extmod/vfs_reader: Add support for opening a memory-mappable file.

If the file can be memory mapped (because it responds to the buffer
protocol) then return a memory-reader that directly references the ROM data
of the file.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George
2024-12-18 11:30:33 +11:00
parent f870e8d2d4
commit 5e9dd4b6a2

View File

@@ -85,6 +85,17 @@ void mp_reader_new_file(mp_reader_t *reader, qstr filename) {
const mp_stream_p_t *stream_p = mp_get_stream(file);
int errcode = 0;
#if MICROPY_VFS_ROM
// Check if the stream can be memory mapped.
mp_buffer_info_t bufinfo;
if (mp_get_buffer(file, &bufinfo, MP_BUFFER_READ)) {
mp_reader_new_mem(reader, bufinfo.buf, bufinfo.len, MP_READER_IS_ROM);
return;
}
#endif
// Determine how big the input buffer should be, if the stream requests a certain size or not.
mp_uint_t bufsize = stream_p->ioctl(file, MP_STREAM_GET_BUFFER_SIZE, 0, &errcode);
if (bufsize == MP_STREAM_ERROR || bufsize == 0) {
// bufsize == 0 is included here to support mpremote v1.21 and older where mount file ioctl
@@ -94,6 +105,7 @@ void mp_reader_new_file(mp_reader_t *reader, qstr filename) {
bufsize = MIN(MICROPY_READER_VFS_MAX_BUFFER_SIZE, MAX(MICROPY_READER_VFS_MIN_BUFFER_SIZE, bufsize));
}
// Create the reader.
mp_reader_vfs_t *rf = m_new_obj_var(mp_reader_vfs_t, buf, byte, bufsize);
rf->file = file;
rf->bufsize = bufsize;