Rework haptic backend to properly support hotplugging of haptic devices.
authorEdward Rudd <urkle@outoforder.cc>
Tue, 04 Feb 2014 15:44:09 -0500
changeset 8170 3b7bb407fcf7
parent 8169 663ba61243ff
child 8171 e4f51a5bc1ed
Rework haptic backend to properly support hotplugging of haptic devices. * currently only linux backend updated.
src/haptic/SDL_haptic.c
src/haptic/SDL_syshaptic.h
src/haptic/linux/SDL_syshaptic.c
--- a/src/haptic/SDL_haptic.c	Tue Feb 04 15:40:51 2014 -0500
+++ b/src/haptic/SDL_haptic.c	Tue Feb 04 15:44:09 2014 -0500
@@ -25,8 +25,7 @@
 #include "../joystick/SDL_joystick_c.h" /* For SDL_PrivateJoystickValid */
 #include "SDL_assert.h"
 
-Uint8 SDL_numhaptics = 0;
-SDL_Haptic **SDL_haptics = NULL;
+SDL_Haptic *SDL_haptics = NULL;
 
 
 /*
@@ -35,20 +34,10 @@
 int
 SDL_HapticInit(void)
 {
-    int arraylen;
     int status;
 
-    SDL_numhaptics = 0;
     status = SDL_SYS_HapticInit();
     if (status >= 0) {
-        arraylen = (status + 1) * sizeof(*SDL_haptics);
-        SDL_haptics = (SDL_Haptic **) SDL_malloc(arraylen);
-        if (SDL_haptics == NULL) {      /* Out of memory. */
-            SDL_numhaptics = 0;
-        } else {
-            SDL_memset(SDL_haptics, 0, arraylen);
-            SDL_numhaptics = status;
-        }
         status = 0;
     }
 
@@ -62,16 +51,19 @@
 static int
 ValidHaptic(SDL_Haptic * haptic)
 {
-    int i;
     int valid;
+    SDL_Haptic *hapticlist;
 
     valid = 0;
     if (haptic != NULL) {
-        for (i = 0; i < SDL_numhaptics; i++) {
-            if (SDL_haptics[i] == haptic) {
+        hapticlist = SDL_haptics;
+        while ( hapticlist )
+        {
+            if (hapticlist == haptic) {
                 valid = 1;
                 break;
             }
+            hapticlist = hapticlist->next;
         }
     }
 
@@ -90,7 +82,7 @@
 int
 SDL_NumHaptics(void)
 {
-    return SDL_numhaptics;
+    return SDL_SYS_NumHaptics();
 }
 
 
@@ -100,9 +92,9 @@
 const char *
 SDL_HapticName(int device_index)
 {
-    if ((device_index < 0) || (device_index >= SDL_numhaptics)) {
+    if ((device_index < 0) || (device_index >= SDL_NumHaptics())) {
         SDL_SetError("Haptic: There are %d haptic devices available",
-                     SDL_numhaptics);
+                     SDL_NumHaptics());
         return NULL;
     }
     return SDL_SYS_HapticName(device_index);
@@ -115,22 +107,27 @@
 SDL_Haptic *
 SDL_HapticOpen(int device_index)
 {
-    int i;
     SDL_Haptic *haptic;
+    SDL_Haptic *hapticlist;
 
-    if ((device_index < 0) || (device_index >= SDL_numhaptics)) {
+    if ((device_index < 0) || (device_index >= SDL_NumHaptics())) {
         SDL_SetError("Haptic: There are %d haptic devices available",
-                     SDL_numhaptics);
+                     SDL_NumHaptics());
         return NULL;
     }
 
-    /* If the haptic is already open, return it */
-    for (i = 0; SDL_haptics[i]; i++) {
-        if (device_index == SDL_haptics[i]->index) {
-            haptic = SDL_haptics[i];
+    hapticlist = SDL_haptics;
+    /* If the haptic is already open, return it
+    * TODO: Should we create haptic instance IDs like the Joystick API?
+    */
+    while ( hapticlist )
+    {
+        if (device_index == hapticlist->index) {
+            haptic = hapticlist;
             ++haptic->ref_count;
             return haptic;
         }
+        hapticlist = hapticlist->next;
     }
 
