cursor: Move pointer barrier code over to XI

In order to send events to specific windows associated with the barrier,
we need to move the code that handles barriers to somewhere where it's
easier to construct and send events. Rather than duplicating XSync with
its XSyncSelectAlarm, re-use the existing XI infrastructure.

For now, just move a bunch of code over, rename some things, and initialize
the new structures, but still consider it a separate codebase. Pointer barrier
requests are still handled by XFixes, so this is a weird intermediate state.
It's unknown whether we'll add explicit requests to pointer barriers inside
XI.

Signed-off-by: Jasper St. Pierre <jstpierre@mecheye.net>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

4 files changed, 601 insertions, 0 deletions

diff --git a/Xi/Makefile.am b/Xi/Makefile.am
index 69c7886b9..af85bd049 100644
--- a/Xi/Makefile.am
+++ b/Xi/Makefile.am
@@ -78,6 +78,8 @@ libXi_la_SOURCES =	\
 	ungrdevk.h \
 	xiallowev.c \
 	xiallowev.h \
+	xibarriers.c \
+	xibarriers.h \
 	xichangecursor.c \
 	xichangecursor.h \
 	xichangehierarchy.c \
diff --git a/Xi/extinit.c b/Xi/extinit.c
index 7e3075551..1074b237c 100644
--- a/Xi/extinit.c
+++ b/Xi/extinit.c
@@ -122,6 +122,7 @@ SOFTWARE.
 #include "xiqueryversion.h"
 #include "xisetclientpointer.h"
 #include "xiwarppointer.h"
+#include "xibarriers.h"
 
 /* Masks for XI events have to be aligned with core event (partially anyway).
  * If DeviceButtonMotionMask is != ButtonMotionMask, event delivery
@@ -1263,6 +1264,9 @@ XInputExtensionInit(void)
     if (!AddCallback(&ClientStateCallback, XIClientCallback, 0))
         FatalError("Failed to add callback to XI.\n");
 
+    if (!XIBarrierInit())
+        FatalError("Could not initialize barriers.\n");
+
     extEntry = AddExtension(INAME, IEVENTS, IERRORS, ProcIDispatch,
                             SProcIDispatch, IResetProc, StandardMinorOpcode);
     if (extEntry) {
diff --git a/Xi/xibarriers.c b/Xi/xibarriers.c
new file mode 100644
index 000000000..ba9fd063e
--- /dev/null
+++ b/Xi/xibarriers.c
@@ -0,0 +1,548 @@
+/*
+ * Copyright 2012 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.
+ *
+ * Copyright © 2002 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Keith Packard not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Keith Packard makes no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include "xibarriers.h"
+#include "scrnintstr.h"
+#include "cursorstr.h"
+#include "dixevents.h"
+#include "servermd.h"
+#include "mipointer.h"
+#include "inputstr.h"
+#include "windowstr.h"
+#include "xace.h"
+#include "list.h"
+#include "exglobals.h"
+
+RESTYPE PointerBarrierType;
+
+static DevPrivateKeyRec BarrierScreenPrivateKeyRec;
+
+#define BarrierScreenPrivateKey (&BarrierScreenPrivateKeyRec)
+
+typedef struct PointerBarrierClient *PointerBarrierClientPtr;
+
+struct PointerBarrierClient {
+    ScreenPtr screen;
+    struct PointerBarrier barrier;
+    struct xorg_list entry;
+    int num_devices;
+    int *device_ids; /* num_devices */
+};
+
+typedef struct _BarrierScreen {
+    CloseScreenProcPtr CloseScreen;
+    ConstrainCursorHarderProcPtr ConstrainCursorHarder;
+    struct xorg_list barriers;
+} BarrierScreenRec, *BarrierScreenPtr;
+
+#define GetBarrierScreen(s) ((BarrierScreenPtr)dixLookupPrivate(&(s)->devPrivates, BarrierScreenPrivateKey))
+#define GetBarrierScreenIfSet(s) GetBarrierScreen(s)
+#define SetBarrierScreen(s,p) dixSetPrivate(&(s)->devPrivates, BarrierScreenPrivateKey, p)
+#define Wrap(as,s,elt,func)	(((as)->elt = (s)->elt), (s)->elt = func)
+#define Unwrap(as,s,elt,backup)	(((backup) = (s)->elt), (s)->elt = (as)->elt)
+
+static BOOL
+barrier_is_horizontal(const struct PointerBarrier *barrier)
+{
+    return barrier->y1 == barrier->y2;
+}
+
+static BOOL
+barrier_is_vertical(const struct PointerBarrier *barrier)
+{
+    return barrier->x1 == barrier->x2;
+}
+
+/**
+ * @return The set of barrier movement directions the movement vector
+ * x1/y1 → x2/y2 represents.
