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py: Allow lexer to raise exceptions during construction.

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This patch refactors the error handling in the lexer, to simplify it (ie
reduce code size).

A long time ago, when the lexer/parser/compiler were first written, the
lexer and parser were designed so they didn't use exceptions (ie nlr) to
report errors but rather returned an error code.  Over time that has
gradually changed, the parser in particular has more and more ways of
raising exceptions.  Also, the lexer never really handled all errors without
raising, eg there were some memory errors which could raise an exception
(and in these rare cases one would get a fatal nlr-not-handled fault).

This patch accepts the fact that the lexer can raise exceptions in some
cases and allows it to raise exceptions to handle all its errors, which are
for the most part just out-of-memory errors during construction of the
lexer.  This makes the lexer a bit simpler, and also the persistent code
stuff is simplified.

What this means for users of the lexer is that calls to it must be wrapped
in a nlr handler.  But all uses of the lexer already have such an nlr
handler for the parser (and compiler) so that doesn't put any extra burden
on the callers.
This commit is contained in:
Damien George 2017-03-14 11:16:31 +11:00
parent 9773506ab1
commit 1831034be1
7 changed files with 31 additions and 92 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
extmod/vfs_reader.c
View File

@ -27,7 +27,7 @@
#include <stdio.h>
#include <string.h>
#include "py/nlr.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "py/reader.h"
#include "extmod/vfs.h"
@ -69,30 +69,19 @@ STATIC void mp_reader_vfs_close(void *data) {
m_del_obj(mp_reader_vfs_t, reader);
}
int mp_reader_new_file(mp_reader_t *reader, const char *filename) {
mp_reader_vfs_t *rf = m_new_obj_maybe(mp_reader_vfs_t);
if (rf == NULL) {
return MP_ENOMEM;
}
// TODO we really should just let this function raise a uPy exception
nlr_buf_t nlr;
if (nlr_push(&nlr) == 0) {
void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
mp_reader_vfs_t *rf = m_new_obj(mp_reader_vfs_t);
mp_obj_t arg = mp_obj_new_str(filename, strlen(filename), false);
rf->file = mp_vfs_open(1, &arg, (mp_map_t*)&mp_const_empty_map);
int errcode;
rf->len = mp_stream_rw(rf->file, rf->buf, sizeof(rf->buf), &errcode, MP_STREAM_RW_READ | MP_STREAM_RW_ONCE);
nlr_pop();
if (errcode != 0) {
return errcode;
}
} else {
return MP_ENOENT; // assume error was "file not found"
mp_raise_OSError(errcode);
}
rf->pos = 0;
reader->data = rf;
reader->readbyte = mp_reader_vfs_readbyte;
reader->close = mp_reader_vfs_close;
return 0; // success
}
#endif // MICROPY_READER_VFS

3
py/builtinevex.c
View File

@ -136,9 +136,6 @@ STATIC mp_obj_t eval_exec_helper(size_t n_args, const mp_obj_t *args, mp_parse_i
mp_lexer_t *lex;
if (MICROPY_PY_BUILTINS_EXECFILE && parse_input_kind == MP_PARSE_SINGLE_INPUT) {
lex = mp_lexer_new_from_file(str);
if (lex == NULL) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "could not open file '%s'", str));
}
parse_input_kind = MP_PARSE_FILE_INPUT;
} else {
lex = mp_lexer_new_from_str_len(MP_QSTR__lt_string_gt_, str, str_len, 0);

17
py/builtinimport.c
View File

@ -131,18 +131,7 @@ STATIC mp_import_stat_t find_file(const char *file_str, uint file_len, vstr_t *d
}
#if MICROPY_ENABLE_COMPILER
STATIC void do_load_from_lexer(mp_obj_t module_obj, mp_lexer_t *lex, const char *fname) {
if (lex == NULL) {
// we verified the file exists using stat, but lexer could still fail
if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
mp_raise_msg(&mp_type_ImportError, "module not found");
} else {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError,
"no module named '%s'", fname));
}
}
STATIC void do_load_from_lexer(mp_obj_t module_obj, mp_lexer_t *lex) {
#if MICROPY_PY___FILE__
qstr source_name = lex->source_name;
mp_store_attr(module_obj, MP_QSTR___file__, MP_OBJ_NEW_QSTR(source_name));
@ -207,7 +196,7 @@ STATIC void do_load(mp_obj_t module_obj, vstr_t *file) {
// found the filename in the list of frozen files, then load and execute it.
#if MICROPY_MODULE_FROZEN_STR
if (frozen_type == MP_FROZEN_STR) {
do_load_from_lexer(module_obj, modref, file_str);
do_load_from_lexer(module_obj, modref);
return;
}
#endif
@ -235,7 +224,7 @@ STATIC void do_load(mp_obj_t module_obj, vstr_t *file) {
#if MICROPY_ENABLE_COMPILER
{
mp_lexer_t *lex = mp_lexer_new_from_file(file_str);
do_load_from_lexer(module_obj, lex, file_str);
do_load_from_lexer(module_obj, lex);
return;
}
#endif

