# <!-- rdoc-file=trace_point.rb -->
# A class that provides the functionality of Kernel#set_trace_func in a nice
# Object-Oriented API.
#
# ## Example
#
# We can use TracePoint to gather information specifically for exceptions:
#
#     trace = TracePoint.new(:raise) do |tp|
#         p [tp.lineno, tp.event, tp.raised_exception]
#     end
#     #=> #<TracePoint:disabled>
#
#     trace.enable
#     #=> false
#
#     0 / 0
#     #=> [5, :raise, #<ZeroDivisionError: divided by 0>]
#
# ## Events
#
# If you don't specify the type of events you want to listen for, TracePoint
# will include all available events.
#
# **Note** do not depend on current event set, as this list is subject to
# change. Instead, it is recommended you specify the type of events you want to
# use.
#
# To filter what is traced, you can pass any of the following as `events`:
#
# `:line`
# :   execute an expression or statement on a new line
# `:class`
# :   start a class or module definition
# `:end`
# :   finish a class or module definition
# `:call`
# :   call a Ruby method
# `:return`
# :   return from a Ruby method
# `:c_call`
# :   call a C-language routine
# `:c_return`
# :   return from a C-language routine
# `:raise`
# :   raise an exception
# `:b_call`
# :   event hook at block entry
# `:b_return`
# :   event hook at block ending
# `:a_call`
# :   event hook at all calls (`call`, `b_call`, and `c_call`)
# `:a_return`
# :   event hook at all returns (`return`, `b_return`, and `c_return`)
# `:thread_begin`
# :   event hook at thread beginning
# `:thread_end`
# :   event hook at thread ending
# `:fiber_switch`
# :   event hook at fiber switch
# `:script_compiled`
# :   new Ruby code compiled (with `eval`, `load` or `require`)
#
class TracePoint < Object
  # <!--
  #   rdoc-file=trace_point.rb
  #   - TracePoint.new(*events) { |obj| block }         -> obj
  # -->
  # Returns a new TracePoint object, not enabled by default.
  #
  # Next, in order to activate the trace, you must use TracePoint#enable
  #
  #     trace = TracePoint.new(:call) do |tp|
  #         p [tp.lineno, tp.defined_class, tp.method_id, tp.event]
  #     end
  #     #=> #<TracePoint:disabled>
  #
  #     trace.enable
  #     #=> false
  #
  #     puts "Hello, TracePoint!"
  #     # ...
  #     # [48, IRB::Notifier::AbstractNotifier, :printf, :call]
  #     # ...
  #
  # When you want to deactivate the trace, you must use TracePoint#disable
  #
  #     trace.disable
  #
  # See TracePoint@Events for possible events and more information.
  #
  # A block must be given, otherwise an ArgumentError is raised.
  #
  # If the trace method isn't included in the given events filter, a RuntimeError
  # is raised.
  #
  #     TracePoint.trace(:line) do |tp|
  #         p tp.raised_exception
  #     end
  #     #=> RuntimeError: 'raised_exception' not supported by this event
  #
  # If the trace method is called outside block, a RuntimeError is raised.
  #
  #     TracePoint.trace(:line) do |tp|
  #       $tp = tp
  #     end
  #     $tp.lineno #=> access from outside (RuntimeError)
  #
  # Access from other threads is also forbidden.
  #
  def initialize: (*Symbol events) { (TracePoint tp) -> void } -> void

  # <!--
  #   rdoc-file=trace_point.rb
  #   - TracePoint.allow_reentry { block }
  # -->
  # In general, while a TracePoint callback is running, other registered callbacks
  # are not called to avoid confusion by reentrance. This method allows the
  # reentrance in a given block. This method should be used carefully, otherwise
  # the callback can be easily called infinitely.
  #
  # If this method is called when the reentrance is already allowed, it raises a
  # RuntimeError.
  #
  # **Example:**
  #
  #     # Without reentry
  #     # ---------------
  #
  #     line_handler = TracePoint.new(:line) do |tp|
  #       next if tp.path != __FILE__ # only work in this file
  #       puts "Line handler"
  #       binding.eval("class C; end")
  #     end.enable
  #
  #     class_handler = TracePoint.new(:class) do |tp|
  #       puts "Class handler"
  #     end.enable
  #
  #     class B
  #     end
  #
  #     # This script will print "Class handler" only once: when inside :line
  #     # handler, all other handlers are ignored
  #
  #     # With reentry
  #     # ------------
  #
  #     line_handler = TracePoint.new(:line) do |tp|
  #       next if tp.path != __FILE__ # only work in this file
  #       next if (__LINE__..__LINE__+3).cover?(tp.lineno) # don't be invoked from itself
  #       puts "Line handler"
  #       TracePoint.allow_reentry { binding.eval("class C; end") }
  #     end.enable
  #
  #     class_handler = TracePoint.new(:class) do |tp|
  #       puts "Class handler"
  #     end.enable
  #
  #     class B
  #     end
  #
  #     # This wil print "Class handler" twice: inside allow_reentry block in :line
  #     # handler, other handlers are enabled.
  #
  # Note that the example shows the principal effect of the method, but its
  # practical usage is for debugging libraries that sometimes require other
  # libraries hooks to not be affected by debugger being inside trace point
  # handling. Precautions should be taken against infinite recursion in this case
  # (note that we needed to filter out calls by itself from :line handler,
  # otherwise it will call itself infinitely).
  #
  def self.allow_reentry: () { () -> void } -> void

