diff options
| -rw-r--r-- | src/blueshift_drm.pyx | 53 |
1 files changed, 50 insertions, 3 deletions
diff --git a/src/blueshift_drm.pyx b/src/blueshift_drm.pyx index 7de8c70..16ad4a5 100644 --- a/src/blueshift_drm.pyx +++ b/src/blueshift_drm.pyx @@ -16,7 +16,7 @@ # along with this program. If not, see <http://www.gnu.org/licenses/>. cimport cython -from libc.stdlib cimport malloc, free +from libc.stdlib cimport malloc, free, realloc from libc.stdint cimport * @@ -516,22 +516,69 @@ def drm_get_edid(int connection, int connector_index): cdef char* edid cdef bytes rc + # Prototype side of the hexadecimal representation + # of the EDID, should be exact size = 256 + # Allocate storage space for the EDID, with one + # extra character for NUL-termination edid = <char*>malloc((size + 1) * sizeof(char)) + # Check for out-of-memory error if edid is NULL: raise MemoryError() + # Fill the storage space for the EDID, with the + # EDID of the monitor connected to the selected + # connector, in hexadecimal, representation. got = blueshift_drm_get_edid(connection, connector_index, edid, size, 1) + # If the length of the EDID is zero, if got == 0: + # the free the storage space, free(edid) + # and return that it failed. return None + # But if we got an non-zero length, it is of the + # EDID's byte-length, not in hexadecimal representation + # that is twice as long. if got * 2 > size: - size = got - blueshift_drm_get_edid(connection, connector_index, edid, size, 1) + # In if that length is larger than we have anticipated, + # update to new size (of the hexadecimal representation), + size = got * 2 + # and reallocate the storage. + edid = <char*>realloc(edid, (size + 1) * sizeof(char)) + # Check for out-of-memory error + if edid is NULL: + raise MemoryError() + # Get the full EDID. + got = blueshift_drm_get_edid(connection, connector_index, edid, size, 1) + # Check that we got the EDID. There is an unlikely + # race condition where the user can have unplugged + # the monitor. + if got == 0: + # If we did not get an EDID, + # free the storage for it, + free(edid) + # and return that it failed. + return None + # If we got a large EDID yet, + if got * 2 > size: + # ignore it because it should happen, + # EDID:s are 128 bytes long and the risk that + # the use plugged in new monitor that did not + # have the same EDID format, is super unlikely. + # She would have to pause the program or used + # a KVM switch between the two readings. + # Instead just truncate the EDID to the size + # that we expected; it is not fatal. + got = size // 2 + # NUL-terminate the EDID, edid[got * 2] = 0 + # and convert it to bytes so that we can + # later convert it to a Python string, rc = edid + # and deallocate the C string. free(edid) + # Convert the EDID to a Sython string return rc.decode('utf-8', 'replace') |