     /* Create the haptic device */
@@ -150,15 +147,10 @@
     }
 
     /* Add haptic to list */
-    for (i = 0; SDL_haptics[i]; i++)
-        /* Skip to next haptic */ ;
-    if (i >= SDL_numhaptics) {
-        SDL_free(haptic);
-        SDL_SetError("Haptic: Trying to add device past the number originally detected");
-        return NULL;
-    }
-    SDL_haptics[i] = haptic;
     ++haptic->ref_count;
+    /* Link the haptic in the list */
+    haptic->next = SDL_haptics;
+    SDL_haptics = haptic;
 
     /* Disable autocenter and set gain to max. */
     if (haptic->supported & SDL_HAPTIC_GAIN)
@@ -176,21 +168,26 @@
 int
 SDL_HapticOpened(int device_index)
 {
-    int i, opened;
+    int opened;
+    SDL_Haptic *hapticlist;
 
     /* Make sure it's valid. */
-    if ((device_index < 0) || (device_index >= SDL_numhaptics)) {
+    if ((device_index < 0) || (device_index >= SDL_NumHaptics())) {
         SDL_SetError("Haptic: There are %d haptic devices available",
-                     SDL_numhaptics);
+                     SDL_NumHaptics());
         return 0;
     }
 
     opened = 0;
-    for (i = 0; SDL_haptics[i]; i++) {
-        if (SDL_haptics[i]->index == (Uint8) device_index) {
+    hapticlist = SDL_haptics;
+    /* TODO Should this use an instance ID? */
+    while ( hapticlist )
+    {
+        if (hapticlist->index == (Uint8) device_index) {
             opened = 1;
             break;
         }
+        hapticlist = hapticlist->next;
     }
     return opened;
 }
@@ -271,13 +268,13 @@
 SDL_Haptic *
 SDL_HapticOpenFromJoystick(SDL_Joystick * joystick)
 {
-    int i;
     SDL_Haptic *haptic;
+    SDL_Haptic *hapticlist;
 
     /* Make sure there is room. */
-    if (SDL_numhaptics <= 0) {
+    if (SDL_NumHaptics() <= 0) {
         SDL_SetError("Haptic: There are %d haptic devices available",
-                     SDL_numhaptics);
+                     SDL_NumHaptics());
         return NULL;
     }
 
@@ -293,13 +290,16 @@
         return NULL;
     }
 
+    hapticlist = SDL_haptics;
     /* Check to see if joystick's haptic is already open */
-    for (i = 0; SDL_haptics[i]; i++) {
-        if (SDL_SYS_JoystickSameHaptic(SDL_haptics[i], joystick)) {
-            haptic = SDL_haptics[i];
+    while ( hapticlist )
+    {
+        if (SDL_SYS_JoystickSameHaptic(hapticlist, joystick)) {
+            haptic = hapticlist;
             ++haptic->ref_count;
             return haptic;
         }
+        hapticlist = hapticlist->next;
     }
 
     /* Create the haptic device */
@@ -318,15 +318,10 @@
     }
 
     /* Add haptic to list */
-    for (i = 0; SDL_haptics[i]; i++)
-        /* Skip to next haptic */ ;
-    if (i >= SDL_numhaptics) {
-        SDL_free(haptic);
-        SDL_SetError("Haptic: Trying to add device past the number originally detected");
-        return NULL;
-    }
-    SDL_haptics[i] = haptic;
     ++haptic->ref_count;
+    /* Link the haptic in the list */
+    haptic->next = SDL_haptics;
+    SDL_haptics = haptic;
 
     return haptic;
 }
@@ -339,6 +334,8 @@
 SDL_HapticClose(SDL_Haptic * haptic)
 {
     int i;
+    SDL_Haptic *hapticlist;
+    SDL_Haptic *hapticlistprev;
 