  # <!--
  #   rdoc-file=trace_point.rb
  #   - TracePoint.stat -> obj
  # -->
  # Returns internal information of TracePoint.
  #
  # The contents of the returned value are implementation specific. It may be
  # changed in future.
  #
  # This method is only for debugging TracePoint itself.
  #
  def self.stat: () -> untyped

  # <!--
  #   rdoc-file=trace_point.rb
  #   - TracePoint.trace(*events) { |obj| block }        -> obj
  # -->
  # A convenience method for TracePoint.new, that activates the trace
  # automatically.
  #
  #     trace = TracePoint.trace(:call) { |tp| [tp.lineno, tp.event] }
  #     #=> #<TracePoint:enabled>
  #
  #     trace.enabled? #=> true
  #
  def self.trace: (*Symbol events) { (TracePoint tp) -> void } -> TracePoint

  # <!--
  #   rdoc-file=trace_point.rb
  #   - binding()
  # -->
  # Return the generated binding object from event.
  #
  # Note that for `c_call` and `c_return` events, the method will return `nil`,
  # since C methods themselves do not have bindings.
  #
  def binding: () -> Binding?

  # <!--
  #   rdoc-file=trace_point.rb
  #   - callee_id()
  # -->
  # Return the called name of the method being called
  #
  def callee_id: () -> Symbol

  # <!--
  #   rdoc-file=trace_point.rb
  #   - defined_class()
  # -->
  # Return class or module of the method being called.
  #
  #     class C; def foo; end; end
  #     trace = TracePoint.new(:call) do |tp|
  #       p tp.defined_class #=> C
  #     end.enable do
  #       C.new.foo
  #     end
  #
  # If method is defined by a module, then that module is returned.
  #
  #     module M; def foo; end; end
  #     class C; include M; end;
  #     trace = TracePoint.new(:call) do |tp|
  #       p tp.defined_class #=> M
  #     end.enable do
  #       C.new.foo
  #     end
  #
  # **Note:** #defined_class returns singleton class.
  #
  # 6th block parameter of Kernel#set_trace_func passes original class of attached
  # by singleton class.
  #
  # **This is a difference between Kernel#set_trace_func and TracePoint.**
  #
  #     class C; def self.foo; end; end
  #     trace = TracePoint.new(:call) do |tp|
  #       p tp.defined_class #=> #<Class:C>
  #     end.enable do
  #       C.foo
  #     end
  #
  def defined_class: () -> Module

  # <!--
  #   rdoc-file=trace_point.rb
  #   - trace.disable               -> true or false
  #   - trace.disable { block } -> obj
  # -->
  # Deactivates the trace
  #
  # Return true if trace was enabled. Return false if trace was disabled.
  #
  #     trace.enabled?      #=> true
  #     trace.disable       #=> true (previous status)
  #     trace.enabled?      #=> false
  #     trace.disable       #=> false
  #
  # If a block is given, the trace will only be disable within the scope of the
  # block.
  #
  #     trace.enabled?
  #     #=> true
  #
  #     trace.disable do
  #         trace.enabled?
  #         # only disabled for this block
  #     end
  #
  #     trace.enabled?
  #     #=> true
  #
  # Note: You cannot access event hooks within the block.
  #
  #     trace.disable { p tp.lineno }
  #     #=> RuntimeError: access from outside
  #
  def disable: () -> bool
             | () { () -> void } -> void

