stmhal, file: Implement a,x,+ open modes, seek and tell.

Also now returns correct POSIX errno when an IO operation fails.

Addresses issues #516 and #676.

stmhal/file.c

@@ -25,9 +25,11 @@
  */
 
 #include <stdio.h>
+#include <errno.h>
 
-#include "misc.h"
 #include "mpconfig.h"
+#include "nlr.h"
+#include "misc.h"
 #include "qstr.h"
 #include "obj.h"
 #include "runtime.h"
@@ -35,6 +37,33 @@
 #include "file.h"
 #include "ff.h"
 
+extern const mp_obj_type_t mp_type_fileio;
+extern const mp_obj_type_t mp_type_textio;
+
+// this table converts from FRESULT to POSIX errno
+STATIC const byte fresult_to_errno_table[] = {
+    [FR_OK] = 0,
+    [FR_DISK_ERR] = EIO,
+    [FR_INT_ERR] = EIO,
+    [FR_NOT_READY] = EBUSY,
+    [FR_NO_FILE] = ENOENT,
+    [FR_NO_PATH] = ENOENT,
+    [FR_INVALID_NAME] = EINVAL,
+    [FR_DENIED] = EACCES,
+    [FR_EXIST] = EEXIST,
+    [FR_INVALID_OBJECT] = EINVAL,
+    [FR_WRITE_PROTECTED] = EROFS,
+    [FR_INVALID_DRIVE] = ENODEV,
+    [FR_NOT_ENABLED] = ENODEV,
+    [FR_NO_FILESYSTEM] = ENODEV,
+    [FR_MKFS_ABORTED] = EIO,
+    [FR_TIMEOUT] = EIO,
+    [FR_LOCKED] = EIO,
+    [FR_NOT_ENOUGH_CORE] = ENOMEM,
+    [FR_TOO_MANY_OPEN_FILES] = EMFILE,
+    [FR_INVALID_PARAMETER] = EINVAL,
+};
+
 typedef struct _pyb_file_obj_t {
     mp_obj_base_t base;
     FIL fp;
@@ -44,17 +73,25 @@ void file_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, m
     printf("<io.%s %p>", mp_obj_get_type_str(self_in), self_in);
 }
 
-STATIC machine_int_t file_read(mp_obj_t self_in, void *buf, machine_uint_t size, int *errcode) {
+STATIC machine_int_t file_obj_read(mp_obj_t self_in, void *buf, machine_uint_t size, int *errcode) {
     pyb_file_obj_t *self = self_in;
     UINT sz_out;
-    *errcode = f_read(&self->fp, buf, size, &sz_out);
+    FRESULT res = f_read(&self->fp, buf, size, &sz_out);
+    if (res != FR_OK) {
+        *errcode = fresult_to_errno_table[res];
+        return -1;
+    }
     return sz_out;
 }
 
-STATIC machine_int_t file_write(mp_obj_t self_in, const void *buf, machine_uint_t size, int *errcode) {
+STATIC machine_int_t file_obj_write(mp_obj_t self_in, const void *buf, machine_uint_t size, int *errcode) {
     pyb_file_obj_t *self = self_in;
     UINT sz_out;
-    *errcode = f_write(&self->fp, buf, size, &sz_out);
+    FRESULT res = f_write(&self->fp, buf, size, &sz_out);
+    if (res != FR_OK) {
+        *errcode = fresult_to_errno_table[res];
+        return -1;
+    }
     return sz_out;
 }
 
