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binutils-gdb/gdb/python/py-prettyprint.c

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/* Python pretty-printing
Copyright (C) 2008-2012 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 <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "exceptions.h"
#include "objfiles.h"
#include "symtab.h"
#include "language.h"
#include "valprint.h"
#include "python.h"
#ifdef HAVE_PYTHON
#include "python-internal.h"
/* Return type of print_string_repr. */
enum 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
};
/* 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 PyObject *
search_pp_list (PyObject *list, PyObject *value)
{
Py_ssize_t pp_list_size, list_index;
PyObject *function, *printer = NULL;
pp_list_size = PyList_Size (list);
for (list_index = 0; list_index < pp_list_size; list_index++)
{
function = PyList_GetItem (list, list_index);
if (! function)
return NULL;
/* Skip if disabled. */
if (PyObject_HasAttr (function, gdbpy_enabled_cst))
{
PyObject *attr = PyObject_GetAttr (function, gdbpy_enabled_cst);
int cmp;
if (!attr)
return NULL;
cmp = PyObject_IsTrue (attr);
if (cmp == -1)
return NULL;
if (!cmp)
continue;
}
printer = PyObject_CallFunctionObjArgs (function, value, NULL);
if (! printer)
return NULL;
else if (printer != Py_None)
return printer;
Py_DECREF (printer);
}
Py_RETURN_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)
{
PyObject *pp_list;
PyObject *function;
struct objfile *obj;
ALL_OBJFILES (obj)
{
PyObject *objf = objfile_to_objfile_object (obj);
if (!objf)
{
/* Ignore the error and continue. */
PyErr_Clear ();
continue;
}
pp_list = objfpy_get_printers (objf, NULL);
function = search_pp_list (pp_list, value);
Py_XDECREF (pp_list);
/* If there is an error in any objfile list, abort the search and exit. */
if (! function)
return NULL;
if (function != Py_None)
return function;
Py_DECREF (function);
}
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 PyObject *
find_pretty_printer_from_progspace (PyObject *value)
{
PyObject *pp_list;
PyObject *function;
PyObject *obj = pspace_to_pspace_object (current_program_space);
if (!obj)
return NULL;
pp_list = pspy_get_printers (obj, NULL);
function = search_pp_list (pp_list, value);
Py_XDECREF (pp_list);
return function;
}
/* 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 PyObject *
find_pretty_printer_from_gdb (PyObject *value)
{
PyObject *pp_list;
PyObject *function;
/* Fetch the global pretty printer list. */
if (! PyObject_HasAttrString (gdb_module, "pretty_printers"))
Py_RETURN_NONE;
pp_list = PyObject_GetAttrString (gdb_module, "pretty_printers");
if (pp_list == NULL || ! PyList_Check (pp_list))
{
Py_XDECREF (pp_list);
Py_RETURN_NONE;
}
function = search_pp_list (pp_list, value);
Py_XDECREF (pp_list);
return function;
}
/* 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 PyObject *
find_pretty_printer (PyObject *value)
{
PyObject *function;
/* Look at the pretty-printer list for each objfile
in the current program-space. */
function = find_pretty_printer_from_objfiles (value);
if (function == NULL || function != Py_None)
return function;
Py_DECREF (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;
Py_DECREF (function);
/* Look at the pretty-printer list in the gdb module. */
function = find_pretty_printer_from_gdb (value);
return function;
}
/* 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 PyObject *
pretty_print_one_value (PyObject *printer, struct value **out_value)
{
volatile struct gdb_exception except;
PyObject *result = NULL;
*out_value = NULL;
TRY_CATCH (except, RETURN_MASK_ALL)
