gdb/python/lib/gdb/dap/evaluate.py

   1 # Copyright 2022, 2023 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 import gdb
  17 import gdb.printing
  18
  19 # This is deprecated in 3.9, but required in older versions.
  20 from typing import Optional
  21
  22 from .frames import frame_for_id
  23 from .server import capability, request
  24 from .startup import send_gdb_with_response, in_gdb_thread
  25 from .varref import find_variable, VariableReference
  26
  27
  28 class EvaluateResult(VariableReference):
  29     def __init__(self, value):
  30         super().__init__(None, value, "result")
  31
  32
  33 # Helper function to evaluate an expression in a certain frame.
  34 @in_gdb_thread
  35 def _evaluate(expr, frame_id):
  36     global_context = True
  37     if frame_id is not None:
  38         frame = frame_for_id(frame_id)
  39         frame.select()
  40         global_context = False
  41     val = gdb.parse_and_eval(expr, global_context=global_context)
  42     ref = EvaluateResult(val)
  43     return ref.to_object()
  44
  45
  46 # Helper function to perform an assignment.
  47 @in_gdb_thread
  48 def _set_expression(expression, value, frame_id):
  49     global_context = True
  50     if frame_id is not None:
  51         frame = frame_for_id(frame_id)
  52         frame.select()
  53         global_context = False
  54     lhs = gdb.parse_and_eval(expression, global_context=global_context)
  55     rhs = gdb.parse_and_eval(value, global_context=global_context)
  56     lhs.assign(rhs)
  57     return EvaluateResult(lhs).to_object()
  58
  59
  60 # Helper function to evaluate a gdb command in a certain frame.
  61 @in_gdb_thread
  62 def _repl(command, frame_id):
  63     if frame_id is not None:
  64         frame = frame_for_id(frame_id)
  65         frame.select()
  66     val = gdb.execute(command, from_tty=True, to_string=True)
  67     return {
  68         "result": val,
  69         "variablesReference": 0,
  70     }
  71
  72
  73 # FIXME supportsVariableType handling
  74 @request("evaluate")
  75 def eval_request(
  76     *,
  77     expression: str,
  78     frameId: Optional[int] = None,
  79     context: str = "variables",
  80     **args,
  81 ):
  82     if context in ("watch", "variables"):
  83         # These seem to be expression-like.
  84         return send_gdb_with_response(lambda: _evaluate(expression, frameId))
  85     elif context == "repl":
  86         return send_gdb_with_response(lambda: _repl(expression, frameId))
  87     else:
  88         raise Exception(f'unknown evaluate context "{context}"')
  89
  90
  91 @in_gdb_thread
  92 def _variables(ref, start, count):
  93     var = find_variable(ref)
  94     children = var.fetch_children(start, count)
  95     return [x.to_object() for x in children]
  96
  97
  98 @request("variables")
  99 # Note that we ignore the 'filter' field.  That seems to be
 100 # specific to javascript.
 101 def variables(*, variablesReference: int, start: int = 0, count: int = 0, **args):
 102     result = send_gdb_with_response(
 103         lambda: _variables(variablesReference, start, count)
 104     )
 105     return {"variables": result}
 106
 107
 108 @capability("supportsSetExpression")
 109 @request("setExpression")
 110 def set_expression(
 111     *, expression: str, value: str, frameId: Optional[int] = None, **args
 112 ):
 113     return send_gdb_with_response(lambda: _set_expression(expression, value, frameId))