result, extra_data)
+ end
+ end
+end
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