dix: add helper functions to create DDX touch recs

DDX touch points are the ones that keep records of the driver-submitted
touchpoints. They're unaffected by the grab state and terminate on a
TouchEnd submitted by the driver.

The client ID assigned is server-global.

Since drivers usually submit in the SIGIO handler, we cannot allocate in the
these functions.

Co-authored-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>

dix/touch.c

@@ -31,6 +31,122 @@
 #include "inputstr.h"
 #include "scrnintstr.h"
 
+#include "eventstr.h"
+#include "exevents.h"
+
+/**
+ * Some documentation about touch points:
+ * The driver submits touch events with it's own (unique) touch point ID.
+ * The driver may re-use those IDs, the DDX doesn't care. It just passes on
+ * the data to the DIX. In the server, the driver's ID is referred to as the
+ * DDX id anyway.
+ *
+ * On a TouchBegin, we create a DDXTouchPointInfo that contains the DDX id
+ * and the client ID that this touchpoint will have. The client ID is the
+ * one visible on the protocol.
+ *
+ * TouchUpdate and TouchEnd will only be processed if there is an active
+ * touchpoint with the same DDX id.
+ *
+ * The DDXTouchPointInfo struct is stored dev->last.touches. When the event
+ * being processed, it becomes a TouchPointInfo in dev->touch-touches which
+ * contains amongst other things the sprite trace and delivery information.
+ */
+
+/**
+ * Given the DDX-facing ID (which is _not_ DeviceEvent::detail.touch), find the
+ * associated DDXTouchPointInfoRec.
+ *
+ * @param dev The device to create the touch point for
+ * @param ddx_id Touch id assigned by the driver/ddx
+ * @param create Create the touchpoint if it cannot be found
+ */
+DDXTouchPointInfoPtr
+TouchFindByDDXID(DeviceIntPtr dev, uint32_t ddx_id, Bool create)
+{
+    DDXTouchPointInfoPtr ti;
+    int i;
+
+    if (!dev->touch)
+        return NULL;
+
+    for (i = 0; i < dev->last.num_touches; i++)
+    {
+        ti = &dev->last.touches[i];
+        if (ti->active && ti->ddx_id == ddx_id)
+            return ti;
+    }
+
+    return create ? TouchBeginDDXTouch(dev, ddx_id) : NULL;
+}
+
+/**
+ * Given a unique DDX ID for a touchpoint, create a touchpoint record and
+ * return it.
+ *
+ * If no other touch points are active, mark new touchpoint for pointer
+ * emulation.
+ *
+ * Returns NULL on failure (i.e. if another touch with that ID is already active,
+ * allocation failure).
+ */
+DDXTouchPointInfoPtr
+TouchBeginDDXTouch(DeviceIntPtr dev, uint32_t ddx_id)
+{
+    static int next_client_id = 1;
+    int i;
+    TouchClassPtr t = dev->touch;
+    DDXTouchPointInfoPtr ti = NULL;
+    Bool emulate_pointer = (t->mode == XIDirectTouch);
+
+    if (!t)
+        return NULL;
+
+    /* Look for another active touchpoint with the same DDX ID. DDX
+     * touchpoints must be unique. */
+    if (TouchFindByDDXID(dev, ddx_id, FALSE))
+        return NULL;
+
+    for (i = 0; i < dev->last.num_touches; i++)
+    {
+        /* Only emulate pointer events on the first touch */
+        if (dev->last.touches[i].active)
+            emulate_pointer = FALSE;
+        else if (!ti) /* ti is now first non-active touch rec */
+            ti = &dev->last.touches[i];
+
+        if (!emulate_pointer && ti)
+            break;
+    }
+
+    if (ti)
+    {
+        int client_id;
+        ti->active = TRUE;
+        ti->ddx_id = ddx_id;
+        client_id = next_client_id;
+        next_client_id++;
+        if (next_client_id == 0)
+            next_client_id = 1;
+        ti->client_id = client_id;
+        ti->emulate_pointer = emulate_pointer;
+        return ti;
+    }
+
+    /* If we get here, then we've run out of touches, drop the event */
+    return NULL;
+}
+
+void
+TouchEndDDXTouch(DeviceIntPtr dev, DDXTouchPointInfoPtr ti)
+{
+    TouchClassPtr t = dev->touch;
+
+    if (!t)
+        return;
+
+    ti->active = FALSE;
+}
 
 void
 TouchInitDDXTouchPoint(DeviceIntPtr dev, DDXTouchPointInfoPtr ddxtouch)

include/input.h

@@ -587,6 +587,11 @@ enum TouchListenerType {
 };
 
 extern void TouchInitDDXTouchPoint(DeviceIntPtr dev, DDXTouchPointInfoPtr ddxtouch);
+extern DDXTouchPointInfoPtr TouchBeginDDXTouch(DeviceIntPtr dev, uint32_t ddx_id);
+extern void TouchEndDDXTouch(DeviceIntPtr dev, DDXTouchPointInfoPtr ti);
+extern DDXTouchPointInfoPtr TouchFindByDDXID(DeviceIntPtr dev,
+                                             uint32_t ddx_id,
+                                             Bool create);
 extern Bool TouchInitTouchPoint(TouchClassPtr touch, ValuatorClassPtr v, int index);
 extern void TouchFreeTouchPoint(DeviceIntPtr dev, int index);
 

