Share variable inspection logic between CDP and DAP

Author: amomchilov

lib/debug/limited_pp.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "pp"
+
+module DEBUGGER__
+  class LimitedPP
+    SHORT_INSPECT_LENGTH = 40
+
+    def self.pp(obj, max = 80)
+      out = self.new(max)
+      catch out do
+        ::PP.singleline_pp(obj, out)
+      end
+      out.buf
+    end
+
+    attr_reader :buf
+
+    def initialize max
+      @max = max
+      @cnt = 0
+      @buf = String.new
+    end
+
+    def <<(other)
+      @buf << other
+
+      if @buf.size >= @max
+        @buf = @buf[0..@max] + '...'
+        throw self
+      end
+    end
+
+    def self.safe_inspect obj, max_length: SHORT_INSPECT_LENGTH, short: false
+      if short
+        LimitedPP.pp(obj, max_length)
+      else
+        obj.inspect
+      end
+    rescue NoMethodError => e
+      klass, oid = M_CLASS.bind_call(obj), M_OBJECT_ID.bind_call(obj)
+      if obj == (r = e.receiver)
+        "<\##{klass.name}#{oid} does not have \#inspect>"
+      else
+        rklass, roid = M_CLASS.bind_call(r), M_OBJECT_ID.bind_call(r)
+        "<\##{klass.name}:#{roid} contains <\##{rklass}:#{roid} and it does not have #inspect>"
+      end
+    # rescue Exception => e
+    #   "<#inspect raises #{e.inspect}>"
+    end
+  end
+end

lib/debug/server_cdp.rb

@@ -9,6 +9,7 @@
 require 'tmpdir'
 require 'tempfile'
 require 'timeout'
+require_relative 'variable_inspector'
 
 module DEBUGGER__
   module UI_CDP
@@ -1112,46 +1113,29 @@ def process_cdp args
         event! :protocol_result, :scope, req, vars
       when :properties
         oid = args.shift
-        result = []
-        prop = []
 
         if obj = @obj_map[oid]
-          case obj
-          when Array
-            result = obj.map.with_index{|o, i|
-              variable i.to_s, o
-            }
-          when Hash
-            result = obj.map{|k, v|
-              variable(k, v)
-            }
-          when Struct
-            result = obj.members.map{|m|
-              variable(m, obj[m])
-            }
-          when String
-            prop = [
-              internalProperty('#length', obj.length),
-              internalProperty('#encoding', obj.encoding)
-            ]
-          when Class, Module
-            result = obj.instance_variables.map{|iv|
-              variable(iv, obj.instance_variable_get(iv))
-            }
-            prop = [internalProperty('%ancestors', obj.ancestors[1..])]
-          when Range
-            prop = [
-              internalProperty('#begin', obj.begin),
-              internalProperty('#end', obj.end),
-            ]
+          members = if obj.is_a?(Array)
+            VariableInspector.new.indexed_members_of(obj, start: 0, count: obj.size)
+          else
+            VariableInspector.new.named_members_of(obj)
           end
 
-          result += M_INSTANCE_VARIABLES.bind_call(obj).map{|iv|
-            variable(iv, M_INSTANCE_VARIABLE_GET.bind_call(obj, iv))
-          }
-          prop += [internalProperty('#class', M_CLASS.bind_call(obj))]
+          result = members.filter_map do |member|
+            next if member.internal?
+            variable(member.name, member.value)
+          end
+
+          internal_properties = members.filter_map do |member|
+            next unless member.internal?
+            internalProperty(member.name, member.value)
+          end
+        else
+          result = []
+          internal_properties = []
         end
-        event! :protocol_result, :properties, req, result: result, internalProperties: prop
+
+        event! :protocol_result, :properties, req, result: result, internalProperties: internal_properties
       when :exception
         oid = args.shift
         exc = nil

lib/debug/server_dap.rb

@@ -4,6 +4,7 @@
 require 'irb/completion'
 require 'tmpdir'
 require 'fileutils'
+require_relative 'variable_inspector'
 
 module DEBUGGER__
   module UI_DAP
@@ -765,18 +766,11 @@ def register_vars vars, tid
     end
   end
 
