#4271 move shared pointer via paint callback

xpra/client/gui/window_backing_base.py

@@ -883,7 +883,8 @@ def paint_mmap(self, img_data, x:int, y:int, width:int, height:int, rowstride:in
         """ must be called from UI thread
             see _mmap_send() in server.py for details """
         assert self.mmap_enabled
-        data = mmap_read(self.mmap, *img_data)
+        data, free_cb = mmap_read(self.mmap, *img_data)
+        callbacks.append(free_cb)
         rgb_format = options.strget("rgb_format", "RGB")
         #Note: BGR(A) is only handled by gl_window_backing
         x, y = self.gravity_adjust(x, y, options)

xpra/net/mmap_pipe.py

@@ -6,9 +6,10 @@
 import os
 import sys
 from ctypes import c_ubyte, c_char, c_uint32
-from typing import Tuple, Optional, Any
+from typing import Tuple, Optional, Any, Callable
 
 from xpra.util import roundup
+from xpra.common import noop
 from xpra.os_util import memoryview_to_bytes, shellsub, get_group_id, WIN32, POSIX
 from xpra.scripts.config import FALSE_OPTIONS, TRUE_OPTIONS
 from xpra.simple_stats import std_unit
@@ -245,7 +246,7 @@ def int_from_buffer(mmap_area, pos:int) -> c_uint32:
 
 #descr_data is a list of (offset, length)
 #areas from the mmap region
-def mmap_read(mmap_area, *descr_data) -> bytes:
+def mmap_read(mmap_area, *descr_data) -> tuple[bytes, Callable]:
     """
         Reads data from the mmap_area as written by 'mmap_write'.
         The descr_data is the list of mmap chunks used.
@@ -255,15 +256,16 @@ def mmap_read(mmap_area, *descr_data) -> bytes:
         #construct an array directly from the mmap zone:
         offset, length = descr_data[0]
         arraytype = c_char * length
-        data_start.value = offset+length
-        return arraytype.from_buffer(mmap_area, offset)
+        def free_mem(*_args):
+            data_start.value = offset + length
+        return arraytype.from_buffer(mmap_area, offset), free_mem
     #re-construct the buffer from discontiguous chunks:
     data = []
     for offset, length in descr_data:
         mmap_area.seek(offset)
         data.append(mmap_area.read(length))
         data_start.value = offset+length
-    return b"".join(data)
+    return b"".join(data), noop
 
 
 def mmap_write(mmap_area, mmap_size:int, data):