[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Emacs-diffs] emacs-25 1ed316d: Improve handling of signals and 'throw'
From: |
Eli Zaretskii |
Subject: |
[Emacs-diffs] emacs-25 1ed316d: Improve handling of signals and 'throw' in modules |
Date: |
Fri, 27 Nov 2015 10:53:04 +0000 |
branch: emacs-25
commit 1ed316d275241384f63b4dd6e39c7439d1ca56c9
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>
Improve handling of signals and 'throw' in modules
* src/emacs-module.c: Add commentary explaining how to write
functions in this file.
(module_make_global_ref, module_free_global_ref)
(module_non_local_exit_signal, module_non_local_exit_throw)
(module_make_function, module_funcall, module_intern)
(module_type_of, module_is_not_nil, module_eq)
(module_extract_integer, module_make_integer)
(module_extract_float, module_make_float)
(module_copy_string_contents, module_make_string)
(module_make_user_ptr, module_get_user_ptr, module_set_user_ptr)
(module_get_user_finalizer, module_set_user_finalizer)
(module_vec_set, module_vec_get, module_vec_size)
(module_non_local_exit_signal_1, module_non_local_exit_throw_1):
Do nothing and return with failure indication immediately, if some
previous module call signaled an error or wants to throw. See
http://lists.gnu.org/archive/html/emacs-devel/2015-11/msg02133.html
for the relevant discussions.
---
src/emacs-module.c | 133 +++++++++++++++++++++++++++++++++++++--------------
1 files changed, 96 insertions(+), 37 deletions(-)
diff --git a/src/emacs-module.c b/src/emacs-module.c
index 1388e53..c75ddeb 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -198,7 +198,8 @@ static void module_wrong_type (emacs_env *, Lisp_Object,
Lisp_Object);
its local variable C must stay live in later code. */
#define MODULE_SETJMP_1(handlertype, handlerfunc, retval, c, dummy) \
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return); \
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return) \
+ return retval; \
struct handler *c = push_handler_nosignal (Qt, handlertype); \
if (!c) \
{ \
@@ -236,7 +237,38 @@ struct module_fun_env
static Lisp_Object module_call_func;
-/* Implementation of runtime and environment functions. */
+/* Implementation of runtime and environment functions.
+
+ These should abide by the following rules:
+
+ 1. The first argument should always be a pointer to emacs_env.
+
+ 2. Each function should first call check_main_thread. Note that
+ this function is a no-op unless Emacs was built with
+ --enable-checking.
+
+ 3. The very next thing each function should do is check that the
+ emacs_env object does not have a non-local exit indication set,
+ by calling module_non_local_exit_check. If that returns
+ anything but emacs_funcall_exit_return, the function should do
+ nothing and return immediately with an error indication, without
+ clobbering the existing error indication in emacs_env. This is
+ needed for correct reporting of Lisp errors to the Emacs Lisp
+ interpreter.
+
+ 4. Any function that needs to call Emacs facilities, such as
+ encoding or decoding functions, or 'intern', or 'make_string',
+ should protect itself from signals and 'throw' in the called
+ Emacs functions, by placing the macros MODULE_HANDLE_SIGNALS
+ and/or MODULE_HANDLE_THROW right after the above 2 tests.
+
+ 5. Do NOT use 'eassert' for checking validity of user code in the
+ module. Instead, make those checks part of the code, and if the
+ check fails, call 'module_non_local_exit_signal_1' or
+ 'module_non_local_exit_throw_1' to report the error. This is
+ because using 'eassert' in these situations will abort Emacs
+ instead of reporting the error back to Lisp, and also because
+ 'eassert' is compiled to nothing in the release version. */
/* Catch signals and throws only if the code can actually signal or
throw. If checking is enabled, abort if the current thread is not
@@ -256,7 +288,8 @@ static emacs_value
module_make_global_ref (emacs_env *env, emacs_value ref)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
Lisp_Object new_obj = value_to_lisp (ref);
@@ -287,7 +320,8 @@ static void
module_free_global_ref (emacs_env *env, emacs_value ref)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return;
/* TODO: This probably never signals. */
/* FIXME: Wait a minute. Shouldn't this function report an error if
the hash lookup fails? */
@@ -343,18 +377,18 @@ static void
module_non_local_exit_signal (emacs_env *env, emacs_value sym, emacs_value
data)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
- module_non_local_exit_signal_1 (env, value_to_lisp (sym),
- value_to_lisp (data));
+ if (module_non_local_exit_check (env) == emacs_funcall_exit_return)
+ module_non_local_exit_signal_1 (env, value_to_lisp (sym),
+ value_to_lisp (data));
}
static void
module_non_local_exit_throw (emacs_env *env, emacs_value tag, emacs_value
value)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
- module_non_local_exit_throw_1 (env, value_to_lisp (tag),
- value_to_lisp (value));
+ if (module_non_local_exit_check (env) == emacs_funcall_exit_return)
+ module_non_local_exit_throw_1 (env, value_to_lisp (tag),
+ value_to_lisp (value));
}
/* A module function is lambda function that calls `module-call',
@@ -370,7 +404,8 @@ module_make_function (emacs_env *env, ptrdiff_t min_arity,
ptrdiff_t max_arity,
void *data)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
if (! (0 <= min_arity
@@ -407,7 +442,8 @@ module_funcall (emacs_env *env, emacs_value fun, ptrdiff_t