+ */
+int
+barrier_get_direction(int x1, int y1, int x2, int y2)
+{
+    int direction = 0;
+
+    /* which way are we trying to go */
+    if (x2 > x1)
+        direction |= BarrierPositiveX;
+    if (x2 < x1)
+        direction |= BarrierNegativeX;
+    if (y2 > y1)
+        direction |= BarrierPositiveY;
+    if (y2 < y1)
+        direction |= BarrierNegativeY;
+
+    return direction;
+}
+
+/**
+ * Test if the barrier may block movement in the direction defined by
+ * x1/y1 → x2/y2. This function only tests whether the directions could be
+ * blocked, it does not test if the barrier actually blocks the movement.
+ *
+ * @return TRUE if the barrier blocks the direction of movement or FALSE
+ * otherwise.
+ */
+BOOL
+barrier_is_blocking_direction(const struct PointerBarrier * barrier,
+                              int direction)
+{
+    /* Barriers define which way is ok, not which way is blocking */
+    return (barrier->directions & direction) != direction;
+}
+
+/**
+ * Test if the movement vector x1/y1 → x2/y2 is intersecting with the
+ * barrier. A movement vector with the startpoint or endpoint adjacent to
+ * the barrier itself counts as intersecting.
+ *
+ * @param x1 X start coordinate of movement vector
+ * @param y1 Y start coordinate of movement vector
+ * @param x2 X end coordinate of movement vector
+ * @param y2 Y end coordinate of movement vector
+ * @param[out] distance The distance between the start point and the
+ * intersection with the barrier (if applicable).
+ * @return TRUE if the barrier intersects with the given vector
+ */
+BOOL
+barrier_is_blocking(const struct PointerBarrier * barrier,
+                    int x1, int y1, int x2, int y2, double *distance)
+{
+    BOOL rc = FALSE;
+    float ua, ub, ud;
+    int dir = barrier_get_direction(x1, y1, x2, y2);
+
+    /* Algorithm below doesn't handle edge cases well, hence the extra
+     * checks. */
+    if (barrier_is_vertical(barrier)) {
+        /* handle immediate barrier adjacency, moving away */
+        if (dir & BarrierPositiveX && x1 == barrier->x1)
+            return FALSE;
+        if (dir & BarrierNegativeX && x1 == (barrier->x1 - 1))
+            return FALSE;
+        /* startpoint adjacent to barrier, moving towards -> block */
+        if (dir & BarrierPositiveX && x1 == (barrier->x1 - 1) && y1 >= barrier->y1 && y1 <= barrier->y2) {
+            *distance = 0;
+            return TRUE;
+        }
+        if (dir & BarrierNegativeX && x1 == barrier->x1 && y1 >= barrier->y1 && y1 <= barrier->y2) {
+            *distance = 0;
+            return TRUE;
+        }
+    }
+    else {
+        /* handle immediate barrier adjacency, moving away */
+        if (dir & BarrierPositiveY && y1 == barrier->y1)
+            return FALSE;
+        if (dir & BarrierNegativeY && y1 == (barrier->y1 - 1))
+            return FALSE;
+        /* startpoint adjacent to barrier, moving towards -> block */
+        if (dir & BarrierPositiveY && y1 == (barrier->y1 - 1) && x1 >= barrier->x1 && x1 <= barrier->x2) {
+            *distance = 0;
+            return TRUE;
+        }
+        if (dir & BarrierNegativeY && y1 == barrier->y1 && x1 >= barrier->x1 && x1 <= barrier->x2) {
+            *distance = 0;
+            return TRUE;
+        }
+    }
+
+    /* not an edge case, compute distance */
+    ua = 0;
+    ud = (barrier->y2 - barrier->y1) * (x2 - x1) - (barrier->x2 -
+                                                    barrier->x1) * (y2 - y1);
+    if (ud != 0) {
+        ua = ((barrier->x2 - barrier->x1) * (y1 - barrier->y1) -
+              (barrier->y2 - barrier->y1) * (x1 - barrier->x1)) / ud;
+        ub = ((x2 - x1) * (y1 - barrier->y1) -
+              (y2 - y1) * (x1 - barrier->x1)) / ud;
+        if (ua < 0 || ua > 1 || ub < 0 || ub > 1)
+            ua = 0;