test/Makefile.am

@@ -1,6 +1,6 @@
 if ENABLE_UNIT_TESTS
 SUBDIRS= .
-noinst_PROGRAMS = list string
+noinst_PROGRAMS = list string touch
 if XORG
 # Tests that require at least some DDX functions in order to fully link
 # For now, requires xf86 ddx, could be adjusted to use another
@@ -35,6 +35,7 @@ list_LDADD=$(TEST_LDADD)
 misc_LDADD=$(TEST_LDADD)
 fixes_LDADD=$(TEST_LDADD)
 xfree86_LDADD=$(TEST_LDADD)
+touch_LDADD=$(TEST_LDADD)
 
 libxservertest_la_LIBADD = $(XSERVER_LIBS)
 if XORG

test/touch.c

@@ -0,0 +1,149 @@
+/**
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a
+ *  copy of this software and associated documentation files (the "Software"),
+ *  to deal in the Software without restriction, including without limitation
+ *  the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ *  and/or sell copies of the Software, and to permit persons to whom the
+ *  Software is furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice (including the next
+ *  paragraph) shall be included in all copies or substantial portions of the
+ *  Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ *  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ *  DEALINGS IN THE SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <stdint.h>
+#include "inputstr.h"
+#include "assert.h"
+
+static void touch_find_ddxid(void)
+{
+    DeviceIntRec dev;
+    DDXTouchPointInfoPtr ti;
+    ValuatorClassRec val;
+    TouchClassRec touch;
+    int size = 5;
+    int i;
+
+    memset(&dev, 0, sizeof(dev));
+    dev.id = 2;
+    dev.valuator = &val;
+    val.numAxes = 5;
+    dev.touch = &touch;
+    dev.last.num_touches = size;
+    dev.last.touches = calloc(dev.last.num_touches, sizeof(*dev.last.touches));
+    inputInfo.devices = &dev;
+    assert(dev.last.touches);
+
+
+    dev.last.touches[0].active = TRUE;
+    dev.last.touches[0].ddx_id = 10;
+    dev.last.touches[0].client_id = 20;
+
+
+    /* existing */
+    ti = TouchFindByDDXID(&dev, 10, FALSE);
+    assert(ti == &dev.last.touches[0]);
+
+    /* non-existing */
+    ti = TouchFindByDDXID(&dev, 20, FALSE);
+    assert(ti == NULL);
+
+    /* Non-active */
+    dev.last.touches[0].active = FALSE;
+    ti = TouchFindByDDXID(&dev, 10, FALSE);
+    assert(ti == NULL);
+
+    /* create on number 2*/
+    dev.last.touches[0].active = TRUE;
+
+    ti = TouchFindByDDXID(&dev, 20, TRUE);
+    assert(ti == &dev.last.touches[1]);
+    assert(ti->active);
+    assert(ti->ddx_id == 20);
+
+    /* set all to active */
+    for (i = 0; i < size; i++)
+        dev.last.touches[i].active = TRUE;
+
+    /* Try to create more, fail */
+    ti = TouchFindByDDXID(&dev, 30, TRUE);
+    assert(ti == NULL);
+    ti = TouchFindByDDXID(&dev, 30, TRUE);
+    assert(ti == NULL);
+    /* make sure we haven't resized, we're in the signal handler */
+    assert(dev.last.num_touches == size);
+
+    /* stop one touchpoint, try to create, succeed */
+    dev.last.touches[2].active = FALSE;
+    ti = TouchFindByDDXID(&dev, 30, TRUE);
+    assert(ti == &dev.last.touches[2]);
+    /* but still grow anyway */
+    ProcessWorkQueue();
+    ti = TouchFindByDDXID(&dev, 40, TRUE);
+    assert(ti == &dev.last.touches[size]);
+}
+
+static void touch_begin_ddxtouch(void)
+{
+    DeviceIntRec dev;
+    DDXTouchPointInfoPtr ti;
+    ValuatorClassRec val;
+    TouchClassRec touch;
+    int ddx_id = 123;
+    unsigned int last_client_id = 0;
+    int size = 5;
+
+    memset(&dev, 0, sizeof(dev));
+    dev.id = 2;
+    dev.valuator = &val;
+    val.numAxes = 5;
+    touch.mode = XIDirectTouch;
+    dev.touch = &touch;
+    dev.last.num_touches = size;
+    dev.last.touches = calloc(dev.last.num_touches, sizeof(*dev.last.touches));
+    inputInfo.devices = &dev;
+    assert(dev.last.touches);
+
+    ti = TouchBeginDDXTouch(&dev, ddx_id);
+    assert(ti);
+    assert(ti->ddx_id == ddx_id);
+    /* client_id == ddx_id can happen in real life, but not in this test */
+    assert(ti->client_id != ddx_id);
+    assert(ti->active);
+    assert(ti->client_id > last_client_id);
+    assert(ti->emulate_pointer);
+    last_client_id = ti->client_id;
+
+    ddx_id += 10;
+    ti = TouchBeginDDXTouch(&dev, ddx_id);
+    assert(ti);
+    assert(ti->ddx_id == ddx_id);
+    /* client_id == ddx_id can happen in real life, but not in this test */
+    assert(ti->client_id != ddx_id);
+    assert(ti->active);
+    assert(ti->client_id > last_client_id);
+    assert(!ti->emulate_pointer);
+    last_client_id = ti->client_id;
+}
+
+int main(int argc, char** argv)
+{
+    touch_find_ddxid();
+    touch_begin_ddxtouch();
+
+    return 0;
+}