@@ -63,78 +100,164 @@ mp_obj_t file_obj_close(mp_obj_t self_in) {
     f_close(&self->fp);
     return mp_const_none;
 }
-
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(file_obj_close_obj, file_obj_close);
 
 mp_obj_t file_obj___exit__(uint n_args, const mp_obj_t *args) {
     return file_obj_close(args[0]);
 }
-static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(file_obj___exit___obj, 4, 4, file_obj___exit__);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(file_obj___exit___obj, 4, 4, file_obj___exit__);
+
+mp_obj_t file_obj_seek(uint n_args, const mp_obj_t *args) {
+    pyb_file_obj_t *self = args[0];
+    machine_int_t offset = mp_obj_get_int(args[1]);
+    machine_int_t whence = 0;
+    if (n_args == 3) {
+        whence = mp_obj_get_int(args[2]);
+    }
+
+    switch (whence) {
+        case 0: // SEEK_SET
+            f_lseek(&self->fp, offset);
+            break;
+
+        case 1: // SEEK_CUR
+            if (offset != 0) {
+                goto error;
+            }
+            // no-operation
+            break;
+
+        case 2: // SEEK_END
+            if (offset != 0) {
+                goto error;
+            }
+            f_lseek(&self->fp, f_size(&self->fp));
+            break;
+
+        default:
+            goto error;
+    }
+
+    return mp_obj_new_int_from_uint(f_tell(&self->fp));
+
+error:
+    // A bad whence is a ValueError, while offset!=0 is an io.UnsupportedOperation.
+    // But the latter inherits ValueError (as well as IOError), so we just raise ValueError.
+    nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "invalid whence and/or offset"));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(file_obj_seek_obj, 2, 3, file_obj_seek);
+
+mp_obj_t file_obj_tell(mp_obj_t self_in) {
+    pyb_file_obj_t *self = self_in;
+    return mp_obj_new_int_from_uint(f_tell(&self->fp));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(file_obj_tell_obj, file_obj_tell);
+
+STATIC mp_obj_t file_obj_make_new(mp_obj_t type, uint n_args, uint n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 1, 2, false);
+
+    const char *fname = mp_obj_str_get_str(args[0]);
+
+    int mode = 0;
+    if (n_args == 1) {
+        mode = FA_READ;
+    } else {
+        const char *mode_s = mp_obj_str_get_str(args[1]);
+        // TODO make sure only one of r, w, x, a, and b, t are specified
+        while (*mode_s) {
+            switch (*mode_s++) {
+                case 'r':
+                    mode |= FA_READ;
+                    break;
+                case 'w':
+                    mode |= FA_WRITE | FA_CREATE_ALWAYS;
+                    break;
+                case 'x':
+                    mode |= FA_WRITE | FA_CREATE_NEW;
+                    break;
+                case 'a':
+                    mode |= FA_WRITE | FA_OPEN_ALWAYS;
+                    break;
+                case '+':
+                    mode |= FA_READ | FA_WRITE;
+                    break;
+                #if MICROPY_PY_IO_FILEIO
+                case 'b':
+                    type = (mp_obj_t)&mp_type_fileio;
+                    break;
+                #endif
+                case 't':
+                    type = (mp_obj_t)&mp_type_textio;
+                    break;
+            }
+        }
+    }
+
+    pyb_file_obj_t *o = m_new_obj_with_finaliser(pyb_file_obj_t);
+    o->base.type = type;
+
+    FRESULT res = f_open(&o->fp, fname, mode);
+    if (res != FR_OK) {
+        m_del_obj(pyb_file_obj_t, o);
+        nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT((machine_int_t)fresult_to_errno_table[res])));
+    }
+
+    return o;
+}
 
 // TODO gc hook to close the file if not already closed
 
-STATIC const mp_map_elem_t file_locals_dict_table[] = {
+STATIC const mp_map_elem_t rawfile_locals_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&mp_stream_read_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_readall), (mp_obj_t)&mp_stream_readall_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_readline), (mp_obj_t)&mp_stream_unbuffered_readline_obj},
     { MP_OBJ_NEW_QSTR(MP_QSTR_readlines), (mp_obj_t)&mp_stream_unbuffered_readlines_obj},
     { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_close), (mp_obj_t)&file_obj_close_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_seek), (mp_obj_t)&file_obj_seek_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_tell), (mp_obj_t)&file_obj_tell_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR___del__), (mp_obj_t)&file_obj_close_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR___enter__), (mp_obj_t)&mp_identity_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR___exit__), (mp_obj_t)&file_obj___exit___obj },
 };
 
