extmod/modwebrepl: Module to handle WebREPL protocol.

While just a websocket is enough for handling terminal part of WebREPL,
handling file transfer operations requires demultiplexing and acting
upon, which is encapsulated in _webrepl class provided by this module,
which wraps a websocket object.

extmod/modwebrepl.c

+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Paul Sokolovsky
+ *
+ * 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 <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+#include "py/nlr.h"
+#include "py/obj.h"
+#include "py/runtime.h"
+#include "py/stream.h"
+#include "py/builtin.h"
+#include "extmod/modwebsocket.h"
+
+#if MICROPY_PY_WEBREPL
+
+#if 1 // print debugging info
+#define DEBUG_printf DEBUG_printf
+#else // don't print debugging info
+#define DEBUG_printf(...) (void)0
+#endif
+
+struct webrepl_file {
+    char sig[2];
+    char type;
+    char flags;
+    uint64_t offset;
+    uint32_t size;
+    uint16_t fname_len;
+    char fname[64];
+} __attribute__((packed));
+
+typedef struct _mp_obj_webrepl_t {
+    mp_obj_base_t base;
+    mp_obj_t sock;
+    byte state;
+    byte hdr_to_recv;
+    uint32_t data_to_recv;
+    struct webrepl_file hdr;
+    mp_obj_t cur_file;
+} mp_obj_webrepl_t;
+
+
+static inline void close_meth(mp_obj_t stream) {
+    mp_obj_t dest[2];
+    mp_load_method(stream, MP_QSTR_close, dest);
+    mp_call_method_n_kw(0, 0, dest);
+}
+
+STATIC void write_webrepl(mp_obj_t websock, const void *buf, size_t len) {
+    const mp_stream_p_t *sock_stream = mp_get_stream_raise(websock, MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
+    int err;
+    int old_opts = sock_stream->ioctl(websock, MP_STREAM_SET_DATA_OPTS, FRAME_BIN, &err);
+    sock_stream->write(websock, buf, len, &err);
+    sock_stream->ioctl(websock, MP_STREAM_SET_DATA_OPTS, old_opts, &err);
+}
+
+STATIC void write_webrepl_resp(mp_obj_t websock, uint16_t code) {
+    char buf[4] = {'W', 'B', code & 0xff, code >> 8};
+    write_webrepl(websock, buf, sizeof(buf));
+}
+
+STATIC mp_obj_t webrepl_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 1, 2, false);
+    mp_get_stream_raise(args[0], MP_STREAM_OP_READ | MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
+    DEBUG_printf("sizeof(struct webrepl_file) = %lu\n", sizeof(struct webrepl_file));
+    mp_obj_webrepl_t *o = m_new_obj(mp_obj_webrepl_t);
+    o->base.type = type;
+    o->sock = args[0];
+    o->hdr_to_recv = sizeof(struct webrepl_file);
+    o->data_to_recv = 0;
+    return o;
+}
+
+STATIC mp_uint_t webrepl_read(mp_obj_t self_in, void *buf, mp_uint_t size, int *errcode) {
+    // We know that os.dupterm always calls with size = 1
+    assert(size == 1);
+    mp_obj_webrepl_t *self = self_in;
+    const mp_stream_p_t *sock_stream = mp_get_stream_raise(self->sock, MP_STREAM_OP_READ);
+    mp_uint_t out_sz = sock_stream->read(self->sock, buf, size, errcode);
+    if (out_sz == 0 || out_sz == MP_STREAM_ERROR) {
+        return out_sz;
+    }
+    // If last read data belonged to text record (== REPL)
+    int err;
+    if (sock_stream->ioctl(self->sock, MP_STREAM_GET_DATA_OPTS, 0, &err) == 1) {
+        return out_sz;
+    }
+
+    DEBUG_printf("webrepl: received bin data, hdr_to_recv: %d, data_to_recv=%d\n", self->hdr_to_recv, self->data_to_recv);
+
+    if (self->hdr_to_recv != 0) {
+        char *p = (char*)&self->hdr + sizeof(self->hdr) - self->hdr_to_recv;
+        *p++ = *(char*)buf;
+        if (--self->hdr_to_recv != 0) {
+            mp_uint_t hdr_sz = sock_stream->read(self->sock, p, self->hdr_to_recv, errcode);
+            if (hdr_sz == MP_STREAM_ERROR) {
+                return hdr_sz;
+            }
+            self->hdr_to_recv -= hdr_sz;
+            if (self->hdr_to_recv != 0) {
+                *errcode = EAGAIN;
+                return MP_STREAM_ERROR;
+            }
+        }
+
+        DEBUG_printf("webrepl: op: %d, file: %s, chunk @%x, sz=%d\n", self->hdr.type, self->hdr.fname, (uint32_t)self->hdr.offset, self->hdr.size);
+
+        // Process header
+        mp_obj_t open_args[2] = {
+            mp_obj_new_str(self->hdr.fname, strlen(self->hdr.fname), false),
+            MP_OBJ_NEW_QSTR(MP_QSTR_wb)
+        };
+
+        self->cur_file = mp_builtin_open(2, open_args, (mp_map_t*)&mp_const_empty_map);
+        const mp_stream_p_t *file_stream = mp_get_stream_raise(self->cur_file, MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
+        struct mp_stream_seek_t seek = { .offset = self->hdr.offset, .whence = 0 };
+        int err;
+        mp_uint_t res = file_stream->ioctl(self->cur_file, MP_STREAM_SEEK, (uintptr_t)&seek, &err);
+        assert(res != MP_STREAM_ERROR);
+
+        write_webrepl_resp(self->sock, 0);
+        self->data_to_recv = self->hdr.size;
+
+        *errcode = EAGAIN;
+        return MP_STREAM_ERROR;
+    }
+
+    if (self->data_to_recv != 0) {
+        static byte filebuf[256];
+        filebuf[0] = *(byte*)buf;
+        mp_uint_t buf_sz = 1;
+        if (--self->data_to_recv != 0) {
+            size_t to_read = MIN(sizeof(filebuf) - 1, self->data_to_recv);
+            mp_uint_t sz = sock_stream->read(self->sock, filebuf + 1, to_read, errcode);
+            if (sz == MP_STREAM_ERROR) {
+                return sz;
+            }
+            self->data_to_recv -= sz;
+            buf_sz += sz;
+        }
+
+        DEBUG_printf("webrepl: Writing %lu bytes to file\n", buf_sz);
+        int err;
+        mp_uint_t res = mp_stream_writeall(self->cur_file, filebuf, buf_sz, &err);
+        if(res == MP_STREAM_ERROR) {
+            assert(0);
+        }
+
+        if (self->data_to_recv == 0) {
+            close_meth(self->cur_file);
+            self->hdr_to_recv = sizeof(struct webrepl_file);
+            DEBUG_printf("webrepl: Finished writing file\n");
+            write_webrepl_resp(self->sock, 0);
+        }
+    }
+
+    *errcode = EAGAIN;
+    return MP_STREAM_ERROR;
+}
+
+STATIC mp_uint_t webrepl_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
+    mp_obj_webrepl_t *self = self_in;
+    const mp_stream_p_t *stream_p = mp_get_stream_raise(self->sock, MP_STREAM_OP_WRITE);
+    return stream_p->write(self->sock, buf, size, errcode);
+}
+
+STATIC const mp_map_elem_t webrepl_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&mp_stream_read_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
+};
+STATIC MP_DEFINE_CONST_DICT(webrepl_locals_dict, webrepl_locals_dict_table);
+
+STATIC const mp_stream_p_t webrepl_stream_p = {
+    .read = webrepl_read,
+    .write = webrepl_write,
+};
+
+STATIC const mp_obj_type_t webrepl_type = {
+    { &mp_type_type },
+    .name = MP_QSTR__webrepl,
+    .make_new = webrepl_make_new,
+    .stream_p = &webrepl_stream_p,
+    .locals_dict = (mp_obj_t)&webrepl_locals_dict,
+};
+
+STATIC const mp_map_elem_t webrepl_module_globals_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_websocket) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR__webrepl), (mp_obj_t)&webrepl_type },
+};
+
+STATIC MP_DEFINE_CONST_DICT(webrepl_module_globals, webrepl_module_globals_table);
+
+const mp_obj_module_t mp_module_webrepl = {
+    .base = { &mp_type_module },
+    .name = MP_QSTR__webrepl,
+    .globals = (mp_obj_dict_t*)&webrepl_module_globals,
+};
+
+#endif // MICROPY_PY_WEBREPL

