Class: AppMap::Hook

Inherits:
Object show all
Defined in:
lib/appmap/hook.rb,
lib/appmap/hook/method.rb,
lib/appmap/hook/method/ruby2.rb,
lib/appmap/hook/method/ruby3.rb,
lib/appmap/hook/record_around.rb,
ext/appmap/appmap.c

Defined Under Namespace

Modules: RecordAround Classes: Method

Constant Summary collapse

OBJECT_INSTANCE_METHODS = 
%i[! != !~ <=> == === =~ __id__ __send__ class clone define_singleton_method display dup
enum_for eql? equal? extend freeze frozen? hash inspect instance_eval instance_exec instance_of? instance_variable_defined? instance_variable_get instance_variable_set instance_variables is_a? itself kind_of? method methods nil? object_id private_methods protected_methods public_method public_methods public_send remove_instance_variable respond_to? send singleton_class singleton_method singleton_methods taint tainted? tap then to_enum to_s to_h to_a trust untaint untrust untrusted? yield_self].freeze
OBJECT_STATIC_METHODS = 
%i[! != !~ < <= <=> == === =~ > >= __id__ __send__ alias_method allocate ancestors attr
attr_accessor attr_reader attr_writer autoload autoload? class class_eval class_exec class_variable_defined? class_variable_get class_variable_set class_variables clone const_defined? const_get const_missing const_set constants define_method define_singleton_method deprecate_constant display dup enum_for eql? equal? extend freeze frozen? hash include include? included_modules inspect instance_eval instance_exec instance_method instance_methods instance_of? instance_variable_defined? instance_variable_get instance_variable_set instance_variables is_a? itself kind_of? method method_defined? methods module_eval module_exec name new nil? object_id prepend private_class_method private_constant private_instance_methods private_method_defined? private_methods protected_instance_methods protected_method_defined? protected_methods public_class_method public_constant public_instance_method public_instance_methods public_method public_method_defined? public_methods public_send remove_class_variable remove_instance_variable remove_method respond_to? send singleton_class singleton_class? singleton_method singleton_methods superclass taint tainted? tap then to_enum to_s trust undef_method untaint untrust untrusted? yield_self].freeze
SLOW_PACKAGE_THRESHOLD = 
0.001
SIGNATURES = 
{}
LOOKUP_SIGNATURE = 
lambda do |id|
  method = super(id)

  hash_key = Hook.method_hash_key(method.owner, method)
  return method unless hash_key

  signature = SIGNATURES[hash_key]
  if signature
    method.singleton_class.module_eval do
      define_method(:parameters) do
        signature
      end
    end
  end

  method
end

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ Hook

Returns a new instance of Hook.



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# File 'lib/appmap/hook.rb', line 57

def initialize(config)
  @config = config
  @trace_enabled = []
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/appmap/hook.rb', line 55

def config
  @config
end

Class Method Details

.already_hooked?(method) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/appmap/hook.rb', line 35

def already_hooked?(method)
  # After a method is defined, the statement "module_function <the-method>" can convert that method
  # into a module (class) method. The method is hooked first when it's defined, then AppMap will attempt to
  # hook it again when it's redefined as a module method. So we check the method source location - if it's
  # part of the AppMap source tree, we ignore it.
  method.source_location && method.source_location[0].index(__dir__) == 0
end

.hook_builtins? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/appmap/hook.rb', line 24

def hook_builtins?
  Mutex.new.synchronize do
    @hook_builtins = true if @hook_builtins.nil?

    next false unless @hook_builtins

    @hook_builtins = false
    true
  end
end

.method_hash_key(cls, method) ⇒ Object 



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# File 'lib/appmap/hook/method.rb', line 8

def method_hash_key(cls, method)
  [cls, method.name].hash
rescue TypeError => e
  warn "Error building hash key for #{cls}, #{method}: #{e}"
end

.qualify_method_name(method) ⇒ Object

Return the class, separator (‘.’ or ‘#’), and method name for the given method.