-STATIC MP_DEFINE_CONST_DICT(file_locals_dict, file_locals_dict_table);
+STATIC MP_DEFINE_CONST_DICT(rawfile_locals_dict, rawfile_locals_dict_table);
 
-STATIC mp_obj_t file_obj_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args);
+#if MICROPY_PY_IO_FILEIO
+STATIC const mp_stream_p_t fileio_stream_p = {
+    .read = file_obj_read,
+    .write = file_obj_write,
+    .is_bytes = true,
+};
 
-STATIC const mp_stream_p_t file_obj_stream_p = {
+const mp_obj_type_t mp_type_fileio = {
-    .read = file_read,
+    { &mp_type_type },
-    .write = file_write,
+    .name = MP_QSTR_FileIO,
+    .print = file_obj_print,
+    .make_new = file_obj_make_new,
+    .getiter = mp_identity,
+    .iternext = mp_stream_unbuffered_iter,
+    .stream_p = &fileio_stream_p,
+    .locals_dict = (mp_obj_t)&rawfile_locals_dict,
+};
+#endif
+
+STATIC const mp_stream_p_t textio_stream_p = {
+    .read = file_obj_read,
+    .write = file_obj_write,
 };
 
 const mp_obj_type_t mp_type_textio = {
     { &mp_type_type },
-    .name = MP_QSTR_FileIO,
+    .name = MP_QSTR_TextIOWrapper,
-    .make_new = file_obj_make_new,
     .print = file_obj_print,
+    .make_new = file_obj_make_new,
     .getiter = mp_identity,
     .iternext = mp_stream_unbuffered_iter,
-    .stream_p = &file_obj_stream_p,
+    .stream_p = &textio_stream_p,
-    .locals_dict = (mp_obj_t)&file_locals_dict,
+    .locals_dict = (mp_obj_t)&rawfile_locals_dict,
 };
 
-STATIC mp_obj_t file_obj_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
-    mp_arg_check_num(n_args, n_kw, 1, 2, false);
-    const char *filename = mp_obj_str_get_str(args[0]);
-    const char *mode = "r";
-    if (n_args > 1) {
-        mode = mp_obj_str_get_str(args[1]);
-    }
-    pyb_file_obj_t *self = m_new_obj_with_finaliser(pyb_file_obj_t);
-    self->base.type = &mp_type_textio;
-    if (mode[0] == 'r') {
-        // open for reading
-        FRESULT res = f_open(&self->fp, filename, FA_READ);
-        if (res != FR_OK) {
-            printf("FileNotFoundError: [Errno 2] No such file or directory: '%s'\n", filename);
-            return mp_const_none;
-        }
-    } else if (mode[0] == 'w') {
-        // open for writing, truncate the file first
-        FRESULT res = f_open(&self->fp, filename, FA_WRITE | FA_CREATE_ALWAYS);
-        if (res != FR_OK) {
-            printf("?FileError: could not create file: '%s'\n", filename);
-            return mp_const_none;
-        }
-    } else {
-        printf("ValueError: invalid mode: '%s'\n", mode);
-        return mp_const_none;
-    }
-    return self;
-}
-
 // Factory function for I/O stream classes
 STATIC mp_obj_t pyb_io_open(uint n_args, const mp_obj_t *args) {
     // TODO: analyze mode and buffering args and instantiate appropriate type

stmhal/mpconfigport.h

@@ -48,6 +48,8 @@
 #define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_CMATH            (1)
+#define MICROPY_PY_IO               (1)
+#define MICROPY_PY_IO_FILEIO        (1)
 
 // extra built in names to add to the global namespace
 extern const struct _mp_obj_fun_native_t mp_builtin_help_obj;

stmhal/qstrdefsport.h

@@ -66,6 +66,10 @@ Q(0:/)
 Q(0:/lib)
 Q(millis)
 
+// for file class
+Q(seek)
+Q(tell)
+
 // for RTC class
 Q(RTC)
 Q(info)