     /* Must be valid */
     if (!ValidHaptic(haptic)) {
@@ -359,13 +356,26 @@
     SDL_SYS_HapticClose(haptic);
 
     /* Remove from the list */
-    for (i = 0; SDL_haptics[i]; ++i) {
-        if (haptic == SDL_haptics[i]) {
-            SDL_haptics[i] = NULL;
-            SDL_memcpy(&SDL_haptics[i], &SDL_haptics[i + 1],
-                       (SDL_numhaptics - i) * sizeof(haptic));
+    hapticlist = SDL_haptics;
+    hapticlistprev = NULL;
+    while ( hapticlist )
+    {
+        if (haptic == hapticlist)
+        {
+            if ( hapticlistprev )
+            {
+                /* unlink this entry */
+                hapticlistprev->next = hapticlist->next;
+            }
+            else
+            {
+                SDL_haptics = haptic->next;
+            }
+
             break;
         }
+        hapticlistprev = hapticlist;
+        hapticlist = hapticlist->next;
     }
 
     /* Free */
@@ -379,9 +389,8 @@
 SDL_HapticQuit(void)
 {
     SDL_SYS_HapticQuit();
-    SDL_free(SDL_haptics);
+    SDL_assert(SDL_haptics == NULL);
     SDL_haptics = NULL;
-    SDL_numhaptics = 0;
 }
 
 /*
--- a/src/haptic/SDL_syshaptic.h	Tue Feb 04 15:40:51 2014 -0500
+++ b/src/haptic/SDL_syshaptic.h	Tue Feb 04 15:44:09 2014 -0500
@@ -54,6 +54,7 @@
 
     int rumble_id;              /* ID of rumble effect for simple rumble API. */
     SDL_HapticEffect rumble_effect; /* Rumble effect. */
+    struct _SDL_Haptic *next; /* pointer to next haptic we have allocated */
 };
 
 /*
@@ -63,6 +64,9 @@
  */
 extern int SDL_SYS_HapticInit(void);
 
+/* Function to return the number of haptic devices plugged in right now */
+extern int SDL_SYS_NumHaptics();
+
 /*
  * Gets the device dependent name of the haptic device
  */
--- a/src/haptic/linux/SDL_syshaptic.c	Tue Feb 04 15:40:51 2014 -0500
+++ b/src/haptic/linux/SDL_syshaptic.c	Tue Feb 04 15:44:09 2014 -0500
@@ -22,11 +22,13 @@
 
 #ifdef SDL_HAPTIC_LINUX
 
+#include "SDL_assert.h"
 #include "SDL_haptic.h"
 #include "../SDL_syshaptic.h"
 #include "SDL_joystick.h"
 #include "../../joystick/SDL_sysjoystick.h"     /* For the real SDL_Joystick */
 #include "../../joystick/linux/SDL_sysjoystick_c.h"     /* For joystick hwdata */
+#include "../../core/linux/SDL_udev.h"
 
 #include <unistd.h>             /* close */
 #include <linux/input.h>        /* Force feedback linux stuff. */
@@ -44,15 +46,21 @@
 
 #define MAX_HAPTICS  32         /* It's doubtful someone has more then 32 evdev */
 
+static int MaybeAddDevice(const char *path);
+#if SDL_USE_LIBUDEV
+static int MaybeRemoveDevice(const char *path);
+void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);
+#endif /* SDL_USE_LIBUDEV */
 
 /*
  * List of available haptic devices.
  */
-static struct
+typedef struct SDL_hapticlist_item
 {
     char *fname;                /* Dev path name (like /dev/input/event1) */
     SDL_Haptic *haptic;         /* Assosciated haptic. */
-} SDL_hapticlist[MAX_HAPTICS];
+	struct SDL_hapticlist_item *next;
+} SDL_hapticlist_item;
 
