Add generic impl of stream .readall() method. Use one for unix io.FileIO.

py/stream.c

@@ -51,5 +51,47 @@ static mp_obj_t stream_write(mp_obj_t self_in, mp_obj_t arg) {
     }
 }
 
+// TODO: should be in mpconfig.h
+#define READ_SIZE 256
+static mp_obj_t stream_readall(mp_obj_t self_in) {
+    struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
+    if (o->type->stream_p.read == NULL) {
+        // CPython: io.UnsupportedOperation, OSError subclass
+        nlr_jump(mp_obj_new_exception_msg(MP_QSTR_OSError, "Operation not supported"));
+    }
+
+    int total_size = 0;
+    vstr_t *vstr = vstr_new_size(READ_SIZE);
+    char *buf = vstr_str(vstr);
+    char *p = buf;
+    int error;
+    int current_read = READ_SIZE;
+    while (true) {
+        machine_int_t out_sz = o->type->stream_p.read(self_in, p, current_read, &error);
+        if (out_sz == -1) {
+            nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_OSError, "[Errno %d]", error));
+        }
+        if (out_sz == 0) {
+            break;
+        }
+        total_size += out_sz;
+        if (out_sz < current_read) {
+            current_read -= out_sz;
+            p += out_sz;
+        } else {
+            current_read = READ_SIZE;
+            p = vstr_extend(vstr, current_read);
+            if (p == NULL) {
+                // TODO
+                nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_OSError/*MP_QSTR_RuntimeError*/, "Out of memory"));
+            }
+        }
+    }
+    vstr_set_size(vstr, total_size + 1); // TODO: for \0
+    buf[total_size] = 0;
+    return mp_obj_new_str(qstr_from_str_take(buf, total_size + 1));
+}
+
 MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_read_obj, stream_read);
+MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_readall_obj, stream_readall);
 MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write_obj, stream_write);

py/stream.h

 extern const mp_obj_fun_native_t mp_stream_read_obj;
+extern const mp_obj_fun_native_t mp_stream_readall_obj;
 extern const mp_obj_fun_native_t mp_stream_write_obj;

unix/file.c

@@ -90,6 +90,7 @@ static mp_obj_t fdfile_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *ar
 
 static const mp_method_t rawfile_type_methods[] = {
         { "read", &mp_stream_read_obj },
+        { "readall", &mp_stream_readall_obj },
         { "write", &mp_stream_write_obj },
         { "close", &fdfile_close_obj },
         { NULL, NULL },