  # <!--
  #   rdoc-file=trace_point.rb
  #   - trace.enable(target: nil, target_line: nil, target_thread: nil)    -> true or false
  #   - trace.enable(target: nil, target_line: nil, target_thread: :default) { block }  -> obj
  # -->
  # Activates the trace.
  #
  # Returns `true` if trace was enabled. Returns `false` if trace was disabled.
  #
  #     trace.enabled?  #=> false
  #     trace.enable    #=> false (previous state)
  #                     #   trace is enabled
  #     trace.enabled?  #=> true
  #     trace.enable    #=> true (previous state)
  #                     #   trace is still enabled
  #
  # If a block is given, the trace will only be enabled during the block call. If
  # target and target_line are both nil, then target_thread will default to the
  # current thread if a block is given.
  #
  #     trace.enabled?
  #     #=> false
  #
  #     trace.enable do
  #       trace.enabled?
  #       # only enabled for this block and thread
  #     end
  #
  #     trace.enabled?
  #     #=> false
  #
  # `target`, `target_line` and `target_thread` parameters are used to limit
  # tracing only to specified code objects. `target` should be a code object for
  # which RubyVM::InstructionSequence.of will return an instruction sequence.
  #
  #     t = TracePoint.new(:line) { |tp| p tp }
  #
  #     def m1
  #       p 1
  #     end
  #
  #     def m2
  #       p 2
  #     end
  #
  #     t.enable(target: method(:m1))
  #
  #     m1
  #     # prints #<TracePoint:line test.rb:4 in `m1'>
  #     m2
  #     # prints nothing
  #
  # Note: You cannot access event hooks within the `enable` block.
  #
  #     trace.enable { p tp.lineno }
  #     #=> RuntimeError: access from outside
  #
  def enable:     (?target: (Method | UnboundMethod | Proc)?, ?target_line: Integer?, ?target_thread: Thread?) -> bool
            | [R] (?target: (Method | UnboundMethod | Proc)?, ?target_line: Integer?, ?target_thread: Thread?) { () -> R } -> R

  # <!--
  #   rdoc-file=trace_point.rb
  #   - trace.enabled?          -> true or false
  # -->
  # The current status of the trace
  #
  def enabled?: () -> bool

  # <!--
  #   rdoc-file=trace_point.rb
  #   - event()
  # -->
  # Type of event
  #
  # See TracePoint@Events for more information.
  #
  def event: () -> ::Symbol

  # <!--
  #   rdoc-file=trace_point.rb
  #   - trace.inspect  -> string
  # -->
  # Return a string containing a human-readable TracePoint status.
  #
  def inspect: () -> String

  # <!--
  #   rdoc-file=trace_point.rb
  #   - lineno()
  # -->
  # Line number of the event
  #
  def lineno: () -> Integer

  # <!--
  #   rdoc-file=trace_point.rb
  #   - method_id()
  # -->
  # Return the name at the definition of the method being called
  #
  def method_id: () -> Symbol

  # <!--
  #   rdoc-file=trace_point.rb
  #   - path()
  # -->
  # Path of the file being run
  #
  def path: () -> String

  # <!--
  #   rdoc-file=trace_point.rb
  #   - parameters()
  # -->
  # Return the parameters definition of the method or block that the current hook
  # belongs to. Format is the same as for Method#parameters
  #
  def parameters: () -> ::Array[[ :req | :opt | :rest | :keyreq | :key | :keyrest | :block, Symbol ] | [ :rest | :keyrest ]]

  # <!--
  #   rdoc-file=trace_point.rb
  #   - raised_exception()
  # -->
  # Value from exception raised on the `:raise` event
  #
  def raised_exception: () -> untyped

  # <!--
  #   rdoc-file=trace_point.rb
  #   - return_value()
  # -->
  # Return value from `:return`, `c_return`, and `b_return` event
  #
  def return_value: () -> untyped

  # <!--
  #   rdoc-file=trace_point.rb
  #   - self()
  # -->
  # Return the trace object during event
  #
  # Same as the following, except it returns the correct object (the method
  # receiver) for `c_call` and `c_return` events:
  #
  #     trace.binding.eval('self')
  #
  def self: () -> untyped

  # <!--
  #   rdoc-file=trace_point.rb
  #   - eval_script()
  # -->
  # Compiled source code (String) on *eval methods on the `:script_compiled`
  # event. If loaded from a file, it will return nil.
  #
  def eval_script: () -> String?

  # <!--
  #   rdoc-file=trace_point.rb
  #   - instruction_sequence()
  # -->
  # Compiled instruction sequence represented by a RubyVM::InstructionSequence
  # instance on the `:script_compiled` event.
  #
  # Note that this method is MRI specific.
  #
  def instruction_sequence: () -> RubyVM::InstructionSequence
end