 
 /*
@@ -73,7 +81,9 @@
     struct ff_effect effect;    /* The linux kernel effect structure. */
 };
 
-
+static SDL_hapticlist_item *SDL_hapticlist = NULL;
+static SDL_hapticlist_item *SDL_hapticlist_tail = NULL;
+static int numhaptics = 0;
 
 #define test_bit(nr, addr) \
    (((1UL << ((nr) & 31)) & (((const unsigned int *) addr)[(nr) >> 5])) != 0)
@@ -147,15 +157,8 @@
 SDL_SYS_HapticInit(void)
 {
     const char joydev_pattern[] = "/dev/input/event%d";
-    dev_t dev_nums[MAX_HAPTICS];
     char path[PATH_MAX];
-    struct stat sb;
-    int fd;
-    int i, j, k;
-    int duplicate;
-    int numhaptics;
-
-    numhaptics = 0;
+    int i, j;
 
     /*
      * Limit amount of checks to MAX_HAPTICS since we may or may not have
@@ -165,44 +168,189 @@
     for (j = 0; j < MAX_HAPTICS; ++j) {
 
         snprintf(path, PATH_MAX, joydev_pattern, i++);
+        MaybeAddDevice(path);
+    }
 
-        /* check to see if file exists */
-        if (stat(path, &sb) != 0)
-            break;
+#if SDL_USE_LIBUDEV
+	if (SDL_UDEV_Init() < 0) {
+        return SDL_SetError("Could not initialize UDEV");
+    }
+
+	if ( SDL_UDEV_AddCallback(haptic_udev_callback) < 0) {
+		SDL_UDEV_Quit();
+		return SDL_SetError("Could not setup haptic <-> udev callback");
+	}
+#endif /* SDL_USE_LIBUDEV */
+	
+    return numhaptics;
+}
+
+int
+SDL_SYS_NumHaptics()
+{
+    return numhaptics;
+}
+
+static SDL_hapticlist_item *
+HapticByDevIndex(int device_index)
+{
+    SDL_hapticlist_item *item = SDL_hapticlist;
+
+    if ((device_index < 0) || (device_index >= numhaptics)) {
+        return NULL;
+    }
+
+    while (device_index > 0) {
+        SDL_assert(item != NULL);
+        device_index--;
+        item = item->next;
+    }
+
+    return item;
+}
 
-        /* check for duplicates */
-        duplicate = 0;
-        for (k = 0; (k < numhaptics) && !duplicate; ++k) {
-            if (sb.st_rdev == dev_nums[k]) {
-                duplicate = 1;
-            }
+#if SDL_USE_LIBUDEV
+void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)
+{
+    if (devpath == NULL || !(udev_class & SDL_UDEV_DEVICE_JOYSTICK)) {
+        return;
+    }
+    
+    switch( udev_type )
+    {
+        case SDL_UDEV_DEVICEADDED:
+            MaybeAddDevice(devpath);
+            break;
+            
+        case SDL_UDEV_DEVICEREMOVED:
+            MaybeRemoveDevice(devpath);
+            break;
+            
+        default:
+            break;
+    }
+    
+}
+#endif /* SDL_USE_LIBUDEV */
+
+static int
+MaybeAddDevice(const char *path)
+{
+    dev_t dev_nums[MAX_HAPTICS];
+    struct stat sb;
+    int fd;
+    int k;
+    int duplicate;
+    int success;
+    SDL_hapticlist_item *item;
+
+
+    if (path == NULL) {
+        return -1;
+    }
+
+    /* check to see if file exists */
+    if (stat(path, &sb) != 0) {
+        return -1;
+	}
+
+    /* check for duplicates */
+    duplicate = 0;
+    for (k = 0; (k < numhaptics) && !duplicate; ++k) {
+        if (sb.st_rdev == dev_nums[k]) {
+            duplicate = 1;
         }
-        if (duplicate) {
-            continue;
-        }
+    }
+    if (duplicate) {
+        return -1;
+    }
 
