py: Add basic _thread module, with ability to start a new thread.

py/modthread.c

@@ -0,0 +1,148 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "py/runtime.h"
+#include "py/stackctrl.h"
+
+#if MICROPY_PY_THREAD
+
+#include "py/mpthread.h"
+
+#if 0 // print debugging info
+#define DEBUG_PRINT (1)
+#define DEBUG_printf DEBUG_printf
+#else // don't print debugging info
+#define DEBUG_PRINT (0)
+#define DEBUG_printf(...) (void)0
+#endif
+
+/****************************************************************/
+// _thread module
+
+STATIC mp_obj_t mod_thread_get_ident(void) {
+    return mp_obj_new_int_from_uint((uintptr_t)mp_thread_get_state());
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_thread_get_ident_obj, mod_thread_get_ident);
+
+typedef struct _thread_entry_args_t {
+    mp_obj_t fun;
+    size_t n_args;
+    size_t n_kw;
+    const mp_obj_t *args;
+} thread_entry_args_t;
+
+STATIC void *thread_entry(void *args_in) {
+    thread_entry_args_t *args = (thread_entry_args_t*)args_in;
+
+    mp_state_thread_t ts;
+    mp_thread_set_state(&ts);
+
+    mp_stack_set_top(&ts + 1); // need to include ts in root-pointer scan
+    mp_stack_set_limit(16 * 1024); // fixed stack limit for now
+
+    // TODO set more thread-specific state here:
+    //  mp_pending_exception? (root pointer)
+    //  cur_exception (root pointer)
+    //  dict_locals? (root pointer) uPy doesn't make a new locals dict for functions, just for classes, so it's different to CPy
+
+    DEBUG_printf("[thread] start ts=%p args=%p stack=%p\n", &ts, &args, MP_STATE_THREAD(stack_top));
+
+    nlr_buf_t nlr;
+    if (nlr_push(&nlr) == 0) {
+        mp_call_function_n_kw(args->fun, args->n_args, args->n_kw, args->args);
+        nlr_pop();
+    } else {
+        // uncaught exception
+        // check for SystemExit
+        if (mp_obj_is_subclass_fast(mp_obj_get_type((mp_obj_t)nlr.ret_val), &mp_type_SystemExit)) {
+            // swallow exception silently
+        } else {
+            // print exception out
+            mp_printf(&mp_plat_print, "Unhandled exception in thread started by ");
+            mp_obj_print_helper(&mp_plat_print, args->fun, PRINT_REPR);
+            mp_printf(&mp_plat_print, "\n");
+            mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
+        }
+    }
+
+    DEBUG_printf("[thread] finish ts=%p\n", &ts);
+
+    return NULL;
+}
+
+STATIC mp_obj_t mod_thread_start_new_thread(size_t n_args, const mp_obj_t *args) {
+    mp_uint_t pos_args_len;
+    mp_obj_t *pos_args_items;
+    mp_obj_get_array(args[1], &pos_args_len, &pos_args_items);
+    thread_entry_args_t *th_args = m_new_obj(thread_entry_args_t);
+    th_args->fun = args[0];
+    if (n_args == 2) {
+        // just position arguments
+        th_args->n_args = pos_args_len;
+        th_args->n_kw = 0;
+        th_args->args = pos_args_items;
+    } else {
+        // positional and keyword arguments
+        if (mp_obj_get_type(args[2]) != &mp_type_dict) {
+            nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "expecting a dict for keyword args"));
+        }
+        mp_map_t *map = &((mp_obj_dict_t*)MP_OBJ_TO_PTR(args[2]))->map;
+        th_args->n_args = pos_args_len;
+        th_args->n_kw = map->used;
+        mp_obj_t *all_args = m_new(mp_obj_t, th_args->n_args + 2 * th_args->n_kw);
+        memcpy(all_args, pos_args_items, pos_args_len * sizeof(mp_obj_t));
+        for (size_t i = 0, n = pos_args_len; i < map->alloc; ++i) {
+            if (MP_MAP_SLOT_IS_FILLED(map, i)) {
+                all_args[n++] = map->table[i].key;
+                all_args[n++] = map->table[i].value;
+            }
+        }
+        th_args->args = all_args;
+    }
+    // TODO implement setting thread stack size
+    mp_thread_create(thread_entry, th_args);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_thread_start_new_thread_obj, 2, 3, mod_thread_start_new_thread);
+
+STATIC const mp_rom_map_elem_t mp_module_thread_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR__thread) },
+    { MP_ROM_QSTR(MP_QSTR_get_ident), MP_ROM_PTR(&mod_thread_get_ident_obj) },
+    { MP_ROM_QSTR(MP_QSTR_start_new_thread), MP_ROM_PTR(&mod_thread_start_new_thread_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(mp_module_thread_globals, mp_module_thread_globals_table);
+
+const mp_obj_module_t mp_module_thread = {
+    .base = { &mp_type_module },
+    .name = MP_QSTR__thread,
+    .globals = (mp_obj_dict_t*)&mp_module_thread_globals,
+};
+
+#endif // MICROPY_PY_THREAD