Rewrite mouse handlers to use QTAILQ and to have an activation function

And convert usb-hid to use it (to avoid regression with bisection)

Right now, when we do info mice and we've added a usb tablet, we don't see it
until the guest starts using the tablet.  We implement this behavior in order
to provide a means to delay registration of a mouse handler since we treat
the last registered handler as the current handler.

This is a usability problem though as we would like to give the user feedback
that they've either 1) not added an absolute device 2) there is an absolute
device but the guest isn't using it 3) we have an absolute device and it's
active.

By using QTAILQ and having an explicit activation function that moves the
handler to the front of the queue, we can implement the same semantics as
before with respect to automatically switching to usb tablet while providing
the user with a whole lot more information.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

console.h

@@ -28,8 +28,10 @@ typedef struct QEMUPutMouseEntry {
     int qemu_put_mouse_event_absolute;
     char *qemu_put_mouse_event_name;
 
+    int index;
+
     /* used internally by qemu for handling mice */
-    struct QEMUPutMouseEntry *next;
+    QTAILQ_ENTRY(QEMUPutMouseEntry) node;
 } QEMUPutMouseEntry;
 
 typedef struct QEMUPutLEDEntry {
@@ -43,6 +45,8 @@ QEMUPutMouseEntry *qemu_add_mouse_event_handler(QEMUPutMouseEvent *func,
                                                 void *opaque, int absolute,
                                                 const char *name);
 void qemu_remove_mouse_event_handler(QEMUPutMouseEntry *entry);
+void qemu_activate_mouse_event_handler(QEMUPutMouseEntry *entry);
+
 QEMUPutLEDEntry *qemu_add_led_event_handler(QEMUPutLEDEvent *func, void *opaque);
 void qemu_remove_led_event_handler(QEMUPutLEDEntry *entry);
 

hw/usb-hid.c

@@ -511,8 +511,7 @@ static int usb_mouse_poll(USBHIDState *hs, uint8_t *buf, int len)
     USBMouseState *s = &hs->ptr;
 
     if (!s->mouse_grabbed) {
-	s->eh_entry = qemu_add_mouse_event_handler(usb_mouse_event, hs,
-                                                  0, "QEMU USB Mouse");
+        qemu_activate_mouse_event_handler(s->eh_entry);
 	s->mouse_grabbed = 1;
     }
 
@@ -553,8 +552,7 @@ static int usb_tablet_poll(USBHIDState *hs, uint8_t *buf, int len)
     USBMouseState *s = &hs->ptr;
 
     if (!s->mouse_grabbed) {
-	s->eh_entry = qemu_add_mouse_event_handler(usb_tablet_event, hs,
-                                                  1, "QEMU USB Tablet");
+        qemu_activate_mouse_event_handler(s->eh_entry);
 	s->mouse_grabbed = 1;
     }
 
@@ -866,6 +864,15 @@ static int usb_hid_initfn(USBDevice *dev, int kind)
     USBHIDState *s = DO_UPCAST(USBHIDState, dev, dev);
     s->dev.speed = USB_SPEED_FULL;
     s->kind = kind;
+
+    if (s->kind == USB_MOUSE) {
+        s->ptr.eh_entry = qemu_add_mouse_event_handler(usb_mouse_event, s,
+                                                       0, "QEMU USB Mouse");
+    } else if (s->kind == USB_TABLET) {
+        s->ptr.eh_entry = qemu_add_mouse_event_handler(usb_tablet_event, s,
+                                                       1, "QEMU USB Tablet");
+    }
+        
     /* Force poll routine to be run and grab input the first time.  */
     s->changed = 1;
     return 0;

input.c

@@ -31,9 +31,9 @@
 
 static QEMUPutKBDEvent *qemu_put_kbd_event;
 static void *qemu_put_kbd_event_opaque;
-static QEMUPutMouseEntry *qemu_put_mouse_event_head;
-static QEMUPutMouseEntry *qemu_put_mouse_event_current;
 static QTAILQ_HEAD(, QEMUPutLEDEntry) led_handlers = QTAILQ_HEAD_INITIALIZER(led_handlers);
+static QTAILQ_HEAD(, QEMUPutMouseEntry) mouse_handlers =
+    QTAILQ_HEAD_INITIALIZER(mouse_handlers);
 
 void qemu_add_kbd_event_handler(QEMUPutKBDEvent *func, void *opaque)
 {
@@ -45,7 +45,8 @@ QEMUPutMouseEntry *qemu_add_mouse_event_handler(QEMUPutMouseEvent *func,
                                                 void *opaque, int absolute,
                                                 const char *name)
 {
-    QEMUPutMouseEntry *s, *cursor;
+    QEMUPutMouseEntry *s;
+    static int mouse_index = 0;
 
     s = qemu_mallocz(sizeof(QEMUPutMouseEntry));
 
@@ -53,51 +54,24 @@ QEMUPutMouseEntry *qemu_add_mouse_event_handler(QEMUPutMouseEvent *func,
     s->qemu_put_mouse_event_opaque = opaque;
     s->qemu_put_mouse_event_absolute = absolute;
     s->qemu_put_mouse_event_name = qemu_strdup(name);
-    s->next = NULL;
+    s->index = mouse_index++;
 