-        /* try to open */
-        fd = open(path, O_RDWR, 0);
-        if (fd < 0)
-            continue;
+    /* try to open */
+    fd = open(path, O_RDWR, 0);
+    if (fd < 0) {
+        return -1;
+	}
 
 #ifdef DEBUG_INPUT_EVENTS
-        printf("Checking %s\n", path);
+    printf("Checking %s\n", path);
 #endif
 
-        /* see if it works */
-        if (EV_IsHaptic(fd) > 0) {
-            SDL_hapticlist[numhaptics].fname = SDL_strdup(path);
-            SDL_hapticlist[numhaptics].haptic = NULL;
-            dev_nums[numhaptics] = sb.st_rdev;
-            ++numhaptics;
-        }
-        close(fd);
+    /* see if it works */
+    success = EV_IsHaptic(fd);
+    close(fd);
+    if (success <= 0) {
+        return -1;
+    }
+
+    item = (SDL_hapticlist_item *) SDL_malloc(sizeof (SDL_hapticlist_item));
+    if (item == NULL) {
+        return -1;
     }
+    SDL_zerop(item);
+    item->fname = SDL_strdup(path);
+    if ( (item->fname == NULL) ) {
+        SDL_free(item->fname);
+        SDL_free(item);
+        return -1;
+    }
+
+    /* TODO: should we add instance IDs? */
+    if (SDL_hapticlist_tail == NULL) {
+        SDL_hapticlist = SDL_hapticlist_tail = item;
+    } else {
+        SDL_hapticlist_tail->next = item;
+        SDL_hapticlist_tail = item;
+    }
+
+    dev_nums[numhaptics] = sb.st_rdev;
+
+    ++numhaptics;
+
+    /* !!! TODO: Send a haptic add event? */
 
     return numhaptics;
 }
 
+#if SDL_USE_LIBUDEV
+static int
+MaybeRemoveDevice(const char* path)
+{
+    SDL_hapticlist_item *item;
+    SDL_hapticlist_item *prev = NULL;
+
+    if (path == NULL) {
+        return -1;
+    }
+
+    for (item = SDL_hapticlist; item != NULL; item = item->next) {
+        /* found it, remove it. */
+        if (SDL_strcmp(path, item->fname) == 0) {
+            const int retval = item->haptic ? item->haptic->index : -1;
+
+            if (prev != NULL) {
+                prev->next = item->next;
+            } else {
+                SDL_assert(SDL_hapticlist == item);
+                SDL_hapticlist = item->next;
+            }
+            if (item == SDL_hapticlist_tail) {
+                SDL_hapticlist_tail = prev;
+            }
+
+            /* Need to decrement the haptic count */
+            --numhaptics;
+            /* !!! TODO: Send a haptic remove event? */
+
+            SDL_free(item->fname);
+            SDL_free(item);
+            return retval;
+        }
+        prev = item;
+    }
+
+    return -1;
+}
+#endif /* SDL_USE_LIBUDEV */
 
 /*
  * Gets the name from a file descriptor.
@@ -227,19 +375,21 @@
 const char *
 SDL_SYS_HapticName(int index)
 {
+	SDL_hapticlist_item *item;
     int fd;
     const char *name;
 
+	item = HapticByDevIndex(index);
     /* Open the haptic device. */
     name = NULL;
-    fd = open(SDL_hapticlist[index].fname, O_RDONLY, 0);
+    fd = open(item->fname, O_RDONLY, 0);
 
     if (fd >= 0) {
 
         name = SDL_SYS_HapticNameFromFD(fd);
         if (name == NULL) {
             /* No name found, return device character device */
-            name = SDL_hapticlist[index].fname;
+            name = item->fname;
         }
     }
     close(fd);
@@ -306,12 +456,14 @@
 {
     int fd;
     int ret;
+	SDL_hapticlist_item *item;
 