+    }
+
+    if (ua > 0 && ua <= 1) {
+        double ix = barrier->x1 + ua * (barrier->x2 - barrier->x1);
+        double iy = barrier->y1 + ua * (barrier->y2 - barrier->y1);
+
+        *distance = sqrt(pow(x1 - ix, 2) + pow(y1 - iy, 2));
+        rc = TRUE;
+    }
+
+    return rc;
+}
+
+static BOOL
+barrier_blocks_device(struct PointerBarrierClient *client,
+                      DeviceIntPtr dev)
+{
+    int i;
+    int master_id;
+
+    /* Clients with no devices are treated as
+     * if they specified XIAllDevices. */
+    if (client->num_devices == 0)
+        return TRUE;
+
+    master_id = GetMaster(dev, POINTER_OR_FLOAT)->id;
+
+    for (i = 0; i < client->num_devices; i++) {
+        int device_id = client->device_ids[i];
+        if (device_id == XIAllDevices ||
+            device_id == XIAllMasterDevices ||
+            device_id == master_id)
+            return TRUE;
+    }
+
+    return FALSE;
+}
+
+/**
+ * Find the nearest barrier that is blocking movement from x1/y1 to x2/y2.
+ *
+ * @param dir Only barriers blocking movement in direction dir are checked
+ * @param x1 X start coordinate of movement vector
+ * @param y1 Y start coordinate of movement vector
+ * @param x2 X end coordinate of movement vector
+ * @param y2 Y end coordinate of movement vector
+ * @return The barrier nearest to the movement origin that blocks this movement.
+ */
+static struct PointerBarrier *
+barrier_find_nearest(BarrierScreenPtr cs, DeviceIntPtr dev,
+                     int dir,
+                     int x1, int y1, int x2, int y2)
+{
+    struct PointerBarrierClient *c;
+    struct PointerBarrier *nearest = NULL;
+    double min_distance = INT_MAX;      /* can't get higher than that in X anyway */
+
+    xorg_list_for_each_entry(c, &cs->barriers, entry) {
+        struct PointerBarrier *b = &c->barrier;
+        double distance;
+
+        if (!barrier_is_blocking_direction(b, dir))
+            continue;
+
+        if (!barrier_blocks_device(c, dev))
+            continue;
+
+        if (barrier_is_blocking(b, x1, y1, x2, y2, &distance)) {
+            if (min_distance > distance) {
+                min_distance = distance;
+                nearest = b;
+            }
+        }
+    }
+
+    return nearest;
+}
+
+/**
+ * Clamp to the given barrier given the movement direction specified in dir.
+ *
+ * @param barrier The barrier to clamp to
+ * @param dir The movement direction
+ * @param[out] x The clamped x coordinate.
+ * @param[out] y The clamped x coordinate.
+ */
+void
+barrier_clamp_to_barrier(struct PointerBarrier *barrier, int dir, int *x,
+                         int *y)
+{
+    if (barrier_is_vertical(barrier)) {
+        if ((dir & BarrierNegativeX) & ~barrier->directions)
+            *x = barrier->x1;
+        if ((dir & BarrierPositiveX) & ~barrier->directions)
+            *x = barrier->x1 - 1;
+    }
+    if (barrier_is_horizontal(barrier)) {
+        if ((dir & BarrierNegativeY) & ~barrier->directions)
+            *y = barrier->y1;
+        if ((dir & BarrierPositiveY) & ~barrier->directions)
+            *y = barrier->y1 - 1;
+    }
+}
+
+static void
+BarrierConstrainCursorHarder(DeviceIntPtr dev, ScreenPtr screen, int mode,
+                             int *x, int *y)
+{
+    BarrierScreenPtr cs = GetBarrierScreen(screen);
+
+    if (!xorg_list_is_empty(&cs->barriers) && !IsFloating(dev) &&
+        mode == Relative) {
+        int ox, oy;
+        int dir;
+        int i;
+        struct PointerBarrier *nearest = NULL;
+
+        /* where are we coming from */
+        miPointerGetPosition(dev, &ox, &oy);
+
+        /* How this works:
+         * Given the origin and the movement vector, get the nearest barrier
+         * to the origin that is blocking the movement.
+         * Clamp to that barrier.