{
result = PyObject_CallMethodObjArgs (printer, gdbpy_to_string_cst, NULL);
if (result)
{
if (! gdbpy_is_string (result) && ! gdbpy_is_lazy_string (result)
&& result != Py_None)
{
*out_value = convert_value_from_python (result);
if (PyErr_Occurred ())
*out_value = NULL;
Py_DECREF (result);
result = NULL;
}
}
}
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. */
char *
gdbpy_get_display_hint (PyObject *printer)
{
PyObject *hint;
char *result = NULL;
if (! PyObject_HasAttr (printer, gdbpy_display_hint_cst))
return NULL;
hint = PyObject_CallMethodObjArgs (printer, gdbpy_display_hint_cst, NULL);
if (hint)
{
if (gdbpy_is_string (hint))
{
result = python_string_to_host_string (hint);
if (result == NULL)
gdbpy_print_stack ();
}
Py_DECREF (hint);
}
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))
{
struct cleanup *cleanup;
PyObject *type, *value, *trace;
char *msg;
PyErr_Fetch (&type, &value, &trace);
cleanup = make_cleanup_py_decref (type);
make_cleanup_py_decref (value);
make_cleanup_py_decref (trace);
msg = gdbpy_exception_to_string (type, value);
make_cleanup (xfree, msg);
if (msg == NULL || *msg == '\0')
fprintf_filtered (stream, _("<error reading variable>"));
else
fprintf_filtered (stream, _("<error reading variable: %s>"), msg);
do_cleanups (cleanup);
}
else
gdbpy_print_stack ();
}
/* Helper for apply_val_pretty_printer which calls to_string and
formats the result. */
static enum 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;
PyObject *py_str = NULL;
enum string_repr_result result = string_repr_ok;
py_str = pretty_print_one_value (printer, &replacement);
if (py_str)
{
struct cleanup *cleanup = make_cleanup_py_decref (py_str);
if (py_str == Py_None)
result = string_repr_none;
else if (gdbpy_is_lazy_string (py_str))
{
CORE_ADDR addr;
long length;
struct type *type;
char *encoding = NULL;
struct value_print_options local_opts = *options;
make_cleanup (free_current_contents, &encoding);
gdbpy_extract_lazy_string (py_str, &addr, &type,
&length, &encoding);
local_opts.addressprint = 0;
val_print_string (type, encoding, addr, (int) length,
stream, &local_opts);
}
else
{
PyObject *string;
string = python_string_to_target_python_string (py_str);
if (string)
{
gdb_byte *output;
long length;
struct type *type;
make_cleanup_py_decref (string);
output = PyString_AsString (string);
length = PyString_Size (string);
type = builtin_type (gdbarch)->builtin_char;
if (hint && !strcmp (hint, "string"))
LA_PRINT_STRING (stream, type, output, length, NULL,
0, options);
else
fputs_filtered (output, stream);
}
else
{
result = string_repr_error;
print_stack_unless_memory_error (stream);
}
}
do_cleanups (cleanup);
}
else if (replacement)
{
struct value_print_options opts = *options;
opts.addressprint = 0;
common_val_print (replacement, stream, recurse, &opts, language);
}
else
{
result = string_repr_error;
print_stack_unless_memory_error (stream);
}
return result;
}
static void
py_restore_tstate (void *p)
{
PyFrameObject *frame = p;
PyThreadState *tstate = PyThreadState_GET ();
tstate->frame = frame;
}
/* Create a dummy PyFrameObject, needed to work around
a Python-2.4 bug with generators. */
static PyObject *
push_dummy_python_frame (void)
{
PyObject *empty_string, *null_tuple, *globals;
PyCodeObject *code;
PyFrameObject *frame;
PyThreadState *tstate;
empty_string = PyString_FromString ("");
if (!empty_string)
return NULL;
null_tuple = PyTuple_New (0);
if (!null_tuple)
{
Py_DECREF (empty_string);
return NULL;
}
code = PyCode_New (0, /* argcount */
0, /* nlocals */
0, /* stacksize */
0, /* flags */
empty_string, /* code */
