/* Python pretty-printing Copyright (C) 2008-2023 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "defs.h" #include "objfiles.h" #include "symtab.h" #include "language.h" #include "valprint.h" #include "extension-priv.h" #include "python.h" #include "python-internal.h" #include "cli/cli-style.h" extern PyTypeObject printer_object_type; /* Return type of print_string_repr. */ enum gdbpy_string_repr_result { /* The string method returned None. */ string_repr_none, /* The string method had an error. */ string_repr_error, /* Everything ok. */ string_repr_ok }; /* If non-null, points to options that are in effect while printing. */ const struct value_print_options *gdbpy_current_print_options; /* Helper function for find_pretty_printer which iterates over a list, calls each function and inspects output. This will return a printer object if one recognizes VALUE. If no printer is found, it will return None. On error, it will set the Python error and return NULL. */ static gdbpy_ref<> search_pp_list (PyObject *list, PyObject *value) { Py_ssize_t pp_list_size, list_index; pp_list_size = PyList_Size (list); for (list_index = 0; list_index < pp_list_size; list_index++) { PyObject *function = PyList_GetItem (list, list_index); if (! function) return NULL; /* Skip if disabled. */ if (PyObject_HasAttr (function, gdbpy_enabled_cst)) { gdbpy_ref<> attr (PyObject_GetAttr (function, gdbpy_enabled_cst)); int cmp; if (attr == NULL) return NULL; cmp = PyObject_IsTrue (attr.get ()); if (cmp == -1) return NULL; if (!cmp) continue; } gdbpy_ref<> printer (PyObject_CallFunctionObjArgs (function, value, NULL)); if (printer == NULL) return NULL; else if (printer != Py_None) return printer; } return gdbpy_ref<>::new_reference (Py_None); } /* Subroutine of find_pretty_printer to simplify it. Look for a pretty-printer to print VALUE in all objfiles. The result is NULL if there's an error and the search should be terminated. The result is Py_None, suitably inc-ref'd, if no pretty-printer was found. Otherwise the result is the pretty-printer function, suitably inc-ref'd. */ static PyObject * find_pretty_printer_from_objfiles (PyObject *value) { for (objfile *obj : current_program_space->objfiles ()) { gdbpy_ref<> objf = objfile_to_objfile_object (obj); if (objf == NULL) { /* Ignore the error and continue. */ PyErr_Clear (); continue; } gdbpy_ref<> pp_list (objfpy_get_printers (objf.get (), NULL)); gdbpy_ref<> function (search_pp_list (pp_list.get (), value)); /* If there is an error in any objfile list, abort the search and exit. */ if (function == NULL) return NULL; if (function != Py_None) return function.release (); } Py_RETURN_NONE; } /* Subroutine of find_pretty_printer to simplify it. Look for a pretty-printer to print VALUE in the current program space. The result is NULL if there's an error and the search should be terminated. The result is Py_None, suitably inc-ref'd, if no pretty-printer was found. Otherwise the result is the pretty-printer function, suitably inc-ref'd. */ static gdbpy_ref<> find_pretty_printer_from_progspace (PyObject *value) { gdbpy_ref<> obj = pspace_to_pspace_object (current_program_space); if (obj == NULL) return NULL; gdbpy_ref<> pp_list (pspy_get_printers (obj.get (), NULL)); return search_pp_list (pp_list.get (), value); } /* Subroutine of find_pretty_printer to simplify it. Look for a pretty-printer to print VALUE in the gdb module. The result is NULL if there's an error and the search should be terminated. The result is Py_None, suitably inc-ref'd, if no pretty-printer was found. Otherwise the result is the pretty-printer function, suitably inc-ref'd. */ static gdbpy_ref<> find_pretty_printer_from_gdb (PyObject *value) { /* Fetch the global pretty printer list. */ if (gdb_python_module == NULL || ! PyObject_HasAttrString (gdb_python_module, "pretty_printers")) return gdbpy_ref<>::new_reference (Py_None); gdbpy_ref<> pp_list (PyObject_GetAttrString (gdb_python_module, "pretty_printers")); if (pp_list == NULL || ! PyList_Check (pp_list.get ())) return gdbpy_ref<>::new_reference (Py_None); return search_pp_list (pp_list.get (), value); } /* Find the pretty-printing constructor function for VALUE. If