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

   1 # Copyright 2022-2024 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
  18 # This is deprecated in 3.9, but required in older versions.
  19 from typing import Optional
  20
  21 from .frames import select_frame
  22 from .server import capability, request, client_bool_capability
  23 from .startup import in_gdb_thread, parse_and_eval, DAPException
  24 from .varref import find_variable, VariableReference, apply_format
  25
  26
  27 class EvaluateResult(VariableReference):
  28     def __init__(self, value):
  29         super().__init__(None, value, "result")
  30
  31
  32 # Helper function to evaluate an expression in a certain frame.
  33 @in_gdb_thread
  34 def _evaluate(expr, frame_id, value_format):
  35     with apply_format(value_format):
  36         global_context = True
  37         if frame_id is not None:
  38             select_frame(frame_id)
  39             global_context = False
  40         val = parse_and_eval(expr, global_context=global_context)
  41         ref = EvaluateResult(val)
  42         return ref.to_object()
  43
  44
  45 # Like _evaluate but ensure that the expression cannot cause side
  46 # effects.
  47 @in_gdb_thread
  48 def _eval_for_hover(expr, frame_id, value_format):
  49     with gdb.with_parameter("may-write-registers", "off"):
  50         with gdb.with_parameter("may-write-memory", "off"):
  51             with gdb.with_parameter("may-call-functions", "off"):
  52                 return _evaluate(expr, frame_id, value_format)
  53
  54
  55 class _SetResult(VariableReference):
  56     def __init__(self, value):
  57         super().__init__(None, value, "value")
  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         select_frame(frame_id)
  65     val = gdb.execute(command, from_tty=True, to_string=True)
  66     return {
  67         "result": val,
  68         "variablesReference": 0,
  69     }
  70
  71
  72 @request("evaluate")
  73 @capability("supportsEvaluateForHovers")
  74 @capability("supportsValueFormattingOptions")
  75 def eval_request(
  76     *,
  77     expression: str,
  78     frameId: Optional[int] = None,
  79     context: str = "variables",
  80     format=None,
  81     **args,
  82 ):
  83     if context in ("watch", "variables"):
  84         # These seem to be expression-like.
  85         return _evaluate(expression, frameId, format)
  86     elif context == "hover":
  87         return _eval_for_hover(expression, frameId, format)
  88     elif context == "repl":
  89         # Ignore the format for repl evaluation.
  90         return _repl(expression, frameId)
  91     else:
  92         raise DAPException('unknown evaluate context "' + context + '"')
  93
  94
  95 @request("variables")
  96 # Note that we ignore the 'filter' field.  That seems to be
  97 # specific to javascript.
  98 def variables(
  99     *, variablesReference: int, start: int = 0, count: int = 0, format=None, **args
 100 ):
 101     # This behavior was clarified here:
 102     # https://github.com/microsoft/debug-adapter-protocol/pull/394
 103     if not client_bool_capability("supportsVariablePaging"):
 104         start = 0
 105         count = 0
 106     with apply_format(format):
 107         var = find_variable(variablesReference)
 108         children = var.fetch_children(start, count)
 109         return {"variables": [x.to_object() for x in children]}
 110
 111
 112 @capability("supportsSetExpression")
 113 @request("setExpression")
 114 def set_expression(
 115     *, expression: str, value: str, frameId: Optional[int] = None, format=None, **args
 116 ):
 117     with apply_format(format):
 118         global_context = True
 119         if frameId is not None:
 120             select_frame(frameId)
 121             global_context = False
 122         lhs = parse_and_eval(expression, global_context=global_context)
 123         rhs = parse_and_eval(value, global_context=global_context)
 124         lhs.assign(rhs)
 125         return _SetResult(lhs).to_object()
 126
 127
 128 @capability("supportsSetVariable")
 129 @request("setVariable")
 130 def set_variable(
 131     *, variablesReference: int, name: str, value: str, format=None, **args
 132 ):
 133     with apply_format(format):
 134         var = find_variable(variablesReference)
 135         lhs = var.find_child_by_name(name)
 136         rhs = parse_and_eval(value)
 137         lhs.assign(rhs)
 138         return lhs.to_object()