null_tuple, /* consts */
null_tuple, /* names */
null_tuple, /* varnames */
#if PYTHON_API_VERSION >= 1010
null_tuple, /* freevars */
null_tuple, /* cellvars */
#endif
empty_string, /* filename */
empty_string, /* name */
1, /* firstlineno */
empty_string /* lnotab */
);
Py_DECREF (empty_string);
Py_DECREF (null_tuple);
if (!code)
return NULL;
globals = PyDict_New ();
if (!globals)
{
Py_DECREF (code);
return NULL;
}
tstate = PyThreadState_GET ();
frame = PyFrame_New (tstate, code, globals, NULL);
Py_DECREF (globals);
Py_DECREF (code);
if (!frame)
return NULL;
tstate->frame = frame;
make_cleanup (py_restore_tstate, frame->f_back);
return (PyObject *) frame;
}
/* Helper for 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;
PyObject *children, *iter, *frame;
struct cleanup *cleanups;
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");
children = PyObject_CallMethodObjArgs (printer, gdbpy_children_cst,
NULL);
if (! children)
{
print_stack_unless_memory_error (stream);
return;
}
cleanups = make_cleanup_py_decref (children);
iter = PyObject_GetIter (children);
if (!iter)
{
print_stack_unless_memory_error (stream);
goto done;
}
make_cleanup_py_decref (iter);
/* Use the prettyprint_arrays option if we are printing an array,
and the pretty option otherwise. */
if (is_array)
pretty = options->prettyprint_arrays;
else
{
if (options->pretty == Val_prettyprint)
pretty = 1;
else
pretty = options->prettyprint_structs;
}
/* Manufacture a dummy Python frame to work around Python 2.4 bug,
where it insists on having a non-NULL tstate->frame when
a generator is called. */
frame = push_dummy_python_frame ();
if (!frame)
{
gdbpy_print_stack ();
goto done;
}
make_cleanup_py_decref (frame);
done_flag = 0;
for (i = 0; i < options->print_max; ++i)
{
PyObject *py_v, *item = PyIter_Next (iter);
const char *name;
struct cleanup *inner_cleanup;
if (! item)
{
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 (! PyArg_ParseTuple (item, "sO", &name, &py_v))
{
gdbpy_print_stack ();
Py_DECREF (item);
continue;
}
inner_cleanup = make_cleanup_py_decref (item);
/* Print initial "{". 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)
fputs_filtered ("{", stream);
else
fputs_filtered (" = {", stream);
}
else if (! is_map || i % 2 == 0)
fputs_filtered (pretty ? "," : ", ", 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)
{
fputs_filtered ("\n", stream);
print_spaces_filtered (2 + 2 * recurse, stream);
}
else
wrap_here (n_spaces (2 + 2 *recurse));
}
if (is_map && i % 2 == 0)
fputs_filtered ("[", stream);
else if (is_array)
{
/* We print the index, not whatever the child method
returned as the name. */
if (options->print_array_indexes)
fprintf_filtered (stream, "[%d] = ", i);
}
else if (! is_map)
{
fputs_filtered (name, stream);
fputs_filtered (" = ", stream);
}
if (gdbpy_is_lazy_string (py_v))
{
CORE_ADDR addr;
struct type *type;
long length;
char *encoding = NULL;
struct value_print_options local_opts = *options;
make_cleanup (free_current_contents, &encoding);
gdbpy_extract_lazy_string (py_v, &addr, &type, &length, &encoding);
local_opts.addressprint = 0;
val_print_string (type, encoding, addr, (int) length, stream,
&local_opts);
do_cleanups (inner_cleanup);
}
else if (gdbpy_is_string (py_v))
{
gdb_byte *output;
output = python_string_to_host_string (py_v);
if (!output)
gdbpy_print_stack ();
else
{
fputs_filtered (output, stream);
xfree (output);
}
}
else
{
struct value *value = convert_value_from_python (py_v);
if (value == NULL)
{
gdbpy_print_stack ();
error (_("Error while executing Python code."));
}
else
common_val_print (value, stream, recurse + 1, options, language);
