From 07ca107c2d958b45633ef0cdcce7219a95f0cf01 Mon Sep 17 00:00:00 2001 From: Doug Evans Date: Tue, 25 May 2010 15:27:17 +0000 Subject: [PATCH] Add python gdb.GdbError and gdb.string_to_argv. * NEWS: Document them. * python/py-cmd.c (cmdpy_function): Don't print a traceback if the exception is gdb.GdbError. Print a second traceback if there's an error computing the error message. (gdbpy_string_to_argv): New function. * python/py-utils.c (gdbpy_obj_to_string): New function. (gdbpy_exception_to_string): New function. * python/python-internal.h (gdbpy_string_to_argv): Declare. (gdbpy_obj_to_string, gdbpy_exception_to_string): Declare. (gdbpy_gdberror_exc): Declare. * python/python.c (gdbpy_gdberror_exc): New global. (_initialize_python): Initialize gdbpy_gdberror_exc and create gdb.GdbError. (GdbMethods): Add string_to_argv. doc/ * gdb.texinfo (Exception Handling): Document gdb.GdbError. (Commands In Python): Document gdb.string_to_argv. testsuite/ * gdb.python/py-cmd.exp: Add tests for gdb.GdbError and gdb.string_to_argv. --- gdb/ChangeLog | 18 +++++++ gdb/NEWS | 4 +- gdb/doc/ChangeLog | 5 ++ gdb/doc/gdb.texinfo | 38 +++++++++++++++ gdb/python/py-cmd.c | 95 +++++++++++++++++++++++++++++++++---- gdb/python/py-utils.c | 50 +++++++++++++++++++ gdb/python/python-internal.h | 6 +++ gdb/python/python.c | 11 +++++ gdb/testsuite/ChangeLog | 5 ++ gdb/testsuite/gdb.python/py-cmd.exp | 32 +++++++++++++ 10 files changed, 253 insertions(+), 11 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index da246a0..23ae0eb 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,21 @@ +2010-05-25 Doug Evans + + Add python gdb.GdbError and gdb.string_to_argv. + * NEWS: Document them. + * python/py-cmd.c (cmdpy_function): Don't print a traceback if + the exception is gdb.GdbError. Print a second traceback if there's + an error computing the error message. + (gdbpy_string_to_argv): New function. + * python/py-utils.c (gdbpy_obj_to_string): New function. + (gdbpy_exception_to_string): New function. + * python/python-internal.h (gdbpy_string_to_argv): Declare. + (gdbpy_obj_to_string, gdbpy_exception_to_string): Declare. + (gdbpy_gdberror_exc): Declare. + * python/python.c (gdbpy_gdberror_exc): New global. + (_initialize_python): Initialize gdbpy_gdberror_exc and create + gdb.GdbError. + (GdbMethods): Add string_to_argv. + 2010-05-21 Pierre Muller * windows-nat.c (display_selector): Call GetLastError to give better diff --git a/gdb/NEWS b/gdb/NEWS index 6612099..f91fe2e 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -87,7 +87,9 @@ is now deprecated. set/show in the CLI. ** New functions gdb.target_charset, gdb.target_wide_charset, - gdb.progspaces, and gdb.current_progspace. + gdb.progspaces, gdb.current_progspace, and gdb.string_to_argv. + +** New exception gdb.GdbError. ** Pretty-printers are now also looked up in the current program space. diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index eb46098..2124414 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,8 @@ +2010-05-25 Doug Evans + + * gdb.texinfo (Exception Handling): Document gdb.GdbError. + (Commands In Python): Document gdb.string_to_argv. + 2010-05-02 Jan Kratochvil * gdbint.texinfo (Host Definition): Remove items NORETURN and diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index e929481..9466745 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -20082,6 +20082,30 @@ message as its value, and the Python call stack backtrace at the Python statement closest to where the @value{GDBN} error occured as the traceback. +@findex gdb.GdbError +When implementing @value{GDBN} commands in Python via @code{gdb.Command}, +it is useful to be able to throw an exception that doesn't cause a +traceback to be printed. For