-    if (!qemu_put_mouse_event_head) {
-        qemu_put_mouse_event_head = qemu_put_mouse_event_current = s;
-        return s;
-    }
-
-    cursor = qemu_put_mouse_event_head;
-    while (cursor->next != NULL)
-        cursor = cursor->next;
-
-    cursor->next = s;
-    qemu_put_mouse_event_current = s;
+    QTAILQ_INSERT_TAIL(&mouse_handlers, s, node);
 
     return s;
 }
 
-void qemu_remove_mouse_event_handler(QEMUPutMouseEntry *entry)
+void qemu_activate_mouse_event_handler(QEMUPutMouseEntry *entry)
 {
-    QEMUPutMouseEntry *prev = NULL, *cursor;
-
-    if (!qemu_put_mouse_event_head || entry == NULL)
-        return;
-
-    cursor = qemu_put_mouse_event_head;
-    while (cursor != NULL && cursor != entry) {
-        prev = cursor;
-        cursor = cursor->next;
-    }
+    QTAILQ_REMOVE(&mouse_handlers, entry, node);
+    QTAILQ_INSERT_HEAD(&mouse_handlers, entry, node);
 
-    if (cursor == NULL) // does not exist or list empty
-        return;
-    else if (prev == NULL) { // entry is head
-        qemu_put_mouse_event_head = cursor->next;
-        if (qemu_put_mouse_event_current == entry)
-            qemu_put_mouse_event_current = cursor->next;
-        qemu_free(entry->qemu_put_mouse_event_name);
-        qemu_free(entry);
-        return;
-    }
-
-    prev->next = entry->next;
+    check_mode_change();
+}
 
-    if (qemu_put_mouse_event_current == entry)
-        qemu_put_mouse_event_current = prev;
+void qemu_remove_mouse_event_handler(QEMUPutMouseEntry *entry)
+{
+    QTAILQ_REMOVE(&mouse_handlers, entry, node);
 
     qemu_free(entry->qemu_put_mouse_event_name);
     qemu_free(entry);
@@ -142,39 +116,41 @@ void kbd_put_ledstate(int ledstate)
 
 void kbd_mouse_event(int dx, int dy, int dz, int buttons_state)
 {
+    QEMUPutMouseEntry *entry;
     QEMUPutMouseEvent *mouse_event;
     void *mouse_event_opaque;
     int width;
 
-    if (!qemu_put_mouse_event_current) {
+    if (QTAILQ_EMPTY(&mouse_handlers)) {
         return;
     }
 
-    mouse_event =
-        qemu_put_mouse_event_current->qemu_put_mouse_event;
-    mouse_event_opaque =
-        qemu_put_mouse_event_current->qemu_put_mouse_event_opaque;
+    entry = QTAILQ_FIRST(&mouse_handlers);
+
+    mouse_event = entry->qemu_put_mouse_event;
+    mouse_event_opaque = entry->qemu_put_mouse_event_opaque;
 
     if (mouse_event) {
         if (graphic_rotate) {
-            if (qemu_put_mouse_event_current->qemu_put_mouse_event_absolute)
+            if (entry->qemu_put_mouse_event_absolute)
                 width = 0x7fff;
             else
                 width = graphic_width - 1;
             mouse_event(mouse_event_opaque,
-                                 width - dy, dx, dz, buttons_state);
+                        width - dy, dx, dz, buttons_state);
         } else
             mouse_event(mouse_event_opaque,
-                                 dx, dy, dz, buttons_state);
+                        dx, dy, dz, buttons_state);
     }
 }
 
 int kbd_mouse_is_absolute(void)
 {
-    if (!qemu_put_mouse_event_current)
+    if (QTAILQ_EMPTY(&mouse_handlers)) {
         return 0;
+    }
 
-    return qemu_put_mouse_event_current->qemu_put_mouse_event_absolute;
+    return QTAILQ_FIRST(&mouse_handlers)->qemu_put_mouse_event_absolute;
 }
 
 static void info_mice_iter(QObject *data, void *opaque)
@@ -222,23 +198,23 @@ void do_info_mice(Monitor *mon, QObject **ret_data)
 {
     QEMUPutMouseEntry *cursor;
     QList *mice_list;
-    int index = 0;
+    int current;
 
     mice_list = qlist_new();
 
-    if (!qemu_put_mouse_event_head) {
+    if (QTAILQ_EMPTY(&mouse_handlers)) {
         goto out;
     }
 
-    cursor = qemu_put_mouse_event_head;
-    while (cursor != NULL) {
+    current = QTAILQ_FIRST(&mouse_handlers)->index;
+
+    QTAILQ_FOREACH(cursor, &mouse_handlers, node) {
         QObject *obj;
         obj = qobject_from_jsonf("{ 'name': %s, 'index': %d, 'current': %i }",
                                  cursor->qemu_put_mouse_event_name,
-                                 index, cursor == qemu_put_mouse_event_current);
+                                 cursor->index,
+                                 cursor->index == current);
         qlist_append_obj(mice_list, obj);
-        index++;
-        cursor = cursor->next;
     }
 
 out:
@@ -248,22 +224,23 @@ out:
 void do_mouse_set(Monitor *mon, const QDict *qdict)
 {
     QEMUPutMouseEntry *cursor;
-    int i = 0;
     int index = qdict_get_int(qdict, "index");
+    int found = 0;
 
-    if (!qemu_put_mouse_event_head) {
+    if (QTAILQ_EMPTY(&mouse_handlers)) {
         monitor_printf(mon, "No mouse devices connected\n");
         return;
     }
 
-    cursor = qemu_put_mouse_event_head;
-    while (cursor != NULL && index != i) {
-        i++;
-        cursor = cursor->next;
+    QTAILQ_FOREACH(cursor, &mouse_handlers, node) {
+        if (cursor->index == index) {
+            found = 1;
+            qemu_activate_mouse_event_handler(cursor);
+            break;
+        }
     }
 
-    if (cursor != NULL)
-        qemu_put_mouse_event_current = cursor;
-    else
+    if (!found) {
         monitor_printf(mon, "Mouse at given index not found\n");
+    }
 }