diff options
author | Gatis Paeglis <gatis.paeglis@qt.io> | 2019-01-16 15:12:16 +0800 |
---|---|---|
committer | Liang Qi <liang.qi@qt.io> | 2019-02-06 22:11:44 +0000 |
commit | c0ebec51e3dd1b52767878fe7fd56ce6e8f95461 (patch) | |
tree | 906f7dbc0c799dbbe55fa579d63e6ce73b5f4dea /src/plugins/platforms/xcb/qxcbclipboard.cpp | |
parent | edc455c69b7a938f7a7ce98b5b0ffd1398f239c6 (diff) |
xcb: respect big-request encoding in max request size
From big-request specification:
"This extension defines a mechanism for extending the length
field beyond 16 bits. If the normal 16-bit length field of the protocol
request is zero, then an additional 32-bit field containing the actual
length (in 4-byte units) is inserted into the request, immediately
following the 16-bit length field."
Meaning that the request requires 4 additional bytes. This patch provides
a convenience API for calculating maximum request data size.
Besides fixing QTBUG-73044, it was also discovered that calculations
for xcb_image_put (in QXcbBackingStoreImage::flushPixmap) were wrong.
The code assumed that xcb_get_maximum_request_length() returns bytes,
but what it actually returns is length which is measured in four-byte
units. This means that we were sending 4x less bytes than allowed by
the protocol. Furthermore, use the actual 'stride' (bytes per line) value
when calculating rows_per_put. The new stride value was introduced
by 760b2929a3b268e2edf14a561329bdb78fbdc26e, but was not updated in
rows_per_put calculations.
Fixes: QTBUG-73044
Done-with: JiDe Zhang <zccrs@live.com>
Done-with: Mikhail Svetkin <mikhail.svetkin@qt.io>
Change-Id: I06beb6082da3e8bc78225a87603914e796fe5878
Reviewed-by: Błażej Szczygieł <spaz16@wp.pl>
Reviewed-by: JiDe Zhang <zccrs@live.com>
Reviewed-by: Mikhail Svetkin <mikhail.svetkin@qt.io>
Reviewed-by: Uli Schlachter <psychon@znc.in>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Diffstat (limited to 'src/plugins/platforms/xcb/qxcbclipboard.cpp')
-rw-r--r-- | src/plugins/platforms/xcb/qxcbclipboard.cpp | 23 |
1 files changed, 8 insertions, 15 deletions
diff --git a/src/plugins/platforms/xcb/qxcbclipboard.cpp b/src/plugins/platforms/xcb/qxcbclipboard.cpp index ac8b029916..2cb6720d40 100644 --- a/src/plugins/platforms/xcb/qxcbclipboard.cpp +++ b/src/plugins/platforms/xcb/qxcbclipboard.cpp @@ -240,8 +240,8 @@ QXcbClipboard::QXcbClipboard(QXcbConnection *c) xcb_xfixes_select_selection_input_checked(xcb_connection(), m_owner, atom(QXcbAtom::CLIPBOARD), mask); } - // change property protocol request is 24 bytes - m_increment = (xcb_get_maximum_request_length(xcb_connection()) * 4) - 24; + // xcb_change_property_request_t and xcb_get_property_request_t are the same size + m_maxPropertyRequestDataBytes = connection()->maxRequestDataBytes(sizeof(xcb_change_property_request_t)); } QXcbClipboard::~QXcbClipboard() @@ -486,7 +486,7 @@ xcb_atom_t QXcbClipboard::sendSelection(QMimeData *d, xcb_atom_t target, xcb_win if (m_clipboard_closing) allow_incr = false; - if (data.size() > m_increment && allow_incr) { + if (data.size() > m_maxPropertyRequestDataBytes && allow_incr) { long bytes = data.size(); xcb_change_property(xcb_connection(), XCB_PROP_MODE_REPLACE, window, property, atom(QXcbAtom::INCR), 32, 1, (const void *)&bytes); @@ -496,7 +496,7 @@ xcb_atom_t QXcbClipboard::sendSelection(QMimeData *d, xcb_atom_t target, xcb_win } // make sure we can perform the XChangeProperty in a single request - if (data.size() > m_increment) + if (data.size() > m_maxPropertyRequestDataBytes) return XCB_NONE; // ### perhaps use several XChangeProperty calls w/ PropModeAppend? int dataSize = data.size() / (dataFormat / 8); // use a single request to transfer data @@ -678,17 +678,8 @@ void QXcbClipboard::handleXFixesSelectionRequest(xcb_xfixes_selection_notify_eve emitChanged(mode); } - -static inline int maxSelectionIncr(xcb_connection_t *c) -{ - int l = xcb_get_maximum_request_length(c); - return (l > 65536 ? 65536*4 : l*4) - 100; -} - bool QXcbClipboard::clipboardReadProperty(xcb_window_t win, xcb_atom_t property, bool deleteProperty, QByteArray *buffer, int *size, xcb_atom_t *type, int *format) { - int maxsize = maxSelectionIncr(xcb_connection()); - ulong bytes_left; // bytes_after xcb_atom_t dummy_type; int dummy_format; @@ -705,7 +696,8 @@ bool QXcbClipboard::clipboardReadProperty(xcb_window_t win, xcb_atom_t property, } *type = reply->type; *format = reply->format; - bytes_left = reply->bytes_after; + + auto bytes_left = reply->bytes_after; int offset = 0, buffer_offset = 0; @@ -720,7 +712,8 @@ bool QXcbClipboard::clipboardReadProperty(xcb_window_t win, xcb_atom_t property, while (bytes_left) { // more to read... - reply = Q_XCB_REPLY(xcb_get_property, xcb_connection(), false, win, property, XCB_GET_PROPERTY_TYPE_ANY, offset, maxsize/4); + reply = Q_XCB_REPLY(xcb_get_property, xcb_connection(), false, win, property, + XCB_GET_PROPERTY_TYPE_ANY, offset, m_maxPropertyRequestDataBytes / 4); if (!reply || reply->type == XCB_NONE) break; |