extmod/modwebsocket: Implement read support.

extmod/modwebsocket.c

@@ -26,6 +26,8 @@
 
 #include <stdio.h>
 #include <stdint.h>
+#include <string.h>
+#include <errno.h>
 
 #include "py/nlr.h"
 #include "py/obj.h"
@@ -38,11 +40,13 @@ enum { FRAME_HEADER, FRAME_OPT, PAYLOAD };
 typedef struct _mp_obj_websocket_t {
     mp_obj_base_t base;
     mp_obj_t sock;
-    uint32_t mask;
+    uint32_t msg_sz;
+    byte mask[4];
     byte state;
     byte to_recv;
     byte mask_pos;
-    byte buf[4];
+    byte buf_pos;
+    byte buf[6];
 } mp_obj_websocket_t;
 
 STATIC mp_obj_t websocket_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
@@ -53,9 +57,95 @@ STATIC mp_obj_t websocket_make_new(const mp_obj_type_t *type, size_t n_args, siz
     o->state = FRAME_HEADER;
     o->to_recv = 2;
     o->mask_pos = 0;
+    o->buf_pos = 0;
     return o;
 }
 
+STATIC mp_uint_t websocket_read(mp_obj_t self_in, void *buf, mp_uint_t size, int *errcode) {
+    mp_obj_websocket_t *self = self_in;
+    const mp_stream_p_t *stream_p = mp_get_stream_raise(self->sock, MP_STREAM_OP_READ);
+    while (1) {
+        if (self->to_recv != 0) {
+            mp_uint_t out_sz = stream_p->read(self->sock, self->buf + self->buf_pos, self->to_recv, errcode);
+            if (out_sz == MP_STREAM_ERROR) {
+                return out_sz;
+            }
+            self->buf_pos += out_sz;
+            self->to_recv -= out_sz;
+            if (self->to_recv != 0) {
+                *errcode = EAGAIN;
+                return MP_STREAM_ERROR;
+            }
+        }
+
+        switch (self->state) {
+            case FRAME_HEADER: {
+                assert(self->buf[0] & 0x80);
+                int to_recv = 0;
+                size_t sz = self->buf[1] & 0x7f;
+                if (sz == 126) {
+                    // Msg size is next 2 bytes
+                    to_recv += 2;
+                } else if (sz == 127) {
+                    // Msg size is next 2 bytes
+                    assert(0);
+                }
+                if (self->buf[1] & 0x80) {
+                    // Next 4 bytes is mask
+                    to_recv += 4;
+                }
+
+                self->buf_pos = 0;
+                self->to_recv = to_recv;
+                self->msg_sz = sz; // May be overriden by FRAME_OPT
+                if (to_recv != 0) {
+                    self->state = FRAME_OPT;
+                } else {
+                    self->state = PAYLOAD;
+                }
+                continue;
+            }
+
+            case FRAME_OPT: {
+                if ((self->buf_pos & 3) == 2) {
+                    // First two bytes are message length
+                    self->msg_sz = (self->buf[0] << 8) | self->buf[1];
+                }
+                if (self->buf_pos >= 4) {
+                    // Last 4 bytes is mask
+                    memcpy(self->mask, self->buf + self->buf_pos - 4, 4);
+                }
+                self->buf_pos = 0;
+                self->state = PAYLOAD;
+                continue;
+            }
+
+            case PAYLOAD: {
+                size_t sz = MIN(size, self->msg_sz);
+                mp_uint_t out_sz = stream_p->read(self->sock, buf, sz, errcode);
+                if (out_sz == MP_STREAM_ERROR) {
+                    return out_sz;
+                }
+
+                sz = out_sz;
+                for (byte *p = buf; sz--; p++) {
+                    *p ^= self->mask[self->mask_pos++ & 3];
+                }
+
+                self->msg_sz -= out_sz;
+                if (self->msg_sz == 0) {
+                    self->state = FRAME_HEADER;
+                    self->to_recv = 2;
+                    self->mask_pos = 0;
+                    self->buf_pos = 0;
+                }
+                return out_sz;
+            }
+
+        }
+    }
+}
+
 STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
     mp_obj_websocket_t *self = self_in;
     assert(size < 126);
@@ -69,12 +159,13 @@ STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t si
 }
 
 STATIC const mp_map_elem_t websocket_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(websocket_locals_dict, websocket_locals_dict_table);
 
 STATIC const mp_stream_p_t websocket_stream_p = {
-//    .read = websocket_read,
+    .read = websocket_read,
     .write = websocket_write,
 };