+         * Then, check from the clamped intersection to the original
+         * destination, again finding the nearest barrier and clamping.
+         */
+        dir = barrier_get_direction(ox, oy, *x, *y);
+
+#define MAX_BARRIERS 2
+        for (i = 0; i < MAX_BARRIERS; i++) {
+            nearest = barrier_find_nearest(cs, dev, dir, ox, oy, *x, *y);
+            if (!nearest)
+                break;
+
+            barrier_clamp_to_barrier(nearest, dir, x, y);
+
+            if (barrier_is_vertical(nearest)) {
+                dir &= ~(BarrierNegativeX | BarrierPositiveX);
+                ox = *x;
+            }
+            else if (barrier_is_horizontal(nearest)) {
+                dir &= ~(BarrierNegativeY | BarrierPositiveY);
+                oy = *y;
+            }
+        }
+    }
+
+    if (cs->ConstrainCursorHarder) {
+        screen->ConstrainCursorHarder = cs->ConstrainCursorHarder;
+        screen->ConstrainCursorHarder(dev, screen, mode, x, y);
+        screen->ConstrainCursorHarder = BarrierConstrainCursorHarder;
+    }
+}
+
+static int
+CreatePointerBarrierClient(ClientPtr client,
+                           xXFixesCreatePointerBarrierReq * stuff,
+                           PointerBarrierClientPtr *client_out)
+{
+    WindowPtr pWin;
+    ScreenPtr screen;
+    BarrierScreenPtr cs;
+    int err;
+    int size;
+    int i;
+    struct PointerBarrierClient *ret;
+    CARD16 *in_devices;
+
+    size = sizeof(*ret) + sizeof(DeviceIntPtr) * stuff->num_devices;
+    ret = malloc(size);
+
+    if (!ret) {
+        return BadAlloc;
+    }
+
+    err = dixLookupWindow(&pWin, stuff->window, client, DixReadAccess);
+    if (err != Success) {
+        client->errorValue = stuff->window;
+        goto error;
+    }
+
+    screen = pWin->drawable.pScreen;
+    cs = GetBarrierScreen(screen);
+
+    ret->screen = screen;
+    ret->num_devices = stuff->num_devices;
+    if (ret->num_devices > 0)
+        ret->device_ids = (int*)&ret[1];
+    else
+        ret->device_ids = NULL;
+
+    in_devices = (CARD16 *) &stuff[1];
+    for (i = 0; i < stuff->num_devices; i++) {
+        int device_id = in_devices[i];
+        DeviceIntPtr device;
+
+        if ((err = dixLookupDevice (&device, device_id,
+                                    client, DixReadAccess))) {
+            client->errorValue = device_id;
+            goto error;
+        }
+
+        if (!IsMaster (device)) {
+            client->errorValue = device_id;
+            err = BadDevice;
+            goto error;
+        }
+
+        ret->device_ids[i] = device_id;
+    }
+
+    ret->barrier.x1 = min(stuff->x1, stuff->x2);
+    ret->barrier.x2 = max(stuff->x1, stuff->x2);
+    ret->barrier.y1 = min(stuff->y1, stuff->y2);
+    ret->barrier.y2 = max(stuff->y1, stuff->y2);
+    ret->barrier.directions = stuff->directions & 0x0f;
+    if (barrier_is_horizontal(&ret->barrier))
+        ret->barrier.directions &= ~(BarrierPositiveX | BarrierNegativeX);
+    if (barrier_is_vertical(&ret->barrier))
+        ret->barrier.directions &= ~(BarrierPositiveY | BarrierNegativeY);
+    xorg_list_add(&ret->entry, &cs->barriers);
+
+    *client_out = ret;
+    return Success;
+
+ error:
+    *client_out = NULL;
+    free(ret);
+    return err;
+}
+
+static int
+BarrierFreeBarrier(void *data, XID id)
+{
+    struct PointerBarrierClient *b = NULL, *barrier;
+    ScreenPtr screen;
+    BarrierScreenPtr cs;
+
+    barrier = container_of(data, struct PointerBarrierClient, barrier);
+
+    screen = barrier->screen;
+    cs = GetBarrierScreen(screen);
+
+    /* find and unlink from the screen private */
+    xorg_list_for_each_entry(b, &cs->barriers, entry) {
+        if (b == barrier) {