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# File 'lib/appmap/hook.rb', line 45

def qualify_method_name(method)
  if method.owner.singleton_class?
    class_name = singleton_method_owner_name(method)
    [class_name, ".", method.name]
  else
    [method.owner.name, "#", method.name]
  end
end

.singleton_method_owner_name(method) ⇒ Object 



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# File 'ext/appmap/appmap.c', line 16

static VALUE
singleton_method_owner_name(VALUE klass, VALUE method)
{
  VALUE owner = rb_funcall(method, rb_intern("owner"), 0);
  VALUE attached = rb_ivar_get(owner, rb_intern("__attached__"));
  if (!CLASS_OR_MODULE_P(attached)) {
    attached = rb_funcall(attached, rb_intern("class"), 0);
  }

  // Did __attached__.class return an object that's a Module or a
  // Class?
  if (CLASS_OR_MODULE_P(attached)) {
    // Yup, get it's name
    return rb_mod_name(attached);
  }

  // Nope (which seems weird, but whatever). Fall back to calling
  // #to_s on the method's owner and hope for the best.
  return rb_funcall(owner, rb_intern("to_s"), 0);
}

Instance Method Details

#enable(&block) ⇒ Object

Observe class loading and hook all methods which match the config.



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# File 'lib/appmap/hook.rb', line 63

def enable(&block)
  require "appmap/hook/method"

  hook_builtins

  # Paths that are known to be non-tracing.
  @notrace_paths = Set.new
  # Locations that have already been visited.
  @trace_locations = Set.new
  @module_load_times = Hash.new { |memo, k| memo[k] = 0 }
  @slow_packages = Set.new

  if ENV["APPMAP_PROFILE_HOOK"] == "true"
    dump_times = lambda do
      @module_load_times
        .keys
        .select { |key| !@slow_packages.member?(key) }
        .each do |key|
        elapsed = @module_load_times[key]
        if elapsed >= SLOW_PACKAGE_THRESHOLD
          @slow_packages.add(key)
          warn "AppMap: Package #{key} took #{@module_load_times[key]} seconds to hook"
        end
      end
    end

    at_exit(&dump_times)
    Thread.new do
      while true
        dump_times.call
        sleep 5
      end
    end
  end

  @trace_end = TracePoint.new(:end, &method(:trace_end))
  @trace_end.enable(&block)
end

#hook_builtins ⇒ Object

hook_builtins builds hooks for code that is built in to the Ruby standard library. No TracePoint events are emitted for builtins, so a separate hooking mechanism is needed.



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# File 'lib/appmap/hook.rb', line 104

def hook_builtins
  return unless self.class.hook_builtins?

  hook_loaded_code = lambda do |hooks_by_class, builtin|
    hooks_by_class.each do |class_name, hooks|
      Array(hooks).each do |hook|
        HookLog.builtin class_name do
          if builtin && hook.package.require_name && hook.package.require_name != "ruby"
            begin
              require hook.package.require_name
            rescue
              HookLog.load_error hook.package.require_name, "Unable to require #{hook.package.require_name}: #{$!}" if HookLog.enabled?
              next
            end
          end

          begin
            base_cls = Object.const_get class_name
          rescue NameError
            HookLog.load_error class_name, "Class #{class_name} not found in global scope" if HookLog.enabled?
            next
          end

          Array(hook.method_names).each do |method_name|
            method_name = method_name.to_sym

            hook_method = lambda do |entry|
              cls, method = entry
              next if config.never_hook?(cls, method)

              hook.package.handler_class.new(hook.package, cls, method).activate
            end

            methods = []
            # irb(main):001:0> Kernel.public_instance_method(:system)
            # (irb):1:in `public_instance_method': method `system' for module `Kernel' is  private (NameError)
            if base_cls == Kernel
              begin
                methods << [base_cls, base_cls.instance_method(method_name)]
              rescue
                nil
              end
            end
            begin
              methods << [base_cls, base_cls.public_instance_method(method_name)]
            rescue
              nil
            end
            begin
              methods << [base_cls, base_cls.protected_instance_method(method_name)]
            rescue
              nil
            end
            if base_cls.respond_to?(:singleton_class)
              begin
                methods << [base_cls.singleton_class, base_cls.singleton_class.public_instance_method(method_name)]
              rescue
                nil
              end
              begin
                methods << [base_cls.singleton_class, base_cls.singleton_class.protected_instance_method(method_name)]
              rescue
                nil
              end
            end
            methods.compact!
            if methods.empty?
              HookLog.load_error [base_cls.name, method_name].join("[#.]"), "Method #{method_name} not found on #{base_cls.name}" if HookLog.enabled?
            else
              methods.each(&hook_method)
            end
          end
        end
      end
    end
  end

  hook_loaded_code.call(config.builtin_hooks, true)
end