py/objarray: Fix constructing a memoryview from a memoryview.

Fixes issue #7261.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2021-05-18 00:23:13 +10:00
parent 1446107b4d
commit 6d2680fa36
2 changed files with 18 additions and 0 deletions

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@ -220,6 +220,14 @@ STATIC mp_obj_t memoryview_make_new(const mp_obj_type_t *type_in, size_t n_args,
bufinfo.len / mp_binary_get_size('@', bufinfo.typecode, NULL),
bufinfo.buf));
// If the input object is a memoryview then need to point the items of the
// new memoryview to the start of the buffer so the GC can trace it.
if (mp_obj_get_type(args[0]) == &mp_type_memoryview) {
mp_obj_array_t *other = MP_OBJ_TO_PTR(args[0]);
self->memview_offset = other->memview_offset;
self->items = other->items;
}
// test if the object can be written to
if (mp_get_buffer(args[0], &bufinfo, MP_BUFFER_RW)) {
self->typecode |= MP_OBJ_ARRAY_TYPECODE_FLAG_RW; // indicate writable buffer

View File

@ -21,3 +21,13 @@ for i in range(100000):
# check that the memoryview is still what we want
print(list(m))
# check that creating a memoryview of a memoryview retains the underlying data
m = None
gc.collect() # cleanup from previous test
m = memoryview(memoryview(bytearray(i for i in range(50)))[5:-5])
print(sum(m), list(m[:10]))
gc.collect()
for i in range(10):
list(range(10)) # allocate memory to overwrite any reclaimed heap
print(sum(m), list(m[:10]))