no pretty-printer exists, return None. If one exists, return a new reference. On error, set the Python error and return NULL. */ static gdbpy_ref<> find_pretty_printer (PyObject *value) { /* Look at the pretty-printer list for each objfile in the current program-space. */ gdbpy_ref<> function (find_pretty_printer_from_objfiles (value)); if (function == NULL || function != Py_None) return function; /* Look at the pretty-printer list for the current program-space. */ function = find_pretty_printer_from_progspace (value); if (function == NULL || function != Py_None) return function; /* Look at the pretty-printer list in the gdb module. */ return find_pretty_printer_from_gdb (value); } /* Pretty-print a single value, via the printer object PRINTER. If the function returns a string, a PyObject containing the string is returned. If the function returns Py_NONE that means the pretty printer returned the Python None as a value. Otherwise, if the function returns a value, *OUT_VALUE is set to the value, and NULL is returned. On error, *OUT_VALUE is set to NULL, NULL is returned, with a python exception set. */ static gdbpy_ref<> pretty_print_one_value (PyObject *printer, struct value **out_value) { gdbpy_ref<> result; *out_value = NULL; try { if (!PyObject_HasAttr (printer, gdbpy_to_string_cst)) result = gdbpy_ref<>::new_reference (Py_None); else { result.reset (PyObject_CallMethodObjArgs (printer, gdbpy_to_string_cst, NULL)); if (result != NULL) { if (! gdbpy_is_string (result.get ()) && ! gdbpy_is_lazy_string (result.get ()) && result != Py_None) { *out_value = convert_value_from_python (result.get ()); if (PyErr_Occurred ()) *out_value = NULL; result = NULL; } } } } catch (const gdb_exception &except) { } return result; } /* Return the display hint for the object printer, PRINTER. Return NULL if there is no display_hint method, or if the method did not return a string. On error, print stack trace and return NULL. On success, return an xmalloc()d string. */ gdb::unique_xmalloc_ptr gdbpy_get_display_hint (PyObject *printer) { gdb::unique_xmalloc_ptr result; if (! PyObject_HasAttr (printer, gdbpy_display_hint_cst)) return NULL; gdbpy_ref<> hint (PyObject_CallMethodObjArgs (printer, gdbpy_display_hint_cst, NULL)); if (hint != NULL) { if (gdbpy_is_string (hint.get ())) { result = python_string_to_host_string (hint.get ()); if (result == NULL) gdbpy_print_stack (); } } else gdbpy_print_stack (); return result; } /* A wrapper for gdbpy_print_stack that ignores MemoryError. */ static void print_stack_unless_memory_error (struct ui_file *stream) { if (PyErr_ExceptionMatches (gdbpy_gdb_memory_error)) { gdbpy_err_fetch fetched_error; gdb::unique_xmalloc_ptr msg = fetched_error.to_string (); if (msg == NULL || *msg == '\0') fprintf_styled (stream, metadata_style.style (), _("")); else fprintf_styled (stream, metadata_style.style (), _(""), msg.get ()); } else gdbpy_print_stack (); } /* Helper for gdbpy_apply_val_pretty_printer which calls to_string and formats the result. */ static enum gdbpy_string_repr_result print_string_repr (PyObject *printer, const char *hint, struct ui_file *stream, int recurse, const struct value_print_options *options, const struct language_defn *language, struct gdbarch *gdbarch) { struct value *replacement = NULL; enum gdbpy_string_repr_result result = string_repr_ok; gdbpy_ref<> py_str = pretty_print_one_value (printer, &replacement); if (py_str != NULL) { if (py_str == Py_None) result = string_repr_none; else if (gdbpy_is_lazy_string (py_str.get ())) { CORE_ADDR addr; long length; struct type *type; gdb::unique_xmalloc_ptr encoding; struct value_print_options local_opts = *options; gdbpy_extract_lazy_string (py_str.get (), &addr, &type, &length, &encoding); local_opts.addressprint = false; val_print_string (type, encoding.get (), addr, (int) length, stream, &local_opts); } else { gdbpy_ref<> string = python_string_to_target_python_string (py_str.get ()); if (string != NULL) { char *output; long length; struct type *type; output = PyBytes_AS_STRING (string.get ()); length = PyBytes_GET_SIZE (string.get ()); type = builtin_type (gdbarch)->builtin_char; if (hint && !strcmp (hint, "string")) language->printstr (stream, type, (gdb_byte *) output, length, NULL, 0, options); else gdb_puts (output, stream); } else { result = string_repr_error; print_stack_unless_memory_error (stream); } } } else if (replacement) { struct value_print_options opts = *options; opts.addressprint = false; common_val_print (replacement, stream, recurse, &opts, language); } else { result = string_repr_error; print_stack_unless_memory_error (stream); } return result; } /* Helper for gdbpy_apply_val_pretty_printer that formats children of the printer, if any exist. If is_py_none is true, then nothing has been printed by to_string, and format output accordingly. */ static void print_children (PyObject *printer, const char *hint, struct ui_file *stream, int recurse, const struct value_print_options *options, const struct language_defn *language, int is_py_none) { int is_map, is_array, done_flag, pretty; unsigned int i; if (! PyObject_HasAttr (printer, gdbpy_children_cst)) return; /* If we are printing a map or an array, we want some special formatting. */ is_map = hint && ! strcmp (hint, "map"); is_array = hint && ! strcmp (hint, "array"); gdbpy_ref<> children (PyObject_CallMethodObjArgs (printer, gdbpy_children_cst, NULL)); if (children == NULL) { print_stack_unless_memory_error (stream); return; } gdbpy_ref<> iter (PyObject_GetIter (children.get ())); if (iter == NULL) { print_stack_unless_memory_error (stream); return; } /* Use the prettyformat_arrays option if we are printing an array, and the pretty option otherwise. */ if (is_array) pretty = options->prettyformat_arrays; else { if (options->prettyformat == Val_prettyformat) pretty = 1; else pretty = options->prettyformat_structs; } done_flag = 0; for (i = 0; i < options->print_max; ++i) { PyObject *py_v; const char *name; gdbpy_ref<> item (PyIter_Next (iter.get ())); if (item == NULL) { if (PyErr_Occurred ()) print_stack_unless_memory_error (stream); /* Set a flag so we can know whether we printed all the available elements. */ else done_flag = 1; break; } if (! PyTuple_Check (item.get ()) || PyTuple_Size (item.get ()) != 2) { PyErr_SetString (PyExc_TypeError, _("Result of children iterator not a tuple" " of two elements.")); gdbpy_print_stack (); continue; } if (! PyArg_ParseTuple (item.get (), "sO", &name, &py_v)) { /* The user won't necessarily get a stack trace here, so provide more context. */ if (gdbpy_print_python_errors_p ()) gdb_printf (gdb_stderr, _("Bad result from children iterator.\n")); gdbpy_print_stack (); continue; } /* Print initial "=" to separate print_string_repr output and children. For other elements, there are three cases: 1. Maps. Print a "," after each value element. 2. Arrays. Always print a ",". 3. Other. Always print a ",". */ if (i == 0) { if (!is_py_none) gdb_puts (" = ", stream); } else if (! is_map || i % 2 == 0) gdb_puts (pretty ? "," : ", ", stream); /* Skip printing children if max_depth has been reached. This check is performed after print_string_repr and the "=" separator so that these steps are not skipped if the variable is located within the permitted depth. */ if (val_print_check_max_depth (stream, recurse, options, language)) return; else if (i == 0) /* Print initial "{" to bookend children. */ gdb_puts ("{", stream); /* In summary mode, we just want to print "= {...}" if there is a value. */ if (options->summary) { /* This increment tricks the post-loop logic to print what we want. */ ++i; /* Likewise. */ pretty = 0; break; } if (! is_map || i % 2 == 0) { if (pretty) { gdb_puts ("\n", stream); print_spaces (2 + 2 * recurse, stream); } else stream->wrap_here (2 + 2 *recurse); } if (is_map && i % 2 == 0) gdb_puts ("[", stream); else if (is_array) { /* We print the index, not whatever the child method returned as the name. */ if (options->print_array_indexes) gdb_printf (stream, "[%d] = ", i); } else if (! is_map) { gdb_puts (name, stream); gdb_puts (" = ", stream); } if (gdbpy_is_lazy_string (py_v)) { CORE_ADDR addr; struct type *type; long length; gdb::unique_xmalloc_ptr encoding; struct value_print_options local_opts = *options; gdbpy_extract_lazy_string (py_v, &addr, &type, &length, &encoding); local_opts.addressprint = false; val_print_string (type, encoding.get (), addr, (int) length, stream, &local_opts); } else if (gdbpy_is_string (py_v)) { gdb::unique_xmalloc_ptr output; output = python_string_to_host_string (py_v); if (!output) gdbpy_print_stack (); else gdb_puts (output.get (), stream); } else { struct value *value = convert_value_from_python (py_v); if (value == NULL) { gdbpy_print_stack (); error (_("Error while executing Python code.")); } else { /* When printing the key of a map we allow one additional level of depth. This means the key will print before the value does. */ struct value_print_options opt = *options; if (is_map && i % 2 == 0 && opt.max_depth != -1 && opt.max_depth < INT_MAX) ++opt.max_depth; common_val_print (value, stream, recurse + 1, &opt, language); } } if (is_map && i % 2 == 0) gdb_puts ("] = ", stream); } if (i) { if (!done_flag) { if (pretty) { gdb_puts ("\n", stream); print_spaces (2 + 2 * recurse, stream); } gdb_puts ("...", stream); } if (pretty) { gdb_puts ("\n", stream); print_spaces (2 * recurse, stream); } gdb_puts ("}", stream); } } enum ext_lang_rc gdbpy_apply_val_pretty_printer (const struct extension_language_defn *extlang, struct value *value, struct ui_file *stream, int recurse, const struct value_print_options *options, const struct language_defn *language) { struct type *type = value->type (); struct gdbarch *gdbarch = type->arch (); enum gdbpy_string_repr_result print_result; if (value->lazy ()) value->fetch_lazy (); /* No pretty-printer support for unavailable values. */ if (!value->bytes_available (0, type->length ())) return EXT_LANG_RC_NOP; if (!gdb_python_initialized) return EXT_LANG_RC_NOP; gdbpy_enter enter_py (gdbarch, language); gdbpy_ref<> val_obj (value_to_value_object (value)); if (val_obj == NULL) { print_stack_unless_memory_error (stream); return EXT_LANG_RC_ERROR; } /* Find the constructor. */ gdbpy_ref<> printer (find_pretty_printer (val_obj.get ())); if (printer == NULL) { print_stack_unless_memory_error (stream); return EXT_LANG_RC_ERROR; } if (printer == Py_None) return EXT_LANG_RC_NOP; scoped_restore set_options = make_scoped_restore (&gdbpy_current_print_options, options); /* If we are printing a map, we want some special formatting. */ gdb::unique_xmalloc_ptr hint (gdbpy_get_display_hint (printer.get ())); /* Print the section */ print_result = print_string_repr (printer.get (), hint.get (), stream, recurse, options, language, gdbarch); if (print_result != string_repr_error) print_children (printer.get (), hint.get (), stream, recurse, options, language, print_result == string_repr_none); if (PyErr_Occurred ()) print_stack_unless_memory_error (stream); return EXT_LANG_RC_OK; } /* Apply a pretty-printer for the varobj code. PRINTER_OBJ is the print object. It must have a 'to_string' method (but this is checked by varobj, not here) which takes no arguments and returns a string. The printer will return a value and in the case of a Python string being returned, this function will return a PyObject containing the string. For any other type, *REPLACEMENT is set to the replacement value and this function returns NULL. On error, *REPLACEMENT is set to NULL and this function also returns NULL. */ gdbpy_ref<> apply_varobj_pretty_printer (PyObject *printer_obj, struct value **replacement, struct ui_file *stream, const value_print_options *opts) { scoped_restore set_options = make_scoped_restore (&gdbpy_current_print_options, opts); *replacement = NULL; gdbpy_ref<> py_str = pretty_print_one_value (printer_obj, replacement); if (*replacement == NULL && py_str == NULL) print_stack_unless_memory_error (stream); return py_str; } /* Find a pretty-printer object for the varobj module. Returns a new reference to the object if successful; returns NULL if not. VALUE is the value for which a printer tests to determine if it can pretty-print the value. */ gdbpy_ref<> gdbpy_get_varobj_pretty_printer (struct value *value) { gdbpy_ref<> val_obj (value_to_value_object (value)); if (val_obj == NULL) return NULL; return find_pretty_printer (val_obj.get ()); } /* A Python function which wraps find_pretty_printer and instantiates the resulting class. This accepts a Value argument and returns a