-  class NaiveString
-    attr_reader :str
-    def initialize str
-      @str = str
-    end
-  end
-
   class ThreadClient
     MAX_LENGTH = 180
 
     def value_inspect obj, short: true
-      # TODO: max length should be configuarable?
+      # TODO: max length should be configurable?
       str = DEBUGGER__.safe_inspect obj, short: short, max_length: MAX_LENGTH
 
       if str.encoding == Encoding::UTF_8
@@ -875,48 +869,18 @@ def process_dap args
         vid = args.shift
         obj = @var_map[vid]
         if obj
-          case req.dig('arguments', 'filter')
+          members = case req.dig('arguments', 'filter')
           when 'indexed'
-            start = req.dig('arguments', 'start') || 0
-            count = req.dig('arguments', 'count') || obj.size
-            vars = (start ... (start + count)).map{|i|
-              variable(i.to_s, obj[i])
-            }
+            VariableInspector.new.indexed_members_of(
+              obj,
+              start: req.dig('arguments', 'start') || 0,
+              count: req.dig('arguments', 'count') || obj.size,
+            )
           else
-            vars = []
-
-            case obj
-            when Hash
-              vars = obj.map{|k, v|
-                variable(value_inspect(k), v,)
-              }
-            when Struct
-              vars = obj.members.map{|m|
-                variable(m, obj[m])
-              }
-            when String
-              vars = [
-                variable('#length', obj.length),
-                variable('#encoding', obj.encoding),
-              ]
-              printed_str = value_inspect(obj)
-              vars << variable('#dump', NaiveString.new(obj)) if printed_str.end_with?('...')
-            when Class, Module
-              vars << variable('%ancestors', obj.ancestors[1..])
-            when Range
-              vars = [
-                variable('#begin', obj.begin),
-                variable('#end', obj.end),
-              ]
-            end
-
-            unless NaiveString === obj
-              vars += M_INSTANCE_VARIABLES.bind_call(obj).sort.map{|iv|
-                variable(iv, M_INSTANCE_VARIABLE_GET.bind_call(obj, iv))
-              }
-              vars.unshift variable('#class', M_CLASS.bind_call(obj))
-            end
+            VariableInspector.new.named_members_of(obj)
           end
+
+          vars = members.map { |member| variable(member.name, member.value) }
         end
         event! :protocol_result, :variable, req, variables: (vars || []), tid: self.id
 
@@ -1059,7 +1023,7 @@ def variable_ name, obj, indexedVariables: 0, namedVariables: 0
 
       namedVariables += M_INSTANCE_VARIABLES.bind_call(obj).size
 
-      if NaiveString === obj
+      if VariableInspector::NaiveString === obj
         str = obj.str.dump
         vid = indexedVariables = namedVariables = 0
       else

lib/debug/session.rb

@@ -34,6 +34,8 @@
 require_relative 'source_repository'
 require_relative 'breakpoint'
 require_relative 'tracer'
+require_relative 'limited_pp'
+require_relative 'variable_inspector'
 
 # To prevent loading old lib/debug.rb in Ruby 2.6 to 3.0
 $LOADED_FEATURES << 'debug.rb'
@@ -2302,53 +2304,8 @@ def self.load_rc
     end
   end
 
-  # Inspector
-
-  SHORT_INSPECT_LENGTH = 40
-
-  class LimitedPP
-    def self.pp(obj, max=80)
-      out = self.new(max)
-      catch out do
-        PP.singleline_pp(obj, out)
-      end
-      out.buf
-    end
-
-    attr_reader :buf
-
-    def initialize max
-      @max = max
-      @cnt = 0
-      @buf = String.new
-    end
-
-    def <<(other)
-      @buf << other
-
-      if @buf.size >= @max
-        @buf = @buf[0..@max] + '...'
-        throw self
-      end
-    end
-  end
-
-  def self.safe_inspect obj, max_length: SHORT_INSPECT_LENGTH, short: false
-    if short
-      LimitedPP.pp(obj, max_length)
-    else
-      obj.inspect
-    end
-  rescue NoMethodError => e
-    klass, oid = M_CLASS.bind_call(obj), M_OBJECT_ID.bind_call(obj)
-    if obj == (r = e.receiver)
-      "<\##{klass.name}#{oid} does not have \#inspect>"
-    else
-      rklass, roid = M_CLASS.bind_call(r), M_OBJECT_ID.bind_call(r)
-      "<\##{klass.name}:#{roid} contains <\##{rklass}:#{roid} and it does not have #inspect>"
-    end
-  rescue Exception => e
-    "<#inspect raises #{e.inspect}>"
+  def self.safe_inspect obj, max_length: LimitedPP::SHORT_INSPECT_LENGTH, short: false
+    LimitedPP.safe_inspect(obj, max_length: max_length, short: short)
   end
 