}
if (is_map && i % 2 == 0)
fputs_filtered ("] = ", stream);
do_cleanups (inner_cleanup);
}
if (i)
{
if (!done_flag)
{
if (pretty)
{
fputs_filtered ("\n", stream);
print_spaces_filtered (2 + 2 * recurse, stream);
}
fputs_filtered ("...", stream);
}
if (pretty)
{
fputs_filtered ("\n", stream);
print_spaces_filtered (2 * recurse, stream);
}
fputs_filtered ("}", stream);
}
done:
do_cleanups (cleanups);
}
int
apply_val_pretty_printer (struct type *type, const gdb_byte *valaddr,
int embedded_offset, CORE_ADDR address,
struct ui_file *stream, int recurse,
const struct value *val,
const struct value_print_options *options,
const struct language_defn *language)
{
struct gdbarch *gdbarch = get_type_arch (type);
PyObject *printer = NULL;
PyObject *val_obj = NULL;
struct value *value;
char *hint = NULL;
struct cleanup *cleanups;
int result = 0;
enum string_repr_result print_result;
/* No pretty-printer support for unavailable values. */
if (!value_bytes_available (val, embedded_offset, TYPE_LENGTH (type)))
return 0;
cleanups = ensure_python_env (gdbarch, language);
/* Instantiate the printer. */
if (valaddr)
valaddr += embedded_offset;
value = value_from_contents_and_address (type, valaddr,
address + embedded_offset);
set_value_component_location (value, val);
/* set_value_component_location resets the address, so we may
need to set it again. */
if (VALUE_LVAL (value) != lval_internalvar
&& VALUE_LVAL (value) != lval_internalvar_component
&& VALUE_LVAL (value) != lval_computed)
set_value_address (value, address + embedded_offset);
val_obj = value_to_value_object (value);
if (! val_obj)
goto done;
/* Find the constructor. */
printer = find_pretty_printer (val_obj);
Py_DECREF (val_obj);
make_cleanup_py_decref (printer);
if (! printer || printer == Py_None)
goto done;
/* If we are printing a map, we want some special formatting. */
hint = gdbpy_get_display_hint (printer);
make_cleanup (free_current_contents, &hint);
/* Print the section */
print_result = print_string_repr (printer, hint, stream, recurse,
options, language, gdbarch);
if (print_result != string_repr_error)
print_children (printer, hint, stream, recurse, options, language,
print_result == string_repr_none);
result = 1;
done:
if (PyErr_Occurred ())
print_stack_unless_memory_error (stream);
do_cleanups (cleanups);
return result;
}
/* 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. */
PyObject *
apply_varobj_pretty_printer (PyObject *printer_obj,
struct value **replacement,
struct ui_file *stream)
{
PyObject *py_str = NULL;
*replacement = NULL;
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. */
PyObject *
gdbpy_get_varobj_pretty_printer (struct value *value)
{
PyObject *val_obj;
PyObject *pretty_printer = NULL;
volatile struct gdb_exception except;
TRY_CATCH (except, RETURN_MASK_ALL)
{
value = value_copy (value);
}
GDB_PY_HANDLE_EXCEPTION (except);
val_obj = value_to_value_object (value);
if (! val_obj)
return NULL;
pretty_printer = find_pretty_printer (val_obj);
Py_DECREF (val_obj);
return pretty_printer;
}
/* 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;
PyObject *cons;
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;
}
cons = find_pretty_printer (val_obj);
return cons;
}
#else /* HAVE_PYTHON */
int
apply_val_pretty_printer (struct type *type, const gdb_byte *valaddr,
int embedded_offset, CORE_ADDR address,
struct ui_file *stream, int recurse,
const struct value *val,
const struct value_print_options *options,
const struct language_defn *language)
{
return 0;
}
#endif /* HAVE_PYTHON */
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