pretty printer instance, or None. This function is useful as an argument to the MI command -var-set-visualizer. */ PyObject * gdbpy_default_visualizer (PyObject *self, PyObject *args) { PyObject *val_obj; struct value *value; if (! PyArg_ParseTuple (args, "O", &val_obj)) return NULL; value = value_object_to_value (val_obj); if (! value) { PyErr_SetString (PyExc_TypeError, _("Argument must be a gdb.Value.")); return NULL; } return find_pretty_printer (val_obj).release (); } /* Helper function to set a boolean in a dictionary. */ static int set_boolean (PyObject *dict, const char *name, bool val) { gdbpy_ref<> val_obj (PyBool_FromLong (val)); if (val_obj == nullptr) return -1; return PyDict_SetItemString (dict, name, val_obj.get ()); } /* Helper function to set an integer in a dictionary. */ static int set_unsigned (PyObject *dict, const char *name, unsigned int val) { gdbpy_ref<> val_obj = gdb_py_object_from_ulongest (val); if (val_obj == nullptr) return -1; return PyDict_SetItemString (dict, name, val_obj.get ()); } /* Implement gdb.print_options. */ PyObject * gdbpy_print_options (PyObject *unused1, PyObject *unused2) { gdbpy_ref<> result (PyDict_New ()); if (result == nullptr) return nullptr; value_print_options opts; gdbpy_get_print_options (&opts); if (set_boolean (result.get (), "raw", opts.raw) < 0 || set_boolean (result.get (), "pretty_arrays", opts.prettyformat_arrays) < 0 || set_boolean (result.get (), "pretty_structs", opts.prettyformat_structs) < 0 || set_boolean (result.get (), "array_indexes", opts.print_array_indexes) < 0 || set_boolean (result.get (), "symbols", opts.symbol_print) < 0 || set_boolean (result.get (), "unions", opts.unionprint) < 0 || set_boolean (result.get (), "address", opts.addressprint) < 0 || set_boolean (result.get (), "deref_refs", opts.deref_ref) < 0 || set_boolean (result.get (), "actual_objects", opts.objectprint) < 0 || set_boolean (result.get (), "static_members", opts.static_field_print) < 0 || set_boolean (result.get (), "deref_refs", opts.deref_ref) < 0 || set_boolean (result.get (), "nibbles", opts.nibblesprint) < 0 || set_boolean (result.get (), "summary", opts.summary) < 0 || set_unsigned (result.get (), "max_elements", opts.print_max) < 0 || set_unsigned (result.get (), "max_depth", opts.max_depth) < 0 || set_unsigned (result.get (), "repeat_threshold", opts.repeat_count_threshold) < 0) return nullptr; if (opts.format != 0) { char str[2] = { (char) opts.format, 0 }; gdbpy_ref<> fmtstr = host_string_to_python_string (str); if (fmtstr == nullptr) return nullptr; if (PyDict_SetItemString (result.get (), "format", fmtstr.get ()) < 0) return nullptr; } return result.release (); } /* Helper function that either finds the prevailing print options, or calls get_user_print_options. */ void gdbpy_get_print_options (value_print_options *opts) { if (gdbpy_current_print_options != nullptr) *opts = *gdbpy_current_print_options; else get_user_print_options (opts); } /* A ValuePrinter is just a "tag", so it has no state other than that required by Python. */ struct printer_object { PyObject_HEAD }; /* The ValuePrinter type object. */ PyTypeObject printer_object_type = { PyVarObject_HEAD_INIT (NULL, 0) "gdb.ValuePrinter", /*tp_name*/ sizeof (printer_object), /*tp_basicsize*/ 0, /*tp_itemsize*/ 0, /*tp_dealloc*/ 0, /*tp_print*/ 0, /*tp_getattr*/ 0, /*tp_setattr*/ 0, /*tp_compare*/ 0, /*tp_repr*/ 0, /*tp_as_number*/ 0, /*tp_as_sequence*/ 0, /*tp_as_mapping*/ 0, /*tp_hash*/ 0, /*tp_call*/ 0, /*tp_str*/ 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/ "GDB value printer object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ 0, /* tp_iter */ 0, /* tp_iternext */ 0, /* tp_methods */ 0, /* tp_members */ 0, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ 0, /* tp_descr_get */ 0, /* tp_descr_set */ 0, /* tp_dictoffset */ 0, /* tp_init */ 0, /* tp_alloc */ PyType_GenericNew, /* tp_new */ }; /* Set up the ValuePrinter type. */ static int gdbpy_initialize_prettyprint () { if (PyType_Ready (&printer_object_type) < 0) return -1; return gdb_pymodule_addobject (gdb_module, "ValuePrinter", (PyObject *) &printer_object_type); } GDBPY_INITIALIZE_FILE (gdbpy_initialize_prettyprint);