31
py/lexer.c
View File

@ -699,13 +699,7 @@ void mp_lexer_to_next(mp_lexer_t *lex) {
}
mp_lexer_t *mp_lexer_new(qstr src_name, mp_reader_t reader) {
mp_lexer_t *lex = m_new_obj_maybe(mp_lexer_t);
// check for memory allocation error
if (lex == NULL) {
reader.close(reader.data);
return NULL;
}
mp_lexer_t *lex = m_new_obj(mp_lexer_t);
lex->source_name = src_name;
lex->reader = reader;
@ -715,16 +709,9 @@ mp_lexer_t *mp_lexer_new(qstr src_name, mp_reader_t reader) {
lex->nested_bracket_level = 0;
lex->alloc_indent_level = MICROPY_ALLOC_LEXER_INDENT_INIT;
lex->num_indent_level = 1;
lex->indent_level = m_new_maybe(uint16_t, lex->alloc_indent_level);
lex->indent_level = m_new(uint16_t, lex->alloc_indent_level);
vstr_init(&lex->vstr, 32);
// check for memory allocation error
// note: vstr_init above may fail on malloc, but so may mp_lexer_to_next below
if (lex->indent_level == NULL) {
mp_lexer_free(lex);
return NULL;
}
// store sentinel for first indentation level
lex->indent_level[0] = 0;
@ -764,9 +751,7 @@ mp_lexer_t *mp_lexer_new(qstr src_name, mp_reader_t reader) {
mp_lexer_t *mp_lexer_new_from_str_len(qstr src_name, const char *str, size_t len, size_t free_len) {
mp_reader_t reader;
if (!mp_reader_new_mem(&reader, (const byte*)str, len, free_len)) {
return NULL;
}
mp_reader_new_mem(&reader, (const byte*)str, len, free_len);
return mp_lexer_new(src_name, reader);
}
@ -774,10 +759,7 @@ mp_lexer_t *mp_lexer_new_from_str_len(qstr src_name, const char *str, size_t len
mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
mp_reader_t reader;
int ret = mp_reader_new_file(&reader, filename);
if (ret != 0) {
return NULL;
}
mp_reader_new_file(&reader, filename);
return mp_lexer_new(qstr_from_str(filename), reader);
}
@ -785,10 +767,7 @@ mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
mp_lexer_t *mp_lexer_new_from_fd(qstr filename, int fd, bool close_fd) {
mp_reader_t reader;
int ret = mp_reader_new_file_from_fd(&reader, fd, close_fd);
if (ret != 0) {
return NULL;
}
mp_reader_new_file_from_fd(&reader, fd, close_fd);
return mp_lexer_new(filename, reader);
}

9
py/persistentcode.c
View File

@ -225,18 +225,13 @@ mp_raw_code_t *mp_raw_code_load(mp_reader_t *reader) {
mp_raw_code_t *mp_raw_code_load_mem(const byte *buf, size_t len) {
mp_reader_t reader;
if (!mp_reader_new_mem(&reader, buf, len, 0)) {
m_malloc_fail(BYTES_PER_WORD); // we need to raise a MemoryError
}
mp_reader_new_mem(&reader, buf, len, 0);
return mp_raw_code_load(&reader);
}
mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
mp_reader_t reader;
int ret = mp_reader_new_file(&reader, filename);
if (ret != 0) {
mp_raise_OSError(ret);
}
mp_reader_new_file(&reader, filename);
return mp_raw_code_load(&reader);
}

28
py/reader.c
View File

@ -27,6 +27,7 @@
#include <stdio.h>
#include <assert.h>
#include "py/runtime.h"
#include "py/mperrno.h"
#include "py/reader.h"
@ -54,11 +55,8 @@ STATIC void mp_reader_mem_close(void *data) {
m_del_obj(mp_reader_mem_t, reader);
}
bool mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t free_len) {
mp_reader_mem_t *rm = m_new_obj_maybe(mp_reader_mem_t);
if (rm == NULL) {
return false;
}
void mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t free_len) {
mp_reader_mem_t *rm = m_new_obj(mp_reader_mem_t);
rm->free_len = free_len;
rm->beg = buf;
rm->cur = buf;
@ -66,7 +64,6 @@ bool mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t
reader->data = rm;
reader->readbyte = mp_reader_mem_readbyte;
reader->close = mp_reader_mem_close;
return true;
}
#if MICROPY_READER_POSIX
@ -110,14 +107,8 @@ STATIC void mp_reader_posix_close(void *data) {
m_del_obj(mp_reader_posix_t, reader);
}
int mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
mp_reader_posix_t *rp = m_new_obj_maybe(mp_reader_posix_t);
if (rp == NULL) {
if (close_fd) {
close(fd);
}
return MP_ENOMEM;
}
void mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
mp_reader_posix_t *rp = m_new_obj(mp_reader_posix_t);
rp->close_fd = close_fd;
rp->fd = fd;
int n = read(rp->fd, rp->buf, sizeof(rp->buf));
@ -125,22 +116,21 @@ int mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd) {
if (close_fd) {
close(fd);
}
return errno;
mp_raise_OSError(errno);
}
rp->len = n;
rp->pos = 0;
reader->data = rp;
reader->readbyte = mp_reader_posix_readbyte;
reader->close = mp_reader_posix_close;
return 0; // success
}
int mp_reader_new_file(mp_reader_t *reader, const char *filename) {
void mp_reader_new_file(mp_reader_t *reader, const char *filename) {
int fd = open(filename, O_RDONLY, 0644);
if (fd < 0) {
return errno;
mp_raise_OSError(errno);
}
return mp_reader_new_file_from_fd(reader, fd, true);
mp_reader_new_file_from_fd(reader, fd, true);
}
#endif

6
py/reader.h
View File

@ -39,8 +39,8 @@ typedef struct _mp_reader_t {
void (*close)(void *data);
} mp_reader_t;
bool mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t free_len);
int mp_reader_new_file(mp_reader_t *reader, const char *filename);
int mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd);
void mp_reader_new_mem(mp_reader_t *reader, const byte *buf, size_t len, size_t free_len);
void mp_reader_new_file(mp_reader_t *reader, const char *filename);
void mp_reader_new_file_from_fd(mp_reader_t *reader, int fd, bool close_fd);
#endif // MICROPY_INCLUDED_PY_READER_H