nargs,
emacs_value args[])
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
MODULE_HANDLE_THROW;
@@ -428,7 +464,8 @@ static emacs_value
module_intern (emacs_env *env, const char *name)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
return lisp_to_value (env, intern (name));
}
@@ -437,7 +474,8 @@ static emacs_value
module_type_of (emacs_env *env, emacs_value value)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
return lisp_to_value (env, Ftype_of (value_to_lisp (value)));
}
@@ -445,7 +483,8 @@ static bool
module_is_not_nil (emacs_env *env, emacs_value value)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return false;
return ! NILP (value_to_lisp (value));
}
@@ -453,7 +492,8 @@ static bool
module_eq (emacs_env *env, emacs_value a, emacs_value b)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return false;
return EQ (value_to_lisp (a), value_to_lisp (b));
}
@@ -461,7 +501,8 @@ static intmax_t
module_extract_integer (emacs_env *env, emacs_value n)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return 0;
Lisp_Object l = value_to_lisp (n);
if (! INTEGERP (l))
{
@@ -475,7 +516,8 @@ static emacs_value
module_make_integer (emacs_env *env, intmax_t n)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
if (! (MOST_NEGATIVE_FIXNUM <= n && n <= MOST_POSITIVE_FIXNUM))
{
module_non_local_exit_signal_1 (env, Qoverflow_error, Qnil);
@@ -488,7 +530,8 @@ static double
module_extract_float (emacs_env *env, emacs_value f)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return 0;
Lisp_Object lisp = value_to_lisp (f);
if (! FLOATP (lisp))
{
@@ -502,7 +545,8 @@ static emacs_value
module_make_float (emacs_env *env, double d)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
return lisp_to_value (env, make_float (d));
}
@@ -512,7 +556,8 @@ module_copy_string_contents (emacs_env *env, emacs_value
value, char *buffer,
ptrdiff_t *length)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return false;
MODULE_HANDLE_SIGNALS;
Lisp_Object lisp_str = value_to_lisp (value);
if (! STRINGP (lisp_str))
@@ -557,7 +602,8 @@ static emacs_value
module_make_string (emacs_env *env, const char *str, ptrdiff_t length)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
MODULE_HANDLE_SIGNALS;
if (length > STRING_BYTES_BOUND)
{
@@ -573,6 +619,8 @@ static emacs_value
module_make_user_ptr (emacs_env *env, emacs_finalizer_function fin, void *ptr)
{
check_main_thread ();
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
return lisp_to_value (env, make_user_ptr (fin, ptr));
}
@@ -580,7 +628,8 @@ static void *
module_get_user_ptr (emacs_env *env, emacs_value uptr)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
{
@@ -594,7 +643,8 @@ static void
module_set_user_ptr (emacs_env *env, emacs_value uptr, void *ptr)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return;
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
module_wrong_type (env, Quser_ptr, lisp);
@@ -605,7 +655,8 @@ static emacs_finalizer_function
module_get_user_finalizer (emacs_env *env, emacs_value uptr)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
{
@@ -620,7 +671,8 @@ module_set_user_finalizer (emacs_env *env, emacs_value uptr,
emacs_finalizer_function fin)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return;
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
module_wrong_type (env, Quser_ptr, lisp);
@@ -631,7 +683,8 @@ static void
module_vec_set (emacs_env *env, emacs_value vec, ptrdiff_t i, emacs_value val)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return;
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
@@ -653,7 +706,8 @@ static emacs_value
module_vec_get (emacs_env *env, emacs_value vec, ptrdiff_t i)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return NULL;
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
@@ -675,7 +729,8 @@ static ptrdiff_t
module_vec_size (emacs_env *env, emacs_value vec)
{
check_main_thread ();
- eassert (module_non_local_exit_check (env) == emacs_funcall_exit_return);
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
+ return 0;
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
@@ -806,10 +861,12 @@ module_non_local_exit_signal_1 (emacs_env *env,
Lisp_Object sym,
Lisp_Object data)
{
struct emacs_env_private *p = env->private_members;
- eassert (p->pending_non_local_exit == emacs_funcall_exit_return);
- p->pending_non_local_exit = emacs_funcall_exit_signal;
- p->non_local_exit_symbol.v = sym;
- p->non_local_exit_data.v = data;
+ if (p->pending_non_local_exit == emacs_funcall_exit_return)
+ {
+ p->pending_non_local_exit = emacs_funcall_exit_signal;
+ p->non_local_exit_symbol.v = sym;
+ p->non_local_exit_data.v = data;
+ }
}
static void
@@ -817,10 +874,12 @@ module_non_local_exit_throw_1 (emacs_env *env,
Lisp_Object tag,
Lisp_Object value)
{
struct emacs_env_private *p = env->private_members;
- eassert (p->pending_non_local_exit == emacs_funcall_exit_return);
- p->pending_non_local_exit = emacs_funcall_exit_throw;
- p->non_local_exit_symbol.v = tag;
- p->non_local_exit_data.v = value;
+ if (p->pending_non_local_exit == emacs_funcall_exit_return)
+ {
+ p->pending_non_local_exit = emacs_funcall_exit_throw;
+ p->non_local_exit_symbol.v = tag;
+ p->non_local_exit_data.v = value;
+ }
}
/* Module version of `wrong_type_argument'. */
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Emacs-diffs] emacs-25 1ed316d: Improve handling of signals and 'throw' in modules,
Eli Zaretskii <=