py/builtin.h

@@ -110,6 +110,7 @@ extern const mp_obj_module_t mp_module_ussl;
 extern const mp_obj_module_t mp_module_machine;
 extern const mp_obj_module_t mp_module_lwip;
 extern const mp_obj_module_t mp_module_websocket;
+extern const mp_obj_module_t mp_module_webrepl;
 extern const mp_obj_module_t mp_module_framebuf;
 
 // extmod functions

py/objmodule.c

@@ -196,6 +196,9 @@ STATIC const mp_rom_map_elem_t mp_builtin_module_table[] = {
 #if MICROPY_PY_WEBSOCKET
     { MP_ROM_QSTR(MP_QSTR_websocket), MP_ROM_PTR(&mp_module_websocket) },
 #endif
+#if MICROPY_PY_WEBREPL
+    { MP_ROM_QSTR(MP_QSTR__webrepl), MP_ROM_PTR(&mp_module_webrepl) },
+#endif
 #if MICROPY_PY_FRAMEBUF
     { MP_ROM_QSTR(MP_QSTR_framebuf), MP_ROM_PTR(&mp_module_framebuf) },
 #endif

py/py.mk

@@ -178,6 +178,7 @@ PY_O_BASENAME = \
 	../extmod/modussl.o \
 	../extmod/modurandom.o \
 	../extmod/modwebsocket.o \
+	../extmod/modwebrepl.o \
 	../extmod/modframebuf.o \
 	../extmod/fsusermount.o \
 	../extmod/vfs_fat.o \