   def self.warn msg

lib/debug/variable_inspector.rb

@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+require_relative 'limited_pp'
+
+module DEBUGGER__
+  class VariableInspector
+    class Member
+      attr_reader :name, :value
+
+      def initialize(name:, value:, internal: false)
+        @name = name
+        @value = value
+        @is_internal = internal
+      end
+
+      def internal?
+        @is_internal
+      end
+
+      def self.internal name:, value:
+        new(name:, value:, internal: true)
+      end
+
+      def ==(other)
+        other.instance_of?(self.class) &&
+          @name == other.name &&
+          @value == other.value &&
+          @is_internal == other.internal?
+      end
+
+      def inspect
+        "#<Member name=#{@name.inspect} value=#{@value.inspect}#{@is_internal ? " internal" : ""}>"
+      end
+    end
+
+    def indexed_members_of obj, start:, count:
+      return [] if start > (obj.length - 1)
+
+      capped_count = [count, obj.length - start].min
+
+      (start...(start + capped_count)).map do |i|
+        Member.new(name: i.to_s, value: obj[i])
+      end
+    end
+
+    def named_members_of obj
+      members = case obj
+      when Hash then obj.map { |k, v| Member.new(name: value_inspect(k), value: v) }
+      when Struct then obj.members.map { |name| Member.new(name:, value: obj[name]) }
+      when String
+        members = [
+          Member.internal(name: '#length', value: obj.length),
+          Member.internal(name: '#encoding', value: obj.encoding),
+        ]
+
+        printed_str = value_inspect(obj)
+        members << Member.internal(name: "#dump", value: NaiveString.new(obj)) if printed_str.end_with?('...')
+
+        members
+      when Class, Module then [Member.internal(name: "%ancestors", value: obj.ancestors[1..])]
+      when Range then [
+        Member.internal(name: "#begin", value: obj.begin),
+        Member.internal(name: "#end", value: obj.end),
+      ]
+      else []
+      end
+
+      unless NaiveString === obj
+        members += M_INSTANCE_VARIABLES.bind_call(obj).sort.map{|iv|
+          Member.new(name: iv, value: M_INSTANCE_VARIABLE_GET.bind_call(obj, iv))
+        }
+        members.unshift  Member.internal(name: '#class', value: M_CLASS.bind_call(obj))
+      end
+
+      members
+    end
+
+    private
+
+    MAX_LENGTH = 180
+
+    def value_inspect obj, short: true
+      # TODO: max length should be configurable?
+      str = LimitedPP.safe_inspect obj, short: short, max_length: MAX_LENGTH
+
+      if str.encoding == Encoding::UTF_8
+        str.scrub
+      else
+        str.encode(Encoding::UTF_8, invalid: :replace, undef: :replace)
+      end
+    end
+
+    # TODO: Replace with Reflection helpers once they are merged
+    # https://github.com/ruby/debug/pull/1002
+    M_INSTANCE_VARIABLES = method(:instance_variables).unbind
+    M_INSTANCE_VARIABLE_GET = method(:instance_variable_get).unbind
+    M_CLASS = method(:class).unbind
+
+    class NaiveString
+      attr_reader :str
+      def initialize str
+        @str = str
+      end
+
+      def == other
+        other.instance_of?(self.class) && @str == other.str
+      end
+    end
+  end
+end