+            xorg_list_del(&b->entry);
+            break;
+        }
+    }
+
+    free(barrier);
+    return Success;
+}
+
+int
+XICreatePointerBarrier(ClientPtr client,
+                       xXFixesCreatePointerBarrierReq * stuff)
+{
+    int err;
+    struct PointerBarrierClient *barrier;
+    struct PointerBarrier b;
+
+    b.x1 = stuff->x1;
+    b.x2 = stuff->x2;
+    b.y1 = stuff->y1;
+    b.y2 = stuff->y2;
+
+    if (!barrier_is_horizontal(&b) && !barrier_is_vertical(&b))
+        return BadValue;
+
+    /* no 0-sized barriers */
+    if (barrier_is_horizontal(&b) && barrier_is_vertical(&b))
+        return BadValue;
+
+    if ((err = CreatePointerBarrierClient(client, stuff, &barrier)))
+        return err;
+
+    if (!AddResource(stuff->barrier, PointerBarrierType, &barrier->barrier))
+        return BadAlloc;
+
+    return Success;
+}
+
+int
+XIDestroyPointerBarrier(ClientPtr client,
+                        xXFixesDestroyPointerBarrierReq * stuff)
+{
+    int err;
+    void *barrier;
+
+    err = dixLookupResourceByType((void **) &barrier, stuff->barrier,
+                                  PointerBarrierType, client, DixDestroyAccess);
+    if (err != Success) {
+        client->errorValue = stuff->barrier;
+        return err;
+    }
+
+    FreeResource(stuff->barrier, RT_NONE);
+    return Success;
+}
+
+static Bool
+BarrierCloseScreen(ScreenPtr pScreen)
+{
+    BarrierScreenPtr cs = GetBarrierScreen(pScreen);
+    Bool ret;
+    _X_UNUSED CloseScreenProcPtr close_proc;
+    _X_UNUSED ConstrainCursorHarderProcPtr constrain_proc;
+
+    Unwrap(cs, pScreen, CloseScreen, close_proc);
+    Unwrap(cs, pScreen, ConstrainCursorHarder, constrain_proc);
+    ret = (*pScreen->CloseScreen) (pScreen);
+    free(cs);
+    return ret;
+}
+
+Bool
+XIBarrierInit(void)
+{
+    int i;
+
+    if (!dixRegisterPrivateKey(&BarrierScreenPrivateKeyRec, PRIVATE_SCREEN, 0))
+        return FALSE;
+
+    for (i = 0; i < screenInfo.numScreens; i++) {
+        ScreenPtr pScreen = screenInfo.screens[i];
+        BarrierScreenPtr cs;
+
+        cs = (BarrierScreenPtr) calloc(1, sizeof(BarrierScreenRec));
+        if (!cs)
+            return FALSE;
+        xorg_list_init(&cs->barriers);
+        Wrap(cs, pScreen, CloseScreen, BarrierCloseScreen);
+        Wrap(cs, pScreen, ConstrainCursorHarder, BarrierConstrainCursorHarder);
+        SetBarrierScreen(pScreen, cs);
+    }
+
+    PointerBarrierType = CreateNewResourceType(BarrierFreeBarrier,
+                                               "XIPointerBarrier");
+
+    return PointerBarrierType;
+}
diff --git a/Xi/xibarriers.h b/Xi/xibarriers.h
new file mode 100644
index 000000000..8f2993f85
--- /dev/null
+++ b/Xi/xibarriers.h
@@ -0,0 +1,47 @@
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#ifndef _XIBARRIERS_H_
+#define _XIBARRIERS_H_
+
+#include "resource.h"
+
+extern _X_EXPORT RESTYPE PointerBarrierType;
+
+struct PointerBarrier {
+    CARD16 x1, x2, y1, y2;
+    CARD32 directions;
+};
+
+int
+barrier_get_direction(int, int, int, int);
+BOOL
+barrier_is_blocking(const struct PointerBarrier *, int, int, int, int,
+                        double *);
+BOOL
+barrier_is_blocking_direction(const struct PointerBarrier *, int);
+void
+barrier_clamp_to_barrier(struct PointerBarrier *barrier, int dir, int *x,
+                             int *y);
+
+#include <xfixesint.h>
+
+int
+XICreatePointerBarrier(ClientPtr client,
+                       xXFixesCreatePointerBarrierReq * stuff);
+
+int
+XIDestroyPointerBarrier(ClientPtr client,
+                        xXFixesDestroyPointerBarrierReq * stuff);
+
+Bool
+XIBarrierInit(void);
+
+#endif /* _XIBARRIERS_H_ */
+
+
+
+
+