example, the user may have invoked the +command incorrectly. Use the @code{gdb.GdbError} exception +to handle this case. Example: + +@smallexample +(gdb) python +>class HelloWorld (gdb.Command): +> """Greet the whole world.""" +> def __init__ (self): +> super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE) +> def invoke (self, args, from_tty): +> argv = gdb.string_to_argv (args) +> if len (argv) != 0: +> raise gdb.GdbError ("hello-world takes no arguments") +> print "Hello, World!" +>HelloWorld () +>end +(gdb) hello-world 42 +hello-world takes no arguments +@end smallexample + @node Values From Inferior @subsubsection Values From Inferior @cindex values from inferior, with Python @@ -20773,6 +20797,20 @@ that the command came from elsewhere. If this method throws an exception, it is turned into a @value{GDBN} @code{error} call. Otherwise, the return value is ignored. + +@findex gdb.string_to_argv +To break @var{argument} up into an argv-like string use +@code{gdb.string_to_argv}. This function behaves identically to +@value{GDBN}'s internal argument lexer @code{buildargv}. +It is recommended to use this for consistency. +Arguments are separated by spaces and may be quoted. +Example: + +@smallexample +print gdb.string_to_argv ("1 2\ \\\"3 '4 \"5' \"6 '7\"") +['1', '2 "3', '4 "5', "6 '7"] +@end smallexample + @end defmethod @cindex completion of Python commands diff --git a/gdb/python/py-cmd.c b/gdb/python/py-cmd.c index f9a4130..2cff4ba 100644 --- a/gdb/python/py-cmd.c +++ b/gdb/python/py-cmd.c @@ -88,6 +88,7 @@ cmdpy_dont_repeat (PyObject *self, PyObject *args) /* Called if the gdb cmd_list_element is destroyed. */ + static void cmdpy_destroyer (struct cmd_list_element *self, void *context) { @@ -111,6 +112,7 @@ cmdpy_destroyer (struct cmd_list_element *self, void *context) } /* Called by gdb to invoke the command. */ + static void cmdpy_function (struct cmd_list_element *command, char *args, int from_tty) { @@ -145,30 +147,51 @@ cmdpy_function (struct cmd_list_element *command, char *args, int from_tty) ttyobj, NULL); Py_DECREF (argobj); Py_DECREF (ttyobj); + if (! result) { PyObject *ptype, *pvalue, *ptraceback; + char *msg; PyErr_Fetch (&ptype, &pvalue, &ptraceback); - if (pvalue && PyString_Check (pvalue)) - { - /* Make a temporary copy of the string data. */ - char *s = PyString_AsString (pvalue); - char *copy = alloca (strlen (s) + 1); + /* Try to fetch an error message contained within ptype, pvalue. + When fetching the error message we need to make our own copy, + we no longer own ptype, pvalue after the call to PyErr_Restore. */ - strcpy (copy, s); - PyErr_Restore (ptype, pvalue, ptraceback); + msg = gdbpy_exception_to_string (ptype, pvalue); + make_cleanup (xfree, msg); + + if (msg == NULL) + { + /* An error occurred computing the string representation of the + error message. This is rare, but we should inform the user. */ + printf_filtered (_("An error occurred in a Python command\n" + "and then another occurred computing the error message.\n")); gdbpy_print_stack (); - error (_("Error occurred in Python command: %s"), copy); } - else + + /* Don't print the stack for gdb.GdbError exceptions. + It is generally used to flag user errors. + + We also don't want to print "Error occurred in Python command" + for user errors. However, a missing message for gdb.GdbError + exceptions is arguably a bug, so we flag it as such. */ + + if (! PyErr_GivenExceptionMatches (ptype, gdbpy_gdberror_exc) + || msg == NULL || *msg == '\0') { PyErr_Restore (ptype, pvalue, ptraceback); gdbpy_print_stack (); - error (_("Error occurred in Python command.")); + if (msg != NULL && *msg != '\0') + error (_("Error occurred in Python command: %s"), msg); + else + error (_("Error occurred