Merge pull request #165 from gsamokovarov/revamped-integrations

Revamped integrations for CRuby and Rubinius

lib/web_console.rb

@@ -1,5 +1,3 @@
-require 'binding_of_caller'
-
 require 'active_support/lazy_load_hooks'
 require 'active_support/logger'
 

lib/web_console/helper.rb

@@ -11,7 +11,7 @@ module Helper
     def console(binding = nil)
       raise DoubleRenderError if request.env['web_console.binding']
 
-      request.env['web_console.binding'] = binding || ::Kernel.binding.of_caller(1)
+      request.env['web_console.binding'] = binding || ::WebConsole.caller_bindings.first
 
       # Make sure nothing is rendered from the view helper. Otherwise
       # you're gonna see unexpected #<Binding:0x007fee4302b078> in the

lib/web_console/integration.rb

@@ -1,3 +1,28 @@
+module WebConsole
+  # Returns the Ruby bindings of Kernel#callers locations.
+  #
+  # The list of bindings here doesn't map 1 to 1 with Kernel#callers, as we
+  # can't build Ruby bindings for C functions or the equivalent native
+  # implementations in JRuby and Rubinius.
+  #
+  # This method needs to be overridden by every integration.
+  def self.caller_bindings
+    raise NotImplementedError
+  end
+end
+
+class Exception
+  # Returns an array of the exception backtrace locations bindings.
+  #
+  # The list won't map to the traces in #backtrace 1 to 1, because we can't
+  # build bindings for every trace (C functions, for example).
+  #
+  # Every integration should the instance variable.
+  def bindings
+    @bindings || []
+  end
+end
+
 case RUBY_ENGINE
 when 'rbx'
   require 'web_console/integration/rubinius'

lib/web_console/integration/cruby.rb

@@ -1,40 +1,23 @@
-class Exception
-  begin
-    # We share the same exception binding extraction mechanism as better_errors,
-    # so try to use it if it is already available. It also solves problems like
-    # charliesome/better_errors#272, caused by an infinite recursion.
-    require 'better_errors'
+require 'debug_inspector'
 
-    # The bindings in which the exception originated in.
-    def bindings
-      @bindings || __better_errors_bindings_stack
-    end
-  rescue LoadError
-    # The bindings in which the exception originated in.
-    def bindings
-      @bindings || []
-    end
-
-    # CRuby calls #set_backtrace every time it raises an exception. Overriding
-    # it to assign the #bindings.
-    def set_backtrace_with_binding_of_caller(*args)
-      # Thanks to @charliesome who wrote this bit for better_errors.
-      unless Thread.current[:__web_console_exception_lock]
-        Thread.current[:__web_console_exception_lock] = true
-        begin
-          # Raising an exception here will cause all of the rubies to go into a
-          # stack overflow. Some rubies may even segfault. See
-          # https://bugs.ruby-lang.org/issues/10164 for details.
-          @bindings = binding.callers.drop(1)
-        ensure
-          Thread.current[:__web_console_exception_lock] = false
-        end
-      end
+def WebConsole.caller_bindings
+  bindings = RubyVM::DebugInspector.open do |context|
+    context.backtrace_locations.each_index.map { |i| context.frame_binding(i) }
+  end
 
-      set_backtrace_without_binding_of_caller(*args)
-    end
+  # For C functions, we can't extract a binding. In this case,
+  # DebugInspector#frame_binding would have returned us nil. That's why we need
+  # to compact the bindings.
+  #
+  # Dropping two bindings, removes the current Ruby one in this exact method,
+  # and the one in the caller method. The caller method binding can be obtained
+  # by Kernel#binding, if needed.
+  bindings.compact.drop(2)
+end
 
-    alias_method :set_backtrace_without_binding_of_caller, :set_backtrace
-    alias_method :set_backtrace, :set_backtrace_with_binding_of_caller
+TracePoint.trace(:raise) do |context|
+  exc = context.raised_exception
+  if exc.bindings.empty?
+    exc.instance_variable_set(:@bindings, WebConsole.caller_bindings)
   end
 end

lib/web_console/integration/rubinius.rb

@@ -1,62 +1,34 @@
-module WebConsole
-  module Rubinius
-    # Filters internal Rubinius locations.
-    #
-    # There are a couple of reasons why we wanna filter out the locations.
-    #
-    # * ::Kernel.raise, is implemented in Ruby for Rubinius. We don't wanna
-    #   have the frame for it to align with the CRuby and JRuby implementations.
-    #
-    # * For internal methods location variables can be nil. We can't create a
-    #   bindings for them.
-    #
-    # * Bindings from the current file are considered internal and ignored.
-    #
-    # We do that all that so we can align the bindings with the backtraces
-    # entries.
-    class InternalLocationFilter
-      def initialize(locations)
-        @locations = locations
-      end
+def WebConsole.caller_bindings
+  locations = ::Rubinius::VM.backtrace(1, true)
 
-      def filter
-        @locations.reject do |location|
-          location.file.start_with?('kernel/delta/kernel.rb') ||
-            location.file == __FILE__ ||
-            location.variables.nil?
-        end
-      end
-    end
-
-    # Gets the current bindings for all available Ruby frames.
-    #
-    # Filters the internal Rubinius and WebConsole frames.
-    def self.current_bindings
-      locations = ::Rubinius::VM.backtrace(1, true)
-
-      InternalLocationFilter.new(locations).filter.map do |location|
-        Binding.setup(
-          location.variables,
-          location.variables.method,
-          location.constant_scope,
-          location.variables.self,
-          location
-        )
-      end
-    end
+  # Kernel.raise, is implemented in Ruby for Rubinius. We don't wanna have
+  # the frame for it to align with the CRuby and JRuby implementations.
+  #
+  # For internal methods location variables can be nil. We can't create a
+  # bindings for them.
+  locations.reject! do |location|
+    location.file.start_with?('kernel/delta/kernel.rb') || location.variables.nil?
   end
-end
 
-::Exception.class_eval do
-  def bindings
-    @bindings || []
+  bindings = locations.map do |location|
+    Binding.setup(
+      location.variables,
+      location.variables.method,
+      location.constant_scope,
+      location.variables.self,
+      location
+    )
   end
+
+  # Drop the binding of the direct caller. That one can be created by
+  # Kernel#binding.
+  bindings.drop(1)
 end
 
 ::Rubinius.singleton_class.class_eval do
   def raise_exception_with_current_bindings(exc)
     if exc.bindings.empty?
-      exc.instance_variable_set(:@bindings, WebConsole::Rubinius.current_bindings)
+      exc.instance_variable_set(:@bindings, WebConsole.caller_bindings)
     end
 
     raise_exception_without_current_bindings(exc)

web-console.gemspec

@@ -17,10 +17,10 @@ Gem::Specification.new do |s|
 
   rails_version = ">= 4.0"
 
-  s.add_dependency "railties",          rails_version
-  s.add_dependency "activemodel",       rails_version
-  s.add_dependency "sprockets-rails",   ">= 2.0", "< 4.0"
-  s.add_dependency "binding_of_caller", ">= 0.7.2"
+  s.add_dependency "railties",        rails_version
+  s.add_dependency "activemodel",     rails_version
+  s.add_dependency "sprockets-rails", ">= 2.0", "< 4.0"
+  s.add_dependency "debug_inspector"
 
   # We need those for the testing application to run.
   s.add_development_dependency "actionmailer", rails_version