+	item = HapticByDevIndex(haptic->index);
     /* Open the character device */
-    fd = open(SDL_hapticlist[haptic->index].fname, O_RDWR, 0);
+    fd = open(item->fname, O_RDWR, 0);
     if (fd < 0) {
         return SDL_SetError("Haptic: Unable to open %s: %s",
-                            SDL_hapticlist[haptic->index], strerror(errno));
+                            item->fname, strerror(errno));
     }
 
     /* Try to create the haptic. */
@@ -321,7 +473,7 @@
     }
 
     /* Set the fname. */
-    haptic->hwdata->fname = SDL_hapticlist[haptic->index].fname;
+    haptic->hwdata->fname = item->fname;
     return 0;
 }
 
@@ -333,24 +485,27 @@
 SDL_SYS_HapticMouse(void)
 {
     int fd;
-    int i;
+    int device_index = 0;
+	SDL_hapticlist_item *item;
 
-    for (i = 0; i < SDL_numhaptics; i++) {
-
+	
+    for (item = SDL_hapticlist; item; item = item->next) {
         /* Open the device. */
-        fd = open(SDL_hapticlist[i].fname, O_RDWR, 0);
+        fd = open(item->fname, O_RDWR, 0);
         if (fd < 0) {
             return SDL_SetError("Haptic: Unable to open %s: %s",
-                                SDL_hapticlist[i], strerror(errno));
+                                item->fname, strerror(errno));
         }
 
         /* Is it a mouse? */
         if (EV_IsMouse(fd)) {
             close(fd);
-            return i;
+            return device_index;
         }
 
         close(fd);
+
+		++device_index;
     }
 
     return -1;
@@ -388,22 +543,21 @@
 int
 SDL_SYS_HapticOpenFromJoystick(SDL_Haptic * haptic, SDL_Joystick * joystick)
 {
-    int i;
+    int device_index = 0;
     int fd;
     int ret;
+	SDL_hapticlist_item *item;
 
 
     /* Find the joystick in the haptic list. */
-    for (i = 0; i < MAX_HAPTICS; i++) {
-        if (SDL_hapticlist[i].fname != NULL) {
-            if (SDL_strcmp(SDL_hapticlist[i].fname, joystick->hwdata->fname)
-                == 0) {
-                haptic->index = i;
-                break;
-            }
-        }
+    for (item = SDL_hapticlist; item; item = item->next) {
+		if (SDL_strcmp(item->fname, joystick->hwdata->fname) == 0) {
+			haptic->index = device_index;
+			break;
+		}
+		++device_index;
     }
-    if (i >= MAX_HAPTICS) {
+    if (device_index >= MAX_HAPTICS) {
         return SDL_SetError("Haptic: Joystick doesn't have Haptic capabilities");
     }
 
@@ -417,7 +571,7 @@
         return -1;
     }
 
-    haptic->hwdata->fname = SDL_hapticlist[haptic->index].fname;
+    haptic->hwdata->fname = item->fname;
     return 0;
 }
 
@@ -454,15 +608,23 @@
 void
 SDL_SYS_HapticQuit(void)
 {
-    int i;
+    SDL_hapticlist_item *item = NULL;
+	SDL_hapticlist_item *next = NULL;
 
-    for (i = 0; SDL_hapticlist[i].fname != NULL; i++) {
+    for (item = SDL_hapticlist; item; item = next) {
+		next = item->next;
         /* Opened and not closed haptics are leaked, this is on purpose.
          * Close your haptic devices after usage. */
+		SDL_free(item->fname);
+		item->fname = NULL;
+    }
 
-        SDL_free(SDL_hapticlist[i].fname);
-    }
-    SDL_hapticlist[0].fname = NULL;
+#if SDL_USE_LIBUDEV
+    SDL_UDEV_DelCallback(haptic_udev_callback);
+    SDL_UDEV_Quit();
+#endif /* SDL_USE_LIBUDEV */
+
+    numhaptics = 0;
 }