[RFA 20/23] Avoid some manual memory management in Python

Tom Tromey
2017-05-03T22:46:53Z

This changes a few places in the Python code to avoid manual memory
management, in favor of letting std::string do the work.

2017-05-02 Tom Tromey <tom@tromey.com>

* python/python.c (compute_python_string): Return std::string.
(gdbpy_eval_from_control_command): Update.
(do_start_initialization): Use std::string.
* python/py-varobj.c (py_varobj_iter_next): Use string_printf, not
xstrprintf.
* python/py-breakpoint.c (local_setattro): Use string_printf, not
xstrprintf.
---
gdb/ChangeLog | 10 ++++++++++
gdb/python/py-breakpoint.c | 15 ++++++---------
gdb/python/py-varobj.c | 9 ++++-----
gdb/python/python.c | 37 +++++++++----------------------------
4 files changed, 29 insertions(+), 42 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5e37c48..fc88456 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,15 @@
2017-05-02 Tom Tromey <tom@tromey.com>

+ * python/python.c (compute_python_string): Return std::string.
+ (gdbpy_eval_from_control_command): Update.
+ (do_start_initialization): Use std::string.
+ * python/py-varobj.c (py_varobj_iter_next): Use string_printf, not
+ xstrprintf.
+ * python/py-breakpoint.c (local_setattro): Use string_printf, not
+ xstrprintf.
+
+2017-05-02 Tom Tromey <tom@tromey.com>
+
* top.h (do_restore_instream_cleanup): Remove.
* top.c (do_restore_instream_cleanup): Remove.
(read_command_file): Use scoped_restore.
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 64de803..6156eb6 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -1026,15 +1026,12 @@ local_setattro (PyObject *self, PyObject *name, PyObject *v)
extlang = get_breakpoint_cond_ext_lang (obj->bp, EXT_LANG_PYTHON);
if (extlang != NULL)
{
- char *error_text;
-
- error_text
- = xstrprintf (_("Only one stop condition allowed. There is"
- " currently a %s stop condition defined for"
- " this breakpoint."),
- ext_lang_capitalized_name (extlang));
- PyErr_SetString (PyExc_RuntimeError, error_text);
- xfree (error_text);
+ std::string error_text
+ = string_printf (_("Only one stop condition allowed. There is"
+ " currently a %s stop condition defined for"
+ " this breakpoint."),
+ ext_lang_capitalized_name (extlang));
+ PyErr_SetString (PyExc_RuntimeError, error_text.c_str ());
return -1;
}
}
diff --git a/gdb/python/py-varobj.c b/gdb/python/py-varobj.c
index e858556..5f6ab64 100644
--- a/gdb/python/py-varobj.c
+++ b/gdb/python/py-varobj.c
@@ -71,7 +71,6 @@ py_varobj_iter_next (struct varobj_iter *self)
if (PyErr_ExceptionMatches (gdbpy_gdb_memory_error))
{
PyObject *type, *value, *trace;
- char *name_str;

PyErr_Fetch (&type, &value, &trace);
gdb::unique_xmalloc_ptr<char>
@@ -85,10 +84,10 @@ py_varobj_iter_next (struct varobj_iter *self)
return NULL;
}

- name_str = xstrprintf ("<error at %d>",
- self->next_raw_index++);
- item.reset (Py_BuildValue ("(ss)", name_str, value_str.get ()));
- xfree (name_str);
+ std::string name_str = string_printf ("<error at %d>",
+ self->next_raw_index++);
+ item.reset (Py_BuildValue ("(ss)", name_str.c_str (),
+ value_str.get ()));
if (item == NULL)
{
gdbpy_print_stack ();
diff --git a/gdb/python/python.c b/gdb/python/python.c
index be92f36..17ab04e 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -365,32 +365,19 @@ python_run_simple_file (FILE *file, const char *filename)
}

/* Given a command_line, return a command string suitable for passing
- to Python. Lines in the string are separated by newlines. The
- return value is allocated using xmalloc and the caller is
- responsible for freeing it. */
+ to Python. Lines in the string are separated by newlines. */

-static char *
+static std::string
compute_python_string (struct command_line *l)
{
struct command_line *iter;
- char *script = NULL;
- int size = 0;
- int here;
+ std::string script;

for (iter = l; iter; iter = iter->next)
- size += strlen (iter->line) + 1;
-
- script = (char *) xmalloc (size + 1);
- here = 0;
- for (iter = l; iter; iter = iter->next)
{
- int len = strlen (iter->line);
-
- strcpy (&script[here], iter->line);
- here += len;
- script[here++] = '\n';
+ script += iter->line;
+ script += "\n";
}
- script[here] = '\0';
return script;
}

@@ -402,16 +389,14 @@ gdbpy_eval_from_control_command (const struct extension_language_defn *extlang,
struct command_line *cmd)
{
int ret;
- char *script;

if (cmd->body_count != 1)
error (_("Invalid \"python\" block structure."));

gdbpy_enter enter_py (get_current_arch (), current_language);

- script = compute_python_string (cmd->body_list[0]);
- ret = PyRun_SimpleString (script);
- xfree (script);
+ std::string script = compute_python_string (cmd->body_list[0]);
+ ret = PyRun_SimpleString (script.c_str ());
if (ret)
error (_("Error while executing Python code."));
}
@@ -1532,7 +1517,6 @@ do_start_initialization ()
#ifdef IS_PY3K
int i;
size_t progsize, count;
- char *oldloc;
wchar_t *progname_copy;
#endif

@@ -1546,25 +1530,22 @@ do_start_initialization ()
progname = concat (ldirname (python_libdir).c_str (), SLASH_STRING, "bin",
SLASH_STRING, "python", (char *) NULL);
#ifdef IS_PY3K
- oldloc = xstrdup (setlocale (LC_ALL, NULL));
+ std::string oldloc = setlocale (LC_ALL, NULL);
setlocale (LC_ALL, "");
progsize = strlen (progname);
progname_copy = (wchar_t *) PyMem_Malloc ((progsize + 1) * sizeof (wchar_t));
if (!progname_copy)
{
- xfree (oldloc);
fprintf (stderr, "out of memory\n");
return false;
}
count = mbstowcs (progname_copy, progname, progsize + 1);
if (count == (size_t) -1)
{
- xfree (oldloc);
fprintf (stderr, "Could not convert python path to string\n");
return false;
}
- setlocale (LC_ALL, oldloc);
- xfree (oldloc);
+ setlocale (LC_ALL, oldloc.c_str ());

/* Note that Py_SetProgramName expects the string it is passed to
remain alive for the duration of the program's execution, so
--
2.9.3