in Python command.")); } + else + error ("%s", msg); } + Py_DECREF (result); do_cleanups (cleanup); } @@ -589,3 +612,55 @@ static PyTypeObject cmdpy_object_type = 0, /* tp_alloc */ PyType_GenericNew /* tp_new */ }; + + + +/* Utility to build a buildargv-like result from ARGS. + This intentionally parses arguments the way libiberty/argv.c:buildargv + does. It splits up arguments in a reasonable way, and we want a standard + way of parsing arguments. Several gdb commands use buildargv to parse their + arguments. Plus we want to be able to write compatible python + implementations of gdb commands. */ + +PyObject * +gdbpy_string_to_argv (PyObject *self, PyObject *args) +{ + PyObject *py_argv; + char *input; + + if (!PyArg_ParseTuple (args, "s", &input)) + return NULL; + + py_argv = PyList_New (0); + + /* buildargv uses NULL to represent an empty argument list, but we can't use + that in Python. Instead, if ARGS is "" then return an empty list. + This undoes the NULL -> "" conversion that cmdpy_function does. */ + + if (*input != '\0') + { + char **c_argv = gdb_buildargv (input); + int i; + + for (i = 0; c_argv[i] != NULL; ++i) + { + PyObject *argp = PyString_FromString (c_argv[i]); + + if (argp == NULL + || PyList_Append (py_argv, argp) < 0) + { + if (argp != NULL) + { + Py_DECREF (argp); + } + Py_DECREF (py_argv); + freeargv (c_argv); + return NULL; + } + } + + freeargv (c_argv); + } + + return py_argv; +} diff --git a/gdb/python/py-utils.c b/gdb/python/py-utils.c index cd11834..944e6b4 100644 --- a/gdb/python/py-utils.c +++ b/gdb/python/py-utils.c @@ -222,3 +222,53 @@ gdbpy_is_string (PyObject *obj) { return PyString_Check (obj) || PyUnicode_Check (obj); } + +/* Return the string representation of OBJ, i.e., str (obj). + Space for the result is malloc'd, the caller must free. + If the result is NULL a python error occurred, the caller must clear it. */ + +char * +gdbpy_obj_to_string (PyObject *obj) +{ + PyObject *str_obj = PyObject_Str (obj); + + if (str_obj != NULL) + { + char *msg = xstrdup (PyString_AsString (str_obj)); + + Py_DECREF (str_obj); + return msg; + } + + return NULL; +} + +/* Return the string representation of the exception represented by + TYPE, VALUE which is assumed to have been obtained with PyErr_Fetch, + i.e., the error indicator is currently clear. + Space for the result is malloc'd, the caller must free. + If the result is NULL a python error occurred, the caller must clear it. */ + +char * +gdbpy_exception_to_string (PyObject *ptype, PyObject *pvalue) +{ + PyObject *str_obj = PyObject_Str (pvalue); + char *str; + + /* There are a few cases to consider. + For example: + pvalue is a string when PyErr_SetString is used. + pvalue is not a string when raise "foo" is used, instead it is None + and ptype is "foo". + So the algorithm we use is to print `str (pvalue)' if it's not + None, otherwise we print `str (ptype)'. + Using str (aka PyObject_Str) will fetch the error message from + gdb.GdbError ("message"). */ + + if (pvalue && pvalue != Py_None) + str = gdbpy_obj_to_string (pvalue); + else + str = gdbpy_obj_to_string (ptype); + + return str; +} diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h index f41f32a..bc07b5d 100644 --- a/gdb/python/python-internal.h +++ b/gdb/python/python-internal.h @@ -92,6 +92,7 @@ PyObject *gdbpy_block_for_pc (PyObject *self, PyObject *args); PyObject *gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw); PyObject *gdbpy_create_lazy_string_object (CORE_ADDR address, long length, const char *encoding, struct type *type); +PyObject *gdbpy_string_to_argv (PyObject *self, PyObject *args); PyObject *gdbpy_get_hook_function (const char *); PyObject *gdbpy_parameter (PyObject *self, PyObject *args); PyObject *gdbpy_parameter_value (enum var_types type, void *var); @@ -179,6 +180,9 @@ PyObject *python_string_to_target_python_string (PyObject *obj); char *python_string_to_host_string (PyObject *obj); PyObject *target_string_to_unicode (const gdb_byte *str, int length); int gdbpy_is_string (PyObject *obj); +char *gdbpy_obj_to_string (PyObject *obj); +char *gdbpy_exception_to_string (PyObject *ptype, PyObject *pvalue); + int gdbpy_is_lazy_string (PyObject *result); gdb_byte *gdbpy_extract_lazy_string (PyObject *string, struct type **str_type, @@ -197,4 +201,6 @@ extern PyObject *gdbpy_children_cst; extern PyObject *gdbpy_to_string_cst; extern PyObject *gdbpy_display_hint_cst; +extern PyObject *gdbpy_gdberror_exc; + #endif /* GDB_PYTHON_INTERNAL_H */ diff --git a/gdb/python/python.c b/gdb/python/python.c index 3110328..288c701 100644 --- a/gdb/python/python.c +++ b/gdb/python/python.c @@ -57,6 +57,8 @@ PyObject *gdbpy_children_cst; PyObject *gdbpy_display_hint_cst; PyObject *gdbpy_doc_cst; +/* The GdbError exception. */ +PyObject *gdbpy_gdberror_exc; /* Architecture and language to be used in callbacks from the Python interpreter. */ @@ -655,6 +657,9 @@ Enables or disables printing of Python stack traces."), PyModule_AddStringConstant (gdb_module, "HOST_CONFIG", (char*) host_name); PyModule_AddStringConstant (gdb_module, "TARGET_CONFIG", (char*) target_name); + gdbpy_gdberror_exc = PyErr_NewException ("gdb.GdbError", NULL, NULL); + PyModule_AddObject (gdb_module, "GdbError", gdbpy_gdberror_exc); + gdbpy_initialize_auto_load (); gdbpy_initialize_values (); gdbpy_initialize_frames (); @@ -771,6 +776,12 @@ Return the name of the current target charset." }, "target_wide_charset () -> string.\n\ Return the name of the current target wide charset." }, + { "string_to_argv", gdbpy_string_to_argv, METH_VARARGS, + "string_to_argv (String) -> Array.\n\ +Parse String and return an argv-like array.\n\ +Arguments are separate by spaces and may be quoted." + }, + { "write", gdbpy_write, METH_VARARGS, "Write a string using gdb's filtered stream." }, { "flush", gdbpy_flush, METH_NOARGS, diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 3da5ebd..6526f1a 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2010-05-25 Doug Evans + + * gdb.python/py-cmd.exp: Add tests for gdb.GdbError and + gdb.string_to_argv. + 2010-05-24 Michael Snyder * gdb.base/call-ar-st.exp: Replace send_gdb with gdb_test. diff --git a/gdb/testsuite/gdb.python/py-cmd.exp b/gdb/testsuite/gdb.python/py-cmd.exp index d3c05ff..0f250d2 100644 --- a/gdb/testsuite/gdb.python/py-cmd.exp +++ b/gdb/testsuite/gdb.python/py-cmd.exp @@ -126,3 +126,35 @@ gdb_py_test_multiple "input new subcommand" \ "end" "" gdb_test "info newsubcmd ugh" "newsubcmd output, arg = ugh" "call newsubcmd" + +# Test a command that throws gdb.GdbError. + +gdb_py_test_multiple "input command to throw error" \ + "python" "" \ + "class test_error_cmd (gdb.Command):" "" \ + " def __init__ (self):" "" \ + " super (test_error_cmd, self).__init__ (\"test_error_cmd\", gdb.COMMAND_OBSCURE)" "" \ + " def invoke (self, arg, from_tty):" "" \ + " raise gdb.GdbError ('you lose!')" "" \ + "test_error_cmd ()" "" \ + "end" "" + +gdb_test "test_error_cmd ugh" "you lose!" "call error command" + +# Test gdb.string_to_argv. + +gdb_test "python print gdb.string_to_argv (\"1 2 3\")" \ + {\['1', '2', '3'\]} \ + "string_to_argv (\"1 2 3\")" + +gdb_test "python print gdb.string_to_argv (\"'1 2' 3\")" \ + {\['1 2', '3'\]} \ + "string_to_argv (\"'1 2' 3\")" + +gdb_test "python print gdb.string_to_argv ('\"1 2\" 3')" \ + {\['1 2', '3'\]} \ + "string_to_argv ('\"1 2\" 3')" + +gdb_test "python print gdb.string_to_argv ('1\\ 2 3')" \ + {\['1 2', '3'\]} \ + "string_to_argv ('1\\ 2 3')" -- 2.7.4